November guide to the bright planets

At nightfall, from northerly latitudes, Mars is easy to catch in the southern sky (outside the sky chart), while fainter Saturn is moderately easy to spot in the southeast sky. From northerly latitudes, like those in the U.S. and Europe, it’ll be difficult to glimpse the planets Mercury and Jupiter (plus the star Antares) in the glow of evening dusk.

Mars is by far the easiest planet to catch in the evening sky in November, 2018. Saturn, though not as bright as Mars, is also a fine evening object, shining as brilliantly as as 1st-magnitude star. Nominally, Mercury and Jupiter are evening planets for most of the month, until their departure from the evening sky in late November. From northerly latitudes, however, these two worlds follow the sun beneath the horizon shortly after sundown, making Mercury and Jupiter hard to view in the glare of evening dusk. Venus, the brightest planet, puts on a good show in the November morning sky, shining at its brilliant best as the morning “star” as the month draws to a close. Click the name of a planet to learn more about its visibility in November 2018: Venus, Jupiter, Saturn, Mars and Mercury

After a night of watching Taurid meteors, you just might be able to catch the moon and Venus before daybreak on November 4, 5 and 6. Read more.

Venus is the brightest planet, beaming mightily in the east before sunrise. Each day throughout November 2018, this blazing beauty of a planet will rise sooner before sunrise and will brighten all the while. Although Venus will be a fixture of the morning sky until mid-August 2019, it’ll shine at its brightest best as the morning “star” in late November and early December 2018.

Look for the waning crescent moon in the vicinity of Venus before sunrise November 4, 5 and 6, as depicted on the above chart. Venus recently entered the morning sky on October 26, 2018, so in early November, Venus will still be rather low in the eastern sky just before sunrise. Find an unobstructed eastern horizon, and, if you have binoculars, bring them along. Venus will be higher up and easier to view in the morning sky as the month progresses.

At mid-northern latitudes, Venus rises roughly one hour before sunrise by around November 4. By the month’s end, Venus will rise some 3 hours before the sun.

At temperate latitudes in the Southern Hemisphere, Venus rises about one hour before the sunup on or near November 6. By late November, Venus will rise two hours before the sun.

View larger. | No, it’s not the moon. It’s Venus – September 30, 2018 – visible through a small telescope in a crescent phase. Venus is up only shortly after sunset now. It’ll pass between us and the sun on October 26. Photo by Radu Anghel in Bacau, Romania. Thank you, Radu!

Live in the Southern Hemisphere? Given an unobstructed horizon in the direction of sunset, you have a good chance of catching the young waxing crescent moon near the planets Mercury and Jupiter on or near November 9, 2018. Read more.

Jupiter will disappear from the evening sky sometime this month. Day by day, Jupiter falls closer to the setting sun, and sets sooner after sundown. By late November 2018, Jupiter will have passed over into the morning sky.

Jupiter stays out longer after sunset in the Southern Hemisphere. That’s because the ecliptic (pathway of the sun, moon and planets) hits the evening horizon at a steeper angle than at comparable latitudes in the Northern Hemisphere.

For instance, at mid-northern latitudes (United States, mainland Europe, Japan), Jupiter sets about one hour after the sun in early November and then sets with the sun near the month’s end.

In contrast, at temperate latitudes in the Southern Hemisphere (Cape Town, South Africa, and southern Australia), Jupiter sets about 1 1/2 hours after the sun in early November and with the sun near the month’s end.

If you live in the Southern Hemisphere or northern tropics, let the slender waxing crescent moon guide your eye to Jupiter (and Mercury) for several evenings, centered on or around November 9 (see the sky chart above).

The moon will set at early evening, providing dark skies for the North Taurid meteor shower. Read more.

Use Mars to find Saturn in November 2018. Although Mars fades somewhat this month, the red planet remains bright and beautiful, shining more brilliantly than a 1st-magnitude star throughout November 2018. In November, Mars transits – reaches its highest point in the sky – around dusk/nightfall in the Northern Hemisphere, and around sunset in the Southern Hemisphere. Once you see Mars, look for Saturn way below Mars and quite low in the southwest sky.

Click here for a recommended sky almanac providing you with the transit times for Mars.

From mid-northern latitudes, Saturn stays out until around 8 p.m. (9 p.m. daylight saving time) in early November. By the month’s end, Saturn will set around 6 p.m. Mars pretty much sets around midnight all month long.

From temperate latitudes in the Southern Hemisphere, Saturn sets around 10 to 11 p.m. in early November and around 9 p.m. in late November. Mars stays out until after midnight throughout the month.

You can tell Mars from Saturn because Mars has a reddish color and Saturn looks golden. Binoculars show their colors better than the eye alone.

Watch for the moon to pair up with Saturn on or near November 11 (see sky chart above) and with Mars on or near November 15 (see sky chart below).

Look for the moon in the vicinity of Mars on November 14, 15 and 16. Read more.

Both Mars and Saturn are slowly dimming throughout the month. Because Mars is dimming at a faster rate than Saturn is, Mars appears nearly 3 times brighter than Saturn at the beginning of the month, yet only somewhat more than 1 1/2 times brighter by the month’s end.

Remember Mars’ historically close opposition of August 28, 2003? That year, it was closer and brighter than it had been in some 60,000 years. The July 2018 opposition was the best since 2003.

Click here for more about close and far Mars oppositions

Diagram by Roy L. Bishop. Copyright Royal Astronomical Society of Canada. Used with permission. Visit the RASC estore to purchase the Observer’s Handbook, a necessary tool for all skywatchers. Read more about this image.

Mercury, the innermost planet of the solar system, is an evening planet (at least nominally) for most of the month in November 2018. Mercury’s greatest elongation falls on November 6, 2018, but the Southern Hemisphere has the big advantage over the Northern Hemisphere for spotting Mercury. Even so, try your luck at catching the young moon with Mercury after sunset around November 8, 9 and 10, as shown on the sky chart below.

At northerly latitudes, like those in the US and Europe, it’ll be quite the challenge to spot the young moon, plus the planet Mercury in the glow of evening dusk. Read more.

What do we mean by bright planet? By bright planet, we mean any solar system planet that is easily visible without an optical aid and that has been watched by our ancestors since time immemorial. In their outward order from the sun, the five bright planets are Mercury, Venus, Mars, Jupiter and Saturn. These planets actually do appear bright in our sky. They are typically as bright as – or brighter than – the brightest stars. Plus, these relatively nearby worlds tend to shine with a steadier light than the distant, twinkling stars. You can spot them, and come to know them as faithful friends, if you try.

Bottom line: In November 2018, two planets shine in the evening sky all month long: Mars and Saturn. Venus lights up eastern sky before sunrise. Mercury and Jupiter for the most part are lost in the glare of evening dusk, but might be possible to see early in the month, low in evening twilight. Click here for recommended almanacs; they can help you know when the planets rise, transit and set in your sky.

Don’t miss anything. Subscribe to EarthSky News by email

Visit EarthSky’s Best Places to Stargaze, and recommend a place we can all enjoy. Zoom out for worldwide map.

Help EarthSky keep going! Donate now.

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At nightfall, from northerly latitudes, Mars is easy to catch in the southern sky (outside the sky chart), while fainter Saturn is moderately easy to spot in the southeast sky. From northerly latitudes, like those in the U.S. and Europe, it’ll be difficult to glimpse the planets Mercury and Jupiter (plus the star Antares) in the glow of evening dusk.

Mars is by far the easiest planet to catch in the evening sky in November, 2018. Saturn, though not as bright as Mars, is also a fine evening object, shining as brilliantly as as 1st-magnitude star. Nominally, Mercury and Jupiter are evening planets for most of the month, until their departure from the evening sky in late November. From northerly latitudes, however, these two worlds follow the sun beneath the horizon shortly after sundown, making Mercury and Jupiter hard to view in the glare of evening dusk. Venus, the brightest planet, puts on a good show in the November morning sky, shining at its brilliant best as the morning “star” as the month draws to a close. Click the name of a planet to learn more about its visibility in November 2018: Venus, Jupiter, Saturn, Mars and Mercury

After a night of watching Taurid meteors, you just might be able to catch the moon and Venus before daybreak on November 4, 5 and 6. Read more.

Venus is the brightest planet, beaming mightily in the east before sunrise. Each day throughout November 2018, this blazing beauty of a planet will rise sooner before sunrise and will brighten all the while. Although Venus will be a fixture of the morning sky until mid-August 2019, it’ll shine at its brightest best as the morning “star” in late November and early December 2018.

Look for the waning crescent moon in the vicinity of Venus before sunrise November 4, 5 and 6, as depicted on the above chart. Venus recently entered the morning sky on October 26, 2018, so in early November, Venus will still be rather low in the eastern sky just before sunrise. Find an unobstructed eastern horizon, and, if you have binoculars, bring them along. Venus will be higher up and easier to view in the morning sky as the month progresses.

At mid-northern latitudes, Venus rises roughly one hour before sunrise by around November 4. By the month’s end, Venus will rise some 3 hours before the sun.

At temperate latitudes in the Southern Hemisphere, Venus rises about one hour before the sunup on or near November 6. By late November, Venus will rise two hours before the sun.

View larger. | No, it’s not the moon. It’s Venus – September 30, 2018 – visible through a small telescope in a crescent phase. Venus is up only shortly after sunset now. It’ll pass between us and the sun on October 26. Photo by Radu Anghel in Bacau, Romania. Thank you, Radu!

Live in the Southern Hemisphere? Given an unobstructed horizon in the direction of sunset, you have a good chance of catching the young waxing crescent moon near the planets Mercury and Jupiter on or near November 9, 2018. Read more.

Jupiter will disappear from the evening sky sometime this month. Day by day, Jupiter falls closer to the setting sun, and sets sooner after sundown. By late November 2018, Jupiter will have passed over into the morning sky.

Jupiter stays out longer after sunset in the Southern Hemisphere. That’s because the ecliptic (pathway of the sun, moon and planets) hits the evening horizon at a steeper angle than at comparable latitudes in the Northern Hemisphere.

For instance, at mid-northern latitudes (United States, mainland Europe, Japan), Jupiter sets about one hour after the sun in early November and then sets with the sun near the month’s end.

In contrast, at temperate latitudes in the Southern Hemisphere (Cape Town, South Africa, and southern Australia), Jupiter sets about 1 1/2 hours after the sun in early November and with the sun near the month’s end.

If you live in the Southern Hemisphere or northern tropics, let the slender waxing crescent moon guide your eye to Jupiter (and Mercury) for several evenings, centered on or around November 9 (see the sky chart above).

The moon will set at early evening, providing dark skies for the North Taurid meteor shower. Read more.

Use Mars to find Saturn in November 2018. Although Mars fades somewhat this month, the red planet remains bright and beautiful, shining more brilliantly than a 1st-magnitude star throughout November 2018. In November, Mars transits – reaches its highest point in the sky – around dusk/nightfall in the Northern Hemisphere, and around sunset in the Southern Hemisphere. Once you see Mars, look for Saturn way below Mars and quite low in the southwest sky.

Click here for a recommended sky almanac providing you with the transit times for Mars.

From mid-northern latitudes, Saturn stays out until around 8 p.m. (9 p.m. daylight saving time) in early November. By the month’s end, Saturn will set around 6 p.m. Mars pretty much sets around midnight all month long.

From temperate latitudes in the Southern Hemisphere, Saturn sets around 10 to 11 p.m. in early November and around 9 p.m. in late November. Mars stays out until after midnight throughout the month.

You can tell Mars from Saturn because Mars has a reddish color and Saturn looks golden. Binoculars show their colors better than the eye alone.

Watch for the moon to pair up with Saturn on or near November 11 (see sky chart above) and with Mars on or near November 15 (see sky chart below).

Look for the moon in the vicinity of Mars on November 14, 15 and 16. Read more.

