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

Two faces back to back one young the other old

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.

Earth's orbit showing perihelion. Image credit: NASA

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

Two faces back to back one young the other old

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.

Earth's orbit showing perihelion. Image credit: NASA

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) 

Hurricane Michael Impact on Mexico Beach Florida 

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

Calgary Flooding

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...

2018 Toon 52

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...

 2018 Poster 52


SkS Week in Review... 



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) 

Hurricane Michael Impact on Mexico Beach Florida 

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

Calgary Flooding

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...

2018 Toon 52

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...

 2018 Poster 52


SkS Week in Review... 



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

2018 SkS Weekly Climate Change & Global Warming News Roundup #52

A chronological listing of news articles posted on the Skeptical Science Facebook Page during the past week, i.e., Sun, Dec 23 through Sat, Dec 30

Editor's Pick

Green New Deal: what is the progressive plan, and is it technically possible?

The idea, central to Ocasio-Cortez’s campaign, aims to eliminate greenhouse gas pollution – but lacks key political support

Sunrise Movement Sit-In, Pelosi's Office, Dec 10 2018

Members of the Sunrise Movement advocate for the Green New Deal in Nancy Pelosi’s office on 10 December. Photograph: Michael Brochstein/Zuma Wire/Rex/Shutterstock

Most US voters would support a “Green New Deal”, for the country to transform its infrastructure with a rapid shift to clean energy. But while the idea is gaining attention on Capitol Hill, it lacks key political support.

According to a survey from the Yale Climate Change Communicationprogram, 81% of voters backed its description of a Green New Deal.

Similar plans vary in detail, but all are inspired by the New Deal that Franklin Delano Roosevelt launched to battle the effects of the Great Depression. The idea was central to the high-profile campaign of Alexandria Ocasio-Cortez, the young Democratic socialist from New York who won a US House seat in November. Ocasio-Cortez and the youth-led Sunrise Movement are encouraging Democrats, who will retake the House majority in January, to produce a blueprint.

Their Green New Deal would center around creating new jobs and lessening inequality. Aiming to virtually eliminate US greenhouse gas pollution in a decade, it would be radical compared with other climate proposals. It would require massive government spending.

Dozens of Democrats have signaled support, including potential 2020 presidential candidates Bernie Sanders and Cory Booker. This month, New York’s Governor Andrew Cuomo said his state would launch its own Green New Deal, seeking carbon-neutral electricity by 2040.

But Nancy Pelosi, Democrats’ nominee to run the House, has not agreed to direct a select committee on climate change to focus on the strategy. 

Green New Deal: what is the progressive plan, and is it technically possible? by Emily Holden, Environment, Guardian, Dec 29, 2018


Links posted on Facebook

Sun Dec 23, 2018

Mon Dec 24, 2018

Tue Dec 25, 2018

Wed Dec 26, 2018

Thu Dec 27, 2018

Fri Dec 28, 2018

Sat Dec 29, 2018



from Skeptical Science http://bit.ly/2AjTHAw
A chronological listing of news articles posted on the Skeptical Science Facebook Page during the past week, i.e., Sun, Dec 23 through Sat, Dec 30

Editor's Pick

Green New Deal: what is the progressive plan, and is it technically possible?

The idea, central to Ocasio-Cortez’s campaign, aims to eliminate greenhouse gas pollution – but lacks key political support

Sunrise Movement Sit-In, Pelosi's Office, Dec 10 2018

Members of the Sunrise Movement advocate for the Green New Deal in Nancy Pelosi’s office on 10 December. Photograph: Michael Brochstein/Zuma Wire/Rex/Shutterstock

Most US voters would support a “Green New Deal”, for the country to transform its infrastructure with a rapid shift to clean energy. But while the idea is gaining attention on Capitol Hill, it lacks key political support.

According to a survey from the Yale Climate Change Communicationprogram, 81% of voters backed its description of a Green New Deal.

Similar plans vary in detail, but all are inspired by the New Deal that Franklin Delano Roosevelt launched to battle the effects of the Great Depression. The idea was central to the high-profile campaign of Alexandria Ocasio-Cortez, the young Democratic socialist from New York who won a US House seat in November. Ocasio-Cortez and the youth-led Sunrise Movement are encouraging Democrats, who will retake the House majority in January, to produce a blueprint.

