February guide to the bright planets

sky chart finding Saturn

In late January and early February, watch the waning crescent moon slide past a string of morning planets: Jupiter, Venus and Saturn. Read more.

Click the name of a planet to learn more about its visibility in February 2019: Venus, Jupiter, Saturn, Mars and Mercury

Post your planet photos at EarthSky Community Photos

Venus is the brightest planet, beaming mightily in the east in the predawn/dawn sky all month long. Watch for the waning crescent moon to join up with Venus in the morning sky for a few days, centered on or near January 31. After that, the waning crescent moon will next pair up with Venus in early March.

This world reached a milestone in the morning sky on January 6, 2019, as this blazing world showcased its greatest elongation from the sun. In other words, on that date, Venus was a maximum angular distance of 46 degrees from the sun on our sky’s dome. Ever since, Venus has been slowly but surely sinking sunward.

The month starts out with Venus shining above Saturn in the morning sky, yet the month ends with Saturn shining above Venus. Day by day, Saturn climbs upward, away from the sunrise, while Venus sinks downward, toward the rising sun. The two will meet for a conjunction in the morning sky on February 18, 2019. All the while, Jupiter remains at the top of this line-up of three morning planets.

After this month, Venus will spend less time in the predawn sky before sunrise each morning, but it’ll still be dazzlingly bright and visible at dawn for months to come. At mid-northern latitudes, Venus will rise before astronomical twilight (dawn’s first light) until mid-March 2019; and at temperate latitudes in the Southern Hemisphere, Venus will rise before astronomical twilight until the end of May 2019.

Click here to find out when astronomical twilight comes to your sky, remembering to check the astronomical twilight box.

At mid-northern latitudes, Venus rises about three hours before sunrise in early January. By the month’s end, that’ll taper to about two hours.

At temperate latitudes in the Southern Hemisphere, Venus rises about 3 1/2 hours before sunup all month long.

At the month’s end and early March, watch for the waning crescent moon to promenade past Venus and the two other morning planets, Jupiter and Saturn. See a sky chart for the event below.

Sky chart of moon and morning planets

In late February and early March, watch the moon go by Jupiter, Saturn and Venus. Read more.

Jupiter is the second-brightest planet after Venus. The king planet reigns at the top of the morning line-up of planets all month long. At the beginning of February, Venus is found in between Jupiter and Saturn. On February 18, 2019, the planets Venus and Saturn are in conjunction beneath Jupiter. In the final week of February, the planet Saturn is found between Jupiter and Venus.

If you’re up during the predawn hours, you might notice a bright ruddy star in the vicinity of Jupiter on the sky’s dome. That’s Antares, the brightest star in the constellation Scorpius the Scorpion. Although Jupiter shines in the vicinity of Antares all year long, Jupiter can be seen to wander relative to this “fixed” star of the zodiac. Jupiter travels eastward, away from Antares, until April 10, 2019. Then, for a period of four months (April 10 to August 11, 2019), Jupiter actually moves in retrograde (or westward), closing the gap between itself and the star Antares. Midway through this retrograde, Jupiter will reach opposition on June 10, 2019, to shine at its brilliant best for the year.

Watch for the waning crescent moon to swing by Jupiter around January 30 and 31 and then again around February 27.

From mid-northern latitudes, Jupiter rises about 3 1/2 hours before the sun in early February. By the month’s end, that’ll increase to about four hours.

From temperate latitudes in the Southern Hemisphere, Jupiter comes up about four hours before sunrise at the beginning of the month. By the month’s end, Jupiter rises around the midnight hour.

Sky chart of Venus and Saturn in conjunction

Watch for the conjunction of Venus and Saturn on February 18, 2019. Thereafter, Saturn will climb upward, away from the sunrise, while, Venus will descend in the direction of sunrise. Read more.

Saturn swung over to the morning sky, at least nominally, on January 2, 2019. But, for the most of January, this world sat too deeply in the glare of sunrise to be visible. Starting on or near January 30, avid sky watchers will use the waning crescent moon and the two brilliant planets, Venus and Jupiter, to guide them to Saturn’s place near the horizon as darkness begins to give way to dawn. This may present the first good opportunity for you to view Saturn in the morning sky in 2019.

Day by day throughout February, Saturn climbs upward, away from the sunrise. Venus, on the other hand, sinks sunward by the day. Saturn should be quite easy to see by the time that Venus and Saturn have their conjunction in the morning sky on February 18. Saturn, although as bright as a 1st-magnitude star, pales next to Venus. Venus ranks as the 3rd-brightest celestial object to light up the heavens, after the sun and moon, to outshine Saturn by some 80 times on their February 18th conjunction date.

From mid-northern latitudes, Saturn rises about 1 1/2 hours before the sun in early February. That’ll increase to about 2 1/2 hours before sunup by the month’s end.

From temperate latitudes in the Southern Hemisphere, Saturn rises about two hours before sunrise in early February, and by the month’s end, comes up about 3 1/2 hours before the sun.

Sky chart of Mercury and Mars

Starting in the second half of February 2019, try to find Mercury beneath Mars as evening twilight gives way to nightfall. Binoculars always come in handy for any Mercury quest. Read more.

Mercury, the innermost planet of the solar system, shifted over to the evening sky on January 30. But Mercury won’t be far enough from the setting sun to become visible in the evening sky until around mid-month (at northerly latitudes).

Mercury’s apparition in the evening sky will be especially favorable for the Northern Hemisphere in the last few weeks of February and early March 2019. But this will be an especially poor evening showing of Mercury at temperate latitudes in the Southern Hemisphere.

At mid-northern latitudes, Mercury sets about one hour after the sun by around mid-month, and by the month’s end, that’ll increase to about 1 1/2 hours.

Sky chart of moon, Mars and Uranus

Look for the moon in the vicinity of Mars (and Uranus) for several evenings, centered on or near February 10. Read more.

Mars is the only bright planet to appear in the February evening sky all month long. At northerly latitudes, in the second half of the month, you may find Mercury beneath Mars, with Mercury lurking close to the horizon as evening dusk ebbs into darkness. Although Mars dims somewhat over the month, Mars remains modestly-bright, shining as brilliantly a 1st-magnitude star all month long. Moreover, Mars stays out till mid-evening at mid-northern latitudes, and until late evening in the Southern Hemisphere.

Click here for recommended sky almanacs providing you with the setting times for Mars.

Watch for the moon to shine in the vicinity of Mars for several evenings, centered on or near February 10. With binoculars you might even spot Uranus, the 7th planet outward from the sun, in the same binocular field with Mars each evening for about a week, centered on or near February 12. See the sky chart below.

Sky chart of the planets Mars and Uranus on February 12, 2019

On February 12, 2019, the lit side of the moon points right at Mars and Uranus. Despite the moonlit glare, binoculars may enable you to see the Mars/Uranus conjunction in a single binocular field. 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.

silhouette of man against the sunset sky with bright planet and crescent moon

Skywatcher, by Predrag Agatonovic.

Bottom line: In February, Mars shines in the evening sky all month long, whereas Venus, Jupiter and Saturn adorn the morning sky. Mercury comes into view in the evening sky in the second half of the month. Click here for recommended almanacs; they can help you know when the planets rise and set in your sky.

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

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sky chart finding Saturn

In late January and early February, watch the waning crescent moon slide past a string of morning planets: Jupiter, Venus and Saturn. Read more.

Click the name of a planet to learn more about its visibility in February 2019: Venus, Jupiter, Saturn, Mars and Mercury

Post your planet photos at EarthSky Community Photos

Venus is the brightest planet, beaming mightily in the east in the predawn/dawn sky all month long. Watch for the waning crescent moon to join up with Venus in the morning sky for a few days, centered on or near January 31. After that, the waning crescent moon will next pair up with Venus in early March.

This world reached a milestone in the morning sky on January 6, 2019, as this blazing world showcased its greatest elongation from the sun. In other words, on that date, Venus was a maximum angular distance of 46 degrees from the sun on our sky’s dome. Ever since, Venus has been slowly but surely sinking sunward.

The month starts out with Venus shining above Saturn in the morning sky, yet the month ends with Saturn shining above Venus. Day by day, Saturn climbs upward, away from the sunrise, while Venus sinks downward, toward the rising sun. The two will meet for a conjunction in the morning sky on February 18, 2019. All the while, Jupiter remains at the top of this line-up of three morning planets.

After this month, Venus will spend less time in the predawn sky before sunrise each morning, but it’ll still be dazzlingly bright and visible at dawn for months to come. At mid-northern latitudes, Venus will rise before astronomical twilight (dawn’s first light) until mid-March 2019; and at temperate latitudes in the Southern Hemisphere, Venus will rise before astronomical twilight until the end of May 2019.

Click here to find out when astronomical twilight comes to your sky, remembering to check the astronomical twilight box.

At mid-northern latitudes, Venus rises about three hours before sunrise in early January. By the month’s end, that’ll taper to about two hours.

At temperate latitudes in the Southern Hemisphere, Venus rises about 3 1/2 hours before sunup all month long.

At the month’s end and early March, watch for the waning crescent moon to promenade past Venus and the two other morning planets, Jupiter and Saturn. See a sky chart for the event below.

Sky chart of moon and morning planets

In late February and early March, watch the moon go by Jupiter, Saturn and Venus. Read more.

Jupiter is the second-brightest planet after Venus. The king planet reigns at the top of the morning line-up of planets all month long. At the beginning of February, Venus is found in between Jupiter and Saturn. On February 18, 2019, the planets Venus and Saturn are in conjunction beneath Jupiter. In the final week of February, the planet Saturn is found between Jupiter and Venus.

If you’re up during the predawn hours, you might notice a bright ruddy star in the vicinity of Jupiter on the sky’s dome. That’s Antares, the brightest star in the constellation Scorpius the Scorpion. Although Jupiter shines in the vicinity of Antares all year long, Jupiter can be seen to wander relative to this “fixed” star of the zodiac. Jupiter travels eastward, away from Antares, until April 10, 2019. Then, for a period of four months (April 10 to August 11, 2019), Jupiter actually moves in retrograde (or westward), closing the gap between itself and the star Antares. Midway through this retrograde, Jupiter will reach opposition on June 10, 2019, to shine at its brilliant best for the year.

Watch for the waning crescent moon to swing by Jupiter around January 30 and 31 and then again around February 27.

From mid-northern latitudes, Jupiter rises about 3 1/2 hours before the sun in early February. By the month’s end, that’ll increase to about four hours.

From temperate latitudes in the Southern Hemisphere, Jupiter comes up about four hours before sunrise at the beginning of the month. By the month’s end, Jupiter rises around the midnight hour.

Sky chart of Venus and Saturn in conjunction

Watch for the conjunction of Venus and Saturn on February 18, 2019. Thereafter, Saturn will climb upward, away from the sunrise, while, Venus will descend in the direction of sunrise. Read more.

Saturn swung over to the morning sky, at least nominally, on January 2, 2019. But, for the most of January, this world sat too deeply in the glare of sunrise to be visible. Starting on or near January 30, avid sky watchers will use the waning crescent moon and the two brilliant planets, Venus and Jupiter, to guide them to Saturn’s place near the horizon as darkness begins to give way to dawn. This may present the first good opportunity for you to view Saturn in the morning sky in 2019.