Both Mars and Saturn are slowly dimming throughout the month. Because Mars is dimming at a faster rate than Saturn is, Mars appears nearly 3 times brighter than Saturn at the beginning of the month, yet only somewhat more than 1 1/2 times brighter by the month’s end.

Remember Mars’ historically close opposition of August 28, 2003? That year, it was closer and brighter than it had been in some 60,000 years. The July 2018 opposition was the best since 2003.

Click here for more about close and far Mars oppositions

Diagram by Roy L. Bishop. Copyright Royal Astronomical Society of Canada. Used with permission. Visit the RASC estore to purchase the Observer’s Handbook, a necessary tool for all skywatchers. Read more about this image.

Mercury, the innermost planet of the solar system, is an evening planet (at least nominally) for most of the month in November 2018. Mercury’s greatest elongation falls on November 6, 2018, but the Southern Hemisphere has the big advantage over the Northern Hemisphere for spotting Mercury. Even so, try your luck at catching the young moon with Mercury after sunset around November 8, 9 and 10, as shown on the sky chart below.

At northerly latitudes, like those in the US and Europe, it’ll be quite the challenge to spot the young moon, plus the planet Mercury in the glow of evening dusk. Read more.

What do we mean by bright planet? By bright planet, we mean any solar system planet that is easily visible without an optical aid and that has been watched by our ancestors since time immemorial. In their outward order from the sun, the five bright planets are Mercury, Venus, Mars, Jupiter and Saturn. These planets actually do appear bright in our sky. They are typically as bright as – or brighter than – the brightest stars. Plus, these relatively nearby worlds tend to shine with a steadier light than the distant, twinkling stars. You can spot them, and come to know them as faithful friends, if you try.

Bottom line: In November 2018, two planets shine in the evening sky all month long: Mars and Saturn. Venus lights up eastern sky before sunrise. Mercury and Jupiter for the most part are lost in the glare of evening dusk, but might be possible to see early in the month, low in evening twilight. Click here for recommended almanacs; they can help you know when the planets rise, transit and set in your sky.

Don’t miss anything. Subscribe to EarthSky News by email

Visit EarthSky’s Best Places to Stargaze, and recommend a place we can all enjoy. Zoom out for worldwide map.

Help EarthSky keep going! Donate now.

from EarthSky https://ift.tt/1YD00CF

A eulogy to Guardian's Climate Consensus - the 97%

The Guardian editors recently decided to discontinue their Science and Environment blog networks.  This is the story of Climate Consensus - the 97%.

Way back in 2012, newspapers were struggling to hang on to readers. Blogs were all the rage, and with the stability of the Obama administration, a steadily improving economy, the UK still in the EU (how I long for those good old days), there wasn't today's demand for daily newspapers. Papers were trying to come up with new ideas, and the Guardian editors decided to experiment with international blog networks.

It was a very clever idea. There were lots of smart science and environment bloggers out there, writing on their own blogs for free. By folding them into The Guardian, the paper was able to add their expert analysis. By splitting the ad revenue, they guaranteed some profit for the paper while bringing in new readers for the expert analysis, and the bloggers who previously wrote for free got a bit of pay for their work, plus the prestige of affiliation with The Guardian. It was a win-win.

The experiment worked with the Science blog network, so in late 2012 they decided to expand with an Environment blog network. Over 800 bloggers applied. I had a bit of a foot in the door, because I'd been writing for Skeptical Science for about 2 years. Whenever some prominent climate denier regurgitated a myth that was picked up in the media, I would quickly debunk it at Skeptical Science, and a few times The Guardian picked up and re-published my pieces. So I was a known quantity, and they hired me on along with about 10 other Environment bloggers. Some didn't pan out and dropped off, but several like Graham Readfearn and Martin Lukacs (and of course me and John Abraham) lasted for the long haul. They 'handed us the keys' to our blogs, and off we went.

And it worked great. For over 5 years we provided expert analysis, brought in readers and a bit of profit to the paper, required minimal oversight, and had very few problems. We averaged around 20k views per post, topping out at half a million when I wrote one criticizing Trump's pullout of the Paris agreement. But gradually the editors who launched the blogs moved on. And then we got Trump, and Brexit, and there was so much bullshit 'fake news' out there that people started to value and consume reliable media sources like the NYT, WaPo, and Guardian. With this beefed up readership, they hired more journalists, including on the science and environment beats.

The new editors weren't invested in the blogs and were focused on the expanded traditional reporting. Nobody was keeping an eye on the bloggers, which was fine - we had 5 years of experience and hummed along like a well-tuned EV - but I think they started to worry that we represented some liability. A rogue, unsupervised blogger could cause problems. They didn't want to worry about us, and felt they didn't need us anymore. We were no longer an "exciting new experiment," as one Guardian staffer told us. The experiment had worked! But the editors wanted to move to a new era that focused more on traditional journalism.

So, this summer they decided to discontinue all the blogs by the end of August. Though somehow they forgot to tell a bunch of us Environment bloggers, so we kept writing and publishing, blissfully unaware that we had been laid off months earlier. Ironically, October will end up being one of our blog's most-trafficked months. We had some big stories, two months after we were supposed to have been terminated.

It goes to show how little oversight we needed that none of the editors apparently noticed we were still publishing for nearly 2 months until this week, when we finally got the bad news. But, they did tell us that they value our content, and asked that we continue pitching them stories, albeit on a less frequent basis (approx. monthly rather than weekly, depending on what climate news pops up).

I don't agree with the decision. I think the expert analysis and readership we brought in outweighed any small chance that we could create a significant problem for the paper. But that's the editors' call, and I do appreciate that they want us to keep submitting stories. I'm also glad they've been able to expand their science & environment reporting and that people are reading it.

So, that's the whole story of our Guardian blog. All good things must come to an end. I'll miss it - it was really the perfect platform to communicate what I've learned about climate science and economics and policy and politics, and it was great that they gave us free rein to write whatever we wanted. It was a lot of work, but I loved every minute of it. In all likelihood I'll keep publishing in the paper, unless I find another regular gig elsewhere.

A toast to Climate Consensus - the 97%. I'll miss you!

from Skeptical Science https://ift.tt/2EVHdUt

The Guardian editors recently decided to discontinue their Science and Environment blog networks.  This is the story of Climate Consensus - the 97%.

Way back in 2012, newspapers were struggling to hang on to readers. Blogs were all the rage, and with the stability of the Obama administration, a steadily improving economy, the UK still in the EU (how I long for those good old days), there wasn't today's demand for daily newspapers. Papers were trying to come up with new ideas, and the Guardian editors decided to experiment with international blog networks.

It was a very clever idea. There were lots of smart science and environment bloggers out there, writing on their own blogs for free. By folding them into The Guardian, the paper was able to add their expert analysis. By splitting the ad revenue, they guaranteed some profit for the paper while bringing in new readers for the expert analysis, and the bloggers who previously wrote for free got a bit of pay for their work, plus the prestige of affiliation with The Guardian. It was a win-win.

The experiment worked with the Science blog network, so in late 2012 they decided to expand with an Environment blog network. Over 800 bloggers applied. I had a bit of a foot in the door, because I'd been writing for Skeptical Science for about 2 years. Whenever some prominent climate denier regurgitated a myth that was picked up in the media, I would quickly debunk it at Skeptical Science, and a few times The Guardian picked up and re-published my pieces. So I was a known quantity, and they hired me on along with about 10 other Environment bloggers. Some didn't pan out and dropped off, but several like Graham Readfearn and Martin Lukacs (and of course me and John Abraham) lasted for the long haul. They 'handed us the keys' to our blogs, and off we went.

And it worked great. For over 5 years we provided expert analysis, brought in readers and a bit of profit to the paper, required minimal oversight, and had very few problems. We averaged around 20k views per post, topping out at half a million when I wrote one criticizing Trump's pullout of the Paris agreement. But gradually the editors who launched the blogs moved on. And then we got Trump, and Brexit, and there was so much bullshit 'fake news' out there that people started to value and consume reliable media sources like the NYT, WaPo, and Guardian. With this beefed up readership, they hired more journalists, including on the science and environment beats.

The new editors weren't invested in the blogs and were focused on the expanded traditional reporting. Nobody was keeping an eye on the bloggers, which was fine - we had 5 years of experience and hummed along like a well-tuned EV - but I think they started to worry that we represented some liability. A rogue, unsupervised blogger could cause problems. They didn't want to worry about us, and felt they didn't need us anymore. We were no longer an "exciting new experiment," as one Guardian staffer told us. The experiment had worked! But the editors wanted to move to a new era that focused more on traditional journalism.

So, this summer they decided to discontinue all the blogs by the end of August. Though somehow they forgot to tell a bunch of us Environment bloggers, so we kept writing and publishing, blissfully unaware that we had been laid off months earlier. Ironically, October will end up being one of our blog's most-trafficked months. We had some big stories, two months after we were supposed to have been terminated.

It goes to show how little oversight we needed that none of the editors apparently noticed we were still publishing for nearly 2 months until this week, when we finally got the bad news. But, they did tell us that they value our content, and asked that we continue pitching them stories, albeit on a less frequent basis (approx. monthly rather than weekly, depending on what climate news pops up).

I don't agree with the decision. I think the expert analysis and readership we brought in outweighed any small chance that we could create a significant problem for the paper. But that's the editors' call, and I do appreciate that they want us to keep submitting stories. I'm also glad they've been able to expand their science & environment reporting and that people are reading it.

So, that's the whole story of our Guardian blog. All good things must come to an end. I'll miss it - it was really the perfect platform to communicate what I've learned about climate science and economics and policy and politics, and it was great that they gave us free rein to write whatever we wanted. It was a lot of work, but I loved every minute of it. In all likelihood I'll keep publishing in the paper, unless I find another regular gig elsewhere.

A toast to Climate Consensus - the 97%. I'll miss you!

from Skeptical Science https://ift.tt/2EVHdUt

Kepler planet-hunter retires

Artist’s concept of NASA’s 1st space-based exoplanet hunter, the Kepler space telescope. Image via NASA/ Wendy Stenzel/ Daniel Rutter.

Astronomers only began discovering exoplanets – planets orbiting stars in other solar systems – in the 1990s, after a decades-long search. In this century, the number of known exoplanets has exploded in size, mainly due to this spacecraft, NASA’s Kepler space telescope, which was specifically designed as a planet-hunter. Kepler launched into an Earth-trailing heliocentric (sun-centered) orbit in 2009. Its mission lasted longer than expected, but now – after nine years in deep space – Kepler has run out of fuel needed for further science operations. NASA said this week (October 30, 2018), it has decided to retire the spacecraft within its current, safe orbit, away from Earth.

Kepler leaves a legacy of more than 2,600 planet discoveries outside our solar system. It is now passing the planet-hunting torch to the Transiting Exoplanet Survey Satellite (TESS), launched last April. TESS builds on Kepler’s foundation with fresh batches of data in its search of planets orbiting some 200,000 of the brightest and nearest stars to the Earth, worlds that can later be explored for signs of life by missions such as NASA’s James Webb Space Telescope.

A statement from NASA said:

Kepler has opened our eyes to the diversity of planets that exist in our galaxy. The most recent analysis of Kepler’s discoveries concludes that 20 to 50 percent of the stars visible in the night sky are likely to have small, possibly rocky, planets similar in size to Earth, and located within the habitable zone of their parent stars. That means they’re located at distances from their parent stars where liquid water – a vital ingredient to life as we know it – might pool on the planet surface.

The most common size of planet Kepler found doesn’t exist in our solar system – a world between the size of Earth and Neptune – and we have much to learn about these planets. Kepler also found nature often produces jam-packed planetary systems, in some cases with so many planets orbiting close to their parent stars that our own inner solar system looks sparse by comparison.

Kepler’s mission lasted twice as long as planned. Fuel exhaustion was seen in late June. Two weeks ago, the fuel pressure dropped to (zero “the last drop”) but the teams collected all the remaining data.