Their Green New Deal would center around creating new jobs and lessening inequality. Aiming to virtually eliminate US greenhouse gas pollution in a decade, it would be radical compared with other climate proposals. It would require massive government spending.

Dozens of Democrats have signaled support, including potential 2020 presidential candidates Bernie Sanders and Cory Booker. This month, New York’s Governor Andrew Cuomo said his state would launch its own Green New Deal, seeking carbon-neutral electricity by 2040.

But Nancy Pelosi, Democrats’ nominee to run the House, has not agreed to direct a select committee on climate change to focus on the strategy. 

Green New Deal: what is the progressive plan, and is it technically possible? by Emily Holden, Environment, Guardian, Dec 29, 2018


Links posted on Facebook

Sun Dec 23, 2018

Mon Dec 24, 2018

Tue Dec 25, 2018

Wed Dec 26, 2018

Thu Dec 27, 2018

Fri Dec 28, 2018

Sat Dec 29, 2018



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

New research, December 17-23, 2018

A selection of new climate related research articles is shown below.

Couple of hiatus papers (including Skeptical Science authors)

A fluctuation in surface temperature in historical context: reassessment and retrospective on the evidence (open access)

The 'pause' in global warming in historical context: (II). Comparing models to observations (open access)

Climate change mitigation

Climate change communication

Framing Climate Uncertainty: Frame Choices Reveal and Influence Climate Change Beliefs

It is Always Dry Here: Examining Perceptions about Drought and Climate Change in the Southern High Plains

Relationship‐building between climate scientists and publics as an alternative to information transfer (open access)

Climate Policy

What future for the voluntary carbon offset market after Paris? An explorative study based on the Discursive Agency Approach

Quantifying the potential for consumer-oriented policy to reduce European and foreign carbon emissions (open access)

Norms and flexibility: Comparing two mitigation policies implemented in Shanghai

Review and assessment of energy policy developments in Chile

Interactions between federal and state policies for reducing vehicle emissions

Energy production

The Story of an Emerging Energy Issue: National Television News Coverage of Fracking in the United States

The China wind paradox: The role of state-owned enterprises in wind power investment versus wind curtailment

The green flings: Norwegian oil and gas industry’s engagement in offshore wind power

Historical trends in global energy policy and renewable power system issues in Sub-Saharan Africa: The case of solar PV

A comprehensive evaluation of the development and utilization of China's regional renewable energy

Linking soy oil demand from the US Renewable Fuel Standard to palm oil expansion through an analysis on vegetable oil price elasticities

How to reach the EU renewables target by 2030? An analysis of the governance framework

Multi-objective planning of energy storage technologies for a fully renewable system: Implications for the main stakeholders in Chile

Decarbonising domestic heating: What is the peak GB demand? (open access)

Watered down? Civil society organizations and hydropower development in the Darjeeling and Sikkim regions, Eastern Himalaya: A comparative study

The role of biomass in China's long-term mitigation toward the Paris climate goals (open access)

Impact of off-farm income on household energy expenditures in China: Implications for rural energy transition

Exploring public perceptions of benefits and risks, trust, and acceptance of nuclear energy in Thailand and Vietnam: A qualitative approach

Regulating Japan's nuclear power industry to achieve zero-accidents

Response of electricity sector air pollution emissions to drought conditions in the western United States (open access)

Fluvial organic carbon fluxes from oil palm plantations on tropical peatland (open access)

Emission savings

Health and economic benefits of cleaner residential heating in the Beijing–Tianjin–Hebei region in China

Synergy potential between climate change mitigation and forest conservation policies in the Indonesian forest sector: implications for achieving multiple sustainable development objectives

Informing energy consumption uncertainty: an analysis of energy data revisions (open access)

Reducing nitrogen footprints of consumer-level food loss and protein overconsumption in Japan, considering gender and age differences (open access)

Data center growth in the United States: decoupling the demand for services from electricity use (open access)

Linking wastes and climate change: Bandwagoning, contention, and global governance

The challenges of using satellite data sets to assess historical land use change and associated greenhouse gas emissions: a case study of three Indonesian provinces

