January guide to the bright planets

The New Year starts with the waning crescent moon cruising down a cascade of morning planets, ambling by Venus first, Jupiter next and Mercury last. Read more

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

The New Year starts with the waning crescent moon cruising down a cascade of morning planets, ambling by Venus first, Jupiter next and Mercury last. Read more

Venus is the brightest planet, beaming mightily in the east before sunrise. This world will reach a milestone in the morning sky on January 5 or 6, 2019, depending on your time zone, as this blazing world reaches its greatest elongation from the sun. In other words, January 2019 is a great month for watching Venus in the morning sky.

Depending on your time zone, Venus will reach its greatest morning elongation on January 5 or 6, 2019, the same date that the new moon partially eclipses the sun. Read more.

The month starts out with Venus shining above Jupiter in the morning sky, yet the month ends with Jupiter shining above Venus. Day by day, Jupiter 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 January 22, 2019.

After this month, Venus will spend less time in the predawn sky but will still be plenty visible at dawn. 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.

Watch for the waning crescent moon to join Venus in the morning sky for a few days, centered on or near New Year’s Day. Then, at the month’s end, watch for the waning crescent to pair up with Venus again around January 31.

At mid-northern latitudes, Venus rises about 3 1/2 hours before sunrise in early January. By the month’s end, that’ll taper to about 3 hours.

At temperate latitudes in the Southern Hemisphere, Venus rises about 3 hours before sunup in early January. By the month’s end, that’ll increase to nearly 3 1/2 hours.

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

The two brightest planets – Venus and Jupiter – meet up for a conjunction on January 22, 2019. Read more.

Jupiter is the second-brightest planet, after Venus. The king planet is found below Venus in the predawn/dawn sky at the beginning of the month, yet above Venus at the month’s end. The two will meet up for a conjunction in the morning sky on January 22, 2019, or one month after the Jupiter/Mercury conjunction in the morning sky on December 21, 2018.

If you’re up during the predawn hours, you may 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 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 2 or 3, and then to revisit Jupiter near the month’s end, on January 30 and 31.

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

From temperate latitudes in the Southern Hemisphere, Jupiter comes up about 2 hours before sunrise at the beginning of the month. By the month’s end, it’s around 3 1/2 hours.

Near the month’s end, use the waning crescent moon and the two dazzling morning planets, Venus and Jupiter, to help guide your eye to Saturn. Read more.

Saturn swings over to the morning sky on January 2, 2019, leaving Mars as the only bright planet to adorn the January 2019 evening sky. For the most part, Saturn remains hidden in the glare of sunrise until the month’s end. Starting on or near January 30, use the waning crescent moon and the two brilliant planets, Venus and Jupiter, to help guide you to Saturn’s place near the horizon as darkness begins to give way to dawn.

Mercury and Saturn actually have a conjunction in the morning sky on January 13, 2019. But these two worlds will be so deeply buried in the glare of morning twilight that they’ll be next to impossible to see.

The first several mornings of the New Year 2019 feature the waning crescent moon and three morning planets. You may need binoculars to catch Mercury. Read more

Mercury, the innermost planet of the solar system, reached its moment of glory in the morning sky with the conjunction of Mercury and Jupiter on December 21, 2018. In January 2019, your best chance of catching Mercury comes very early in the month. The slender waning crescent moon pairs up with Mercury on or near January 4, providing what may be your last chance to catch Mercury in the January morning sky. After that, Mercury quickly plunges sunward, to disappear in the glare of morning twilight.

Mercury will have shifted over to the evening sky by February 2019. 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.

Look for the moon to pair up with Mars for a few evenings, centered on or near January 12. Read more.

Mars is the only bright planet to appear in the January evening sky. Fortunately, though dimming somewhat through the month, Mars remains modestly-bright and beautiful, shining as brilliantly a 1st-magnitude star. Moreover, Mars stays out till late evening all throughout January 2019 in both the Northern and Southern Hemispheres.

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 January 12.

Once you’ve found Mars, you might want to try your luck with a much fainter planet planet, Uranus. 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.

Skywatcher, by Predrag Agatonovic.

Bottom line: In January 2019, Mars is the sole bright evening planet, while Venus and Jupiter lord over the morning sky. Mercury fades from view as a morning planet in early January whereas Saturn becomes visible near the month’s end. Click here for recommended almanacs; they can help you know when the planets rise, transit and set in your sky.

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

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

Help EarthSky keep going! Donate now.

from EarthSky http://bit.ly/1YD00CF

The New Year starts with the waning crescent moon cruising down a cascade of morning planets, ambling by Venus first, Jupiter next and Mercury last. Read more

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

The New Year starts with the waning crescent moon cruising down a cascade of morning planets, ambling by Venus first, Jupiter next and Mercury last. Read more

Venus is the brightest planet, beaming mightily in the east before sunrise. This world will reach a milestone in the morning sky on January 5 or 6, 2019, depending on your time zone, as this blazing world reaches its greatest elongation from the sun. In other words, January 2019 is a great month for watching Venus in the morning sky.

Depending on your time zone, Venus will reach its greatest morning elongation on January 5 or 6, 2019, the same date that the new moon partially eclipses the sun. Read more.

The month starts out with Venus shining above Jupiter in the morning sky, yet the month ends with Jupiter shining above Venus. Day by day, Jupiter 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 January 22, 2019.

After this month, Venus will spend less time in the predawn sky but will still be plenty visible at dawn. 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.

Watch for the waning crescent moon to join Venus in the morning sky for a few days, centered on or near New Year’s Day. Then, at the month’s end, watch for the waning crescent to pair up with Venus again around January 31.

At mid-northern latitudes, Venus rises about 3 1/2 hours before sunrise in early January. By the month’s end, that’ll taper to about 3 hours.

At temperate latitudes in the Southern Hemisphere, Venus rises about 3 hours before sunup in early January. By the month’s end, that’ll increase to nearly 3 1/2 hours.

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

The two brightest planets – Venus and Jupiter – meet up for a conjunction on January 22, 2019. Read more.

Jupiter is the second-brightest planet, after Venus. The king planet is found below Venus in the predawn/dawn sky at the beginning of the month, yet above Venus at the month’s end. The two will meet up for a conjunction in the morning sky on January 22, 2019, or one month after the Jupiter/Mercury conjunction in the morning sky on December 21, 2018.

If you’re up during the predawn hours, you may 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 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 2 or 3, and then to revisit Jupiter near the month’s end, on January 30 and 31.

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

From temperate latitudes in the Southern Hemisphere, Jupiter comes up about 2 hours before sunrise at the beginning of the month. By the month’s end, it’s around 3 1/2 hours.

Near the month’s end, use the waning crescent moon and the two dazzling morning planets, Venus and Jupiter, to help guide your eye to Saturn. Read more.

Saturn swings over to the morning sky on January 2, 2019, leaving Mars as the only bright planet to adorn the January 2019 evening sky. For the most part, Saturn remains hidden in the glare of sunrise until the month’s end. Starting on or near January 30, use the waning crescent moon and the two brilliant planets, Venus and Jupiter, to help guide you to Saturn’s place near the horizon as darkness begins to give way to dawn.