— Chris B – NSF (@NASASpaceflight) October 30, 2018

The Kepler mission’s founding principal investigator, William Borucki, now retired from NASA’s Ames Research Center in California’s Silicon Valley, said:

When we started conceiving this mission 35 years ago, we didn’t know of a single planet outside our solar system. Now that we know planets are everywhere, Kepler has set us on a new course that’s full of promise for future generations to explore our galaxy.

The Kepler space telescope launched from Earth on March 6, 2009. It was designed for an Earth-trailing heliocentric orbit, which gave the spacecraft a thermally stable environment and let it remain on a single pointing for all of the prime Kepler mission. In other words, during its prime mission, Kepler stared at a single patch of sky – with a field of view of 116 square degrees, containing approximately 150,000 stars – measuring star brightnesses within that field over and over, searching for minute dips in starlight that would indicate planets in orbit around their stars.

Does the fact that Kepler found 2,600 planets around those 150,000 stars mean that we can expect only a small fraction of stars to have planets? No, and in fact the opposite is true.

In order to detect planets, Kepler had to see a distant solar system edge-on, so that the planets were passing in front of their stars from Kepler’s point of view. Finding so many edge-on system among Kepler’s original 150,000 stars likely means that our galaxy – which has more than 100 billion stars – is likely have hundreds of billions of planets.

What has the @NASAKepler space telescope achieved during its time in space? Take a look at the numbers: https://t.co/Ei3m5dSdvh pic.twitter.com/zIgJw0gRSX

— NASA Kepler and K2 (@NASAKepler) October 30, 2018

Leslie Livesay, director for astronomy and physics at NASA’s Jet Propulsion Laboratory, who served as Kepler project manager during mission development, said:

The Kepler mission was based on a very innovative design. It was an extremely clever approach to doing this kind of science. There were definitely challenges, but Kepler had an extremely talented team of scientists and engineers who overcame them.

Four years into the Kepler mission, after the primary mission objectives had been met, mechanical failures temporarily halted observations. The mission team was able to devise a fix, switching the spacecraft’s field of view roughly every three months. This enabled an extended mission for the spacecraft, dubbed K2, which lasted as long as the first mission and bumped Kepler’s count of surveyed stars up to more than 500,000. The NASA statement said:

The observation of so many stars has allowed scientists to better understand stellar behaviors and properties, which is critical information in studying the planets that orbit them. New research into stars with Kepler data also is furthering other areas of astronomy, such as the history of our Milky Way galaxy and the beginning stages of exploding stars called supernovae that are used to study how fast the universe is expanding. The data from the extended mission were also made available to the public and science community immediately, allowing discoveries to be made at an incredible pace and setting a high bar for other missions. Scientists are expected to spend a decade or more in search of new discoveries in the treasure trove of data Kepler provided.

Jessie Dotson, Kepler’s project scientist at NASA’s Ames Research Center in California’s Silicon Valley, pointed out that discoveries from Kepler are still to come:

We know the spacecraft’s retirement isn’t the end of Kepler’s discoveries. I’m excited about the diverse discoveries that are yet to come from our data and how future missions will build upon Kepler’s results.

This gif shows @NASAKepler‘s very final images. The end of K2’s Campaign 19.

Kepler started its mission not knowing whether Earth-sized planets were common. It ran out of fuel while observing a nearby star known to host seven. #ThanksKepler pic.twitter.com/HMfMyv1yog — Geert Barentsen (@GeertHub) October 30, 2018

Bottom line: NASA has now officially retired the highly successful Kepler planet-hunter, after nine years in space. Much of what we know about exoplanets today comes from the Kepler mission.

Read more: Characteristics of the Kepler space telescope

Visit NASA’s exoplanet archive

The 2019 lunar calendars are here! Order yours before they’re gone. Makes a great gift.

Via NASA

from EarthSky https://ift.tt/2EV8bvo

Artist’s concept of NASA’s 1st space-based exoplanet hunter, the Kepler space telescope. Image via NASA/ Wendy Stenzel/ Daniel Rutter.

Astronomers only began discovering exoplanets – planets orbiting stars in other solar systems – in the 1990s, after a decades-long search. In this century, the number of known exoplanets has exploded in size, mainly due to this spacecraft, NASA’s Kepler space telescope, which was specifically designed as a planet-hunter. Kepler launched into an Earth-trailing heliocentric (sun-centered) orbit in 2009. Its mission lasted longer than expected, but now – after nine years in deep space – Kepler has run out of fuel needed for further science operations. NASA said this week (October 30, 2018), it has decided to retire the spacecraft within its current, safe orbit, away from Earth.

Kepler leaves a legacy of more than 2,600 planet discoveries outside our solar system. It is now passing the planet-hunting torch to the Transiting Exoplanet Survey Satellite (TESS), launched last April. TESS builds on Kepler’s foundation with fresh batches of data in its search of planets orbiting some 200,000 of the brightest and nearest stars to the Earth, worlds that can later be explored for signs of life by missions such as NASA’s James Webb Space Telescope.

A statement from NASA said:

Kepler has opened our eyes to the diversity of planets that exist in our galaxy. The most recent analysis of Kepler’s discoveries concludes that 20 to 50 percent of the stars visible in the night sky are likely to have small, possibly rocky, planets similar in size to Earth, and located within the habitable zone of their parent stars. That means they’re located at distances from their parent stars where liquid water – a vital ingredient to life as we know it – might pool on the planet surface.

The most common size of planet Kepler found doesn’t exist in our solar system – a world between the size of Earth and Neptune – and we have much to learn about these planets. Kepler also found nature often produces jam-packed planetary systems, in some cases with so many planets orbiting close to their parent stars that our own inner solar system looks sparse by comparison.

Kepler’s mission lasted twice as long as planned. Fuel exhaustion was seen in late June. Two weeks ago, the fuel pressure dropped to (zero “the last drop”) but the teams collected all the remaining data.

— Chris B – NSF (@NASASpaceflight) October 30, 2018

The Kepler mission’s founding principal investigator, William Borucki, now retired from NASA’s Ames Research Center in California’s Silicon Valley, said:

When we started conceiving this mission 35 years ago, we didn’t know of a single planet outside our solar system. Now that we know planets are everywhere, Kepler has set us on a new course that’s full of promise for future generations to explore our galaxy.

The Kepler space telescope launched from Earth on March 6, 2009. It was designed for an Earth-trailing heliocentric orbit, which gave the spacecraft a thermally stable environment and let it remain on a single pointing for all of the prime Kepler mission. In other words, during its prime mission, Kepler stared at a single patch of sky – with a field of view of 116 square degrees, containing approximately 150,000 stars – measuring star brightnesses within that field over and over, searching for minute dips in starlight that would indicate planets in orbit around their stars.

Does the fact that Kepler found 2,600 planets around those 150,000 stars mean that we can expect only a small fraction of stars to have planets? No, and in fact the opposite is true.

In order to detect planets, Kepler had to see a distant solar system edge-on, so that the planets were passing in front of their stars from Kepler’s point of view. Finding so many edge-on system among Kepler’s original 150,000 stars likely means that our galaxy – which has more than 100 billion stars – is likely have hundreds of billions of planets.

What has the @NASAKepler space telescope achieved during its time in space? Take a look at the numbers: https://t.co/Ei3m5dSdvh pic.twitter.com/zIgJw0gRSX

— NASA Kepler and K2 (@NASAKepler) October 30, 2018

Leslie Livesay, director for astronomy and physics at NASA’s Jet Propulsion Laboratory, who served as Kepler project manager during mission development, said:

The Kepler mission was based on a very innovative design. It was an extremely clever approach to doing this kind of science. There were definitely challenges, but Kepler had an extremely talented team of scientists and engineers who overcame them.

Four years into the Kepler mission, after the primary mission objectives had been met, mechanical failures temporarily halted observations. The mission team was able to devise a fix, switching the spacecraft’s field of view roughly every three months. This enabled an extended mission for the spacecraft, dubbed K2, which lasted as long as the first mission and bumped Kepler’s count of surveyed stars up to more than 500,000. The NASA statement said:

The observation of so many stars has allowed scientists to better understand stellar behaviors and properties, which is critical information in studying the planets that orbit them. New research into stars with Kepler data also is furthering other areas of astronomy, such as the history of our Milky Way galaxy and the beginning stages of exploding stars called supernovae that are used to study how fast the universe is expanding. The data from the extended mission were also made available to the public and science community immediately, allowing discoveries to be made at an incredible pace and setting a high bar for other missions. Scientists are expected to spend a decade or more in search of new discoveries in the treasure trove of data Kepler provided.

Jessie Dotson, Kepler’s project scientist at NASA’s Ames Research Center in California’s Silicon Valley, pointed out that discoveries from Kepler are still to come:

We know the spacecraft’s retirement isn’t the end of Kepler’s discoveries. I’m excited about the diverse discoveries that are yet to come from our data and how future missions will build upon Kepler’s results.

This gif shows @NASAKepler‘s very final images. The end of K2’s Campaign 19.

Kepler started its mission not knowing whether Earth-sized planets were common. It ran out of fuel while observing a nearby star known to host seven. #ThanksKepler pic.twitter.com/HMfMyv1yog — Geert Barentsen (@GeertHub) October 30, 2018

Bottom line: NASA has now officially retired the highly successful Kepler planet-hunter, after nine years in space. Much of what we know about exoplanets today comes from the Kepler mission.

Read more: Characteristics of the Kepler space telescope

Visit NASA’s exoplanet archive

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Via NASA

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Why do we love to scream?

Visiting an extreme haunted house can be delightfully terrifying. Image via AP Photos/John Minchillo.

By Margee Kerr, University of Pittsburgh

John Carpenter’s iconic horror film Halloween celebrates its 40th anniversary this year. Few horror movies have achieved similar notoriety, and it’s credited with kicking off the steady stream of slasher flicks that followed.

Audiences flocked to theaters to witness the seemingly random murder and mayhem a masked man brought to a small suburban town, reminding them that picket fences and manicured lawns cannot protect us from the unjust, the unknown or the uncertainty that awaits us all in both life and death. The film offers no justice for the victims in the end, no rebalancing of good and evil.

A new installment of the Halloween franchise brings the action forward to 2018. Image via Universal Pictures.

Why, then, would anyone want to spend their time and money to watch such macabre scenes filled with depressing reminders of just how unfair and scary our world can be?

I’ve spent the past 10 years investigating just this question, finding the typical answer of “Because I like it! It’s fun!” incredibly unsatisfying. I’ve long been convinced there’s more to it than the “natural high” or adrenaline rush many describe – and indeed, the body does kick into “go” mode when you’re startled or scared, amping up not only adrenaline but a multitude of chemicals that ensure your body is fueled and ready to respond. This “fight or flight” response to threat has helped keep humans alive for millennia.

That still doesn’t explain why people would want to intentionally scare themselves, though. As a sociologist, I’ve kept asking “But, why?” After two years collecting data in a haunted attraction with my colleague Greg Siegle, a cognitive neuroscientist at the University of Pittsburgh, we’ve found the gains from thrills and chills can go further than the natural high.

Around Halloween, some people love to head to haunted attractions like this one in an old Cincinnati schoolhouse. Image via AP Photo/John Minchillo.

Studying fear at a terrifying attraction

To capture in real time what makes fear fun, what motivates people to pay to be scared out of their skin and what they experience when engaging with this material, we needed to gather data in the field. In this case, that meant setting up a mobile lab in the basement of an extreme haunted attraction outside Pittsburgh, Pennsylvania.

This adults-only extreme attraction went beyond the typical startling lights and sounds and animated characters found in a family-friendly haunted house. Over the course of about 35 minutes, visitors experienced a series of intense scenarios where, in addition to unsettling characters and special effects, they were touched by the actors, restrained and exposed to electricity. It was not for the faint of heart.