The long-term relationship between emissions and economic growth for SO2, CO2, and BC (open access)

Climate change mitigation strategies for agriculture: an analysis of nationally determined contributions, biennial reports and biennial update reports

Geoengineering

Reducing sea level rise with submerged barriers and dams in Greenland (open access)

Carbon leakage from geological storage sites: Implications for carbon trading

Climate change

Temperature, precipitation, wind

The realized warming fraction: a multi-model sensitivity study (open access)

Long‐Term Changes in Wintertime Temperature Extremes in Moscow and their Relation to Regional Atmospheric Dynamics

Extreme events

Changes in the severity of compound drought and hot extremes over global land areas (open access)

Adapting attribution science to the climate extremes of tomorrow (open access)

A climatology of thunderstorms across Europe from a synthesis of multiple data sources

The 'Day Zero' Cape Town drought and the poleward migration of moisture corridors (open access)

Forcings and feedbacks

Exploring How Eruption Source Parameters Affect Volcanic Radiative Forcing Using Statistical Emulation

Spatial distribution of melt‐season cloud radiative effects over Greenland: Evaluating satellite observations, reanalyses, and model simulations against in situ measurements

Global Observed and Modeled Impacts of Irrigation on Surface Temperature

Atmospheric Carbon Dioxide variability at Aigüestortes, Central Pyrenees, Spain

Cryosphere

Natural variability has slowed the decline in western‐US snowpack since the 1980s

Snow depth reconstruction over last century: Trend and distribution in the Tianshan Mountains, China

West Antarctic Surface Melt Event of January 2016 Facilitated by Foehn Warming

Velocity response of Petermann Glacier, northwest Greenland, to past and future calving events (open access)

Freshwater Export in the East Greenland Current Freshens the North Atlantic

Global sea-level contribution from Arctic land ice: 1971–2017 (open access)

Hydrosphere 

Watershed-scale retrospective drought analysis and seasonal forecasting using multi-layer, high-resolution simulated soil moisture for Southeastern U.S (open access)

Investigating impacts of drought and disturbance on evapotranspiration over a forested landscape in North Carolina, USA using high spatiotemporal resolution remotely sensed data (open access)

Atmospheric and oceanic circulation

Anthropogenically forced decadal change of South Asian summer monsoon across the mid‐1990s

Global meridional overturning circulation inferred from a data‐constrained ocean & sea‐ice model

On the Drivers of Decadal Variability of the Gulf Stream North Wall

Estimating the Deep Overturning Transport Variability at 26° N Using Bottom Pressure Recorders

A Radar-based Climatology of Mesoscale Convective Systems in the United States

Increased Frequency of Extreme Tropical Deep Convection: AIRS Observations and Climate Model Predictions

The asymmetry of vertical velocity in current and future climate

On the role of the Eastern Pacific teleconnection in ENSO impacts on wintertime weather over East Asia and North America

Stability of the arctic halocline: a new indicator of arctic climate change (open access)

Carbon and nitrogen cycles

Soil organic carbon stability in forests: distinct effects of tree species identity and traits

Detecting changes in Arctic methane emissions: limitations of the inter-polar difference of atmospheric mole fractions (open access)

Attribution of recent increases in atmospheric methane through 3-D inverse modelling (open access)

Using Stable Carbon Isotopes of Seasonal Ecosystem Respiration to Determine Permafrost Carbon Loss

Climate change impacts 

Mankind

Predicting Yellow Fever Through Species Distribution Modeling of Virus, Vector, and Monkeys

The effect characteristics of temperature on stroke mortality in Inner Mongolia and globally

What are the impacts of tropical cyclones on employment? –An Analysis Based on Meta-regression

Maladaptation in Nordic Agriculture (open access)

Direct and indirect effects of CO2 increase on crop yield in West Africa

Adapting to changing climate through improving adaptive capacity at the local level – The case of smallholder horticultural producers in Ghana (open access)

Cities in Asia: how are they adapting to climate change?