Day by day throughout February, Saturn climbs upward, away from the sunrise. Venus, on the other hand, sinks sunward by the day. Saturn should be quite easy to see by the time that Venus and Saturn have their conjunction in the morning sky on February 18. Saturn, although as bright as a 1st-magnitude star, pales next to Venus. Venus ranks as the 3rd-brightest celestial object to light up the heavens, after the sun and moon, to outshine Saturn by some 80 times on their February 18th conjunction date.

From mid-northern latitudes, Saturn rises about 1 1/2 hours before the sun in early February. That’ll increase to about 2 1/2 hours before sunup by the month’s end.

From temperate latitudes in the Southern Hemisphere, Saturn rises about two hours before sunrise in early February, and by the month’s end, comes up about 3 1/2 hours before the sun.

Sky chart of Mercury and Mars

Starting in the second half of February 2019, try to find Mercury beneath Mars as evening twilight gives way to nightfall. Binoculars always come in handy for any Mercury quest. Read more.

Mercury, the innermost planet of the solar system, shifted over to the evening sky on January 30. But Mercury won’t be far enough from the setting sun to become visible in the evening sky until around mid-month (at northerly latitudes).

Mercury’s apparition in the evening sky will be especially favorable for the Northern Hemisphere in the last few weeks of February and early March 2019. But this will be an especially poor evening showing of Mercury at temperate latitudes in the Southern Hemisphere.

At mid-northern latitudes, Mercury sets about one hour after the sun by around mid-month, and by the month’s end, that’ll increase to about 1 1/2 hours.

Sky chart of moon, Mars and Uranus

Look for the moon in the vicinity of Mars (and Uranus) for several evenings, centered on or near February 10. Read more.

Mars is the only bright planet to appear in the February evening sky all month long. At northerly latitudes, in the second half of the month, you may find Mercury beneath Mars, with Mercury lurking close to the horizon as evening dusk ebbs into darkness. Although Mars dims somewhat over the month, Mars remains modestly-bright, shining as brilliantly a 1st-magnitude star all month long. Moreover, Mars stays out till mid-evening at mid-northern latitudes, and until late evening in the Southern Hemisphere.

Click here for recommended sky almanacs providing you with the setting times for Mars.

Watch for the moon to shine in the vicinity of Mars for several evenings, centered on or near February 10. With binoculars you might even spot Uranus, the 7th planet outward from the sun, in the same binocular field with Mars each evening for about a week, centered on or near February 12. See the sky chart below.

Sky chart of the planets Mars and Uranus on February 12, 2019

On February 12, 2019, the lit side of the moon points right at Mars and Uranus. Despite the moonlit glare, binoculars may enable you to see the Mars/Uranus conjunction in a single binocular field. 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.

silhouette of man against the sunset sky with bright planet and crescent moon

Skywatcher, by Predrag Agatonovic.

Bottom line: In February, Mars shines in the evening sky all month long, whereas Venus, Jupiter and Saturn adorn the morning sky. Mercury comes into view in the evening sky in the second half of the month. Click here for recommended almanacs; they can help you know when the planets rise 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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Stargazing destinations: Oregon

Here’s the second episode in the Chasing Darkness video series, a stargazing destination guide by astrophotographer Jack Fusco and adventure photographer Jeff Bartlett.

This episode was shot in March 2018, when the duo visited Oregon’s Cascade Mountain Range and Alvord Desert – two unique and incredibly different locations with just a few hours of driving between them.

Jack told us:

It was definitely a memorable trip as we arrived at the desert at the same time a huge storm was hitting. It was a little challenging and stressful, but it created some really unique conditions.

Man with camera on tripod, rising Milky Way reflected on flat water-covered ground.

Milky Way reflecting off the desert floor after a rain shower. Image via Jack Fusco.

There’s more info about this episode, plus gorgeous still photos, here. If you missed the first episode – dark sky preserves in Alberta, Canada – you can watch it here.

Here’s more about the Chasing Darkness project.

Bottom line: Video of stargazing locations in Oregon’s Cascade Mountains and the Alvord Desert.

Visit EarthSky’s Best Places to Stargaze page

See moon phases for all year on EarthSky’s moon calendar for 2019. Order now!



from EarthSky http://bit.ly/2G0kSVg

Here’s the second episode in the Chasing Darkness video series, a stargazing destination guide by astrophotographer Jack Fusco and adventure photographer Jeff Bartlett.

This episode was shot in March 2018, when the duo visited Oregon’s Cascade Mountain Range and Alvord Desert – two unique and incredibly different locations with just a few hours of driving between them.

Jack told us:

It was definitely a memorable trip as we arrived at the desert at the same time a huge storm was hitting. It was a little challenging and stressful, but it created some really unique conditions.

Man with camera on tripod, rising Milky Way reflected on flat water-covered ground.

Milky Way reflecting off the desert floor after a rain shower. Image via Jack Fusco.

There’s more info about this episode, plus gorgeous still photos, here. If you missed the first episode – dark sky preserves in Alberta, Canada – you can watch it here.

Here’s more about the Chasing Darkness project.

Bottom line: Video of stargazing locations in Oregon’s Cascade Mountains and the Alvord Desert.

Visit EarthSky’s Best Places to Stargaze page

See moon phases for all year on EarthSky’s moon calendar for 2019. Order now!



from EarthSky http://bit.ly/2G0kSVg

Polar vortex 2019 photos and videos

Dark snowy street scene, with mounds of deep snow on the ground.

View larger at EarthSky Community Photos. | Niko Powe in Kewanee, Illinois said he got up before the sun on January 30, 2019, wanting to catch: “… the moon sweeping past Jupiter, Antares and Venus on this -43 a.m. day in the K!”

Brutal cold struck the U.S. Midwest this week, closing roads, schools and businesses and causing multiple states of emergency to be declared as people coped with subzero temperatures. In Chicago on Wednesday, Arctic air from the polar vortex caused temperatures to drop to as low as -28F (-46C). By the end of the day on Wednesday, as many as eight deaths had been reported. And the cold is continuing. Meteorologists at the Washington Post said that temperatures on January 31 will be likely colder than those on the North Slope of Alaska. Here are a few images – from the EarthSky Community and elsewhere – of this week’s cold.

White and gray satellite view of Great Lake area, lines of clouds over lakes, land all white.

It even looks cold from space in this natural-color satellite image, acquired by NASA’s Terra satellite on January 27, 2019. Cloud streets and lake-effect snow stretch across the scene, as frigid Arctic winds blew over the U.S. Great Lakes. Read more at NASA Earth Observatory.

Looking out a window at a snowy street, frost around the edges of the window, inside!

View larger at EarthSky Community Photos. | There were wind chills in Minnesota this week as as low as -62F (-52C). Donna Divine in White Bear Lake, Minnesota, said there was frost inside – yes, we said inside – her bedroom window throughout the day on January 30, 2019. “That’s with the heat on in the apartment,” she wrote.

A swirly frost pattern.

View larger at EarthSky Community Photos. | Jacalyn Margittay in Sturgeon Bay, Wisconsin, wrote on January 27: “Frost on my kitchen window – just pretty.”

Close-up of tiny frost crystals on wood

View larger at EarthSky Community Photos. | And it’s not just the U.S. Midwest that’s cold this week. Jessica Marshall in Birmingham, England, wrote on January 31: “Frost on a fence post this morning in minus 6 degrees!”

Bottom Line: January 2019 images of the brutal cold in the U.S. Midwest and elsewhere around the world.

EarthSky 2019 lunar calendars are cool! Order now. Going fast!



from EarthSky http://bit.ly/2WvXQe8
Dark snowy street scene, with mounds of deep snow on the ground.

View larger at EarthSky Community Photos. | Niko Powe in Kewanee, Illinois said he got up before the sun on January 30, 2019, wanting to catch: “… the moon sweeping past Jupiter, Antares and Venus on this -43 a.m. day in the K!”

Brutal cold struck the U.S. Midwest this week, closing roads, schools and businesses and causing multiple states of emergency to be declared as people coped with subzero temperatures. In Chicago on Wednesday, Arctic air from the polar vortex caused temperatures to drop to as low as -28F (-46C). By the end of the day on Wednesday, as many as eight deaths had been reported. And the cold is continuing. Meteorologists at the Washington Post said that temperatures on January 31 will be likely colder than those on the North Slope of Alaska. Here are a few images – from the EarthSky Community and elsewhere – of this week’s cold.

White and gray satellite view of Great Lake area, lines of clouds over lakes, land all white.

It even looks cold from space in this natural-color satellite image, acquired by NASA’s Terra satellite on January 27, 2019. Cloud streets and lake-effect snow stretch across the scene, as frigid Arctic winds blew over the U.S. Great Lakes. Read more at NASA Earth Observatory.

Looking out a window at a snowy street, frost around the edges of the window, inside!

View larger at EarthSky Community Photos. | There were wind chills in Minnesota this week as as low as -62F (-52C). Donna Divine in White Bear Lake, Minnesota, said there was frost inside – yes, we said inside – her bedroom window throughout the day on January 30, 2019. “That’s with the heat on in the apartment,” she wrote.

A swirly frost pattern.

View larger at EarthSky Community Photos. | Jacalyn Margittay in Sturgeon Bay, Wisconsin, wrote on January 27: “Frost on my kitchen window – just pretty.”

Close-up of tiny frost crystals on wood

View larger at EarthSky Community Photos. | And it’s not just the U.S. Midwest that’s cold this week. Jessica Marshall in Birmingham, England, wrote on January 31: “Frost on a fence post this morning in minus 6 degrees!”

Bottom Line: January 2019 images of the brutal cold in the U.S. Midwest and elsewhere around the world.

EarthSky 2019 lunar calendars are cool! Order now. Going fast!



from EarthSky http://bit.ly/2WvXQe8

Light pillar, a moon pillar, moon dogs

Moon, wide ring around it, two bright planets, meteor streak above, yellow vertical line on left.

View larger at EarthSky Community Photos. | There’s a lot going on in this photo. The planets Venus and Jupiter are on the left, near the bright orange vertical light pillar extending up from the ground. Venus is the brighter planet; Jupiter is slightly fainter but still very bright, nearly caught in the orange light pillar. More details below. Photo by Darlene Tanner in Alberta, Canada.

Darlene Tanner captured this photo on the morning of January 29, 2019. Besides the bright, orange-colored vertical light pillar, you can see a moon pillar extending between the ground and the moon. Plus there’s a lunar halo, with the two prominent moon dogs on either side of the moon. Both the halo and light pillars are caused by ice crystals drifting in the air.

Plus, the moon is sliding past 3 planets in the dawn sky this week, and Darlene caught two of them, Venus and Jupiter. The picture caption explains which is which.

And look at the top of the photo! There’s even a meteor. Wow!

Thank you, Darlene!

Read more: Moon slides past 3 morning planets

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

Read more: What is a sun pillar or light pillar?



from EarthSky http://bit.ly/2WvRhIw
Moon, wide ring around it, two bright planets, meteor streak above, yellow vertical line on left.