Mercury and Saturn actually have a conjunction in the morning sky on January 13, 2019. But these two worlds will be so deeply buried in the glare of morning twilight that they’ll be next to impossible to see.

The first several mornings of the New Year 2019 feature the waning crescent moon and three morning planets. You may need binoculars to catch Mercury. Read more

Mercury, the innermost planet of the solar system, reached its moment of glory in the morning sky with the conjunction of Mercury and Jupiter on December 21, 2018. In January 2019, your best chance of catching Mercury comes very early in the month. The slender waning crescent moon pairs up with Mercury on or near January 4, providing what may be your last chance to catch Mercury in the January morning sky. After that, Mercury quickly plunges sunward, to disappear in the glare of morning twilight.

Mercury will have shifted over to the evening sky by February 2019. 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.

Look for the moon to pair up with Mars for a few evenings, centered on or near January 12. Read more.

Mars is the only bright planet to appear in the January evening sky. Fortunately, though dimming somewhat through the month, Mars remains modestly-bright and beautiful, shining as brilliantly a 1st-magnitude star. Moreover, Mars stays out till late evening all throughout January 2019 in both the Northern and Southern Hemispheres.

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 January 12.

Once you’ve found Mars, you might want to try your luck with a much fainter planet planet, Uranus. 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.

Skywatcher, by Predrag Agatonovic.

Bottom line: In January 2019, Mars is the sole bright evening planet, while Venus and Jupiter lord over the morning sky. Mercury fades from view as a morning planet in early January whereas Saturn becomes visible near the month’s end. Click here for recommended almanacs; they can help you know when the planets rise, transit and set in your sky.

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

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

Help EarthSky keep going! Donate now.

from EarthSky http://bit.ly/1YD00CF

Dark skies for 2019’s Quadrantid meteors

View larger. | In 2014, as the Quadrantids were flying, those at far northern latitudes were seeing auroras. Photo by Tommy Eliassen.

The Quadrantid meteor shower is 2019’s first major meteor shower. We’ll have moon-free skies for the peak this year, expected late night January 3 until dawn January 4. Although the Quadrantids have been known to produce some 50-100 meteors in a dark sky, their peak is extremely narrow, time-wise. Peaks of the Perseid or Geminid meteor showers persist for a day or more, allowing all time zones around the world to enjoy a good display of Perseids or Geminids. But the Quadrantids’ peak lasts only a few hours. So you have to be on the right part of Earth – preferably with the radiant high in your sky – in order to experience the peak of the Quadrantids. What’s more, the shower favors the Northern Hemisphere because its radiant point is so far north on the sky’s dome.

So you need some luck to see the Quadrantids, and being in the Northern Hemisphere does help. Who will see the 2019 shower? Keep in mind the prediction of the Quadrantid peak represents an educated guess, not an ironclad guarantee.

That said, in 2019, the International Meteor Organization gives the peak as January 4 at 2 UTC. If that prediction of the peak holds true, Europe – and areas of the globe surrounding Europe – have a good shot at viewing the shower at its best during the predawn hours on January 4.

Just know that meteor showers are notorious for defying the best-laid forecasts. Thus for the Quadrantids – as for any meteor shower – your best plan is simply to look for yourself.

Barry Simmons in Lake Martin, Alabama captured this Quadrantid meteor during the 2014 shower.

Anyplace at mid-northern and far-northern latitudes might be in a decent position to watch the Quadrantids in 2019, especially as there is no moonlight to ruin this year’s show.

There’s a new moon and partial solar eclipse on January 6, 2019, only two days after the predicted peak for the Quadrantids. You might see the slender waning crescent moon coming up shortly before sunrise January 4, but this fleeting and frail crescent won’t bother this year’s Quadrantid shower.

All other things being equal, for any meteor shower, you are likely to see the most meteors when the radiant is high in the sky.

In the case of the Quadrantid shower, the radiant point is seen highest in the sky in the dark hour before dawn.

From mid-northern latitudes, the radiant point for the Quadrantid shower doesn’t climb over the horizon until after midnight.

Where is the Quadrantids’ radiant point?

The radiant point of the Quadrantid shower makes an approximate right angle with the Big Dipper and the bright star Arcturus. If you trace the paths of the Quadrantid meteors backward, they appear to radiate from this point on the starry sky.

Now for our usual caveat. You don’t need to find the meteor shower radiant to see the Quadrantid meteors.

You just have to be at mid-northern or far-northern latitudes, up in the wee hours of the morning and hope the peak comes at just the right time to your part of the world.

The meteors will radiate from the northern sky, but appear in all parts of the sky.

The now-defunct constellation Quadrans Muralis, for which the Quadrantids are named. Image via Atlas Coelestis.

The Quadrantids are named for a constellation that no longer exists. Most meteor showers are named for the constellations from which they appear to radiate. So it is with the Quadrantids. But the Quadrantids’ constellation no longer exists, except in memory. The name Quadrantids comes from the constellation Quadrans Muralis (Mural Quadrant), created by the French astronomer Jerome Lalande in 1795. This now-obsolete constellation was located between the constellations of Bootes the Herdsman and Draco the Dragon. Where did it go?

To understand the history of the Quadrantids’ name, we have to go back to the earliest observations of this shower. In early January 1825, Antonio Brucalassi in Italy reported that:

… the atmosphere was traversed by a multitude of the luminous bodies known by the name of falling stars.

They appeared to radiate from Quadrans Muralis. In 1839, Adolphe Quetelet of Brussels Observatory in Belgium and Edward C. Herrick in Connecticut independently made the suggestion that the Quadrantids are an annual shower.

But, in 1922, the International Astronomical Union devised a list 88 modern constellations. The list was agreed upon by the International Astronomical Union at its inaugural General Assembly held in Rome in May 1922. It did not include a constellation Quadrans Muralis.

Today, this meteor shower retains the name Quadrantids, for the original and now obsolete constellation Quadrans Muralis.

The radiant point for the Quadrantids is now considered to be at the northern tip of Bootes, near the Big Dipper asterism in our sky, not far from Bootes’ brightest star Arcturus. It is very far north on the sky’s dome, which is why Southern Hemisphere observers probably won’t see many (if any) Quadrantid meteors. Most of the meteors simply won’t make it above the horizon for Southern Hemisphere skywatchers. But some might!

In 2003, Peter Jenniskens proposed that this object, 2003 EH1, is the parent body of the Quadrantid meteor shower.

Quadrantid meteors have a mysterious parent object. In 2003, astronomer Peter Jenniskens tentatively identified the parent body of the Quadrantids as the asteroid 2003 EH1. If indeed this body is the Quadrantids parent, then the Quadrantids, like the Geminid meteors, come from a rocky body – not an icy comet. Strange.

In turn, though, 2003 EH1 might be the same object as the comet C/1490 Y1, which was observed by Chinese, Japanese and Korean astronomers 500 years ago.