Climate change adaptation: a systematic review on domains and indicators

Mapping summer tourism climate resources in China

Adapting and coping with climate change in temperate forests

Assessing sowing window and water availability of rainfed crops in eastern Indian state of Bihar for climate smart agricultural production

Biosphere

Role of host genetics and heat tolerant algal symbionts in sustaining populations of the endangered coral Orbicella faveolata in the Florida Keys with ocean warming

Bottom-up effects on biomechanical properties of the skeletal plates of the sea urchin Paracentrotus lividus (Lamarck, 1816) in an acidified ocean scenario

Body size, reef area and temperature predict global reef‐fish species richness across spatial scales

Warmer and browner waters decrease fish biomass production

Elevated CO2 impairs olfactory‐mediated neural and behavioral responses and gene expression in ocean‐phase coho salmon (Oncorhynchus kisutch) (open access)

Divergent responses of Atlantic cod to ocean acidification and food limitation

Drying drives decline in muskrat population in the Peace-Athabasca Delta, Canada (open access)

Thermal constraints on body size depend on the population's position within the species’ thermal range in temperate songbirds

Climate change resilience of a globally important sea turtle nesting population (open access)

Climate readiness of recovery plans for threatened Australian species

Other impacts

Origin and location of new Arctic islands and straits due to glacial recession (open access)

Other papers

Palaeoclimatology

Asymmetric dynamical ocean responses in warming icehouse and cooling greenhouse climates (open access)

What climate signal is contained in decadal- to centennial-scale isotope variations from Antarctic ice cores? (open access)

Reconstruction of dust storm frequency in China using the SST signals recorded in coral reefs

Other environmental issues 

Diminishing clear winter skies in Beijing towards a possible future (open access)



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

A selection of new climate related research articles is shown below.

Couple of hiatus papers (including Skeptical Science authors)

A fluctuation in surface temperature in historical context: reassessment and retrospective on the evidence (open access)

The 'pause' in global warming in historical context: (II). Comparing models to observations (open access)

Climate change mitigation

Climate change communication

Framing Climate Uncertainty: Frame Choices Reveal and Influence Climate Change Beliefs

It is Always Dry Here: Examining Perceptions about Drought and Climate Change in the Southern High Plains

Relationship‐building between climate scientists and publics as an alternative to information transfer (open access)

Climate Policy

What future for the voluntary carbon offset market after Paris? An explorative study based on the Discursive Agency Approach

Quantifying the potential for consumer-oriented policy to reduce European and foreign carbon emissions (open access)

Norms and flexibility: Comparing two mitigation policies implemented in Shanghai

Review and assessment of energy policy developments in Chile

Interactions between federal and state policies for reducing vehicle emissions

Energy production

The Story of an Emerging Energy Issue: National Television News Coverage of Fracking in the United States

The China wind paradox: The role of state-owned enterprises in wind power investment versus wind curtailment

The green flings: Norwegian oil and gas industry’s engagement in offshore wind power

Historical trends in global energy policy and renewable power system issues in Sub-Saharan Africa: The case of solar PV

A comprehensive evaluation of the development and utilization of China's regional renewable energy

Linking soy oil demand from the US Renewable Fuel Standard to palm oil expansion through an analysis on vegetable oil price elasticities

How to reach the EU renewables target by 2030? An analysis of the governance framework

Multi-objective planning of energy storage technologies for a fully renewable system: Implications for the main stakeholders in Chile

Decarbonising domestic heating: What is the peak GB demand? (open access)

Watered down? Civil society organizations and hydropower development in the Darjeeling and Sikkim regions, Eastern Himalaya: A comparative study

The role of biomass in China's long-term mitigation toward the Paris climate goals (open access)

Impact of off-farm income on household energy expenditures in China: Implications for rural energy transition

Exploring public perceptions of benefits and risks, trust, and acceptance of nuclear energy in Thailand and Vietnam: A qualitative approach

Regulating Japan's nuclear power industry to achieve zero-accidents

Response of electricity sector air pollution emissions to drought conditions in the western United States (open access)

Fluvial organic carbon fluxes from oil palm plantations on tropical peatland (open access)

Emission savings

Health and economic benefits of cleaner residential heating in the Beijing–Tianjin–Hebei region in China

Synergy potential between climate change mitigation and forest conservation policies in the Indonesian forest sector: implications for achieving multiple sustainable development objectives