View larger at EarthSky Community Photos. | There’s a lot going on in this photo. The planets Venus and Jupiter are on the left, near the bright orange vertical light pillar extending up from the ground. Venus is the brighter planet; Jupiter is slightly fainter but still very bright, nearly caught in the orange light pillar. More details below. Photo by Darlene Tanner in Alberta, Canada.

Darlene Tanner captured this photo on the morning of January 29, 2019. Besides the bright, orange-colored vertical light pillar, you can see a moon pillar extending between the ground and the moon. Plus there’s a lunar halo, with the two prominent moon dogs on either side of the moon. Both the halo and light pillars are caused by ice crystals drifting in the air.

Plus, the moon is sliding past 3 planets in the dawn sky this week, and Darlene caught two of them, Venus and Jupiter. The picture caption explains which is which.

And look at the top of the photo! There’s even a meteor. Wow!

Thank you, Darlene!

Read more: Moon slides past 3 morning planets

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

Read more: What is a sun pillar or light pillar?



from EarthSky http://bit.ly/2WvRhIw

Hyades star cluster: Face of Taurus

The Hyades. Copyright Jerry Lodriguss/AstroPix.com. Used with permission.

With the exception of the Ursa Major Moving Cluster, the Hyades cluster is the closest star cluster to Earth, at a distance of 150 light-years. This cluster is very easy to spot in the night sky, because it has a compact and distinctive shape of the letter V. The bright star Aldebaran is part of the V.

The V-shape represents the Face of the Bull in the constellation Taurus. Aldebaran represents the Bull’s fiery red eye.

The Hyades star cluster has the shape of the letter V. The small dipper-shaped Pleiades star cluster is nearby.

The Hyades star cluster can be found easily on January and February evenings, and is edging toward the western half of the sky by March and April evenings. It has the shape of the letter V. The brightest star in the V is Aldebaran. The small dipper-shaped Pleiades star cluster is nearby.

Orion, the bright star Aldebaran in Taurus, and the Pleiades.

Here are Orion, the bright star Aldebaran in Taurus, and the Pleiades. Notice the three stars of Orion’s Belt, that is, three stars in a short row. Notice that these stars point to Aldebaran.

The Hyades cluster is easy to find by using Orion’s Belt, a compact and noticeable line of three blue-white stars in the constellation Orion the Hunter. Draw a line westward (generally toward your sunset direction) through the Belt stars, and you will come to the bright reddish star Aldebaran, the Bull’s fiery red eye.

Although Aldebaran isn’t a true member of the Hyades star cluster, this bright star is a great guide to this cluster. In fact, Aldebaran is only about 65 light-years distant. The Hyades lies about 2.5 times farther off.

The V-shape figure of stars (except Aldebaran) highlights the brightest of the Hyades’ few hundred stars. A dozen or more Hyades stars are visible to the unaided eye in a dark country sky, but several dozen of the cluster’s stars can be resolved through binoculars or low power in a telescope. From the Northern Hemisphere, the Hyades are best seen in the evening sky from around January to April.

The constellation Taurus the Bull is home to another bright star cluster, the Pleiades. The Pleiades cluster is more distant than the Hyades at some 430 light-years away. Both the Hyades and Pleiades are easily visible to the unaided eye. Both are enhanced by viewing with binoculars.

The Hyades – like their half-sisters the Pleiades – were nymphs of Greek mythology. Image via Greek Mythology Link – by Carlos Parada.

History and mythology of the Hyades. According to sky lore, the teary Hyades are the daughters of Atlas and Aethra, who are forever crying for their brother Hyas, who was killed by a lion or a boar. The Hyades are the half-sisters to the Pleiades, the daughters of Atlas and Pleione. The gods purposely kept Atlas’ daughters – the Hyades and the Pleaides – out of reach of Orion, giving them a safe haven from his lustful pursuits.

The gods transformed Hyas into the constellation Aquarius, and the lion that killed him into the constellation Leo. The gods placed Aquarius and Leo on opposite sides of the sky for Hyas’ protection. That’s why Aquarius and Leo do not appear in the same sky together. As one constellation sets in the west, the other rises in the east – and vice versa.

View larger. | David Rojas in Guatemala City, Guatemala caught the waxing crescent moon, Hyades star cluster with the bright star Aldebaran at one tip of the V, and the Pleiades star cluster on March 22, 2018.

A telescope reveals over 100 stars in the Hyades cluster. The bright red star here is Aldebaran. Photo via astronomycafe.net.

A telescope reveals over 100 stars in the Hyades cluster. The bright red star here is Aldebaran. Photo via astronomycafe.net.

Hyades science. Although the Hyades and Pleaides are half-sisters in mythology, science finds no close relationship in space between these two star clusters.

Astronomers find that the Pleiades are composed of hot blue-white suns in the heyday of youth, which puts the age of the cluster at about 100 million years. In contrast, the cooler red giant and white dwarf stars found in the Hyades indicate a vastly older cluster over 700 million years old.

Interestingly, astronomers suspect an actual kinship between the Hyades cluster and the Beehive star cluster in the constellation Cancer the Crab. Even though these two star clusters are separated from one another by hundreds of light-years, they are akin in age and travel in a similar direction in space. Astronomers believe these clusters might have originated from the same gaseous nebula some 700 to 800 million years ago.

Orion's Belt points to the Hyades star cluster. Image credit: unishot

The three bright stars in a row are Orion’s Belt. They point to the Hyades star cluster. Photo via Unishot/Flickr.

View larger. | More detail on the starry sky around the Hyades. Notice that Orion’s Belt (lower left) points to the Hyades.

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Bottom line: On January and February evenings, look for a V-shaped pattern of stars. The Hyades star cluster represents the face of Taurus the Bull. The cluster is easy to spot and beautiful in binoculars.



from EarthSky http://bit.ly/2MHDSbJ

The Hyades. Copyright Jerry Lodriguss/AstroPix.com. Used with permission.

With the exception of the Ursa Major Moving Cluster, the Hyades cluster is the closest star cluster to Earth, at a distance of 150 light-years. This cluster is very easy to spot in the night sky, because it has a compact and distinctive shape of the letter V. The bright star Aldebaran is part of the V.

The V-shape represents the Face of the Bull in the constellation Taurus. Aldebaran represents the Bull’s fiery red eye.

The Hyades star cluster has the shape of the letter V. The small dipper-shaped Pleiades star cluster is nearby.

The Hyades star cluster can be found easily on January and February evenings, and is edging toward the western half of the sky by March and April evenings. It has the shape of the letter V. The brightest star in the V is Aldebaran. The small dipper-shaped Pleiades star cluster is nearby.

Orion, the bright star Aldebaran in Taurus, and the Pleiades.

Here are Orion, the bright star Aldebaran in Taurus, and the Pleiades. Notice the three stars of Orion’s Belt, that is, three stars in a short row. Notice that these stars point to Aldebaran.

The Hyades cluster is easy to find by using Orion’s Belt, a compact and noticeable line of three blue-white stars in the constellation Orion the Hunter. Draw a line westward (generally toward your sunset direction) through the Belt stars, and you will come to the bright reddish star Aldebaran, the Bull’s fiery red eye.

Although Aldebaran isn’t a true member of the Hyades star cluster, this bright star is a great guide to this cluster. In fact, Aldebaran is only about 65 light-years distant. The Hyades lies about 2.5 times farther off.

The V-shape figure of stars (except Aldebaran) highlights the brightest of the Hyades’ few hundred stars. A dozen or more Hyades stars are visible to the unaided eye in a dark country sky, but several dozen of the cluster’s stars can be resolved through binoculars or low power in a telescope. From the Northern Hemisphere, the Hyades are best seen in the evening sky from around January to April.

The constellation Taurus the Bull is home to another bright star cluster, the Pleiades. The Pleiades cluster is more distant than the Hyades at some 430 light-years away. Both the Hyades and Pleiades are easily visible to the unaided eye. Both are enhanced by viewing with binoculars.

The Hyades – like their half-sisters the Pleiades – were nymphs of Greek mythology. Image via Greek Mythology Link – by Carlos Parada.

History and mythology of the Hyades. According to sky lore, the teary Hyades are the daughters of Atlas and Aethra, who are forever crying for their brother Hyas, who was killed by a lion or a boar. The Hyades are the half-sisters to the Pleiades, the daughters of Atlas and Pleione. The gods purposely kept Atlas’ daughters – the Hyades and the Pleaides – out of reach of Orion, giving them a safe haven from his lustful pursuits.

The gods transformed Hyas into the constellation Aquarius, and the lion that killed him into the constellation Leo. The gods placed Aquarius and Leo on opposite sides of the sky for Hyas’ protection. That’s why Aquarius and Leo do not appear in the same sky together. As one constellation sets in the west, the other rises in the east – and vice versa.

View larger. | David Rojas in Guatemala City, Guatemala caught the waxing crescent moon, Hyades star cluster with the bright star Aldebaran at one tip of the V, and the Pleiades star cluster on March 22, 2018.

A telescope reveals over 100 stars in the Hyades cluster. The bright red star here is Aldebaran. Photo via astronomycafe.net.

A telescope reveals over 100 stars in the Hyades cluster. The bright red star here is Aldebaran. Photo via astronomycafe.net.

Hyades science. Although the Hyades and Pleaides are half-sisters in mythology, science finds no close relationship in space between these two star clusters.

Astronomers find that the Pleiades are composed of hot blue-white suns in the heyday of youth, which puts the age of the cluster at about 100 million years. In contrast, the cooler red giant and white dwarf stars found in the Hyades indicate a vastly older cluster over 700 million years old.

Interestingly, astronomers suspect an actual kinship between the Hyades cluster and the Beehive star cluster in the constellation Cancer the Crab. Even though these two star clusters are separated from one another by hundreds of light-years, they are akin in age and travel in a similar direction in space. Astronomers believe these clusters might have originated from the same gaseous nebula some 700 to 800 million years ago.

Orion's Belt points to the Hyades star cluster. Image credit: unishot

The three bright stars in a row are Orion’s Belt. They point to the Hyades star cluster. Photo via Unishot/Flickr.

View larger. | More detail on the starry sky around the Hyades. Notice that Orion’s Belt (lower left) points to the Hyades.

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Bottom line: On January and February evenings, look for a V-shaped pattern of stars. The Hyades star cluster represents the face of Taurus the Bull. The cluster is easy to spot and beautiful in binoculars.



from EarthSky http://bit.ly/2MHDSbJ

How frigid polar vortex blasts are connected to global warming

People in big hooded coats and gloves

Bundled up against the cold in downtown Chicago, Sunday, January 27, 2019. Image via AP Photo/Nam Y. Huh.

By Jennifer Francis, Rutgers University

A record-breaking cold wave is sending literal shivers down the spines of millions of Americans. Temperatures across the upper Midwest are forecast to fall an astonishing 50 degrees Fahrenheit (28 degrees C) below normal this week – as low as 35 degrees below zero. Pile a gusty wind on top, and the air will feel like -60 degrees F (-51 degrees C).

Map of the United States with colored bands of purple and blue.

Predicted near-surface air temperatures (F) for Wednesday morning, January 30, 2019. Forecast by NOAA’s Global Forecast System model. Image via Pivotal Weather.