So the exact story behind the Quadrantids’ parent object remains somewhat mysterious.

Bottom line: The first major meteor shower of 2019, and every year, the Quadrantid meteor shower, will probably be at its best in the hours between midnight and dawn January 4. Fortunately, in 2019, the absence of moonlight means dark skies for this year’s annual Quadrantid meteor shower.

Celebrate 2019 with an EarthSky moon calendar!

from EarthSky http://bit.ly/2s2qBRm

View larger. | In 2014, as the Quadrantids were flying, those at far northern latitudes were seeing auroras. Photo by Tommy Eliassen.

The Quadrantid meteor shower is 2019’s first major meteor shower. We’ll have moon-free skies for the peak this year, expected late night January 3 until dawn January 4. Although the Quadrantids have been known to produce some 50-100 meteors in a dark sky, their peak is extremely narrow, time-wise. Peaks of the Perseid or Geminid meteor showers persist for a day or more, allowing all time zones around the world to enjoy a good display of Perseids or Geminids. But the Quadrantids’ peak lasts only a few hours. So you have to be on the right part of Earth – preferably with the radiant high in your sky – in order to experience the peak of the Quadrantids. What’s more, the shower favors the Northern Hemisphere because its radiant point is so far north on the sky’s dome.

So you need some luck to see the Quadrantids, and being in the Northern Hemisphere does help. Who will see the 2019 shower? Keep in mind the prediction of the Quadrantid peak represents an educated guess, not an ironclad guarantee.

That said, in 2019, the International Meteor Organization gives the peak as January 4 at 2 UTC. If that prediction of the peak holds true, Europe – and areas of the globe surrounding Europe – have a good shot at viewing the shower at its best during the predawn hours on January 4.

Just know that meteor showers are notorious for defying the best-laid forecasts. Thus for the Quadrantids – as for any meteor shower – your best plan is simply to look for yourself.

Barry Simmons in Lake Martin, Alabama captured this Quadrantid meteor during the 2014 shower.

Anyplace at mid-northern and far-northern latitudes might be in a decent position to watch the Quadrantids in 2019, especially as there is no moonlight to ruin this year’s show.

There’s a new moon and partial solar eclipse on January 6, 2019, only two days after the predicted peak for the Quadrantids. You might see the slender waning crescent moon coming up shortly before sunrise January 4, but this fleeting and frail crescent won’t bother this year’s Quadrantid shower.

All other things being equal, for any meteor shower, you are likely to see the most meteors when the radiant is high in the sky.

In the case of the Quadrantid shower, the radiant point is seen highest in the sky in the dark hour before dawn.

From mid-northern latitudes, the radiant point for the Quadrantid shower doesn’t climb over the horizon until after midnight.

Where is the Quadrantids’ radiant point?

The radiant point of the Quadrantid shower makes an approximate right angle with the Big Dipper and the bright star Arcturus. If you trace the paths of the Quadrantid meteors backward, they appear to radiate from this point on the starry sky.

Now for our usual caveat. You don’t need to find the meteor shower radiant to see the Quadrantid meteors.

You just have to be at mid-northern or far-northern latitudes, up in the wee hours of the morning and hope the peak comes at just the right time to your part of the world.

The meteors will radiate from the northern sky, but appear in all parts of the sky.

The now-defunct constellation Quadrans Muralis, for which the Quadrantids are named. Image via Atlas Coelestis.

The Quadrantids are named for a constellation that no longer exists. Most meteor showers are named for the constellations from which they appear to radiate. So it is with the Quadrantids. But the Quadrantids’ constellation no longer exists, except in memory. The name Quadrantids comes from the constellation Quadrans Muralis (Mural Quadrant), created by the French astronomer Jerome Lalande in 1795. This now-obsolete constellation was located between the constellations of Bootes the Herdsman and Draco the Dragon. Where did it go?

To understand the history of the Quadrantids’ name, we have to go back to the earliest observations of this shower. In early January 1825, Antonio Brucalassi in Italy reported that:

… the atmosphere was traversed by a multitude of the luminous bodies known by the name of falling stars.

They appeared to radiate from Quadrans Muralis. In 1839, Adolphe Quetelet of Brussels Observatory in Belgium and Edward C. Herrick in Connecticut independently made the suggestion that the Quadrantids are an annual shower.

But, in 1922, the International Astronomical Union devised a list 88 modern constellations. The list was agreed upon by the International Astronomical Union at its inaugural General Assembly held in Rome in May 1922. It did not include a constellation Quadrans Muralis.

Today, this meteor shower retains the name Quadrantids, for the original and now obsolete constellation Quadrans Muralis.

The radiant point for the Quadrantids is now considered to be at the northern tip of Bootes, near the Big Dipper asterism in our sky, not far from Bootes’ brightest star Arcturus. It is very far north on the sky’s dome, which is why Southern Hemisphere observers probably won’t see many (if any) Quadrantid meteors. Most of the meteors simply won’t make it above the horizon for Southern Hemisphere skywatchers. But some might!

In 2003, Peter Jenniskens proposed that this object, 2003 EH1, is the parent body of the Quadrantid meteor shower.

Quadrantid meteors have a mysterious parent object. In 2003, astronomer Peter Jenniskens tentatively identified the parent body of the Quadrantids as the asteroid 2003 EH1. If indeed this body is the Quadrantids parent, then the Quadrantids, like the Geminid meteors, come from a rocky body – not an icy comet. Strange.

In turn, though, 2003 EH1 might be the same object as the comet C/1490 Y1, which was observed by Chinese, Japanese and Korean astronomers 500 years ago.

So the exact story behind the Quadrantids’ parent object remains somewhat mysterious.

Bottom line: The first major meteor shower of 2019, and every year, the Quadrantid meteor shower, will probably be at its best in the hours between midnight and dawn January 4. Fortunately, in 2019, the absence of moonlight means dark skies for this year’s annual Quadrantid meteor shower.

Celebrate 2019 with an EarthSky moon calendar!

from EarthSky http://bit.ly/2s2qBRm

Welcome to 2019!

Image via Mohamed Laaïfat Photographies.

Best New Year’s gift ever! EarthSky moon calendar for 2019

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

Image via Mohamed Laaïfat Photographies.

Best New Year’s gift ever! EarthSky moon calendar for 2019

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

Why the New Year begins on January 1

Goodbye 2018, and hello 2019! Singapore celebrates the New Year with spectacular fireworks. Image via Channel NewsAsia.

The date of a new year isn’t precisely fixed by any natural or seasonal marker. Instead, our celebration of New Year’s Day on January 1 is a civil event. That’s despite the fact that, for us in the Northern Hemisphere where the amount of daylight has ebbed to its lowest point and the days are getting longer again, there’s a feeling of rebirth in the air.

Our modern celebration of New Year’s Day stems from an ancient Roman custom, the feast of the Roman god Janus – god of doorways and beginnings. The name for the month of January also comes from Janus, who was depicted as having two faces. One face of Janus looked back into the past, and the other peered forward to the future.