For our study, we recruited 262 guests who had already purchased tickets. Before they entered the attraction, each completed a survey about their expectations and how they were feeling. We had them answer questions again about how they were feeling once they had gone through the attraction.

We also used mobile EEG technology to compare 100 participants’ brainwave activity as they sat through 15 minutes of various cognitive and emotional tasks before and after the attraction.

Guests reported significantly higher mood, and felt less anxious and tired, directly after their trip through the haunted attraction. The more terrifying the better: Feeling happy afterward was related to rating the experience as highly intense and scary. This set of volunteers also reported feeling that they’d challenged their personal fears and learned about themselves.

Analysis of the EEG data revealed widespread decreases in brain reactivity from before to after among those whose mood improved. In other words, highly intense and scary activities – at least in a controlled environment like this haunted attraction – may “shut down” the brain to an extent, and that in turn is associated with feeling better. Studies of those who practice mindfulness meditation have made a similar observation.

Coming out stronger on the other side

Together our findings suggest that going through an extreme haunted attraction provides gains similar to choosing to run a 5K race or tackling a difficult climbing wall. There’s a sense of uncertainty, physical exertion, a challenge to push yourself – and eventually achievement when it’s over and done with.

Fun-scary experiences could serve as an in-the-moment recalibration of what registers as stressful and even provide a kind of confidence boost. After watching a scary movie or going through a haunted attraction, maybe everything else seems like no big deal in comparison. You rationally understand that the actors in a haunted house aren’t real, but when you suspend your disbelief and allow yourself to become immersed in the experience, the fear certainly can feel real, as does the satisfaction and sense of accomplishment when you make it through. As I experienced myself after all kinds of scary adventures in Japan, Colombia and all over the U.S., confronting a horde of zombies can actually make you feel pretty invincible.

Movies like Halloween allow people to tackle the big, existential fears we all have, like why bad things happen without reason, through the protective frame of entertainment. Choosing to do fun, scary activities may also serve as a way to practice being scared, building greater self-knowledge and resilience, similar to rough-and-tumble play. It’s an opportunity to engage with fear on your own terms, in environments where you can push your boundaries, safely. Because you’re not in real danger, and thus not occupied with survival, you can choose to observe your reactions and how your body changes, gaining greater insight to yourself.

Friends stuck together in a ‘Gates of Hell’ haunted house. Image via AP Photo/John Locher.

What it takes to be safely scared

While there are countless differences in the nature, content, intensity and overall quality of haunted attractions, horror movies and other forms of scary entertainment, they all share a few critical components that help pave the way for a fun scary time.

First and foremost, you have to make the choice to engage – don’t drag your best friend with you unless she is also on board. But do try to gather some friends when you’re ready. When you engage in activities with other people, even just watching a movie, your own emotional experience is intensified. Doing intense, exciting and thrilling things together can make them more fun and help create rewarding social bonds. Emotions can be contagious, so when you see your friend scream and laugh, you may feel compelled to do the same.

No matter the potential benefits, horror movies and scary entertainment are not for everyone, and that’s OK. While the fight-or-flight response is universal, there are important differences between individuals – for example, in genetic expressions, environment and personal history – that help explain why some loathe and others love thrills and chills.

Regardless of your taste (or distaste) for all things horror or thrill-related, an adventurous and curious mindset can benefit everyone. After all, we’re the descendants of those who were adventurous and curious enough to explore the new and novel, but also quick and smart enough to run or fight when danger appeared. This Halloween, maybe challenge yourself to at least one fun scary experience and prepare to unleash your inner superhero.

Margee Kerr, Adjunct Professor of Sociology, University of Pittsburgh

This article is republished from The Conversation under a Creative Commons license. Read the original article.

Bottom line: A scientist studies why we like scary movies and haunted house and what it takes to be safely scared.

The 2019 lunar calendars are here! Order yours before they’re gone. Makes a great gift.

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Visiting an extreme haunted house can be delightfully terrifying. Image via AP Photos/John Minchillo.

By Margee Kerr, University of Pittsburgh

John Carpenter’s iconic horror film Halloween celebrates its 40th anniversary this year. Few horror movies have achieved similar notoriety, and it’s credited with kicking off the steady stream of slasher flicks that followed.

Audiences flocked to theaters to witness the seemingly random murder and mayhem a masked man brought to a small suburban town, reminding them that picket fences and manicured lawns cannot protect us from the unjust, the unknown or the uncertainty that awaits us all in both life and death. The film offers no justice for the victims in the end, no rebalancing of good and evil.

A new installment of the Halloween franchise brings the action forward to 2018. Image via Universal Pictures.

Why, then, would anyone want to spend their time and money to watch such macabre scenes filled with depressing reminders of just how unfair and scary our world can be?

I’ve spent the past 10 years investigating just this question, finding the typical answer of “Because I like it! It’s fun!” incredibly unsatisfying. I’ve long been convinced there’s more to it than the “natural high” or adrenaline rush many describe – and indeed, the body does kick into “go” mode when you’re startled or scared, amping up not only adrenaline but a multitude of chemicals that ensure your body is fueled and ready to respond. This “fight or flight” response to threat has helped keep humans alive for millennia.

That still doesn’t explain why people would want to intentionally scare themselves, though. As a sociologist, I’ve kept asking “But, why?” After two years collecting data in a haunted attraction with my colleague Greg Siegle, a cognitive neuroscientist at the University of Pittsburgh, we’ve found the gains from thrills and chills can go further than the natural high.

Around Halloween, some people love to head to haunted attractions like this one in an old Cincinnati schoolhouse. Image via AP Photo/John Minchillo.

Studying fear at a terrifying attraction

To capture in real time what makes fear fun, what motivates people to pay to be scared out of their skin and what they experience when engaging with this material, we needed to gather data in the field. In this case, that meant setting up a mobile lab in the basement of an extreme haunted attraction outside Pittsburgh, Pennsylvania.

This adults-only extreme attraction went beyond the typical startling lights and sounds and animated characters found in a family-friendly haunted house. Over the course of about 35 minutes, visitors experienced a series of intense scenarios where, in addition to unsettling characters and special effects, they were touched by the actors, restrained and exposed to electricity. It was not for the faint of heart.

For our study, we recruited 262 guests who had already purchased tickets. Before they entered the attraction, each completed a survey about their expectations and how they were feeling. We had them answer questions again about how they were feeling once they had gone through the attraction.

We also used mobile EEG technology to compare 100 participants’ brainwave activity as they sat through 15 minutes of various cognitive and emotional tasks before and after the attraction.

Guests reported significantly higher mood, and felt less anxious and tired, directly after their trip through the haunted attraction. The more terrifying the better: Feeling happy afterward was related to rating the experience as highly intense and scary. This set of volunteers also reported feeling that they’d challenged their personal fears and learned about themselves.

Analysis of the EEG data revealed widespread decreases in brain reactivity from before to after among those whose mood improved. In other words, highly intense and scary activities – at least in a controlled environment like this haunted attraction – may “shut down” the brain to an extent, and that in turn is associated with feeling better. Studies of those who practice mindfulness meditation have made a similar observation.

Coming out stronger on the other side

Together our findings suggest that going through an extreme haunted attraction provides gains similar to choosing to run a 5K race or tackling a difficult climbing wall. There’s a sense of uncertainty, physical exertion, a challenge to push yourself – and eventually achievement when it’s over and done with.

Fun-scary experiences could serve as an in-the-moment recalibration of what registers as stressful and even provide a kind of confidence boost. After watching a scary movie or going through a haunted attraction, maybe everything else seems like no big deal in comparison. You rationally understand that the actors in a haunted house aren’t real, but when you suspend your disbelief and allow yourself to become immersed in the experience, the fear certainly can feel real, as does the satisfaction and sense of accomplishment when you make it through. As I experienced myself after all kinds of scary adventures in Japan, Colombia and all over the U.S., confronting a horde of zombies can actually make you feel pretty invincible.

Movies like Halloween allow people to tackle the big, existential fears we all have, like why bad things happen without reason, through the protective frame of entertainment. Choosing to do fun, scary activities may also serve as a way to practice being scared, building greater self-knowledge and resilience, similar to rough-and-tumble play. It’s an opportunity to engage with fear on your own terms, in environments where you can push your boundaries, safely. Because you’re not in real danger, and thus not occupied with survival, you can choose to observe your reactions and how your body changes, gaining greater insight to yourself.

Friends stuck together in a ‘Gates of Hell’ haunted house. Image via AP Photo/John Locher.

What it takes to be safely scared

While there are countless differences in the nature, content, intensity and overall quality of haunted attractions, horror movies and other forms of scary entertainment, they all share a few critical components that help pave the way for a fun scary time.

First and foremost, you have to make the choice to engage – don’t drag your best friend with you unless she is also on board. But do try to gather some friends when you’re ready. When you engage in activities with other people, even just watching a movie, your own emotional experience is intensified. Doing intense, exciting and thrilling things together can make them more fun and help create rewarding social bonds. Emotions can be contagious, so when you see your friend scream and laugh, you may feel compelled to do the same.

No matter the potential benefits, horror movies and scary entertainment are not for everyone, and that’s OK. While the fight-or-flight response is universal, there are important differences between individuals – for example, in genetic expressions, environment and personal history – that help explain why some loathe and others love thrills and chills.

Regardless of your taste (or distaste) for all things horror or thrill-related, an adventurous and curious mindset can benefit everyone. After all, we’re the descendants of those who were adventurous and curious enough to explore the new and novel, but also quick and smart enough to run or fight when danger appeared. This Halloween, maybe challenge yourself to at least one fun scary experience and prepare to unleash your inner superhero.

Margee Kerr, Adjunct Professor of Sociology, University of Pittsburgh

This article is republished from The Conversation under a Creative Commons license. Read the original article.

Bottom line: A scientist studies why we like scary movies and haunted house and what it takes to be safely scared.

The 2019 lunar calendars are here! Order yours before they’re gone. Makes a great gift.

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Zoom-in on the Ghost Nebula

Just in time for Halloween, zoom in on the nebula, or space cloud made of gas and dust, known as IC 63, sometimes called the Ghost Nebula. It’s about 550 light-years from us, in the direction to the constellation Cassiopeia the Queen. It looks ghostlike in telescopic images, such as the new one by the Hubble Space Telescope, shown below.

Like any respectable ghost, IC 63 is also slowly melting away; that is, it’s dissipating due to intense radiation from a nearby unpredictably variable star, Gamma Cassiopeiae, aka Gamma Cas. Did we say nearby? We meant several light-years away.

Yet – even from this distance – Gamma Cas is profoundly affecting the Ghost Nebula.

Hubble Space Telescope view of IC-63, nicknamed the Ghost Nebula. Via NASA/ESA/Hubble.

NASA explained in a statement:

Gamma Cassiopeiae is a blue-white subgiant variable star that is surrounded by a gaseous disk. This star is 19 times more massive and 65 000 times brighter than our sun. It also rotates at the incredible speed of 1 milllion miles per hour [1.6 million kilometers per hour] — more than 200 times faster than our parent star. This frenzied rotation gives it a squashed appearance. The fast rotation causes eruptions of mass from the star into a surrounding disk. This mass loss is related to the observed brightness variations.

On autumn evenings in the Northern Hemisphere, you’ll easily see the constellation Cassiopeia as M- or W-shaped star pattern, ascending in the northeast.

The colors in the Ghost Nebula show how the nebula is affected by the powerful radiation from the distant star. NASA said:

The hydrogen within IC 63 is being bombarded with ultraviolet radiation from Gamma Cassiopeiae, causing its electrons to gain energy which they later release as hydrogen-alpha radiation — visible in red in [the Hubble image above].

This hydrogen-alpha radiation makes IC 63 an emission nebula, but we also see blue light in this image. This is light from Gamma Cassiopeiae that has been reflected by dust particles in the nebula, meaning that IC 63 is also a reflection nebula.