This cold is nothing to sneeze at. The National Weather Service is warning of brutal, life-threatening conditions. Frostbite will strike fast on any exposed skin. At the same time, the North Pole is facing a heat wave with temperatures approaching the freezing point – about 25 degrees Fahrenheit (14 degrees C) above normal.

Map of North America and Arctic with blobs of red and blue.

Predicted near-surface air temperature differences (C) from normal, relative to 1981-2010. Image via Pivotal Weather.

What is causing this topsy-turvy pattern? You guessed it: the polar vortex.

In the past several years, thanks to previous cold waves, the polar vortex has become entrenched in our everyday vocabulary and served as a butt of jokes for late-night TV hosts and politicians. But what is it really? Is it escaping from its usual Arctic haunts more often? And a question that looms large in my work: How does global warming fit into the story?

Rivers of air

Actually, there are two polar vortices in the Northern Hemisphere, stacked on top of each other. The lower one is usually and more accurately called the jet stream. It’s a meandering river of strong westerly winds around the Northern Hemisphere, about seven miles above Earth’s surface, near the height where jets fly.

The jet stream exists all year, and is responsible for creating and steering the high- and low-pressure systems that bring us our day-to-day weather: storms and blue skies, warm and cold spells. Way above the jet stream, around 30 miles above the Earth, is the stratospheric polar vortex. This river of wind also rings the North Pole, but only forms during winter, and is usually fairly circular.

Illustration of blue planet Earth with arrows.

Dark arrows indicate rotation of the polar vortex in the Arctic; light arrows indicate the location of the polar jet stream when meanders form and cold, Arctic air dips down to mid-latitudes. Image via L.S. Gardiner/UCAR.

Both of these wind features exist because of the large temperature difference between the cold Arctic and warmer areas farther south, known as the mid-latitudes. Uneven heating creates pressure differences, and air flows from high-pressure to low-pressure areas, creating winds. The spinning Earth then turns winds to the right in the northern hemisphere, creating these belts of westerlies.

Why cold air plunges south

Greenhouse gas emissions from human activities have warmed the globe by about 1.8 degrees Fahrenheit (1 degree C) over the past 50 years. However, the Arctic has warmed more than twice as much. Amplified Arctic warming is due mainly to dramatic melting of ice and snow in recent decades, which exposes darker ocean and land surfaces that absorb a lot more of the sun’s heat.

Because of rapid Arctic warming, the north/south temperature difference has diminished. This reduces pressure differences between the Arctic and mid-latitudes, weakening jet stream winds. And just as slow-moving rivers typically take a winding route, a slower-flowing jet stream tends to meander.

Large north/south undulations in the jet stream generate wave energy in the atmosphere. If they are wavy and persistent enough, the energy can travel upward and disrupt the stratospheric polar vortex. Sometimes this upper vortex becomes so distorted that it splits into two or more swirling eddies.

These “daughter” vortices tend to wander southward, bringing their very cold air with them and leaving behind a warmer-than-normal Arctic. One of these eddies will sit over North America this week, delivering bone-chilling temperatures to much of the nation.

Deep freezes in a warming world

Splits in the stratospheric polar vortex do happen naturally, but should we expect to see them more often thanks to climate change and rapid Arctic warming? It is possible that these cold intrusions could become a more regular winter story. This is a hot research topic and is by no means settled, but a handful of studies offer compelling evidence that the stratospheric polar vortex is changing, and that this trend can explain bouts of unusually cold winter weather.

Undoubtedly this new polar vortex attack will unleash fresh claims that global warming is a hoax. But this ridiculous notion can be quickly dispelled with a look at predicted temperature departures around the globe for early this week. The lobe of cold air over North America is far outweighed by areas elsewhere in the United States and worldwide that are warmer than normal.

Global map with bands of orange and red and spots of blue.

Predicted daily mean, near-surface temperature (C) differences from normal (relative to 1979-2000) for January 28-30, 2019. Data from NOAA’s Global Forecast System model. Image via Climate Reanalyzer, Climate Change Institute, University of Maine.

Symptoms of a changing climate are not always obvious or easy to understand, but their causes and future behaviors are increasingly coming into focus. And it’s clear that at times, coping with global warming means arming ourselves with extra scarfs, mittens and long underwear.

Jennifer Francis, Visiting Professor, Rutgers University

Bottom line: A scientist explains how the frigid polar vortex of January 2019 is connected to global warming.

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

The Conversation



from EarthSky http://bit.ly/2BepRh7
People in big hooded coats and gloves

Bundled up against the cold in downtown Chicago, Sunday, January 27, 2019. Image via AP Photo/Nam Y. Huh.

By Jennifer Francis, Rutgers University

A record-breaking cold wave is sending literal shivers down the spines of millions of Americans. Temperatures across the upper Midwest are forecast to fall an astonishing 50 degrees Fahrenheit (28 degrees C) below normal this week – as low as 35 degrees below zero. Pile a gusty wind on top, and the air will feel like -60 degrees F (-51 degrees C).

Map of the United States with colored bands of purple and blue.

Predicted near-surface air temperatures (F) for Wednesday morning, January 30, 2019. Forecast by NOAA’s Global Forecast System model. Image via Pivotal Weather.

This cold is nothing to sneeze at. The National Weather Service is warning of brutal, life-threatening conditions. Frostbite will strike fast on any exposed skin. At the same time, the North Pole is facing a heat wave with temperatures approaching the freezing point – about 25 degrees Fahrenheit (14 degrees C) above normal.

Map of North America and Arctic with blobs of red and blue.

Predicted near-surface air temperature differences (C) from normal, relative to 1981-2010. Image via Pivotal Weather.

What is causing this topsy-turvy pattern? You guessed it: the polar vortex.

In the past several years, thanks to previous cold waves, the polar vortex has become entrenched in our everyday vocabulary and served as a butt of jokes for late-night TV hosts and politicians. But what is it really? Is it escaping from its usual Arctic haunts more often? And a question that looms large in my work: How does global warming fit into the story?

Rivers of air

Actually, there are two polar vortices in the Northern Hemisphere, stacked on top of each other. The lower one is usually and more accurately called the jet stream. It’s a meandering river of strong westerly winds around the Northern Hemisphere, about seven miles above Earth’s surface, near the height where jets fly.

The jet stream exists all year, and is responsible for creating and steering the high- and low-pressure systems that bring us our day-to-day weather: storms and blue skies, warm and cold spells. Way above the jet stream, around 30 miles above the Earth, is the stratospheric polar vortex. This river of wind also rings the North Pole, but only forms during winter, and is usually fairly circular.

Illustration of blue planet Earth with arrows.

Dark arrows indicate rotation of the polar vortex in the Arctic; light arrows indicate the location of the polar jet stream when meanders form and cold, Arctic air dips down to mid-latitudes. Image via L.S. Gardiner/UCAR.

Both of these wind features exist because of the large temperature difference between the cold Arctic and warmer areas farther south, known as the mid-latitudes. Uneven heating creates pressure differences, and air flows from high-pressure to low-pressure areas, creating winds. The spinning Earth then turns winds to the right in the northern hemisphere, creating these belts of westerlies.

Why cold air plunges south

Greenhouse gas emissions from human activities have warmed the globe by about 1.8 degrees Fahrenheit (1 degree C) over the past 50 years. However, the Arctic has warmed more than twice as much. Amplified Arctic warming is due mainly to dramatic melting of ice and snow in recent decades, which exposes darker ocean and land surfaces that absorb a lot more of the sun’s heat.

Because of rapid Arctic warming, the north/south temperature difference has diminished. This reduces pressure differences between the Arctic and mid-latitudes, weakening jet stream winds. And just as slow-moving rivers typically take a winding route, a slower-flowing jet stream tends to meander.

Large north/south undulations in the jet stream generate wave energy in the atmosphere. If they are wavy and persistent enough, the energy can travel upward and disrupt the stratospheric polar vortex. Sometimes this upper vortex becomes so distorted that it splits into two or more swirling eddies.

These “daughter” vortices tend to wander southward, bringing their very cold air with them and leaving behind a warmer-than-normal Arctic. One of these eddies will sit over North America this week, delivering bone-chilling temperatures to much of the nation.

Deep freezes in a warming world

Splits in the stratospheric polar vortex do happen naturally, but should we expect to see them more often thanks to climate change and rapid Arctic warming? It is possible that these cold intrusions could become a more regular winter story. This is a hot research topic and is by no means settled, but a handful of studies offer compelling evidence that the stratospheric polar vortex is changing, and that this trend can explain bouts of unusually cold winter weather.

Undoubtedly this new polar vortex attack will unleash fresh claims that global warming is a hoax. But this ridiculous notion can be quickly dispelled with a look at predicted temperature departures around the globe for early this week. The lobe of cold air over North America is far outweighed by areas elsewhere in the United States and worldwide that are warmer than normal.

Global map with bands of orange and red and spots of blue.

Predicted daily mean, near-surface temperature (C) differences from normal (relative to 1979-2000) for January 28-30, 2019. Data from NOAA’s Global Forecast System model. Image via Climate Reanalyzer, Climate Change Institute, University of Maine.

Symptoms of a changing climate are not always obvious or easy to understand, but their causes and future behaviors are increasingly coming into focus. And it’s clear that at times, coping with global warming means arming ourselves with extra scarfs, mittens and long underwear.

Jennifer Francis, Visiting Professor, Rutgers University

Bottom line: A scientist explains how the frigid polar vortex of January 2019 is connected to global warming.

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

The Conversation



from EarthSky http://bit.ly/2BepRh7

Some summertime for you

Large, brilliant orange flower with black-dotted, back-curled petals and long, prominent stamens.

View larger at EarthSky Community Photos. | This tiger lily bloomed in Antoni Williams’ garden in Tokoroa, New Zealand, in January 2019. “We have a wonderful garden. Taken 30 years to complete (if it`s ever possible to complete a garden). This is one of my favorites.”

Sunflower, red petals surrounding ring of yellow dots around a black center.

View larger at EarthSky Community Photos. | Antoni’s garden also hosts a brilliant red volunteer sunflower. Antoni said, “Couldn’t capture it complete. Too tall! We didn’t plant these sunflowers, so don’t know where they came from.”



from EarthSky http://bit.ly/2MFx0eS
Large, brilliant orange flower with black-dotted, back-curled petals and long, prominent stamens.

View larger at EarthSky Community Photos. | This tiger lily bloomed in Antoni Williams’ garden in Tokoroa, New Zealand, in January 2019. “We have a wonderful garden. Taken 30 years to complete (if it`s ever possible to complete a garden). This is one of my favorites.”

Sunflower, red petals surrounding ring of yellow dots around a black center.

View larger at EarthSky Community Photos. | Antoni’s garden also hosts a brilliant red volunteer sunflower. Antoni said, “Couldn’t capture it complete. Too tall! We didn’t plant these sunflowers, so don’t know where they came from.”



from EarthSky http://bit.ly/2MFx0eS

Small telescopes detect missing link in planet evolution

A round space rock in the foreground, a distant sun in the background.

View larger. | Artist’s concept of newly discovered small object far from our sun, in the outer solar system, via NAOJ.