Informing energy consumption uncertainty: an analysis of energy data revisions (open access)

Reducing nitrogen footprints of consumer-level food loss and protein overconsumption in Japan, considering gender and age differences (open access)

Data center growth in the United States: decoupling the demand for services from electricity use (open access)

Linking wastes and climate change: Bandwagoning, contention, and global governance

The challenges of using satellite data sets to assess historical land use change and associated greenhouse gas emissions: a case study of three Indonesian provinces

The long-term relationship between emissions and economic growth for SO2, CO2, and BC (open access)

Climate change mitigation strategies for agriculture: an analysis of nationally determined contributions, biennial reports and biennial update reports

Geoengineering

Reducing sea level rise with submerged barriers and dams in Greenland (open access)

Carbon leakage from geological storage sites: Implications for carbon trading

Climate change

Temperature, precipitation, wind

The realized warming fraction: a multi-model sensitivity study (open access)

Long‐Term Changes in Wintertime Temperature Extremes in Moscow and their Relation to Regional Atmospheric Dynamics

Extreme events

Changes in the severity of compound drought and hot extremes over global land areas (open access)

Adapting attribution science to the climate extremes of tomorrow (open access)

A climatology of thunderstorms across Europe from a synthesis of multiple data sources

The 'Day Zero' Cape Town drought and the poleward migration of moisture corridors (open access)

Forcings and feedbacks

Exploring How Eruption Source Parameters Affect Volcanic Radiative Forcing Using Statistical Emulation

Spatial distribution of melt‐season cloud radiative effects over Greenland: Evaluating satellite observations, reanalyses, and model simulations against in situ measurements

Global Observed and Modeled Impacts of Irrigation on Surface Temperature

Atmospheric Carbon Dioxide variability at Aigüestortes, Central Pyrenees, Spain

Cryosphere

Natural variability has slowed the decline in western‐US snowpack since the 1980s

Snow depth reconstruction over last century: Trend and distribution in the Tianshan Mountains, China

West Antarctic Surface Melt Event of January 2016 Facilitated by Foehn Warming

Velocity response of Petermann Glacier, northwest Greenland, to past and future calving events (open access)

Freshwater Export in the East Greenland Current Freshens the North Atlantic

Global sea-level contribution from Arctic land ice: 1971–2017 (open access)

Hydrosphere 

Watershed-scale retrospective drought analysis and seasonal forecasting using multi-layer, high-resolution simulated soil moisture for Southeastern U.S (open access)

Investigating impacts of drought and disturbance on evapotranspiration over a forested landscape in North Carolina, USA using high spatiotemporal resolution remotely sensed data (open access)

Atmospheric and oceanic circulation

Anthropogenically forced decadal change of South Asian summer monsoon across the mid‐1990s

Global meridional overturning circulation inferred from a data‐constrained ocean & sea‐ice model

On the Drivers of Decadal Variability of the Gulf Stream North Wall

Estimating the Deep Overturning Transport Variability at 26° N Using Bottom Pressure Recorders

A Radar-based Climatology of Mesoscale Convective Systems in the United States

Increased Frequency of Extreme Tropical Deep Convection: AIRS Observations and Climate Model Predictions

The asymmetry of vertical velocity in current and future climate

On the role of the Eastern Pacific teleconnection in ENSO impacts on wintertime weather over East Asia and North America

Stability of the arctic halocline: a new indicator of arctic climate change (open access)

Carbon and nitrogen cycles

Soil organic carbon stability in forests: distinct effects of tree species identity and traits

Detecting changes in Arctic methane emissions: limitations of the inter-polar difference of atmospheric mole fractions (open access)

Attribution of recent increases in atmospheric methane through 3-D inverse modelling (open access)

Using Stable Carbon Isotopes of Seasonal Ecosystem Respiration to Determine Permafrost Carbon Loss

Climate change impacts 

Mankind

Predicting Yellow Fever Through Species Distribution Modeling of Virus, Vector, and Monkeys

The effect characteristics of temperature on stroke mortality in Inner Mongolia and globally

What are the impacts of tropical cyclones on employment? –An Analysis Based on Meta-regression

Maladaptation in Nordic Agriculture (open access)

Direct and indirect effects of CO2 increase on crop yield in West Africa

Adapting to changing climate through improving adaptive capacity at the local level – The case of smallholder horticultural producers in Ghana (open access)

Cities in Asia: how are they adapting to climate change?