This colorful and ghostly nebula is slowly dissipating under the influence of ultraviolet radiation from Gamma Cassiopeiae. However, IC 63 is not the only object under the influence of the mighty star. It is part of a much larger nebulous region surrounding Gamma Cassiopeiae that measures approximately two degrees on the sky — roughly four times as wide as the full moon.

Read more via Hubble Space Telescope

Ground-based view of the sky around the Ghost Nebula. The bright star is Gamma Cassiopeiae. Via ESA/Hubble/NASA/ Digitized Sky Survey 2/Davide de Martin.

Bottom line:

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Just in time for Halloween, zoom in on the nebula, or space cloud made of gas and dust, known as IC 63, sometimes called the Ghost Nebula. It’s about 550 light-years from us, in the direction to the constellation Cassiopeia the Queen. It looks ghostlike in telescopic images, such as the new one by the Hubble Space Telescope, shown below.

Like any respectable ghost, IC 63 is also slowly melting away; that is, it’s dissipating due to intense radiation from a nearby unpredictably variable star, Gamma Cassiopeiae, aka Gamma Cas. Did we say nearby? We meant several light-years away.

Yet – even from this distance – Gamma Cas is profoundly affecting the Ghost Nebula.

Hubble Space Telescope view of IC-63, nicknamed the Ghost Nebula. Via NASA/ESA/Hubble.

NASA explained in a statement:

Gamma Cassiopeiae is a blue-white subgiant variable star that is surrounded by a gaseous disk. This star is 19 times more massive and 65 000 times brighter than our sun. It also rotates at the incredible speed of 1 milllion miles per hour [1.6 million kilometers per hour] — more than 200 times faster than our parent star. This frenzied rotation gives it a squashed appearance. The fast rotation causes eruptions of mass from the star into a surrounding disk. This mass loss is related to the observed brightness variations.

On autumn evenings in the Northern Hemisphere, you’ll easily see the constellation Cassiopeia as M- or W-shaped star pattern, ascending in the northeast.

The colors in the Ghost Nebula show how the nebula is affected by the powerful radiation from the distant star. NASA said:

The hydrogen within IC 63 is being bombarded with ultraviolet radiation from Gamma Cassiopeiae, causing its electrons to gain energy which they later release as hydrogen-alpha radiation — visible in red in [the Hubble image above].

This hydrogen-alpha radiation makes IC 63 an emission nebula, but we also see blue light in this image. This is light from Gamma Cassiopeiae that has been reflected by dust particles in the nebula, meaning that IC 63 is also a reflection nebula.

This colorful and ghostly nebula is slowly dissipating under the influence of ultraviolet radiation from Gamma Cassiopeiae. However, IC 63 is not the only object under the influence of the mighty star. It is part of a much larger nebulous region surrounding Gamma Cassiopeiae that measures approximately two degrees on the sky — roughly four times as wide as the full moon.

Read more via Hubble Space Telescope

Ground-based view of the sky around the Ghost Nebula. The bright star is Gamma Cassiopeiae. Via ESA/Hubble/NASA/ Digitized Sky Survey 2/Davide de Martin.

Bottom line:

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Tricks that animals play

Eastern gray squirrel. Image credit: Fyn Kynd via Flickr.

On Halloween, children shout trick or treat hoping to score some candy. While this is all fun and games for us humans, for some animals, tricks are essential to their survival. Below, meet three animals that excel at playing tricks on others.

Eastern gray squirrel. In preparation for a long, cold winter, the eastern gray squirrel will gather up nuts and bury them in the ground where they can be dug up and consumed later when food is scarce. Scientists refer to this nut store as a cache, and a gray squirrel cache can be spread out over several acres. Unfortunately, these nuts are sometimes stolen by other squirrels and birds who witness a nut being buried. To combat the thievery, the eastern gray squirrel will often create a fake cache. It does so by digging a hole and filling it in without ever depositing a nut—a squirrel may do this several times before or after actually burying a nut. This trick is used to confuse the would-be thieves and protect their winter food supply.

Margay. Image credit: Malene Thyssen via Wikimedia.

Margay. The margay is a small wildcat that lives in the jungles of Central and South America. Scientists once observed a margay making vocalizations similar to a baby tamarin monkey, which piqued their interest because the cats are known to prey on tamarins. While this sound successfully attracted adult monkeys into the cat’s range, the cat did not catch a monkey that day. Still, scientists suspect that this sinister trick is an effective hunting strategy. It is not presently known how common this vocal mimicry behavior is among margays.

Female brown-headed cowbird. Image credit: Dick Daniels via Wikimedia.

Brown-headed cowbird. The brown-headed cowbird is native to North America, and it is a master at deception. Female cowbirds lay their eggs in the nests of other species and are often successful at tricking these other birds into raising their young. Scientists call a bird who engages in this type of behavior a “brood parasite.” While a few birds can recognize the foreign egg of a cowbird in their nest and discard it, many cannot. Cowbirds are known to parasitize the nests of more than 220 species of birds.

Happy Halloween from all of us at EarthSky! If you know of any other interesting tricks that animals play, we would love to hear about them in the comments.

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Bottom line: Three animals that play tricks to survive.

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Eastern gray squirrel. Image credit: Fyn Kynd via Flickr.

On Halloween, children shout trick or treat hoping to score some candy. While this is all fun and games for us humans, for some animals, tricks are essential to their survival. Below, meet three animals that excel at playing tricks on others.

Eastern gray squirrel. In preparation for a long, cold winter, the eastern gray squirrel will gather up nuts and bury them in the ground where they can be dug up and consumed later when food is scarce. Scientists refer to this nut store as a cache, and a gray squirrel cache can be spread out over several acres. Unfortunately, these nuts are sometimes stolen by other squirrels and birds who witness a nut being buried. To combat the thievery, the eastern gray squirrel will often create a fake cache. It does so by digging a hole and filling it in without ever depositing a nut—a squirrel may do this several times before or after actually burying a nut. This trick is used to confuse the would-be thieves and protect their winter food supply.

Margay. Image credit: Malene Thyssen via Wikimedia.

Margay. The margay is a small wildcat that lives in the jungles of Central and South America. Scientists once observed a margay making vocalizations similar to a baby tamarin monkey, which piqued their interest because the cats are known to prey on tamarins. While this sound successfully attracted adult monkeys into the cat’s range, the cat did not catch a monkey that day. Still, scientists suspect that this sinister trick is an effective hunting strategy. It is not presently known how common this vocal mimicry behavior is among margays.

Female brown-headed cowbird. Image credit: Dick Daniels via Wikimedia.

Brown-headed cowbird. The brown-headed cowbird is native to North America, and it is a master at deception. Female cowbirds lay their eggs in the nests of other species and are often successful at tricking these other birds into raising their young. Scientists call a bird who engages in this type of behavior a “brood parasite.” While a few birds can recognize the foreign egg of a cowbird in their nest and discard it, many cannot. Cowbirds are known to parasitize the nests of more than 220 species of birds.

Happy Halloween from all of us at EarthSky! If you know of any other interesting tricks that animals play, we would love to hear about them in the comments.

The 2019 lunar calendars are here! Order yours before they’re gone. Makes a great gift.

Bottom line: Three animals that play tricks to survive.

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Pleiades star cluster, aka Seven Sisters

The Pleiades star cluster, by Ernie Rossi in Florida. Russ Drum submitted it and wrote: “The Pleiades (aka the Seven Sisters) is an open star cluster located in the constellation Taurus the Bull. It’s also known as the Halloween Cluster because it’s almost overhead in the sky at midnight on Halloween, October 31.”

The Pleiades star cluster – also known as the Seven Sisters or M45 – is visible from virtually every part of the globe. It can be seen from as far north as the North Pole, and farther south than the southernmost tip of South America. It looks like a tiny misty dipper of stars.

If you’re familiar with the famous constellation Orion, it can help you be sure you’ve found the Pleiades. See the three stars in a row in Orion? That’s Orion’s Belt. Draw a line through these stars to the V-shaped pattern of stars with a bright star in its midst. The V-shaped pattern is the Face of Taurus the Bull. The bright star in the V – called Aldebaran – depicts the Bull’s Eye. A bit past Aldebaran, you’ll see the Pleiades cluster, which marks the Bull’s Shoulder.

The 2019 lunar calendars are here! Order yours before they’re gone. Makes a great gift.

If you can find the prominent constellation Orion, you can find the Pleiades. Orion’s Belt points to the bright reddish star Aldebaran … then generally toward the Pleiades.

The Pleiades and Aldebaran. star name Aldebaran comes from an Arabic word for follower. It’s thought to be a reference to this star’s forever chasing the Pleiades across the heavens. As a general rule, the Pleiades cluster rises into the eastern sky before Aldebaran rises, and sets in the west before Aldebaran sets.

The only exception to this rule happens at far southern latitudes – for example, at South America’s Tierra del Fuego – where the Pleiades rise a short while after Aldebaran rises.

In our Northern Hemispheres skies, the Pleiades cluster is associated with the winter season. It’s easy to imagine this misty patch of icy-blue suns as hoarfrost clinging to the dome of night. Frosty November is often called the month of the Pleiades, because it’s at this time that the Pleiades shine from dusk until dawn. But you can see the Pleiades cluster in the evening sky well into April.

Tom Wildoner in Weatherly, Pennsylvania captured this image on October 31, 2016. He wrote: “It shows the Seven Sisters, Pleiades star cluster rising in the east behind some maple trees still sporting some late leaves.”

Legend of the Lost Pleiad. Most people see 6, not 7, Pleiades stars in a dark country sky.

However, the story about the lost 7th Pleiad harbors a universal theme. The astronomer Robert Burnham Jr. found the lost Pleaid myth prevalent in the star lore of European, African, Asian, Indonesian, Native American and Aboriginal Australian populations.

Moreover, Burnham suggested that the “lost Pleiad” may have basis in fact. After all, modern astronomy has found that the 7th brightest Pleiades star – Pleione – is a complicated and hard-to-understand “shell star” that goes through numerous permutations. These changes cause this star to vary in brightness.

Plus people with exceptional eyesight have been known to see many more stars in the Pleiades cluster. Claims go up as high as 20 stars. Agnes Clerke, an astronomer and writer in the late 1800s, reported that Michael Maestlin, the mentor of Johannes Kepler, mapped out 11 Pleiades stars before the invention of the telescope.

To see more than 6 or 7 Pleaides stars, you must have very good eyesight (or a pair of binoculars). And you must be willing to spend time under a dark, moonless sky. Stephen O’Meara, a dark-sky connoisseur, claims that eyes dark-adapted for 30 minutes are 6 times more sensitive to light than eyes dark-adapted for 15 minutes. The surest way to see additional Pleiades stars is to look at this cluster through binoculars or low power in a telescope.

The Lost Pleiad, a painting by French artist William-Adolphe Bouguereau (1825-1905). Image via Wikimedia Commons.

Pleiades as calendar, in history and in modern science. Historically, the Pleiades have served as a calendar for many civilizations. The Greek name “Pleiades” probably means “to sail.” In the ancient Mediterranean world, the day that the Pleaides cluster first appeared in the morning sky before sunrise announced the opening of the navigation season.

The modern-day festival of Halloween originates from an old Druid rite that coincided with the midnight culmination of the Pleiades cluster. It was believed that the veil dividing the living from the dead is at its thinnest when the Pleaides culminates – reaches its highest point in the sky – at midnight.

On a lighter note, the Zuni of New Mexico call the Pleiades the “Seed Stars,” because this cluster’s disappearance in the evening sky every spring signals the seed-planting season.

In both myth and science, the Pleiades are considered to be sibling stars. Modern astronomers say the Pleiades stars were born from the same cloud of gas and dust some 100 million years ago. This gravitationally bound cluster of several hundred stars looms some 430 light-years distant, and these sibling stars drift through space together at about 25 miles per second. Many of these Pleiades stars shine hundreds of times more brightly than our sun.