To celebrate the new year, the Romans made promises to Janus. From this ancient practice comes our tradition of making New Year’s Day resolutions.

Best New Year’s gift ever! EarthSky moon calendar for 2019

Janus the doorkeeper via tablesbeyondbelief.

January 1 hasn’t been New Year’s Day throughout history, though. In the past, some New Year’s celebrations took place at an equinox, a day when the sun is above Earth’s equator, and night and day are equal in length. In many cultures, the March or vernal equinox marks a time of transition and new beginnings, and so cultural celebrations of a new year were natural for that equinox. The September or autumnal equinox also had its proponents for the beginning of a new year. For example, the French Republican Calendar – implemented during the French Revolution and used for about 12 years from late 1793 to 1805 – started its year at the September equinox.

The Greeks celebrated the new year on the winter solstice, the shortest day of the year.

Today, although many do celebrate New Year’s Day on January 1, some cultures and religions do not. Jews use a lunar calendar and celebrate the New Year on Rosh Hashanah, the first day of the month of Tishri, which is the first month of the Jewish calendar. This date usually occurs in September.

Most are also familiar with the Chinese New Year, celebrated for weeks in January or early February. In 2019, the Chinese New Year of the Pig begins on February 4-5.

By the way, in addition to the longer days here in the Northern Hemisphere, there’s another astronomical occurrence around January 1 each year that’s also related to Earth’s year, as defined by our orbit around the sun. That is, Earth’s perihelion – or closest point to the sun – happens every year in early January. In 2019, perihelion comes on January 2-3.

We don’t celebrate New Year’s Day on January 1 for this reason, but it would make sense if we did. Perihelion – our closest point to the sun in our yearly orbit – takes place each year around January 3. Image via NASA.

Bottom line: The reason to celebrate New Year’s Day on January 1 is historical, not astronomical. The New Year was celebrated according to astronomical events – such as equinoxes and solstices – eons ago. Our modern New Year’s celebration stems from the ancient, two-faced Roman god Janus, after whom the month of January is also named. One face of Janus looked back into the past, and the other peered forward to the future.

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

Goodbye 2018, and hello 2019! Singapore celebrates the New Year with spectacular fireworks. Image via Channel NewsAsia.

The date of a new year isn’t precisely fixed by any natural or seasonal marker. Instead, our celebration of New Year’s Day on January 1 is a civil event. That’s despite the fact that, for us in the Northern Hemisphere where the amount of daylight has ebbed to its lowest point and the days are getting longer again, there’s a feeling of rebirth in the air.

Our modern celebration of New Year’s Day stems from an ancient Roman custom, the feast of the Roman god Janus – god of doorways and beginnings. The name for the month of January also comes from Janus, who was depicted as having two faces. One face of Janus looked back into the past, and the other peered forward to the future.

To celebrate the new year, the Romans made promises to Janus. From this ancient practice comes our tradition of making New Year’s Day resolutions.

Best New Year’s gift ever! EarthSky moon calendar for 2019

Janus the doorkeeper via tablesbeyondbelief.

January 1 hasn’t been New Year’s Day throughout history, though. In the past, some New Year’s celebrations took place at an equinox, a day when the sun is above Earth’s equator, and night and day are equal in length. In many cultures, the March or vernal equinox marks a time of transition and new beginnings, and so cultural celebrations of a new year were natural for that equinox. The September or autumnal equinox also had its proponents for the beginning of a new year. For example, the French Republican Calendar – implemented during the French Revolution and used for about 12 years from late 1793 to 1805 – started its year at the September equinox.

The Greeks celebrated the new year on the winter solstice, the shortest day of the year.

Today, although many do celebrate New Year’s Day on January 1, some cultures and religions do not. Jews use a lunar calendar and celebrate the New Year on Rosh Hashanah, the first day of the month of Tishri, which is the first month of the Jewish calendar. This date usually occurs in September.

Most are also familiar with the Chinese New Year, celebrated for weeks in January or early February. In 2019, the Chinese New Year of the Pig begins on February 4-5.

By the way, in addition to the longer days here in the Northern Hemisphere, there’s another astronomical occurrence around January 1 each year that’s also related to Earth’s year, as defined by our orbit around the sun. That is, Earth’s perihelion – or closest point to the sun – happens every year in early January. In 2019, perihelion comes on January 2-3.

We don’t celebrate New Year’s Day on January 1 for this reason, but it would make sense if we did. Perihelion – our closest point to the sun in our yearly orbit – takes place each year around January 3. Image via NASA.

Bottom line: The reason to celebrate New Year’s Day on January 1 is historical, not astronomical. The New Year was celebrated according to astronomical events – such as equinoxes and solstices – eons ago. Our modern New Year’s celebration stems from the ancient, two-faced Roman god Janus, after whom the month of January is also named. One face of Janus looked back into the past, and the other peered forward to the future.

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

2018 SkS Weekly Climate Change & Global Warming Digest #52

Story of the Week... Editorial of the Week... Toon of the Week... SkS in the News... Coming Soon on SkS... Poster of the Week... SkS Week in Review... 

Story of the Week...

2018 Was A Milestone Year For Climate Science (If Not Politics) 

 

The devastation from Hurricane Michael over Mexico Beach, Fla. A massive federal report released in November warns that climate change is fueling extreme weather disasters like hurricanes and wildfires. Gerald Herbert/AP

2018 was a hot year — in fact, the fourth warmest on record. The only years that were, on average, warmer were the past three, according to the World Meteorological Organization.

It has been warming for decades now. But 2018 brought several major new and markedly more precise reports from scientists about what climate change is doing to the weather and how dire they expect the consequences to be.

That didn't stop President Trump and others from continuing to question the evidence.

"Is there climate change?" Trump said to reporters from Axios on HBO in November. "Yeah. Will it go back like this?" he added, motioning up and down with his hand. "I mean will it change back? Probably. That's what I think."

Another politician who weighed in on the clear evidence of a warmer planet was Republican Sen. Ted Cruz of Texas, when he was campaigning this past fall.

"Well, listen," he assured a moderator at a televised debate. "Of course the climate is changing. The climate has been changing from the dawn of time. The climate will change as long as we have a planet Earth."

Both statements are at odds with the consensus within the climate science community.

2018 Was A Milestone Year For Climate Science (If Not Politics) by Christopher Joyce NPR News, Dec 27, 2018

---

Editorial of the Week...

Opinion: Our house is on fire, and many Albertans want more lighters

Do we want to save the planet or get rich and watch it die? POSTMEDIA

It boils down to this. 1) Albertans have become very wealthy by exporting fossil fuels. 2) Scientists state that the climate crisis is an existential threat to civilization. 3) The only way to minimize catastrophic climate change is to immediately decrease our fossil fuel use as quickly as possible. 4) 3 threatens 1.

Let’s unpack some of this, shall we? 1) Due to geographical fortune, our province sits on a vast reservoir of fossil fuels: coal, natural gas and oil. With their high energy content and transportability, they have been highly desired for (historically) a much higher value than their extraction cost, which has made us extraordinarily rich. Even now, in the downturn, even as many people are hurting financially, we still have the highest average monthly income in Canada. Being rich is fun, and we don’t want it to end.