Climate change adaptation: a systematic review on domains and indicators

Mapping summer tourism climate resources in China

Adapting and coping with climate change in temperate forests

Assessing sowing window and water availability of rainfed crops in eastern Indian state of Bihar for climate smart agricultural production

Biosphere

Role of host genetics and heat tolerant algal symbionts in sustaining populations of the endangered coral Orbicella faveolata in the Florida Keys with ocean warming

Bottom-up effects on biomechanical properties of the skeletal plates of the sea urchin Paracentrotus lividus (Lamarck, 1816) in an acidified ocean scenario

Body size, reef area and temperature predict global reef‐fish species richness across spatial scales

Warmer and browner waters decrease fish biomass production

Elevated CO2 impairs olfactory‐mediated neural and behavioral responses and gene expression in ocean‐phase coho salmon (Oncorhynchus kisutch) (open access)

Divergent responses of Atlantic cod to ocean acidification and food limitation

Drying drives decline in muskrat population in the Peace-Athabasca Delta, Canada (open access)

Thermal constraints on body size depend on the population's position within the species’ thermal range in temperate songbirds

Climate change resilience of a globally important sea turtle nesting population (open access)

Climate readiness of recovery plans for threatened Australian species

Other impacts

Origin and location of new Arctic islands and straits due to glacial recession (open access)

Other papers

Palaeoclimatology

Asymmetric dynamical ocean responses in warming icehouse and cooling greenhouse climates (open access)

What climate signal is contained in decadal- to centennial-scale isotope variations from Antarctic ice cores? (open access)

Reconstruction of dust storm frequency in China using the SST signals recorded in coral reefs

Other environmental issues 

Diminishing clear winter skies in Beijing towards a possible future (open access)



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

Animal world is awesome: 3 essential reads

Some tropical frogs may be developing resistance to a fungus that has devastated species like Atelopus varius, the variable harlequin frog. Image via Brian Gratwicke/Wikimedia.

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

By Jennifer Weeks, The Conversation

As the effects of climate change become more apparent and widespread, it’s easy to feel that our species is the biggest threat to life on Earth. Indeed, one recent study warned that extreme environmental change could cause an extinction domino effect, in which one species dies out, then another species that depends on it, and so on.

When headlines like this seem overwhelming, I remind myself that scholars are still learning about all kinds of amazing life forms. Here are three 2018 stories that remind us how awesome the animal world is.

Fossa (Cryptoprocta ferox) at the Houston Zoo. Image via Josh Henderson.

1. Madagascar’s ultra-elusive fossa

If Americans have even heard of fossa (Cryptoprocta ferox), a catlike carnivore found only on Madagascar, it’s usually from the animated Madagascar movies. Fossa are the island’s real-life apex predator, but are so rare and hard to track that scientists know very little about them – even how many there are.

Penn State University doctoral candidate Asia Murphy was part of a seven-year project that documented fossa numbers with camera traps. By focusing on features like scars, ear nicks, and tail width and kinkiness, scientists could pick out certain fossa from the population and “follow” them from one camera to another. Their survey data and population density estimates will support habitat protection efforts.

Murphy wrote:

In all of this time, I never personally saw a fossa, but two local field assistants saw fossa in the trees once or twice.

She’d like to see these animals get more attention from the conservation world, and suggests that it’s time for #FossaFriday.

2. Forests at the bottom of the sea

Scientists go to many extremes to find life forms. In August, a research expedition off the coast of South Carolina found a huge series of coldwater coral “forests,” covering about 85 miles, in water more than three miles deep.

Deep sea corals off Florida. Image via NOAA.

Florida State University research scientist Sandra Brooke said that coldwater corals

… are just as ecologically important as their shallow water counterparts.

Brooke was on the cruise and went down in the Alvin submersible to see coral formations on the ocean floor.

Scientists from the August 2018 Deep Search expedition discuss the significance of finding a huge, previously undetected deepwater coral reef off the U.S. East Coast.