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The Pleiades – aka the Seven Sisters – captured by Greg Hogan in Kathleen, Georgia on October 31, 2016.

Bottom line: November is often called the month of the Pleiades – or Seven Sisters – because it’s at this time that the Pleiades shine from dusk until dawn.

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The Pleiades star cluster, by Ernie Rossi in Florida. Russ Drum submitted it and wrote: “The Pleiades (aka the Seven Sisters) is an open star cluster located in the constellation Taurus the Bull. It’s also known as the Halloween Cluster because it’s almost overhead in the sky at midnight on Halloween, October 31.”

The Pleiades star cluster – also known as the Seven Sisters or M45 – is visible from virtually every part of the globe. It can be seen from as far north as the North Pole, and farther south than the southernmost tip of South America. It looks like a tiny misty dipper of stars.

If you’re familiar with the famous constellation Orion, it can help you be sure you’ve found the Pleiades. See the three stars in a row in Orion? That’s Orion’s Belt. Draw a line through these stars to the V-shaped pattern of stars with a bright star in its midst. The V-shaped pattern is the Face of Taurus the Bull. The bright star in the V – called Aldebaran – depicts the Bull’s Eye. A bit past Aldebaran, you’ll see the Pleiades cluster, which marks the Bull’s Shoulder.

The 2019 lunar calendars are here! Order yours before they’re gone. Makes a great gift.

If you can find the prominent constellation Orion, you can find the Pleiades. Orion’s Belt points to the bright reddish star Aldebaran … then generally toward the Pleiades.

The Pleiades and Aldebaran. star name Aldebaran comes from an Arabic word for follower. It’s thought to be a reference to this star’s forever chasing the Pleiades across the heavens. As a general rule, the Pleiades cluster rises into the eastern sky before Aldebaran rises, and sets in the west before Aldebaran sets.

The only exception to this rule happens at far southern latitudes – for example, at South America’s Tierra del Fuego – where the Pleiades rise a short while after Aldebaran rises.

In our Northern Hemispheres skies, the Pleiades cluster is associated with the winter season. It’s easy to imagine this misty patch of icy-blue suns as hoarfrost clinging to the dome of night. Frosty November is often called the month of the Pleiades, because it’s at this time that the Pleiades shine from dusk until dawn. But you can see the Pleiades cluster in the evening sky well into April.

Tom Wildoner in Weatherly, Pennsylvania captured this image on October 31, 2016. He wrote: “It shows the Seven Sisters, Pleiades star cluster rising in the east behind some maple trees still sporting some late leaves.”

Legend of the Lost Pleiad. Most people see 6, not 7, Pleiades stars in a dark country sky.

However, the story about the lost 7th Pleiad harbors a universal theme. The astronomer Robert Burnham Jr. found the lost Pleaid myth prevalent in the star lore of European, African, Asian, Indonesian, Native American and Aboriginal Australian populations.

Moreover, Burnham suggested that the “lost Pleiad” may have basis in fact. After all, modern astronomy has found that the 7th brightest Pleiades star – Pleione – is a complicated and hard-to-understand “shell star” that goes through numerous permutations. These changes cause this star to vary in brightness.

Plus people with exceptional eyesight have been known to see many more stars in the Pleiades cluster. Claims go up as high as 20 stars. Agnes Clerke, an astronomer and writer in the late 1800s, reported that Michael Maestlin, the mentor of Johannes Kepler, mapped out 11 Pleiades stars before the invention of the telescope.

To see more than 6 or 7 Pleaides stars, you must have very good eyesight (or a pair of binoculars). And you must be willing to spend time under a dark, moonless sky. Stephen O’Meara, a dark-sky connoisseur, claims that eyes dark-adapted for 30 minutes are 6 times more sensitive to light than eyes dark-adapted for 15 minutes. The surest way to see additional Pleiades stars is to look at this cluster through binoculars or low power in a telescope.

The Lost Pleiad, a painting by French artist William-Adolphe Bouguereau (1825-1905). Image via Wikimedia Commons.

Pleiades as calendar, in history and in modern science. Historically, the Pleiades have served as a calendar for many civilizations. The Greek name “Pleiades” probably means “to sail.” In the ancient Mediterranean world, the day that the Pleaides cluster first appeared in the morning sky before sunrise announced the opening of the navigation season.

The modern-day festival of Halloween originates from an old Druid rite that coincided with the midnight culmination of the Pleiades cluster. It was believed that the veil dividing the living from the dead is at its thinnest when the Pleaides culminates – reaches its highest point in the sky – at midnight.

On a lighter note, the Zuni of New Mexico call the Pleiades the “Seed Stars,” because this cluster’s disappearance in the evening sky every spring signals the seed-planting season.

In both myth and science, the Pleiades are considered to be sibling stars. Modern astronomers say the Pleiades stars were born from the same cloud of gas and dust some 100 million years ago. This gravitationally bound cluster of several hundred stars looms some 430 light-years distant, and these sibling stars drift through space together at about 25 miles per second. Many of these Pleiades stars shine hundreds of times more brightly than our sun.

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The Pleiades – aka the Seven Sisters – captured by Greg Hogan in Kathleen, Georgia on October 31, 2016.

Bottom line: November is often called the month of the Pleiades – or Seven Sisters – because it’s at this time that the Pleiades shine from dusk until dawn.

from EarthSky https://ift.tt/2SgTchN

Year’s farthest perigee on October 31

At top: Last quarter moon simulated image via U.S. Naval Observatory

The moon sweeps to perigee – its closest point to Earth in its orbit – for the second time this month on October 31, 2018. This perigee counts as the most distant of this year’s 14 perigees. So you might say today’s moon is the farthest close moon.

How far away is the moon today? It’s 230,034 miles (370,204 km) away. That’s in contrast to 2018’s closest perigee of 221,559 miles (356,565 km) on January 1.

Notice … this most distant perigee comes when the moon is at the last quarter phase. That is not an accident. If you’re game, we’ll share a secret with you about why a quarter moon at perigee is farther than the mean perigee of 225,804 miles or 363,396 km, and why a quarter moon at apogee is closer than the mean apogee distance of 251,969 miles or 405,504 km. We’ll also explain why a full moon or new moon at perigee is closer than the mean perigee, yet why a full moon or new moon at apogee is farther than the mean apogee. It all has to do with the varying eccentricity of the moon’s orbit.

The moon’s orbit around Earth isn’t a perfect circle. But it’s very nearly circular, as the above diagram shows. Diagram by Brian Koberlein.

The moon’s eccentric orbit

The moon’s orbit around Earth, like Earth’s orbit around the sun, isn’t a perfect circle. It’s a slightly oblong ellipse. That’s why, every month, the moon reaches a nearest point to Earth at perigee and a farthest point at apogee.

However, the moon’s orbit isn’t highly eccentric (oblong), but nearly circular, as shown on the illustration above.

What’s more, like everything else in nature, the moon’s orbit is always in flux. Its shape, and its orientation relative to the Earth and sun, change all the time.

So we have a moon at perigee – closest to Earth for the month – and also a moon at its last quarter phase on October 31, 2018.

Last quarter moon: October 31, 2018 at 16:40 UTC
Lunar perigee: October 31, 2018 at 20:05 UTC

Image credit: NASA. The moon’s orbit is closer to being a circle than the diagram suggests, but the exaggeration helps to clarify. The moon is closest to Earth in its orbit at perigee and farthest away at apogee.

The illustrations above label perigee (moon’s closest point to Earth) and apogee (moon’s farthest point from Earth). A line drawn from perigee to apogee defines the major axis, or the longest diameter, of the moon’s elliptical orbit. In the parlance of astronomers, the perigee-to-apogee line is called the line of apsides. The center of the line of apsides to either the perigee point or apogee point is called the semi-major axis.

Earth does not lie at the center of the line of apsides. Instead, the Earth is offset from the center of the major axis, or line of apsides, toward the lunar perigee point. To be more precise, the Earth resides at one of the two foci of the ellipse.

Keep in mind, also, that the moon’s major axis (longest diameter of an ellipse) always makes a right angle to the moon’s minor axis (shortest diameter of an ellipse).

Varying eccentricity of the moon’s orbit

When the moon’s major axis, or line of apsides, makes a right angle to the sun-Earth line (B in below diagram), the moon’s eccentricity decreases to a minimum. In other words, the moon’s orbit is closest to being circular when the moon’s minor axis points toward the sun. Although the moon still swings closest to Earth at perigee and farthest from Earth at apogee, the perigee distance increases and the apogee distance decreases whenever the moon’s eccentricity lessens, or more closely approaches a circle in shape.

In short, when the major axis makes a right angle with the sun-Earth line (B in below diagram), the quarter moons closely align with perigee and apogee.

Image via Bedford Astronomy Club.

Close and far moons in 2018

Some 103 days before and after the minor axis points sunward (B in above diagram), it’s then the moon’s major axis that points in the sun’s direction (A and C in above diagram). When the major axis, or line of apsides, aligns with the sun-Earth line, the eccentricity of the moon’s orbit increases to a maximum, and its orbit becomes maximally oblong. That causes the moon to swing extra-far from Earth at lunar apogee – yet extra-close to Earth at lunar perigee.

And that brings us to the full moon. It’s also no accident that 2018’s closest perigee closely aligned with the full moon.

Lunar perigee: 2018 January 1 at 21:54 UTC
Full Moon: 2018 January 2 at 2:24 UTC

When the major axis points sunward (A and C in above diagram), it’s the new moon or full moon that closely aligns with perigee/apogee. In diagram A, it’s a new moon perigee and full moon apogee; and in diagram C, it’s a full moon perigee and new moon apogee.

Farthest perigees often recur in cycles of 14 lunar months (14 returns to the same lunar phase), a period of about 413 days (1 year, 1 month and 18 days). For instance, 14 lunar months ago (from October 31, 2018), the close coincidence of last quarter moon with perigee presented last year’s farthest perigee on September 13, 2017 (229,820 miles or 369,860 km). Moreover, 14 lunar months from today (October 31, 2018), the last quarter moon will again closely align with perigee, to stage next year’s farthest lunar perigee on December 18, 2019 (230,072 miles or 370,265 km).

Want to know more? Eclipses and the moon’s orbit

Resources:

Lunar perigee and apogee calculator

Moon at perigee and apogee: 2001 to 2100

Phases of the moon: 2001 to 2100

Bottom line: In 2018, the moon swings to its most distant perigee of the year on October 31, 2018.

from EarthSky https://ift.tt/2AB9VWm

At top: Last quarter moon simulated image via U.S. Naval Observatory

The moon sweeps to perigee – its closest point to Earth in its orbit – for the second time this month on October 31, 2018. This perigee counts as the most distant of this year’s 14 perigees. So you might say today’s moon is the farthest close moon.

How far away is the moon today? It’s 230,034 miles (370,204 km) away. That’s in contrast to 2018’s closest perigee of 221,559 miles (356,565 km) on January 1.

Notice … this most distant perigee comes when the moon is at the last quarter phase. That is not an accident. If you’re game, we’ll share a secret with you about why a quarter moon at perigee is farther than the mean perigee of 225,804 miles or 363,396 km, and why a quarter moon at apogee is closer than the mean apogee distance of 251,969 miles or 405,504 km. We’ll also explain why a full moon or new moon at perigee is closer than the mean perigee, yet why a full moon or new moon at apogee is farther than the mean apogee. It all has to do with the varying eccentricity of the moon’s orbit.

The moon’s orbit around Earth isn’t a perfect circle. But it’s very nearly circular, as the above diagram shows. Diagram by Brian Koberlein.