Astronomers in Japan report that they’ve detected a very small body – only 1.6 miles wide (2.6-km diameter) – at the edge of our solar system. They’re calling it a missing link in planet evolution. We know of multiple small bodies orbiting far from the sun, in the realm of what astronomers call the Kuiper Belt. The largest of the known Kuiper Belt Objects, or KBOs, are hundreds of miles wide. Some are smaller, like Ultima Thule, recently passed by the New Horizons spacecraft. However, this is the first time a body this small has been found. It’s so small that even the Hubble Space Telescope would not be able to spot it. Instead, astronomers detected it using two small, amateur telescopes, with the help of a distant star.

The astronomers described their work January 28, 2019, in the peer-reviewed journal Nature Astronomy. It was made possible by grants-in-aid from the Japan Society for the Promotion of Science and the support of the Miyako open-air school and the local community in Miyakojima-shi.

Ko Arimatsu at the National Astronomical Observatory of Japan led the research. His statement explained:

Kilometer-sized bodies like the one discovered have been predicted to exist for more than 70 years. These objects acted as an important step in the planet formation process between small initial amalgamations of dust and ice and the planets we see today.

The Edgeworth-Kuiper Belt is a collection of small celestial bodies located beyond Neptune’s orbit. The most famous Edgeworth-Kuiper Belt Object is Pluto. Edgeworth-Kuiper Belt Objects are believed to be remnants left over from the formation of the solar system. While small bodies like asteroids in the inner solar system have been altered by solar radiation, collisions, and the gravity of the planets over time; objects in the cold, dark, lonely Edgeworth-Kuiper Belt preserve the pristine conditions of the early solar system. Thus astronomers study them to learn about the beginning of the planet formation process.

Ultima Thule looks like 2 snowballs stuck together. It is pockmarked with craters.

Here’s Ultima Thule, a Kuiper Belt Object passed on January 1, 2019, by the New Horizons spacecraft. It’s roughly 19 miles (30 km) long, or about 1/60th the diameter of Pluto. Image via NASA/Johns Hopkins University Applied Physics Laboratory/Southwest Research Institute/Spaceflight Insider.

Kuiper Belt Objects as small as the one just discovered – only a few miles across – have been predicted to exist. But even the world’s largest telescopes can’t pick them up by looking directly at them; they are just too small and too dim. Ko Arimatsu and his team instead used the technique of watching for stellar occultations – the blocking of starlight by objects closer to us than the stars – to find this object. They monitored a large number of stars, watching for telltale dips in the stars’ light that would indicate unknown objects.

They called their team OASES (Organized Autotelescopes for Serendipitous Event Survey) and placed two small (28 cm – 11 inch) telescopes on the roof of the Miyako open-air school on Miyako Island, Miyakojima-shi, Okinawa Prefecture, Japan. They monitored approximately 2,000 stars for a total of 60 hours.

Analyzing the data, the team found an event consistent with a star appearing to dim as it is occulted by a 1.6-mile-wide (2.6-km-wide) object in the Kuiper Belt. They said this detection indicates that kilometer-sized Kuiper Belt Objects are more numerous than previously thought.

If so, this fact would support models where planetesimals – the early building blocks of planets – first grow slowly into kilometer-sized objects before runaway growth causes them to merge into planets.

Arimatsu said:

This is a real victory for little projects. Our team had less than 0.3 percent of the budget of large international projects. We didn’t even have enough money to build a second dome to protect our second telescope! Yet we still managed to make a discovery that is impossible for the big projects. Now that we know our system works, we will investigate the Edgeworth-Kuiper Belt in more detail. We also have our sights set on the still undiscovered Oort Cloud out beyond that.

Sphere of dots around our sun's family of known planets, with a disk of dots within the larger sphere.

Artist’s concept of the Kuiper Belt and the Oort Cloud, the distant icy realm of the solar system. Image via NASA.

Bottom line: Astronomers in Japan used two amateur-sized telescopes to discover a very small body in the Kuiper Belt.

Source: A kilometre-sized Kuiper belt object discovered by stellar occultation using amateur telescopes

Via National Astronomical Observatory of Japan



from EarthSky http://bit.ly/2sUT1gK
A round space rock in the foreground, a distant sun in the background.

View larger. | Artist’s concept of newly discovered small object far from our sun, in the outer solar system, via NAOJ.

Astronomers in Japan report that they’ve detected a very small body – only 1.6 miles wide (2.6-km diameter) – at the edge of our solar system. They’re calling it a missing link in planet evolution. We know of multiple small bodies orbiting far from the sun, in the realm of what astronomers call the Kuiper Belt. The largest of the known Kuiper Belt Objects, or KBOs, are hundreds of miles wide. Some are smaller, like Ultima Thule, recently passed by the New Horizons spacecraft. However, this is the first time a body this small has been found. It’s so small that even the Hubble Space Telescope would not be able to spot it. Instead, astronomers detected it using two small, amateur telescopes, with the help of a distant star.

The astronomers described their work January 28, 2019, in the peer-reviewed journal Nature Astronomy. It was made possible by grants-in-aid from the Japan Society for the Promotion of Science and the support of the Miyako open-air school and the local community in Miyakojima-shi.

Ko Arimatsu at the National Astronomical Observatory of Japan led the research. His statement explained:

Kilometer-sized bodies like the one discovered have been predicted to exist for more than 70 years. These objects acted as an important step in the planet formation process between small initial amalgamations of dust and ice and the planets we see today.

The Edgeworth-Kuiper Belt is a collection of small celestial bodies located beyond Neptune’s orbit. The most famous Edgeworth-Kuiper Belt Object is Pluto. Edgeworth-Kuiper Belt Objects are believed to be remnants left over from the formation of the solar system. While small bodies like asteroids in the inner solar system have been altered by solar radiation, collisions, and the gravity of the planets over time; objects in the cold, dark, lonely Edgeworth-Kuiper Belt preserve the pristine conditions of the early solar system. Thus astronomers study them to learn about the beginning of the planet formation process.

Ultima Thule looks like 2 snowballs stuck together. It is pockmarked with craters.

Here’s Ultima Thule, a Kuiper Belt Object passed on January 1, 2019, by the New Horizons spacecraft. It’s roughly 19 miles (30 km) long, or about 1/60th the diameter of Pluto. Image via NASA/Johns Hopkins University Applied Physics Laboratory/Southwest Research Institute/Spaceflight Insider.

Kuiper Belt Objects as small as the one just discovered – only a few miles across – have been predicted to exist. But even the world’s largest telescopes can’t pick them up by looking directly at them; they are just too small and too dim. Ko Arimatsu and his team instead used the technique of watching for stellar occultations – the blocking of starlight by objects closer to us than the stars – to find this object. They monitored a large number of stars, watching for telltale dips in the stars’ light that would indicate unknown objects.

They called their team OASES (Organized Autotelescopes for Serendipitous Event Survey) and placed two small (28 cm – 11 inch) telescopes on the roof of the Miyako open-air school on Miyako Island, Miyakojima-shi, Okinawa Prefecture, Japan. They monitored approximately 2,000 stars for a total of 60 hours.

Analyzing the data, the team found an event consistent with a star appearing to dim as it is occulted by a 1.6-mile-wide (2.6-km-wide) object in the Kuiper Belt. They said this detection indicates that kilometer-sized Kuiper Belt Objects are more numerous than previously thought.

If so, this fact would support models where planetesimals – the early building blocks of planets – first grow slowly into kilometer-sized objects before runaway growth causes them to merge into planets.

Arimatsu said:

This is a real victory for little projects. Our team had less than 0.3 percent of the budget of large international projects. We didn’t even have enough money to build a second dome to protect our second telescope! Yet we still managed to make a discovery that is impossible for the big projects. Now that we know our system works, we will investigate the Edgeworth-Kuiper Belt in more detail. We also have our sights set on the still undiscovered Oort Cloud out beyond that.

Sphere of dots around our sun's family of known planets, with a disk of dots within the larger sphere.

Artist’s concept of the Kuiper Belt and the Oort Cloud, the distant icy realm of the solar system. Image via NASA.

Bottom line: Astronomers in Japan used two amateur-sized telescopes to discover a very small body in the Kuiper Belt.

Source: A kilometre-sized Kuiper belt object discovered by stellar occultation using amateur telescopes

Via National Astronomical Observatory of Japan



from EarthSky http://bit.ly/2sUT1gK

How Titan cooked its atmosphere

Large featureless sphere with smaller, cratered sphere in the foreground.

Saturn’s large moon Titan, with its smaller moon Mimas in the foreground, as seen by the Cassini spacecraft in 2013. Titan’s atmosphere is thick and hazy, and mostly nitrogen, like Earth’s. Where did the nitrogen come from? Image via NASA/JPL-Caltech/Space Science Institute.

Titan is Saturn’s largest moon and, in many ways, seems more like a planet than a moon. It is eerily Earth-like, yet a very different world from Earth, with extreme cold and rivers, lakes and seas of liquid methane/ethane. Also, Titan is the only moon in the solar system that has a thick atmosphere, and, in that way, too, it’s reminiscent of the major planets in our solar system. Titan’s atmosphere is composed primarily of nitrogen, like Earth’s. Just how Titan’s atmosphere developed has been one of the long-standing mysteries of this bizarre world. 

EarthSky lunar calendars are cool! They make great gifts. Order now. Going fast!

A new peer-reviewed study sheds some light on this question. The study was published online in The Astrophysical Journal on January 22, 2019. The study – from the Southwest Research Institute (SwRI) – suggests that the nitrogen in Titan’s atmosphere originated from the “cooking” of organic material in the interior of the moon. Kelly Miller, a research scientist in SwRI’s Space Science and Engineering Division and lead author of the study, provided some background:

Titan is a very interesting moon because it has this very thick atmosphere, which makes it unique among moons in our solar system. It is also the only body in the solar system, other than Earth, that has large quantities of liquid on the surface. Titan, however, has liquid hydrocarbons instead of water.

A lot of organic chemistry is no doubt happening on Titan, so it’s an undeniable source of curiosity.

The main theory about Titan’s atmosphere has been that ammonia ice from comets was converted, by impacts or photochemistry, into nitrogen to form Titan’s atmosphere. While that may still be an important process, it neglects the effects of what we now know is a very substantial portion of comets: complex organic material.

Small machine suspended from parachute in foggy atmosphere above yellowish landscape.

Artist’s concept of the Huygens probe descending through Titan’s thick atmosphere before landing, in 2005. Image via NASA.

Miller’s study was inspired by a mission to a very different object – comet 67P/Churyumov-Gerasimenko – studied in detail by the European Space Agency’s Rosetta spacecraft. It turned out that the composition of the comet was about half-ice, one-quarter rock and one-quarter organic material. The comet’s composition could be significant in terms of figuring out how Titan’s atmosphere came to be, according to Miller:

Comets and primitive bodies in the outer solar system are really interesting because they’re thought to be leftover building blocks of the solar system. Those small bodies could be incorporated into larger bodies, like Titan, and the dense, organic-rich rocky material could be found in its core.

Fuzzy white streaks in Titan's atmosphere.

Titan as seen by Cassini’s radar, showing methane clouds in the atmosphere. Image via NASA/JPL-Caltech.

How exactly does all this apply to Titan? Miller compared thermal models of Titan’s interior to data from organic material in meteorites. The idea was to see how much gaseous material could be produced from meteorite impacts into Titan when it was first forming.