Unlike shallow-water corals, which get much of their energy from sunlight, deepwater corals feed on organic material and zooplankton that drift to them on ocean currents. They grow extremely slowly: One black coral is estimated to be more than 4,200 years old. Industrial fishing, offshore drilling and seabed mining could damage deepsea reefs before they’re even mapped – all the more reason, Brooke asserts, to get out and find them now.

3. Fending off frog plague?

In recent years a chytrid pathogen abbreviated as Bd has caused mass dieoffs of frog populations around the world. But in a study published in March 2018, Vanderbilt University biologist Louise Rollins-Smith and others reported that some tropical frogs in Panama appeared to be developing improved skin defenses against Bd – big news for amphibian researchers.

Panamanian golden frogs (Atelopus zeteki) are listed as critically endangered, and may be extinct in the wild. Image via Jeff Kubina.

Rollins-Smith explained:

Many amphibians have granular glands in their skin that synthesize and sequester antimicrobial peptides and other defensive molecules. When the animal is alarmed or injured, the defensive molecules are released to cleanse and protect the skin.

Scientists don’t know how, but these defenses seemed to improve after Bd entered some frog communities.

Alarmingly, a second chytrid fungus, abbreviated as Bsal, has emerged in Europe and is thought to seriously threaten salamanders. Scholars are urging the U.S. government to suspend all imports of frogs and salamanders until this new threat is better understood. Yet more reason to keep learning about wild species, seen and unseen, all around us.

Bottom line: Three stories from 2018 that remind us how awesome the animal world is.

Jennifer Weeks, Environment + Energy Editor, The Conversation

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

The Conversation



from EarthSky http://bit.ly/2Tdn9yU

Some tropical frogs may be developing resistance to a fungus that has devastated species like Atelopus varius, the variable harlequin frog. Image via Brian Gratwicke/Wikimedia.

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

By Jennifer Weeks, The Conversation

As the effects of climate change become more apparent and widespread, it’s easy to feel that our species is the biggest threat to life on Earth. Indeed, one recent study warned that extreme environmental change could cause an extinction domino effect, in which one species dies out, then another species that depends on it, and so on.

When headlines like this seem overwhelming, I remind myself that scholars are still learning about all kinds of amazing life forms. Here are three 2018 stories that remind us how awesome the animal world is.

Fossa (Cryptoprocta ferox) at the Houston Zoo. Image via Josh Henderson.

1. Madagascar’s ultra-elusive fossa

If Americans have even heard of fossa (Cryptoprocta ferox), a catlike carnivore found only on Madagascar, it’s usually from the animated Madagascar movies. Fossa are the island’s real-life apex predator, but are so rare and hard to track that scientists know very little about them – even how many there are.

Penn State University doctoral candidate Asia Murphy was part of a seven-year project that documented fossa numbers with camera traps. By focusing on features like scars, ear nicks, and tail width and kinkiness, scientists could pick out certain fossa from the population and “follow” them from one camera to another. Their survey data and population density estimates will support habitat protection efforts.

Murphy wrote:

In all of this time, I never personally saw a fossa, but two local field assistants saw fossa in the trees once or twice.

She’d like to see these animals get more attention from the conservation world, and suggests that it’s time for #FossaFriday.

2. Forests at the bottom of the sea

Scientists go to many extremes to find life forms. In August, a research expedition off the coast of South Carolina found a huge series of coldwater coral “forests,” covering about 85 miles, in water more than three miles deep.

Deep sea corals off Florida. Image via NOAA.

Florida State University research scientist Sandra Brooke said that coldwater corals

… are just as ecologically important as their shallow water counterparts.

Brooke was on the cruise and went down in the Alvin submersible to see coral formations on the ocean floor.

Scientists from the August 2018 Deep Search expedition discuss the significance of finding a huge, previously undetected deepwater coral reef off the U.S. East Coast.

Unlike shallow-water corals, which get much of their energy from sunlight, deepwater corals feed on organic material and zooplankton that drift to them on ocean currents. They grow extremely slowly: One black coral is estimated to be more than 4,200 years old. Industrial fishing, offshore drilling and seabed mining could damage deepsea reefs before they’re even mapped – all the more reason, Brooke asserts, to get out and find them now.