The moon’s eccentric orbit

The moon’s orbit around Earth, like Earth’s orbit around the sun, isn’t a perfect circle. It’s a slightly oblong ellipse. That’s why, every month, the moon reaches a nearest point to Earth at perigee and a farthest point at apogee.

However, the moon’s orbit isn’t highly eccentric (oblong), but nearly circular, as shown on the illustration above.

What’s more, like everything else in nature, the moon’s orbit is always in flux. Its shape, and its orientation relative to the Earth and sun, change all the time.

So we have a moon at perigee – closest to Earth for the month – and also a moon at its last quarter phase on October 31, 2018.

Last quarter moon: October 31, 2018 at 16:40 UTC
Lunar perigee: October 31, 2018 at 20:05 UTC

Image credit: NASA. The moon’s orbit is closer to being a circle than the diagram suggests, but the exaggeration helps to clarify. The moon is closest to Earth in its orbit at perigee and farthest away at apogee.

The illustrations above label perigee (moon’s closest point to Earth) and apogee (moon’s farthest point from Earth). A line drawn from perigee to apogee defines the major axis, or the longest diameter, of the moon’s elliptical orbit. In the parlance of astronomers, the perigee-to-apogee line is called the line of apsides. The center of the line of apsides to either the perigee point or apogee point is called the semi-major axis.

Earth does not lie at the center of the line of apsides. Instead, the Earth is offset from the center of the major axis, or line of apsides, toward the lunar perigee point. To be more precise, the Earth resides at one of the two foci of the ellipse.

Keep in mind, also, that the moon’s major axis (longest diameter of an ellipse) always makes a right angle to the moon’s minor axis (shortest diameter of an ellipse).

Varying eccentricity of the moon’s orbit

When the moon’s major axis, or line of apsides, makes a right angle to the sun-Earth line (B in below diagram), the moon’s eccentricity decreases to a minimum. In other words, the moon’s orbit is closest to being circular when the moon’s minor axis points toward the sun. Although the moon still swings closest to Earth at perigee and farthest from Earth at apogee, the perigee distance increases and the apogee distance decreases whenever the moon’s eccentricity lessens, or more closely approaches a circle in shape.

In short, when the major axis makes a right angle with the sun-Earth line (B in below diagram), the quarter moons closely align with perigee and apogee.

Image via Bedford Astronomy Club.

Close and far moons in 2018

Some 103 days before and after the minor axis points sunward (B in above diagram), it’s then the moon’s major axis that points in the sun’s direction (A and C in above diagram). When the major axis, or line of apsides, aligns with the sun-Earth line, the eccentricity of the moon’s orbit increases to a maximum, and its orbit becomes maximally oblong. That causes the moon to swing extra-far from Earth at lunar apogee – yet extra-close to Earth at lunar perigee.

And that brings us to the full moon. It’s also no accident that 2018’s closest perigee closely aligned with the full moon.

Lunar perigee: 2018 January 1 at 21:54 UTC
Full Moon: 2018 January 2 at 2:24 UTC

When the major axis points sunward (A and C in above diagram), it’s the new moon or full moon that closely aligns with perigee/apogee. In diagram A, it’s a new moon perigee and full moon apogee; and in diagram C, it’s a full moon perigee and new moon apogee.

Farthest perigees often recur in cycles of 14 lunar months (14 returns to the same lunar phase), a period of about 413 days (1 year, 1 month and 18 days). For instance, 14 lunar months ago (from October 31, 2018), the close coincidence of last quarter moon with perigee presented last year’s farthest perigee on September 13, 2017 (229,820 miles or 369,860 km). Moreover, 14 lunar months from today (October 31, 2018), the last quarter moon will again closely align with perigee, to stage next year’s farthest lunar perigee on December 18, 2019 (230,072 miles or 370,265 km).

Want to know more? Eclipses and the moon’s orbit

Resources:

Lunar perigee and apogee calculator

Moon at perigee and apogee: 2001 to 2100

Phases of the moon: 2001 to 2100

Bottom line: In 2018, the moon swings to its most distant perigee of the year on October 31, 2018.

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Last quarter moon is October 31

The moon was almost exactly at last quarter when Deirdre Horan in Dublin, Ireland, captured this photo. The terminator line, or line between light and dark on the moon, appears straight.

A last quarter moon appears half-lit by sunshine and half-immersed in its own shadow. It rises in the middle of the night, appears at its highest in the sky around dawn, and sets around midday. The moon reaches its exact half-illuminated phase, as viewed from Earth, on October 31, 2018 at 16:40 UTC; translate UTC to your time.

The October 31 last quarter moon is second of two for this month. The first one came on October 2, when the moon was shining in front of the constellation Gemini. The second last quarter moon on October 31 will appear in front of the constellation Cancer, one degree south of the Beehive star cluster.

On a last quarter moon, the lunar terminator – the shadow line dividing day and night – shows you where it’s sunset on the moon.

A last quarter moon provides a great opportunity to think of yourself on a three-dimensional world in space. For example, it’s fun to see this moon just after moonrise, shortly after midnight. Then the lighted portion points downward, to the sun below your feet. Think of the last quarter moon as a mirror to the world you’re standing on. Think of yourself standing in the middle of Earth’s nightside, on the midnight portion of Earth.

Also, a last quarter moon can be used as a guidepost to Earth’s direction of motion in orbit around the sun.

In other words, when you look toward a last quarter moon high in the predawn sky, for example, you’re gazing out approximately along the path of Earth’s orbit, in a forward direction. The moon is moving in orbit around the sun with the Earth and never holds still. But, if we could somehow anchor the moon in space … tie it down, keep it still … Earth’s orbital speed of 18 miles per second would carry us across the space between us and the moon in only a few hours.

Want to read more about the last quarter moon as a guidepost for Earth’s motion? Astronomer Guy Ottewell talked about it recently, too.

A great thing about using the moon as a guidepost to Earth’s motion is that you can do it anywhere … as, for example, in the photo below, from large cities.

Ben Orlove wrote from New York City: “I was sitting in the roof garden of my building, and there was the moon, right in front of me. You were right, this is a perfect time to visualize … the Earth’s motion.”

As the moon orbits Earth, it changes phase in an orderly way. Follow the links below to understand the phases of the moon.

New moon
Waxing crescent moon
First quarter moon
Waxing gibbous moon
Full moon
Waning gibbous moon
Last quarter moon
Waning crescent moon

Read more: 4 keys to understanding moon phases

Bottom line: Last quarter moon falls on October 31, 2018, at 16:40 UTC; translate UTC to your time.

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The moon was almost exactly at last quarter when Deirdre Horan in Dublin, Ireland, captured this photo. The terminator line, or line between light and dark on the moon, appears straight.

A last quarter moon appears half-lit by sunshine and half-immersed in its own shadow. It rises in the middle of the night, appears at its highest in the sky around dawn, and sets around midday. The moon reaches its exact half-illuminated phase, as viewed from Earth, on October 31, 2018 at 16:40 UTC; translate UTC to your time.

The October 31 last quarter moon is second of two for this month. The first one came on October 2, when the moon was shining in front of the constellation Gemini. The second last quarter moon on October 31 will appear in front of the constellation Cancer, one degree south of the Beehive star cluster.

On a last quarter moon, the lunar terminator – the shadow line dividing day and night – shows you where it’s sunset on the moon.

A last quarter moon provides a great opportunity to think of yourself on a three-dimensional world in space. For example, it’s fun to see this moon just after moonrise, shortly after midnight. Then the lighted portion points downward, to the sun below your feet. Think of the last quarter moon as a mirror to the world you’re standing on. Think of yourself standing in the middle of Earth’s nightside, on the midnight portion of Earth.

Also, a last quarter moon can be used as a guidepost to Earth’s direction of motion in orbit around the sun.

In other words, when you look toward a last quarter moon high in the predawn sky, for example, you’re gazing out approximately along the path of Earth’s orbit, in a forward direction. The moon is moving in orbit around the sun with the Earth and never holds still. But, if we could somehow anchor the moon in space … tie it down, keep it still … Earth’s orbital speed of 18 miles per second would carry us across the space between us and the moon in only a few hours.

Want to read more about the last quarter moon as a guidepost for Earth’s motion? Astronomer Guy Ottewell talked about it recently, too.

A great thing about using the moon as a guidepost to Earth’s motion is that you can do it anywhere … as, for example, in the photo below, from large cities.

Ben Orlove wrote from New York City: “I was sitting in the roof garden of my building, and there was the moon, right in front of me. You were right, this is a perfect time to visualize … the Earth’s motion.”

As the moon orbits Earth, it changes phase in an orderly way. Follow the links below to understand the phases of the moon.

New moon
Waxing crescent moon
First quarter moon
Waxing gibbous moon
Full moon
Waning gibbous moon
Last quarter moon
Waning crescent moon

Read more: 4 keys to understanding moon phases

Bottom line: Last quarter moon falls on October 31, 2018, at 16:40 UTC; translate UTC to your time.

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Parker solar probe becomes closest-yet spacecraft to sun

Parker Solar Probe, shown in this animation, became the closest-ever spacecraft to the sun on October 29, 2018. Image via NASA/JHUAPL.

The Parker Solar Probe now holds the record for closest approach to the sun by a human-made object. The spacecraft – which launched on August 12, 2018 – passed the current record of 26.55 million miles (43 million km) from the sun’s surface yesterday (October 29, 2018).

The previous record for closest solar approach was set by the German-American Helios 2 spacecraft in April 1976. As the Parker Solar Probe mission progresses, the spacecraft will repeatedly break its own records, with a final close approach of 3.83 million miles (6.2 million km) from the sun’s surface expected in 2024.

Parker Solar Probe will begin its first solar encounter tomorrow (October 31), continuing to fly closer and closer to the sun’s surface until it reaches its first perihelion — the point closest to the sun on November 5. The spacecraft will face brutal heat and radiation conditions while providing humanity with unprecedentedly close-up observations of a star and helping us understand phenomena that have puzzled scientists for decades.

Project Manager Andy Driesman, from the Johns Hopkins Applied Physics Laboratory, said in a statement:

It’s been just 78 days since Parker Solar Probe launched, and we’ve now come closer to our star than any other spacecraft in history. It’s a proud moment for the team, though we remain focused on our first solar encounter, which begins on October 31.

Parker Solar Probe is also expected to break the record for fastest spacecraft traveling relative to the sun, also on October 29. The current record for heliocentric speed is 153,454 miles per hour, set by Helios 2 in April 1976.

According to a NASA statement:

The Parker Solar Probe team periodically measures the spacecraft’s precise speed and position using NASA’s Deep Space Network, or DSN. The DSN sends a signal to the spacecraft, which then retransmits it back to the DSN, allowing the team to determine the spacecraft’s speed and position based on the timing and characteristics of the signal. Parker Solar Probe’s speed and position were calculated using DSN measurements made on October 24, and the team used that information along with known orbital forces to calculate the spacecraft’s speed and position from that point on.

The 2019 lunar calendars are here! Order yours before they’re gone. Makes a great gift.

Bottom line: The Parker Solar Probe broke the record for closest approach to the sun by a human-made object on October 29, 2018.

Via NASA

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Parker Solar Probe, shown in this animation, became the closest-ever spacecraft to the sun on October 29, 2018. Image via NASA/JHUAPL.

The Parker Solar Probe now holds the record for closest approach to the sun by a human-made object. The spacecraft – which launched on August 12, 2018 – passed the current record of 26.55 million miles (43 million km) from the sun’s surface yesterday (October 29, 2018).

The previous record for closest solar approach was set by the German-American Helios 2 spacecraft in April 1976. As the Parker Solar Probe mission progresses, the spacecraft will repeatedly break its own records, with a final close approach of 3.83 million miles (6.2 million km) from the sun’s surface expected in 2024.