The result was that about half of the moon’s nitrogen and perhaps also most of its methane could be accounted for in this scenario. The organics would be “cooked” into Titan as it was forming a few billion years ago.

While primarily nitrogen, Titan’s atmosphere also contains about 5% methane, which can form organic compounds. Those organics are all over Titan today – both in the atmosphere (as haze) and coating the surface (including massive “dunes” of organic material).

Diagram, cutaway landscape, methane/ethane clouds floating above it.

Structure of Titan’s atmosphere, which is composed primarily of nitrogen and methane. Image via Anthony J. Colozza.

But Titan’s atmospheric methane supply still needs to be replenished somehow since the gas breaks down over time, and scientists are still not sure how that happens. On Earth, most methane comes from biology, but on Titan – given the extreme conditions – it is more likely to be primordial methane left over from when the moon first formed, similar to that found in the atmospheres of the ice giants Uranus and Neptune.

Some scientists, however, do think that primitive life of some kind is possible on Titan, perhaps in its methane/ethane lakes and seas or in the subsurface water ocean.

Bottom line: Titan’s thick nitrogen atmosphere is unique among moons in the solar system. The nitrogen may have been “cooked” inside Titan.

Source: Contributions from Accreted Organics to Titan’s Atmosphere: New Insights from Cometary and Chondritic Data

Via SwRI



from EarthSky http://bit.ly/2TlfDCu
Large featureless sphere with smaller, cratered sphere in the foreground.

Saturn’s large moon Titan, with its smaller moon Mimas in the foreground, as seen by the Cassini spacecraft in 2013. Titan’s atmosphere is thick and hazy, and mostly nitrogen, like Earth’s. Where did the nitrogen come from? Image via NASA/JPL-Caltech/Space Science Institute.

Titan is Saturn’s largest moon and, in many ways, seems more like a planet than a moon. It is eerily Earth-like, yet a very different world from Earth, with extreme cold and rivers, lakes and seas of liquid methane/ethane. Also, Titan is the only moon in the solar system that has a thick atmosphere, and, in that way, too, it’s reminiscent of the major planets in our solar system. Titan’s atmosphere is composed primarily of nitrogen, like Earth’s. Just how Titan’s atmosphere developed has been one of the long-standing mysteries of this bizarre world. 

EarthSky lunar calendars are cool! They make great gifts. Order now. Going fast!

A new peer-reviewed study sheds some light on this question. The study was published online in The Astrophysical Journal on January 22, 2019. The study – from the Southwest Research Institute (SwRI) – suggests that the nitrogen in Titan’s atmosphere originated from the “cooking” of organic material in the interior of the moon. Kelly Miller, a research scientist in SwRI’s Space Science and Engineering Division and lead author of the study, provided some background:

Titan is a very interesting moon because it has this very thick atmosphere, which makes it unique among moons in our solar system. It is also the only body in the solar system, other than Earth, that has large quantities of liquid on the surface. Titan, however, has liquid hydrocarbons instead of water.

A lot of organic chemistry is no doubt happening on Titan, so it’s an undeniable source of curiosity.

The main theory about Titan’s atmosphere has been that ammonia ice from comets was converted, by impacts or photochemistry, into nitrogen to form Titan’s atmosphere. While that may still be an important process, it neglects the effects of what we now know is a very substantial portion of comets: complex organic material.

Small machine suspended from parachute in foggy atmosphere above yellowish landscape.

Artist’s concept of the Huygens probe descending through Titan’s thick atmosphere before landing, in 2005. Image via NASA.

Miller’s study was inspired by a mission to a very different object – comet 67P/Churyumov-Gerasimenko – studied in detail by the European Space Agency’s Rosetta spacecraft. It turned out that the composition of the comet was about half-ice, one-quarter rock and one-quarter organic material. The comet’s composition could be significant in terms of figuring out how Titan’s atmosphere came to be, according to Miller:

Comets and primitive bodies in the outer solar system are really interesting because they’re thought to be leftover building blocks of the solar system. Those small bodies could be incorporated into larger bodies, like Titan, and the dense, organic-rich rocky material could be found in its core.

Fuzzy white streaks in Titan's atmosphere.

Titan as seen by Cassini’s radar, showing methane clouds in the atmosphere. Image via NASA/JPL-Caltech.

How exactly does all this apply to Titan? Miller compared thermal models of Titan’s interior to data from organic material in meteorites. The idea was to see how much gaseous material could be produced from meteorite impacts into Titan when it was first forming.

The result was that about half of the moon’s nitrogen and perhaps also most of its methane could be accounted for in this scenario. The organics would be “cooked” into Titan as it was forming a few billion years ago.

While primarily nitrogen, Titan’s atmosphere also contains about 5% methane, which can form organic compounds. Those organics are all over Titan today – both in the atmosphere (as haze) and coating the surface (including massive “dunes” of organic material).

Diagram, cutaway landscape, methane/ethane clouds floating above it.

Structure of Titan’s atmosphere, which is composed primarily of nitrogen and methane. Image via Anthony J. Colozza.

But Titan’s atmospheric methane supply still needs to be replenished somehow since the gas breaks down over time, and scientists are still not sure how that happens. On Earth, most methane comes from biology, but on Titan – given the extreme conditions – it is more likely to be primordial methane left over from when the moon first formed, similar to that found in the atmospheres of the ice giants Uranus and Neptune.

Some scientists, however, do think that primitive life of some kind is possible on Titan, perhaps in its methane/ethane lakes and seas or in the subsurface water ocean.

Bottom line: Titan’s thick nitrogen atmosphere is unique among moons in the solar system. The nitrogen may have been “cooked” inside Titan.

Source: Contributions from Accreted Organics to Titan’s Atmosphere: New Insights from Cometary and Chondritic Data

Via SwRI



from EarthSky http://bit.ly/2TlfDCu

Moon slides past 3 morning planets

Starting around January 30, 2019 – and through the morning of February 1 and possibly even February 2 – watch the slender waning crescent moon slide by the planets Jupiter, Venus and then Saturn.

Keep track of moon phases with EarthSky lunar calendars. Order now. Going fast!

On January 30, the moon rises first, followed by Jupiter, then Venus and then Saturn. Given clear skies and an unobstructed horizon in the direction of sunrise, it’ll be easy to catch the moon, Venus and Jupiter. These worlds rank as the second-brightest, third-brightest and fourth-brightest celestial bodies to light up the heavens, respectively, after the sun.

Then just keep watching. The planets and moon will still be there – and the lit side of the moon will still be pointing in the direction of Saturn – on January 31 and February 1.

Large saguaro cactus in foreground, with 2 bright dots - Venus and Jupiter - behind.

Eliot Herman caught Venus (brighter) and Jupiter on the morning of their conjunction (January 22, 2019). Note that, on the morning, Jupiter was below Venus as seen from U.S. latitudes. By the end of January, Jupiter is above Venus as seen from around the world.

Saturn is just now returning to the east before dawn, to begin its yearly trek across Earth’s skies. It’s not very prominent yet, and you might encounter haze or other murk near the horizon.

Thus Saturn will present more of a challenge, sitting, as it does, much closer to the sunrise horizon, with its luster tarnished by the glow of morning dawn. Although Saturn will be nowhere near as bright as the moon, Venus or Jupiter, the ringed planet nonetheless now shines as brightly as a 1st-magnitude star.

On any of these mornings, draw an imaginary line between Venus and Jupiter to spot Saturn near the horizon an hour or so before sunrise. That imaginary line will continue to work for you for awhile, even after the moon has disappeared into the sunrise glare.

If you can’t catch Saturn with the eye alone, try your luck with binoculars.

Want to know when the moon and planets rise into your sky? Click here if you live in the U.S. or Canada.

If you live elsewhere worldwide, click here.

Row of planets of different sizes ranging from tiny dots to large circles.

The planets of the solar system are scaled by size but not distance. Click here to find out planetary distances in astronomical units. Image via International Astronomical Union.

Note that – day by day – the moon shifts eastward (in the direction of sunrise). The lit side of the waning moon always points in the moon’s direction of travel in front of the stars and planets of the zodiac. In other words, the daily change of the moon’s position relative to the backdrop stars reveals how far the moon has traveled in its orbit around Earth.

In the time frame of one month, the moon swings through all the constellations of the zodiac and sweeps by every planet of the solar system. The moon does not actually come close to any of these planets, however. For a day or two each month, the moon and a particular planet more or less align on the sky’s dome, but are not truly close together in space. Click here to know the present distance of the moon (in Earth-radii) from Earth and the present distances of the planets (in astronomical units) from Earth. Incidentally, one astronomical unit = 23,455 Earth-radii.

Now and again, the moon occults – passes directly in front of – a bright star or solar system planet. The moon will occult Venus on January 31, 2019; click here for more about the Venus occultation.

Worldwide map with lines and ovals showing where the occultation will be visible.

For the most part, the lunar occultation of Venus takes place over the Pacific Ocean. The red dotted line depicts where the occultation occurs in daytime, blue at twilight and white in a dark sky. Worldwide map via IOTA.

The moon will occult Saturn on February 2, 2019; click here for more about the Saturn occultation.

Note that you have to be at just the right place on Earth to witness either occultation.

Line of dots by moon, middle ones missing because that is where Venus was behind the moon.

From some parts of the world, the moon passed in front of Venus on September 18, 2017. Mazamir Mazlan of Telok Kemang Observatory in Malaysia caught the near occultation – with Venus sweeping to one side of the moon. Beautiful, yes? On January 31, 2019, from some parts of the world, the moon will occult Venus again. Click here for more about the Venus occultation.

Bottom line: No matter where you live on Earth, let the slender waning crescent moon guide your eye to Jupiter and Venus (and possibly Saturn) before sunup in late January and early February 2019.



from EarthSky http://bit.ly/2DH1ASG

Starting around January 30, 2019 – and through the morning of February 1 and possibly even February 2 – watch the slender waning crescent moon slide by the planets Jupiter, Venus and then Saturn.

Keep track of moon phases with EarthSky lunar calendars. Order now. Going fast!

On January 30, the moon rises first, followed by Jupiter, then Venus and then Saturn. Given clear skies and an unobstructed horizon in the direction of sunrise, it’ll be easy to catch the moon, Venus and Jupiter. These worlds rank as the second-brightest, third-brightest and fourth-brightest celestial bodies to light up the heavens, respectively, after the sun.

Then just keep watching. The planets and moon will still be there – and the lit side of the moon will still be pointing in the direction of Saturn – on January 31 and February 1.

Large saguaro cactus in foreground, with 2 bright dots - Venus and Jupiter - behind.

Eliot Herman caught Venus (brighter) and Jupiter on the morning of their conjunction (January 22, 2019). Note that, on the morning, Jupiter was below Venus as seen from U.S. latitudes. By the end of January, Jupiter is above Venus as seen from around the world.

Saturn is just now returning to the east before dawn, to begin its yearly trek across Earth’s skies. It’s not very prominent yet, and you might encounter haze or other murk near the horizon.

Thus Saturn will present more of a challenge, sitting, as it does, much closer to the sunrise horizon, with its luster tarnished by the glow of morning dawn. Although Saturn will be nowhere near as bright as the moon, Venus or Jupiter, the ringed planet nonetheless now shines as brightly as a 1st-magnitude star.