The problem is Point 2. As time passes, and we put more and more greenhouse gases into the atmosphere, it’s becoming increasingly clear that all that we love is at risk. Our ecosystems, food systems, economic systems, life support systems. Scientists are talking about a doomsday scenario where it all just collapses, within our lifetimes, if we don’t act now.

Opinion: Our house is on fire, and many Albertans want more lighters, Opinion by Joe Vipond & Noel Keough, Calgary Herald, Dec 29, 2018

Joe Vipond is an emergency physician in Calgary. He sits on the board of the Canadian Association of Physicians for the Environment.

Noel Keough is an associate professor of sustainable design at the University of Calgary. He is the president of the board of Sustainable Calgary Society. 

---

Toon of the Week...

Hat tip to the Clean Air Cartoons Facebook page.

---

SkS in the News

The "explainer" article*, 9 questions about climate change you were too embarrassed to ask, contains the following paragraph:

4) There are other human fingerprints that suggest increased greenhouse gases are warming the planet. For instance, back in the 1960s, simple climate models predicted that global warming caused by more carbon dioxide would lead to cooling in the upper atmosphere (because the heat is getting trapped at the surface). Later satellite measurements confirmed exactly that. Here are a few other similar predictions that have also been confirmed.

The first link embedded in the above paragraph is to the SkS article, 10 Indicators of a Human Fingerprint on Climate Change by John Cook, July 30, 2018

* This explainer was updated by Umair Irfan in December 2018 and draws heavily from a card stack written by Brad Plumer in 2015. Brian Resnick contributed the section on the Paris climate accord in 2017. 

---

Coming Soon on SkS...

• 2018 in Review: a recap of the Skeptical Science year (Baerbel)
• Portuguese translation of The Debunking Handbook (Baerbel)
• Climate negotiations made me terrified for our future (Climate Adam)
• New findings on ocean warming: 5 questions answered (Scott Denning)
• New research this week (Ari)
• 2019 SkS Weekly Climate Change & Global Warming News Roundup #1 (John Hartz)
• 2019 SkS Weekly Climate Change & Global Warming Digest #1 (John Hartz)

---

Poster of the Week...

 

---

SkS Week in Review... 

• 2018 SkS Weekly Climate Change & Global Warming News Roundup #52 by John Hartz
• New research, December 17-23, 2018 by Ari Jokimäki
• Greta Thunberg's TEDx talk by Guest Author
• Global warming ‘hiatus’ is the climate change myth that refuses to die by Kevin Cowtan & Stephan Lewandowsky (The Conversation UK)
• 2018 was the hottest La Niña year ever recorded by Dana Nuccitelli (Yale Climate Connection)
• 2018 SkS Weekly Climate Change & Global Warming Digest #51 by John Hartz

from Skeptical Science http://bit.ly/2EVw5VP

Story of the Week... Editorial of the Week... Toon of the Week... SkS in the News... Coming Soon on SkS... Poster of the Week... SkS Week in Review... 

Story of the Week...

2018 Was A Milestone Year For Climate Science (If Not Politics) 

 

The devastation from Hurricane Michael over Mexico Beach, Fla. A massive federal report released in November warns that climate change is fueling extreme weather disasters like hurricanes and wildfires. Gerald Herbert/AP

2018 was a hot year — in fact, the fourth warmest on record. The only years that were, on average, warmer were the past three, according to the World Meteorological Organization.

It has been warming for decades now. But 2018 brought several major new and markedly more precise reports from scientists about what climate change is doing to the weather and how dire they expect the consequences to be.

That didn't stop President Trump and others from continuing to question the evidence.

"Is there climate change?" Trump said to reporters from Axios on HBO in November. "Yeah. Will it go back like this?" he added, motioning up and down with his hand. "I mean will it change back? Probably. That's what I think."

Another politician who weighed in on the clear evidence of a warmer planet was Republican Sen. Ted Cruz of Texas, when he was campaigning this past fall.

"Well, listen," he assured a moderator at a televised debate. "Of course the climate is changing. The climate has been changing from the dawn of time. The climate will change as long as we have a planet Earth."

Both statements are at odds with the consensus within the climate science community.

2018 Was A Milestone Year For Climate Science (If Not Politics) by Christopher Joyce NPR News, Dec 27, 2018

---

Editorial of the Week...

Opinion: Our house is on fire, and many Albertans want more lighters

Do we want to save the planet or get rich and watch it die? POSTMEDIA

It boils down to this. 1) Albertans have become very wealthy by exporting fossil fuels. 2) Scientists state that the climate crisis is an existential threat to civilization. 3) The only way to minimize catastrophic climate change is to immediately decrease our fossil fuel use as quickly as possible. 4) 3 threatens 1.

Let’s unpack some of this, shall we? 1) Due to geographical fortune, our province sits on a vast reservoir of fossil fuels: coal, natural gas and oil. With their high energy content and transportability, they have been highly desired for (historically) a much higher value than their extraction cost, which has made us extraordinarily rich. Even now, in the downturn, even as many people are hurting financially, we still have the highest average monthly income in Canada. Being rich is fun, and we don’t want it to end.

The problem is Point 2. As time passes, and we put more and more greenhouse gases into the atmosphere, it’s becoming increasingly clear that all that we love is at risk. Our ecosystems, food systems, economic systems, life support systems. Scientists are talking about a doomsday scenario where it all just collapses, within our lifetimes, if we don’t act now.

Opinion: Our house is on fire, and many Albertans want more lighters, Opinion by Joe Vipond & Noel Keough, Calgary Herald, Dec 29, 2018

Joe Vipond is an emergency physician in Calgary. He sits on the board of the Canadian Association of Physicians for the Environment.

Noel Keough is an associate professor of sustainable design at the University of Calgary. He is the president of the board of Sustainable Calgary Society. 

---

Toon of the Week...

Hat tip to the Clean Air Cartoons Facebook page.

---

SkS in the News

The "explainer" article*, 9 questions about climate change you were too embarrassed to ask, contains the following paragraph:

4) There are other human fingerprints that suggest increased greenhouse gases are warming the planet. For instance, back in the 1960s, simple climate models predicted that global warming caused by more carbon dioxide would lead to cooling in the upper atmosphere (because the heat is getting trapped at the surface). Later satellite measurements confirmed exactly that. Here are a few other similar predictions that have also been confirmed.

The first link embedded in the above paragraph is to the SkS article, 10 Indicators of a Human Fingerprint on Climate Change by John Cook, July 30, 2018

* This explainer was updated by Umair Irfan in December 2018 and draws heavily from a card stack written by Brad Plumer in 2015. Brian Resnick contributed the section on the Paris climate accord in 2017. 

---

Coming Soon on SkS...