Parker Solar Probe will begin its first solar encounter tomorrow (October 31), continuing to fly closer and closer to the sun’s surface until it reaches its first perihelion — the point closest to the sun on November 5. The spacecraft will face brutal heat and radiation conditions while providing humanity with unprecedentedly close-up observations of a star and helping us understand phenomena that have puzzled scientists for decades.

Project Manager Andy Driesman, from the Johns Hopkins Applied Physics Laboratory, said in a statement:

It’s been just 78 days since Parker Solar Probe launched, and we’ve now come closer to our star than any other spacecraft in history. It’s a proud moment for the team, though we remain focused on our first solar encounter, which begins on October 31.

Parker Solar Probe is also expected to break the record for fastest spacecraft traveling relative to the sun, also on October 29. The current record for heliocentric speed is 153,454 miles per hour, set by Helios 2 in April 1976.

According to a NASA statement:

The Parker Solar Probe team periodically measures the spacecraft’s precise speed and position using NASA’s Deep Space Network, or DSN. The DSN sends a signal to the spacecraft, which then retransmits it back to the DSN, allowing the team to determine the spacecraft’s speed and position based on the timing and characteristics of the signal. Parker Solar Probe’s speed and position were calculated using DSN measurements made on October 24, and the team used that information along with known orbital forces to calculate the spacecraft’s speed and position from that point on.

The 2019 lunar calendars are here! Order yours before they’re gone. Makes a great gift.

Bottom line: The Parker Solar Probe broke the record for closest approach to the sun by a human-made object on October 29, 2018.

Via NASA

from EarthSky https://ift.tt/2DdbVGW

Brightest comet in the night sky

Martin Mobberley posted a new image of comet 46P/Wirtanen taken remotely from Siding Spring in Australia on October 27, 2018. This image shows a large coma – or cloud around the comet – commonly seen when comets come near the sun. Image via Comets and Asteroids on Facebook.

Have you heard about comet 46P/Wirtanen? It’s approaching the inner solar system, due to pass closest to our sun and Earth in December, 2018. Comet Wirtanen is the brightest comet in the night sky now, although that doesn’t mean you can see it with the eye alone. In fact, it’s visible now only to astronomers with telescopes. But – in December 2018 – comet Wirtanen might be visible to the unaided eye, at least from dark skies. Closest approach to the sun will be December 12, 2018, and closest approach to Earth is just a few days later, on December 16.

According to astronomers at the University of Maryland, this passage of comet Wirtanen near the Earth (near by comet standards, that is) will be the 10th closest approach of a comet in modern times. At its closest to us, the comet will be about 30 times the moon’s distance (7.1 million miles, or 11.5 million km).

Contrast that number to another comet that swept relatively near us recently – 21P/Giacobini-Zinner, which caused a brief outburst in this year’s Draconid meteor shower – and which swept closest to Earth on September 9-10, 2018 at 36 million miles (58 million km). That was the closest Giacobini-Zinner had come in 72 years!

And you can see – from the paragraphs above – that Wirtanen is coming much closer, although still many times the moon’s distance.

This is what’s called a lightcurve. It’s a measurement of comet 46P/Wirtanen’s brightness, over time. The comet is getting brighter! It might become bright enough in December to be viewed with the eye alone, from a dark location. Image via University of Maryland’s comet 46P/Wirtanen: current status page.

Estimates indicate Wirtanen might reach a visual magnitude of 3.5 to 6. That would place the comet clearly in the realm of visibility with the unaided eye (although diffuse objects like comets are tougher to see than the pinpoints of stars at comparable magnitudes).

And, of course, comets have been shown to be unpredictable. We will keep you updated.

Want to stay up-to-date on Wirtanen’s brightness? This webpage from the University of Maryland is providing updates.

The December 16, 2018, close approach to Earth of comet Wirtanen will happen less than 4 days after the comet’s perihelion, or closest point to the sun. Because comets are increasingly active as they draw nearer the sun that binds them in orbit, this comet can be expected to be near its brightest around then. It might be visible to the eye from a dark location. Image via University of Maryland.

Bottom line: Comet Wirtanen will come closest to Earth in December. At that point, it might be visible to the eye alone.

from EarthSky https://ift.tt/2OYXKeL

Martin Mobberley posted a new image of comet 46P/Wirtanen taken remotely from Siding Spring in Australia on October 27, 2018. This image shows a large coma – or cloud around the comet – commonly seen when comets come near the sun. Image via Comets and Asteroids on Facebook.

Have you heard about comet 46P/Wirtanen? It’s approaching the inner solar system, due to pass closest to our sun and Earth in December, 2018. Comet Wirtanen is the brightest comet in the night sky now, although that doesn’t mean you can see it with the eye alone. In fact, it’s visible now only to astronomers with telescopes. But – in December 2018 – comet Wirtanen might be visible to the unaided eye, at least from dark skies. Closest approach to the sun will be December 12, 2018, and closest approach to Earth is just a few days later, on December 16.

According to astronomers at the University of Maryland, this passage of comet Wirtanen near the Earth (near by comet standards, that is) will be the 10th closest approach of a comet in modern times. At its closest to us, the comet will be about 30 times the moon’s distance (7.1 million miles, or 11.5 million km).

Contrast that number to another comet that swept relatively near us recently – 21P/Giacobini-Zinner, which caused a brief outburst in this year’s Draconid meteor shower – and which swept closest to Earth on September 9-10, 2018 at 36 million miles (58 million km). That was the closest Giacobini-Zinner had come in 72 years!

And you can see – from the paragraphs above – that Wirtanen is coming much closer, although still many times the moon’s distance.

This is what’s called a lightcurve. It’s a measurement of comet 46P/Wirtanen’s brightness, over time. The comet is getting brighter! It might become bright enough in December to be viewed with the eye alone, from a dark location. Image via University of Maryland’s comet 46P/Wirtanen: current status page.

Estimates indicate Wirtanen might reach a visual magnitude of 3.5 to 6. That would place the comet clearly in the realm of visibility with the unaided eye (although diffuse objects like comets are tougher to see than the pinpoints of stars at comparable magnitudes).

And, of course, comets have been shown to be unpredictable. We will keep you updated.

Want to stay up-to-date on Wirtanen’s brightness? This webpage from the University of Maryland is providing updates.

The December 16, 2018, close approach to Earth of comet Wirtanen will happen less than 4 days after the comet’s perihelion, or closest point to the sun. Because comets are increasingly active as they draw nearer the sun that binds them in orbit, this comet can be expected to be near its brightest around then. It might be visible to the eye from a dark location. Image via University of Maryland.

Bottom line: Comet Wirtanen will come closest to Earth in December. At that point, it might be visible to the eye alone.

from EarthSky https://ift.tt/2OYXKeL

Sun halo over Zimbabwe

Sun halo – October, 2018 – by Ryan Vanderlinde of Zambezi Boy Photography in Zimbabwe.

Footprints Zimbabwe posted this photo to EarthSky Facebook this week and wrote:

Ryan Vanderlinde (Zambezi Boy Photography) captured the recent sun halo seen across many places in Zimbabwe. African mythology claims it is a sign of great change, while other older beliefs say it is a promise of a good rainy season.

It’s easy to see how – in Africa, where these halo are seen less frequently than at latitudes closer to either pole – they’d be associated with change. And it’s also possible to understand the part of the African belief related to rain. In western skylore, we say the same thing, this way:

Ring around the moon (or sun) means rain soon.

In fact, sun or moon halos may mean rain soon. High cirrus clouds containing ice crystals are what cause these halos, and these sorts of clouds often come before a storm.

Read more: What makes a halo around the sun or moon?

Bottom line: A 22-degree halo seen over Zimbabwe in October, 2018.

from EarthSky https://ift.tt/2JpmarV

Sun halo – October, 2018 – by Ryan Vanderlinde of Zambezi Boy Photography in Zimbabwe.

Footprints Zimbabwe posted this photo to EarthSky Facebook this week and wrote:

Ryan Vanderlinde (Zambezi Boy Photography) captured the recent sun halo seen across many places in Zimbabwe. African mythology claims it is a sign of great change, while other older beliefs say it is a promise of a good rainy season.

It’s easy to see how – in Africa, where these halo are seen less frequently than at latitudes closer to either pole – they’d be associated with change. And it’s also possible to understand the part of the African belief related to rain. In western skylore, we say the same thing, this way:

Ring around the moon (or sun) means rain soon.

In fact, sun or moon halos may mean rain soon. High cirrus clouds containing ice crystals are what cause these halos, and these sorts of clouds often come before a storm.

Read more: What makes a halo around the sun or moon?

Bottom line: A 22-degree halo seen over Zimbabwe in October, 2018.

from EarthSky https://ift.tt/2JpmarV

How 600,000 pounds of dead salmon nourished Alaskan trees

The 2019 lunar calendars are here! Order yours before they’re gone. Makes a great gift.

In this video, University of Washington professor Tom Quinn tells the story of an unusual 20-year study in which dead salmon, counted for a different study, were tossed to the side of a shallow creek in Alaska, but only to one side of the creek (so they wouldn’t be counted twice).

After 20 years, Quinn decided to end the study and measure trees to see if they grew differently during this time. It turns out that two decades of carcasses — nearly 600,000 pounds of fish — tossed to the left side of Hansen Creek did have a noticeable effect: White spruce trees on that side of the stream grew faster than their counterparts on the other side that received no salmon.

What’s more, nitrogen derived from salmon was found in high concentration in the needles of the spruce trees on the side of the tossed carcasses.

Essentially, said Quinn, the sockeye carcasses were fertilizing the trees. Quinn, a professor in University of Washington’s School of Aquatic and Fishery Sciences, is lead author of the study, published October 23, 2018 in the peer-reviewed journal Ecology. Quinn said in a statement:

Tossing the carcasses to the left side started out just as a convenience to keep from counting the same fish twice. I thought at some point in the future, it would be kind of cool to see it if had an effect.

An undergraduate student uses a hooked pole to throw a dead sockeye salmon onto the bank of Hansen Creek. Image via Dan DiNicola/U. Washington.

Source: A multidecade experiment shows that fertilization by salmon carcasses enhanced tree growth in the riparian zone

Bottom line: Video tells the story of how dead salmon thrown on one side of a shallow creek by researchers over 20 years had an unexpected benefit: healthier, faster-growing trees.

Via University of Washington

from EarthSky https://ift.tt/2Svj1L5

The 2019 lunar calendars are here! Order yours before they’re gone. Makes a great gift.

In this video, University of Washington professor Tom Quinn tells the story of an unusual 20-year study in which dead salmon, counted for a different study, were tossed to the side of a shallow creek in Alaska, but only to one side of the creek (so they wouldn’t be counted twice).

After 20 years, Quinn decided to end the study and measure trees to see if they grew differently during this time. It turns out that two decades of carcasses — nearly 600,000 pounds of fish — tossed to the left side of Hansen Creek did have a noticeable effect: White spruce trees on that side of the stream grew faster than their counterparts on the other side that received no salmon.

What’s more, nitrogen derived from salmon was found in high concentration in the needles of the spruce trees on the side of the tossed carcasses.

Essentially, said Quinn, the sockeye carcasses were fertilizing the trees. Quinn, a professor in University of Washington’s School of Aquatic and Fishery Sciences, is lead author of the study, published October 23, 2018 in the peer-reviewed journal Ecology. Quinn said in a statement:

Tossing the carcasses to the left side started out just as a convenience to keep from counting the same fish twice. I thought at some point in the future, it would be kind of cool to see it if had an effect.

An undergraduate student uses a hooked pole to throw a dead sockeye salmon onto the bank of Hansen Creek. Image via Dan DiNicola/U. Washington.

Source: A multidecade experiment shows that fertilization by salmon carcasses enhanced tree growth in the riparian zone

Bottom line: Video tells the story of how dead salmon thrown on one side of a shallow creek by researchers over 20 years had an unexpected benefit: healthier, faster-growing trees.

Via University of Washington

from EarthSky https://ift.tt/2Svj1L5