On any of these mornings, draw an imaginary line between Venus and Jupiter to spot Saturn near the horizon an hour or so before sunrise. That imaginary line will continue to work for you for awhile, even after the moon has disappeared into the sunrise glare.

If you can’t catch Saturn with the eye alone, try your luck with binoculars.

Want to know when the moon and planets rise into your sky? Click here if you live in the U.S. or Canada.

If you live elsewhere worldwide, click here.

Row of planets of different sizes ranging from tiny dots to large circles.

The planets of the solar system are scaled by size but not distance. Click here to find out planetary distances in astronomical units. Image via International Astronomical Union.

Note that – day by day – the moon shifts eastward (in the direction of sunrise). The lit side of the waning moon always points in the moon’s direction of travel in front of the stars and planets of the zodiac. In other words, the daily change of the moon’s position relative to the backdrop stars reveals how far the moon has traveled in its orbit around Earth.

In the time frame of one month, the moon swings through all the constellations of the zodiac and sweeps by every planet of the solar system. The moon does not actually come close to any of these planets, however. For a day or two each month, the moon and a particular planet more or less align on the sky’s dome, but are not truly close together in space. Click here to know the present distance of the moon (in Earth-radii) from Earth and the present distances of the planets (in astronomical units) from Earth. Incidentally, one astronomical unit = 23,455 Earth-radii.

Now and again, the moon occults – passes directly in front of – a bright star or solar system planet. The moon will occult Venus on January 31, 2019; click here for more about the Venus occultation.

Worldwide map with lines and ovals showing where the occultation will be visible.

For the most part, the lunar occultation of Venus takes place over the Pacific Ocean. The red dotted line depicts where the occultation occurs in daytime, blue at twilight and white in a dark sky. Worldwide map via IOTA.

The moon will occult Saturn on February 2, 2019; click here for more about the Saturn occultation.

Note that you have to be at just the right place on Earth to witness either occultation.

Line of dots by moon, middle ones missing because that is where Venus was behind the moon.

From some parts of the world, the moon passed in front of Venus on September 18, 2017. Mazamir Mazlan of Telok Kemang Observatory in Malaysia caught the near occultation – with Venus sweeping to one side of the moon. Beautiful, yes? On January 31, 2019, from some parts of the world, the moon will occult Venus again. Click here for more about the Venus occultation.

Bottom line: No matter where you live on Earth, let the slender waning crescent moon guide your eye to Jupiter and Venus (and possibly Saturn) before sunup in late January and early February 2019.



from EarthSky http://bit.ly/2DH1ASG

Star-hop from Orion to Planet 9

Above image of Planet 9’s path via Wikipedia

Tonight, let the constellation Orion the Hunter show you the approximate position of the hypothetical Planet 9 in the starry sky. As of now, nobody has yet seen this hypothetical solar system planet, which, if it exists, is large and very distant. But – still, hypothetically speaking – there are reasons to believe it does exist, and so for astronomers and citizen scientists … the hunt is on.

Two Caltech astronomers – Mike Brown and Konstantin Batygin – claim to have solid theoretical evidence for a 9th major planet in the outer solar system moving in a bizarre, highly elongated orbit. Recently, however, some astronomers have offered an alternative explanation to their data, saying it doesn’t necessitate the presence of a Planet 9.

Mystery orbits don’t require a Planet 9, researchers say

The astronomer Scott S. Sheppard guesses this planet might shine somewhere between 23rd and 25th magnitude, making this world about 6 to 40 million times fainter than the faintest celestial object visible to the unaided eye. Still, it’s fun to imagine the place in the sky where astronomers are searching for Planet 9.

The sky chart at the top of this post shows that location. The chart, which is via Wikipedia, shows Planet 9‘s possible path across our sky, in front of the backdrop stars, from the years 1000 to 3000 AD.

Although this world, if it exits, is way beyond the range of our backyard telescopes, we can still star-hop from the constellation Orion to Planet 9’s possible location in the starry sky.

From around the world at this time of year, the constellation Orion climbs highest up for the night around mid-evening (9 to 10 p.m.) local time. From temperate latitudes in the Northern Hemisphere, Orion appears in the southern sky at mid-evening. From the equator, Orion appears high overhead, and from temperate regions in the Southern Hemisphere, an “upside-down” Orion shines in the northern sky.

Some of you may know how to star-hop from Orion’s Belt to Aldebaran, the brightest star in the constellation Taurus the Bull. If not, refer to the sky chart below. Once you’ve found Aldebaran, you’ve pretty much found the proposed location of Planet 9, which – again, if it exists, and if astronomers are right about its location in our solar system – lodges pretty much directly east of Orion’s Belt and directly south of the star Aldebaran.

Use Orion’s Belt to star-hop to the star Aldebaran.

Caltech astronomers first announced a hypothetical Planet 9 on January 20, 2016. What they called “solid theoretical evidence” exists for a giant planet – a 9th major planet in the outer solar system – moving in what they called a “bizarre, highly elongated orbit.” They nicknamed it Planet 9 then, and they said hoped other astronomers would search for it.

If it exists, the planet has a mass about 10 times that of Earth and orbits about 20 times farther from the sun on average than Neptune, which is currently the 8th major planet and which orbits the sun at an average distance of 2.8 billion miles (4.5 billion km).

The astronomers say it would take this new planet between 10,000 and 20,000 years to make just one full orbit around the sun.

The orbits of 6 extreme trans-Neptunian objects (in magenta), all mysteriously aligned in one direction. These orbits were used by Caltech astronomers to hypothesize a Planet 9 (in orange). Image via Caltech/ R. Hurt (IPAC).

Read more: Solid evidence for a 9th planet

Bottom line: Astronomers are searching for a hypothetical Planet 9 in the starry sky. You can use the constellation Orion to show you approximately where they’re looking.



from EarthSky http://bit.ly/2WoEkjv

Above image of Planet 9’s path via Wikipedia

Tonight, let the constellation Orion the Hunter show you the approximate position of the hypothetical Planet 9 in the starry sky. As of now, nobody has yet seen this hypothetical solar system planet, which, if it exists, is large and very distant. But – still, hypothetically speaking – there are reasons to believe it does exist, and so for astronomers and citizen scientists … the hunt is on.

Two Caltech astronomers – Mike Brown and Konstantin Batygin – claim to have solid theoretical evidence for a 9th major planet in the outer solar system moving in a bizarre, highly elongated orbit. Recently, however, some astronomers have offered an alternative explanation to their data, saying it doesn’t necessitate the presence of a Planet 9.

Mystery orbits don’t require a Planet 9, researchers say

The astronomer Scott S. Sheppard guesses this planet might shine somewhere between 23rd and 25th magnitude, making this world about 6 to 40 million times fainter than the faintest celestial object visible to the unaided eye. Still, it’s fun to imagine the place in the sky where astronomers are searching for Planet 9.

The sky chart at the top of this post shows that location. The chart, which is via Wikipedia, shows Planet 9‘s possible path across our sky, in front of the backdrop stars, from the years 1000 to 3000 AD.

Although this world, if it exits, is way beyond the range of our backyard telescopes, we can still star-hop from the constellation Orion to Planet 9’s possible location in the starry sky.

From around the world at this time of year, the constellation Orion climbs highest up for the night around mid-evening (9 to 10 p.m.) local time. From temperate latitudes in the Northern Hemisphere, Orion appears in the southern sky at mid-evening. From the equator, Orion appears high overhead, and from temperate regions in the Southern Hemisphere, an “upside-down” Orion shines in the northern sky.

Some of you may know how to star-hop from Orion’s Belt to Aldebaran, the brightest star in the constellation Taurus the Bull. If not, refer to the sky chart below. Once you’ve found Aldebaran, you’ve pretty much found the proposed location of Planet 9, which – again, if it exists, and if astronomers are right about its location in our solar system – lodges pretty much directly east of Orion’s Belt and directly south of the star Aldebaran.

Use Orion’s Belt to star-hop to the star Aldebaran.

Caltech astronomers first announced a hypothetical Planet 9 on January 20, 2016. What they called “solid theoretical evidence” exists for a giant planet – a 9th major planet in the outer solar system – moving in what they called a “bizarre, highly elongated orbit.” They nicknamed it Planet 9 then, and they said hoped other astronomers would search for it.

If it exists, the planet has a mass about 10 times that of Earth and orbits about 20 times farther from the sun on average than Neptune, which is currently the 8th major planet and which orbits the sun at an average distance of 2.8 billion miles (4.5 billion km).

The astronomers say it would take this new planet between 10,000 and 20,000 years to make just one full orbit around the sun.

The orbits of 6 extreme trans-Neptunian objects (in magenta), all mysteriously aligned in one direction. These orbits were used by Caltech astronomers to hypothesize a Planet 9 (in orange). Image via Caltech/ R. Hurt (IPAC).

Read more: Solid evidence for a 9th planet

Bottom line: Astronomers are searching for a hypothetical Planet 9 in the starry sky. You can use the constellation Orion to show you approximately where they’re looking.



from EarthSky http://bit.ly/2WoEkjv

Michael Peres on how to photograph snowflakes

Michael Peres uses a black velvet catch tray to capture falling snowflakes. Photo appears courtesy of Michael Peres.

Michael Peres is a professor of biomedical photographic communications at the Rochester Institute of Technology in New York. He’s also an award-winning photo-educator, author, and science photographer, with work featured by CNN, Time, the Weather Channel, Nikon, and Mashable. EarthSky spoke with him via email in January, 2019, to learn more about his amazing photographs.

How did you get interested in photographing snowflakes?

In the winter of 2003–2004, one of my students visited an exhibition of Wilson Snowflake Bentley photographs on display at the Buffalo Museum and Science Center. Her excitement about trying to photograph snowflakes was contagious and within a short period of time on a wintry day in January, my microscopy class moved our gear outside and we tried. Little did I know how infectious the experience would be for me personally. Now, more than 15 years later, I am obsessed with the challenge during the long and snowy Rochester, New York, winters. Rochester on average can receive more than 105 inches of snow per season. One could speculate that amount of snow would provide ample subjects and chances to photograph unique and interesting ice crystals.

Long-armed feathery snowflake.

Snowflake photographed by Michael Peres during a January 19, 2019, snowstorm. Photo appears courtesy of Michael Peres.

Hexagonal flat plate snowflake.

Plate-shaped snow crystal photographed by Michael Peres during a January 19, 2019, snowstorm. Photo appears courtesy of Michael Peres.

Extremely intricate snowflake.

Dendritic-shaped snow crystal photographed by Michael Peres during a January 19, 2019, snowstorm. Photo appears courtesy of Michael Peres.

Snowflakes come in a variety of different shapes. What are some of your favorite shapes to photograph?

During the course of any winter, a wide variety of crystal types fall. My methods and equipment are focused towards photographing crystals that are 1 to 2 millimeters in size and are dendritic [“tree-like”]. All snowflakes start out as water molecules that form hexagons in the right conditions. These embryonic crystals are called stellar plates. They can be infinitely small, but they grow and add water molecules over time. At some time during their formation, they grow wings and other intricate structures. When this happens they become dendritic flakes. They are my favorite crystals to photograph. It has been my experience that I have the best luck when the air temperatures are between 15 and 25 degrees Fahrenheit [about -10 to -5 degrees Celsius].. During the course of a winter, each storm can bring a wide range of crystal types including columns, capped columns, needles, and granular snow to share a few types of crystals that can fall.