• 2018 in Review: a recap of the Skeptical Science year (Baerbel)
• Portuguese translation of The Debunking Handbook (Baerbel)
• Climate negotiations made me terrified for our future (Climate Adam)
• New findings on ocean warming: 5 questions answered (Scott Denning)
• New research this week (Ari)
• 2019 SkS Weekly Climate Change & Global Warming News Roundup #1 (John Hartz)
• 2019 SkS Weekly Climate Change & Global Warming Digest #1 (John Hartz)

---

Poster of the Week...

 

---

SkS Week in Review... 

• 2018 SkS Weekly Climate Change & Global Warming News Roundup #52 by John Hartz
• New research, December 17-23, 2018 by Ari Jokimäki
• Greta Thunberg's TEDx talk by Guest Author
• Global warming ‘hiatus’ is the climate change myth that refuses to die by Kevin Cowtan & Stephan Lewandowsky (The Conversation UK)
• 2018 was the hottest La Niña year ever recorded by Dana Nuccitelli (Yale Climate Connection)
• 2018 SkS Weekly Climate Change & Global Warming Digest #51 by John Hartz

from Skeptical Science http://bit.ly/2EVw5VP

Past-and-future Earths ring in New Year

View larger.| As evening falls, when you look along the ecliptic (sun’s path), approximately at its zenith (highest point in your sky), you’re looking backwards along Earth’s orbit. In this illustration, the blue spheres along the ecliptic are “past Earths” showing where Earth was in its orbit an hour ago (largest Earth), and 10 days ago, 20 days ago, 30 days ago, and so on. Chart via Guy Ottewell.

Originally published at Guy Ottewell’s blog; reprinted here with permission.

The chart above is the sky scene on the last evening of 2018.

Below – a happy New Year to you! – is the view in the opposite eastward direction, Earth’s forward direction in orbit around the sun, on the following morning, the morning of the first day of 2019.

View larger. | As dawn breaks, when you look along the ecliptic (sun’s path), approximately at its zenith (highest point in your sky), you’re looking forwards along Earth’s orbit. In this illustration, the blue spheres along the ecliptic are “future Earths” showing where Earth will be in its orbit an hour from now (largest Earth), and 10 days from now, 20 days from now, 30 days from now, and so on. Chart via Guy Ottewell.

Included again in these pictures are my imaginary Earths as seen from our actual Earth. They are at other points in Earth’s orbit, and serve to show where in space that orbit is. To repeat our simile, it is as if the orbit is a steel ring around the sun and the Earths are like beads sliding along it.

In each picture, the nearest imaginary Earth is only an hour away. They’re an hour into the past in the evening picture, and an hour ahead in the morning picture. In each picture, Earth’s size is shown at true scale. The others are 10 days away, 20 days, 30 days, and so on. These older Earths are exaggerated 100 times in size. That’s how quickly an Earth – days away – dwindles in size, because the orbit (and space in general) is relatively so vast.

Pairing these pictures for the turn of the year was the brilliant suggestion of Deborah Byrd, creator of the popular EarthSky website. I saw it had to be done: it has us looking backward at the old year, forward into the new. As night falls we are on the trailing side of Earth and we look back over the route we have traveled into December. At dawn, on Earth’s prow, we look forward along the curve of our future journey, out of winter into the spring and summer of the coming year.

There are the usual details in the background of the pictures, such as Mars and Neptune out beyond the past-Earths of December, and, in the morning sky of January, an array of the brightest planets, passing each other and the red star Antares and being passed by the waning Moon – as shown also in this detail from our Zodiac Wavy Charts for 2019

A portion of 2019’s Zodiac Wavy Chart, via Guy Ottewell.

2019’s Zodiac Wavy chart – a cool wall poster, containing lots of sky info for the coming year – is available now, via Guy Ottewell.

The imaginary Earths are superimposed on the ecliptic, since that marks the plane of our orbit. But the line of the ecliptic is only a line on the map of the sky; in real space, the nearer Earths curl in toward us.

Yet there’s something of a struggle to understand that curling-in. The nearest past or future Earth appears highest in the evening or morning sky. Is the sequence really going to curl right in to where we are? Yes. If we drew Earths any nearer, only half an hour or only minutes away, they would swell enormously, also be shifted southward by parallax, and would end by hitting and consuming the Earth we stand on – but not symmetrically: if the nearest past Earth could put on speed and catch up with us, its front would make first contact with the rearmost point of the real Earth, on the equator. This, in the evening sky, is down over the horizon to the left, because the scene is set for latitude 40° north.

So I thought of adding a scene as for a place on the equator. But there is something better.

Daniel Cummings of the blog StarInAStar had the idea of visualizing Earth’s orbit as a ring in space, visible from Earth. That was what made me think of the past-and-future Earths as a way of making that ring visible. But I still hadn’t grasped his full idea, which, as he explains, really necessitates seeing the ring as a whole. This means seeing it not after dark but at noon, with the sun at its highest.

Adapting my program to let it show this wasn’t easy, because I had built it basically to show the night sky, and added to it the imaginary Earths in the evening sky or the morning sky, but not both together. But I think I’ve now got close to his conception.

View larger. | Earth’s orbit as a ring in space, visible from Earth, with past-and-future Earths shown on the day of a December solstice, via Daniel Cummings and Guy Ottewell.

Here is the sky at midday, not as seen from a northern location but, for simplicity, from latitude and longitude zero, on the equator. Also, the scene is drawn not for the turn of the calendar year but for the day of the solstice, December 21, so that it is symmetrical.
We see that steel ring, Earth’s orbit, in its entirety. The sun, at the top, is in front of the farthest point of the ring; we are at the nearest point. You can call the sun the gem on the ring, and we are at the clasp!

The imaginary Earths appear all around the ring. They start from behind the sun. They approach us, getting larger, and end with the nearest, an hour ago, on the east point of the horizon. Then there’s the Earth of this moment, with us on it. Then the nearest future Earth, an hour ahead, is over at the west point on the horizon (about to set as the real Earth rolls upward), and the other future Earths reel away to their destination behind the sun.

Because this picture is from our solstice viewpoint, it is symmetrical: the past Earth of last September’s equinox is at the same distance as the future Earth at next March’s equinox. (The Earths marking those events are not precisely at their dates, 2018 September 23 and 2019 March 20, because the Earths are at 10-day intervals.)

I make the horizon into a convex curve so as to remind you that we are on a spherical planet – it’s done simply by setting the center of the projection 10° below the horizon.
In this projection, the trail of past and future Earths looks like a semicircle. Yet the orbit of Earth is a ring – a circle (or very nearly so). Then how come the picture makes it look like a semicircle with ends wide apart?

If you look at something circular, such as a pond, from an oblique viewoint, it appears not as a circle but as an ellipse. Actually even that isn’t quite true, and gets less so the nearer you are to the pond: the ellipse is distorted, the nearer part of it swollen. This effect is rather well shown in the last of the space-sphere pictures in my Astronomical Companion, purporting to show the outer limit of the observable universe, in which for paradoxical effect the eye is brought close to the sphere. And in our sky picture now, the nearest part of the ring is extremely near – in fact, we are on it – and that is why it appears as wide as the whole ring.