Pointing with a needle at a tiny snowflake lying on black velvet.

Technique used to select a snowflake to photograph. Photo appears courtesy of Michael Peres.

Large, complex microscope with a lot of attachments.

The microscope used by Professor Peres to photograph snowflakes. Photo appears courtesy of Michael Peres.

Can you describe the general process you use to take a photograph of a snowflake?

My process starts by frequently watching the weather forecasts. My equipment is kept outside in the garage. Photographing ice crystals requires that everything I use be kept below 32 degrees Fahrenheit [0 Celsius]. I keep an inventory of glass slides with my microscope, and I use a fiber optic light source. Being a snowflake photographer is much like being a fireman and ready at a moment’s notice when things happen. These events can be at night, in the day, when I am at work, and when I am indisposed or when I am ready. When good crystals fall and I am available, I start my photographing.

I catch crystals that are falling using a baking tray with a piece of black velvet draped over the tray. Velvet is useful for isolating the best crystals but also allows for easy retrieval using a small needle taped to a pencil. Depending on the humidity and air temperatures, there is a natural static electricity in the needle and crystal. It allows me to lift the crystal using the needle because they are attracted to one another giving me a chance to position the crystal onto a clear glass slide. It is possible to photograph the crystals in the tray on the fabric but I prefer the isolation against a lighter background and have the opportunity to light from underneath.

I use a low power simple microscope. Basically, the microscope is a repurposed industrial macro stand. I use a 16- or 25-millimeter macro lens and the camera has a bellows. Attached to the bellows (extension tubes can also be used) is a DSLR camera body without a lens.

Once an interesting crystal has been identified in my catch tray, I move it to a glass slide using the needle on the pencil. The slide is placed onto the microscope’s focusing stage where I can compose and focus the image in the viewfinder of the camera.

I use a fiber optic illuminator with a bifurcated gooseneck light guide that illuminates the crystals. I shine light onto a variety of materials located below the stage to provide contrast and color to the light that is refracted into the crystal used to reveal the crystal’s facets.

Hexagonal plate with hexagonal arms on each side.

Snowflake photograph from Michael Peres’s RIT snowflake gallery. Image via Michael Peres, RIT.

Any tips for those of us who have been trying to capture a good snowflake photograph with a macro lens? I for one am wondering if some temperatures are better than others for taking snowflake photos, and how on Earth do I keep my hands warm?

It is possible to photograph snowflakes with a smartphone or DSLR. The features and advantages of each camera are pretty clear. The smartphone has a pretty good sensor but focusing the lens, exposure management, and ability to magnify sometimes 1-millimeter crystals are real obstacles. There are accessory lenses that can be added to the smartphone. Photojojo is an excellent vendor of such lenses.

DSLR cameras are significantly better choices for this work and are equipped with a macro lens capable of at least 1:1. Canon sells a 65-millimeter macro lens that can achieve 5:1 magnification. Adding extension tubes or by using a simple bellows, you can increase the image size that the camera system produces. My typical crystals benefit from a 3 to 6x magnification.

I dress warmly for this work wearing many layers including insulated boots. I use gloves with finger holes but because of the delicate nature of focusing a microscope, moving the crystal in small increments, I benefit from more control and feel having nothing on my hands. Because of the adrenaline, I can typically work for up to 30 minutes before my hands cannot tolerate the conditions any longer.

I photograph using a medium aperture such as ƒ/5.6. Diffraction at these image sizes can cause the crystals to become less defined if I use a smaller aperture. Often I photograph wide open and create increased DOF images.

Feathery snowflake.

Snowflake photograph from Michael Peres’s RIT snowflake gallery. Image via Michael Peres, RIT.

Many thanks to Professor Peres for discussing his snowflake photography with EarthSky. More examples of his work can be viewed on his Instagram account @michael_peres and on his website at the Rochester Institute of Technology (RIT).

Want more? You can read about the attempts one of EarthSky’s intrepid contributors to photograph snowflakes in the archive here.

See some recent favorite snowflake photos from the EarthSky Community

If this post inspires you to give snowflake photography a shot, please submit your photos to EarthSky Community Photos! We love seeing and sharing your recent captures of the natural world!

Bottom line: How to take photos of snowflakes with Professor Michael Peres of the Rochester Institute of Technology.



from EarthSky http://bit.ly/2B9Uhku

Michael Peres uses a black velvet catch tray to capture falling snowflakes. Photo appears courtesy of Michael Peres.

Michael Peres is a professor of biomedical photographic communications at the Rochester Institute of Technology in New York. He’s also an award-winning photo-educator, author, and science photographer, with work featured by CNN, Time, the Weather Channel, Nikon, and Mashable. EarthSky spoke with him via email in January, 2019, to learn more about his amazing photographs.

How did you get interested in photographing snowflakes?

In the winter of 2003–2004, one of my students visited an exhibition of Wilson Snowflake Bentley photographs on display at the Buffalo Museum and Science Center. Her excitement about trying to photograph snowflakes was contagious and within a short period of time on a wintry day in January, my microscopy class moved our gear outside and we tried. Little did I know how infectious the experience would be for me personally. Now, more than 15 years later, I am obsessed with the challenge during the long and snowy Rochester, New York, winters. Rochester on average can receive more than 105 inches of snow per season. One could speculate that amount of snow would provide ample subjects and chances to photograph unique and interesting ice crystals.

Long-armed feathery snowflake.

Snowflake photographed by Michael Peres during a January 19, 2019, snowstorm. Photo appears courtesy of Michael Peres.

Hexagonal flat plate snowflake.

Plate-shaped snow crystal photographed by Michael Peres during a January 19, 2019, snowstorm. Photo appears courtesy of Michael Peres.

Extremely intricate snowflake.

Dendritic-shaped snow crystal photographed by Michael Peres during a January 19, 2019, snowstorm. Photo appears courtesy of Michael Peres.

Snowflakes come in a variety of different shapes. What are some of your favorite shapes to photograph?

During the course of any winter, a wide variety of crystal types fall. My methods and equipment are focused towards photographing crystals that are 1 to 2 millimeters in size and are dendritic [“tree-like”]. All snowflakes start out as water molecules that form hexagons in the right conditions. These embryonic crystals are called stellar plates. They can be infinitely small, but they grow and add water molecules over time. At some time during their formation, they grow wings and other intricate structures. When this happens they become dendritic flakes. They are my favorite crystals to photograph. It has been my experience that I have the best luck when the air temperatures are between 15 and 25 degrees Fahrenheit [about -10 to -5 degrees Celsius].. During the course of a winter, each storm can bring a wide range of crystal types including columns, capped columns, needles, and granular snow to share a few types of crystals that can fall.

Pointing with a needle at a tiny snowflake lying on black velvet.

Technique used to select a snowflake to photograph. Photo appears courtesy of Michael Peres.

Large, complex microscope with a lot of attachments.

The microscope used by Professor Peres to photograph snowflakes. Photo appears courtesy of Michael Peres.

Can you describe the general process you use to take a photograph of a snowflake?

My process starts by frequently watching the weather forecasts. My equipment is kept outside in the garage. Photographing ice crystals requires that everything I use be kept below 32 degrees Fahrenheit [0 Celsius]. I keep an inventory of glass slides with my microscope, and I use a fiber optic light source. Being a snowflake photographer is much like being a fireman and ready at a moment’s notice when things happen. These events can be at night, in the day, when I am at work, and when I am indisposed or when I am ready. When good crystals fall and I am available, I start my photographing.

I catch crystals that are falling using a baking tray with a piece of black velvet draped over the tray. Velvet is useful for isolating the best crystals but also allows for easy retrieval using a small needle taped to a pencil. Depending on the humidity and air temperatures, there is a natural static electricity in the needle and crystal. It allows me to lift the crystal using the needle because they are attracted to one another giving me a chance to position the crystal onto a clear glass slide. It is possible to photograph the crystals in the tray on the fabric but I prefer the isolation against a lighter background and have the opportunity to light from underneath.

I use a low power simple microscope. Basically, the microscope is a repurposed industrial macro stand. I use a 16- or 25-millimeter macro lens and the camera has a bellows. Attached to the bellows (extension tubes can also be used) is a DSLR camera body without a lens.

Once an interesting crystal has been identified in my catch tray, I move it to a glass slide using the needle on the pencil. The slide is placed onto the microscope’s focusing stage where I can compose and focus the image in the viewfinder of the camera.

I use a fiber optic illuminator with a bifurcated gooseneck light guide that illuminates the crystals. I shine light onto a variety of materials located below the stage to provide contrast and color to the light that is refracted into the crystal used to reveal the crystal’s facets.

Hexagonal plate with hexagonal arms on each side.

Snowflake photograph from Michael Peres’s RIT snowflake gallery. Image via Michael Peres, RIT.

Any tips for those of us who have been trying to capture a good snowflake photograph with a macro lens? I for one am wondering if some temperatures are better than others for taking snowflake photos, and how on Earth do I keep my hands warm?

It is possible to photograph snowflakes with a smartphone or DSLR. The features and advantages of each camera are pretty clear. The smartphone has a pretty good sensor but focusing the lens, exposure management, and ability to magnify sometimes 1-millimeter crystals are real obstacles. There are accessory lenses that can be added to the smartphone. Photojojo is an excellent vendor of such lenses.

DSLR cameras are significantly better choices for this work and are equipped with a macro lens capable of at least 1:1. Canon sells a 65-millimeter macro lens that can achieve 5:1 magnification. Adding extension tubes or by using a simple bellows, you can increase the image size that the camera system produces. My typical crystals benefit from a 3 to 6x magnification.

I dress warmly for this work wearing many layers including insulated boots. I use gloves with finger holes but because of the delicate nature of focusing a microscope, moving the crystal in small increments, I benefit from more control and feel having nothing on my hands. Because of the adrenaline, I can typically work for up to 30 minutes before my hands cannot tolerate the conditions any longer.

I photograph using a medium aperture such as ƒ/5.6. Diffraction at these image sizes can cause the crystals to become less defined if I use a smaller aperture. Often I photograph wide open and create increased DOF images.

Feathery snowflake.

Snowflake photograph from Michael Peres’s RIT snowflake gallery. Image via Michael Peres, RIT.

Many thanks to Professor Peres for discussing his snowflake photography with EarthSky. More examples of his work can be viewed on his Instagram account @michael_peres and on his website at the Rochester Institute of Technology (RIT).

Want more? You can read about the attempts one of EarthSky’s intrepid contributors to photograph snowflakes in the archive here.

See some recent favorite snowflake photos from the EarthSky Community

If this post inspires you to give snowflake photography a shot, please submit your photos to EarthSky Community Photos! We love seeing and sharing your recent captures of the natural world!

Bottom line: How to take photos of snowflakes with Professor Michael Peres of the Rochester Institute of Technology.



from EarthSky http://bit.ly/2B9Uhku