The sun is the center of this ring, and the far side of the ring, at the June solstice, is relatively so distant that its width seems to have shrunk to nothing behind the sun.

We jump backward into space to see the ring of Earth’s orbit as a whole. From this huge distance (90 astronomical units or sun-Earth distances) the orbit does appear indistinguishable from an ellipse.

Inner planets in December 2018 and January 2019, via Guy Ottewell.

Shown are the paths of the planets in December 2018 and January 2019, and sightlines from Earth to Sun at the December 21 solstice (blue) and the divide between the years (white). The sightline at the solstice is at a right angle to the March or vernal equinox direction.

Ring in the new! We hope 2019 will be a better year for you and for all creatures great and small.

Bottom line: A way of picturing ourselves moving in Earth’s orbit around the sun as we look backward at the old year – and forward into the new – here.

from EarthSky http://bit.ly/2Qa2ha4

View larger.| As evening falls, when you look along the ecliptic (sun’s path), approximately at its zenith (highest point in your sky), you’re looking backwards along Earth’s orbit. In this illustration, the blue spheres along the ecliptic are “past Earths” showing where Earth was in its orbit an hour ago (largest Earth), and 10 days ago, 20 days ago, 30 days ago, and so on. Chart via Guy Ottewell.

Originally published at Guy Ottewell’s blog; reprinted here with permission.

The chart above is the sky scene on the last evening of 2018.

Below – a happy New Year to you! – is the view in the opposite eastward direction, Earth’s forward direction in orbit around the sun, on the following morning, the morning of the first day of 2019.

View larger. | As dawn breaks, when you look along the ecliptic (sun’s path), approximately at its zenith (highest point in your sky), you’re looking forwards along Earth’s orbit. In this illustration, the blue spheres along the ecliptic are “future Earths” showing where Earth will be in its orbit an hour from now (largest Earth), and 10 days from now, 20 days from now, 30 days from now, and so on. Chart via Guy Ottewell.

Included again in these pictures are my imaginary Earths as seen from our actual Earth. They are at other points in Earth’s orbit, and serve to show where in space that orbit is. To repeat our simile, it is as if the orbit is a steel ring around the sun and the Earths are like beads sliding along it.

In each picture, the nearest imaginary Earth is only an hour away. They’re an hour into the past in the evening picture, and an hour ahead in the morning picture. In each picture, Earth’s size is shown at true scale. The others are 10 days away, 20 days, 30 days, and so on. These older Earths are exaggerated 100 times in size. That’s how quickly an Earth – days away – dwindles in size, because the orbit (and space in general) is relatively so vast.

Pairing these pictures for the turn of the year was the brilliant suggestion of Deborah Byrd, creator of the popular EarthSky website. I saw it had to be done: it has us looking backward at the old year, forward into the new. As night falls we are on the trailing side of Earth and we look back over the route we have traveled into December. At dawn, on Earth’s prow, we look forward along the curve of our future journey, out of winter into the spring and summer of the coming year.

There are the usual details in the background of the pictures, such as Mars and Neptune out beyond the past-Earths of December, and, in the morning sky of January, an array of the brightest planets, passing each other and the red star Antares and being passed by the waning Moon – as shown also in this detail from our Zodiac Wavy Charts for 2019

A portion of 2019’s Zodiac Wavy Chart, via Guy Ottewell.

2019’s Zodiac Wavy chart – a cool wall poster, containing lots of sky info for the coming year – is available now, via Guy Ottewell.

The imaginary Earths are superimposed on the ecliptic, since that marks the plane of our orbit. But the line of the ecliptic is only a line on the map of the sky; in real space, the nearer Earths curl in toward us.

Yet there’s something of a struggle to understand that curling-in. The nearest past or future Earth appears highest in the evening or morning sky. Is the sequence really going to curl right in to where we are? Yes. If we drew Earths any nearer, only half an hour or only minutes away, they would swell enormously, also be shifted southward by parallax, and would end by hitting and consuming the Earth we stand on – but not symmetrically: if the nearest past Earth could put on speed and catch up with us, its front would make first contact with the rearmost point of the real Earth, on the equator. This, in the evening sky, is down over the horizon to the left, because the scene is set for latitude 40° north.

So I thought of adding a scene as for a place on the equator. But there is something better.

Daniel Cummings of the blog StarInAStar had the idea of visualizing Earth’s orbit as a ring in space, visible from Earth. That was what made me think of the past-and-future Earths as a way of making that ring visible. But I still hadn’t grasped his full idea, which, as he explains, really necessitates seeing the ring as a whole. This means seeing it not after dark but at noon, with the sun at its highest.

Adapting my program to let it show this wasn’t easy, because I had built it basically to show the night sky, and added to it the imaginary Earths in the evening sky or the morning sky, but not both together. But I think I’ve now got close to his conception.

View larger. | Earth’s orbit as a ring in space, visible from Earth, with past-and-future Earths shown on the day of a December solstice, via Daniel Cummings and Guy Ottewell.

Here is the sky at midday, not as seen from a northern location but, for simplicity, from latitude and longitude zero, on the equator. Also, the scene is drawn not for the turn of the calendar year but for the day of the solstice, December 21, so that it is symmetrical.
We see that steel ring, Earth’s orbit, in its entirety. The sun, at the top, is in front of the farthest point of the ring; we are at the nearest point. You can call the sun the gem on the ring, and we are at the clasp!

The imaginary Earths appear all around the ring. They start from behind the sun. They approach us, getting larger, and end with the nearest, an hour ago, on the east point of the horizon. Then there’s the Earth of this moment, with us on it. Then the nearest future Earth, an hour ahead, is over at the west point on the horizon (about to set as the real Earth rolls upward), and the other future Earths reel away to their destination behind the sun.

Because this picture is from our solstice viewpoint, it is symmetrical: the past Earth of last September’s equinox is at the same distance as the future Earth at next March’s equinox. (The Earths marking those events are not precisely at their dates, 2018 September 23 and 2019 March 20, because the Earths are at 10-day intervals.)

I make the horizon into a convex curve so as to remind you that we are on a spherical planet – it’s done simply by setting the center of the projection 10° below the horizon.
In this projection, the trail of past and future Earths looks like a semicircle. Yet the orbit of Earth is a ring – a circle (or very nearly so). Then how come the picture makes it look like a semicircle with ends wide apart?

If you look at something circular, such as a pond, from an oblique viewoint, it appears not as a circle but as an ellipse. Actually even that isn’t quite true, and gets less so the nearer you are to the pond: the ellipse is distorted, the nearer part of it swollen. This effect is rather well shown in the last of the space-sphere pictures in my Astronomical Companion, purporting to show the outer limit of the observable universe, in which for paradoxical effect the eye is brought close to the sphere. And in our sky picture now, the nearest part of the ring is extremely near – in fact, we are on it – and that is why it appears as wide as the whole ring.

The sun is the center of this ring, and the far side of the ring, at the June solstice, is relatively so distant that its width seems to have shrunk to nothing behind the sun.

We jump backward into space to see the ring of Earth’s orbit as a whole. From this huge distance (90 astronomical units or sun-Earth distances) the orbit does appear indistinguishable from an ellipse.

Inner planets in December 2018 and January 2019, via Guy Ottewell.

Shown are the paths of the planets in December 2018 and January 2019, and sightlines from Earth to Sun at the December 21 solstice (blue) and the divide between the years (white). The sightline at the solstice is at a right angle to the March or vernal equinox direction.

Ring in the new! We hope 2019 will be a better year for you and for all creatures great and small.

Bottom line: A way of picturing ourselves moving in Earth’s orbit around the sun as we look backward at the old year – and forward into the new – here.

from EarthSky http://bit.ly/2Qa2ha4

As the year turns, watch the moon sweep past 3 planets

Click for info on the Quandrantid meteor shower, peaking late night January 3 to early morning January 4, 2019

Happy New Year! Here’s a cool coincidence that you’ll enjoy. On the final morning of 2018 and first mornings of 2019, look east, the direction of sunrise, before the sun comes up. The moon and three planets will be beautifully aligned across the early morning sky on December 31, and January 1, 2, 3, and 4. In their order from top to bottom, the three planets are Venus, Jupiter and Mercury. That also happens to be their order in brightness: then Venus, then Jupiter and finally Mercury.

You can’t miss the moon, Venus and Jupiter, rising before dawn’s first light. Until the sun rises, they’re the three brightest objects in the sky.

Mercury is another story. It’s also bright enough to see with the eye, but it rises only shortly before sunrise now and so is seen only against a background of bright twilight. You’ll see Mercury only as darkness begins to give way to dawn. It’ll be low in the sky, toughest to spot. Use binoculars to catch Mercury if you need to.

Here’s a chart for the final morning of 2018. Notice that the moon is located above the planets, poised to sweep past them as the year begins:

The moon and planets on December 31, the final morning of 2018. Look east, the direction of sunrise, before the sun comes up.

Can you find Mercury? Note that – on December 31 and January 1 – the lit side of the lunar crescent points down into the line up of planets in the morning sky. Look for Mercury close to the horizon, along line with the moon, Venus and Jupiter, with the unaided eye or binoculars.

Our sky chart is designed for mid-northern North American latitudes. But this chart will work for you, too, from other parts of the globe. At mid-northern latitudes in the world’s Eastern Hemisphere, the moon will appear offset a little with respect to the planets. Everything is moving, after all, with the moon moving in orbit around Earth and Earth itself spinning on its axis.

If you’re in the Southern Hemisphere, the moon and planets will be aligned differently relative to your horizon. That is, a line between them will point downward from left to right, instead of downward from right to left as in the Northern Hemisphere.

Still, for all of us, these planets are visible in the east before sunup, with the moon moving past them! For all of us, Venus will appear highest, Jupiter next-highest, and Mercury closest to the horizon.

By the way, we received many beautiful photos earlier this month, as Jupiter was first coming into view in the morning sky. It swept past Mercury around December 21. Photos of the Jupiter-Mercury conjunction here. Now Mercury is heading back toward the sunrise, and Jupiter is ascending higher in the morning sky. It’ll have a wonderful conjunction with Venus in the coming month.

Matthew Chin in Hong Kong caught Mercury and Jupiter on December 22, 2018, when – from his location on the globe – they appeared side by side. Thanks, Matthew!

By the way, if you live at mid-northern latitudes, you’re now waking up to your latest sunrises of the year. Take advantage of the late sunrises to see the grand sky show in the coming mornings, as the moon slides past the planets Venus, Jupiter, and Mercury!

Bottom line: The last morning of 2018 and 1st mornings of 2019 will feature a dazzling line-up of the moon and 3 planets. Here are tips on how to see the moon sweep past Venus, Jupiter and Mercury. Great start to the New Year!

from EarthSky http://bit.ly/2Qe79uV

Click for info on the Quandrantid meteor shower, peaking late night January 3 to early morning January 4, 2019

Happy New Year! Here’s a cool coincidence that you’ll enjoy. On the final morning of 2018 and first mornings of 2019, look east, the direction of sunrise, before the sun comes up. The moon and three planets will be beautifully aligned across the early morning sky on December 31, and January 1, 2, 3, and 4. In their order from top to bottom, the three planets are Venus, Jupiter and Mercury. That also happens to be their order in brightness: then Venus, then Jupiter and finally Mercury.

You can’t miss the moon, Venus and Jupiter, rising before dawn’s first light. Until the sun rises, they’re the three brightest objects in the sky.

Mercury is another story. It’s also bright enough to see with the eye, but it rises only shortly before sunrise now and so is seen only against a background of bright twilight. You’ll see Mercury only as darkness begins to give way to dawn. It’ll be low in the sky, toughest to spot. Use binoculars to catch Mercury if you need to.

Here’s a chart for the final morning of 2018. Notice that the moon is located above the planets, poised to sweep past them as the year begins:

The moon and planets on December 31, the final morning of 2018. Look east, the direction of sunrise, before the sun comes up.

Can you find Mercury? Note that – on December 31 and January 1 – the lit side of the lunar crescent points down into the line up of planets in the morning sky. Look for Mercury close to the horizon, along line with the moon, Venus and Jupiter, with the unaided eye or binoculars.

Our sky chart is designed for mid-northern North American latitudes. But this chart will work for you, too, from other parts of the globe. At mid-northern latitudes in the world’s Eastern Hemisphere, the moon will appear offset a little with respect to the planets. Everything is moving, after all, with the moon moving in orbit around Earth and Earth itself spinning on its axis.

If you’re in the Southern Hemisphere, the moon and planets will be aligned differently relative to your horizon. That is, a line between them will point downward from left to right, instead of downward from right to left as in the Northern Hemisphere.

Still, for all of us, these planets are visible in the east before sunup, with the moon moving past them! For all of us, Venus will appear highest, Jupiter next-highest, and Mercury closest to the horizon.

By the way, we received many beautiful photos earlier this month, as Jupiter was first coming into view in the morning sky. It swept past Mercury around December 21. Photos of the Jupiter-Mercury conjunction here. Now Mercury is heading back toward the sunrise, and Jupiter is ascending higher in the morning sky. It’ll have a wonderful conjunction with Venus in the coming month.

Matthew Chin in Hong Kong caught Mercury and Jupiter on December 22, 2018, when – from his location on the globe – they appeared side by side. Thanks, Matthew!

By the way, if you live at mid-northern latitudes, you’re now waking up to your latest sunrises of the year. Take advantage of the late sunrises to see the grand sky show in the coming mornings, as the moon slides past the planets Venus, Jupiter, and Mercury!

Bottom line: The last morning of 2018 and 1st mornings of 2019 will feature a dazzling line-up of the moon and 3 planets. Here are tips on how to see the moon sweep past Venus, Jupiter and Mercury. Great start to the New Year!

from EarthSky http://bit.ly/2Qe79uV