3. Fending off frog plague?

In recent years a chytrid pathogen abbreviated as Bd has caused mass dieoffs of frog populations around the world. But in a study published in March 2018, Vanderbilt University biologist Louise Rollins-Smith and others reported that some tropical frogs in Panama appeared to be developing improved skin defenses against Bd – big news for amphibian researchers.

Panamanian golden frogs (Atelopus zeteki) are listed as critically endangered, and may be extinct in the wild. Image via Jeff Kubina.

Rollins-Smith explained:

Many amphibians have granular glands in their skin that synthesize and sequester antimicrobial peptides and other defensive molecules. When the animal is alarmed or injured, the defensive molecules are released to cleanse and protect the skin.

Scientists don’t know how, but these defenses seemed to improve after Bd entered some frog communities.

Alarmingly, a second chytrid fungus, abbreviated as Bsal, has emerged in Europe and is thought to seriously threaten salamanders. Scholars are urging the U.S. government to suspend all imports of frogs and salamanders until this new threat is better understood. Yet more reason to keep learning about wild species, seen and unseen, all around us.

Bottom line: Three stories from 2018 that remind us how awesome the animal world is.

Jennifer Weeks, Environment + Energy Editor, The Conversation

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

The Conversation



from EarthSky http://bit.ly/2Tdn9yU

Top 5 most popular posts 2018

Scientists expect 1st direct black hole image soon: This was one of the most popular posts at EarthSky all year, and no wonder. It’s exciting! In March, scientists said they expect to obtain the 1st-ever direct image of a black hole’s event horizon, soon. Read more.

Situation at Kilauea Volcano ‘steadily worsening’: Hawaii’s Kilauea Volcano erupted for weeks in mid-2018, creating fissure in the land, tossing out large boulders and releasing of toxic gases in a plume called a laze when molten lava met the sea. Images and videos here. Read more.

Fragments of asteroid 2018 LA found in Botswana: Astronomers detected a small asteroid just 8 hours before it struck Earth’s atmosphere over southern Africa on June 2, producing a terrific explosion. A few days later, researchers reported finding its meteorites. Read more.

Brightest Mars since 2003: Why was Mars so bright and red in our sky in July and August 2018? Here’s the answer. Read more.

Mars is very bright now! And it’s very red in color. Dennis Chabot of POSNE NightSky captured this photo of Mars on July 21, 2018.

Curiosity finds strange object on the surface of Mars: The Mars Curiosity rover captured images of this strange object on the planet’s surface on August 13. What is it? NASA scientists have figured it out. Read more.

Image via NASA/JPL-Caltech/MSSS.

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

Bottom line: Read the five most popular posts at earthsky.org in 2018.



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

Scientists expect 1st direct black hole image soon: This was one of the most popular posts at EarthSky all year, and no wonder. It’s exciting! In March, scientists said they expect to obtain the 1st-ever direct image of a black hole’s event horizon, soon. Read more.

Situation at Kilauea Volcano ‘steadily worsening’: Hawaii’s Kilauea Volcano erupted for weeks in mid-2018, creating fissure in the land, tossing out large boulders and releasing of toxic gases in a plume called a laze when molten lava met the sea. Images and videos here. Read more.

Fragments of asteroid 2018 LA found in Botswana: Astronomers detected a small asteroid just 8 hours before it struck Earth’s atmosphere over southern Africa on June 2, producing a terrific explosion. A few days later, researchers reported finding its meteorites. Read more.

Brightest Mars since 2003: Why was Mars so bright and red in our sky in July and August 2018? Here’s the answer. Read more.

Mars is very bright now! And it’s very red in color. Dennis Chabot of POSNE NightSky captured this photo of Mars on July 21, 2018.

Curiosity finds strange object on the surface of Mars: The Mars Curiosity rover captured images of this strange object on the planet’s surface on August 13. What is it? NASA scientists have figured it out. Read more.

Image via NASA/JPL-Caltech/MSSS.

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

Bottom line: Read the five most popular posts at earthsky.org in 2018.



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

Why can’t we feel Earth’s spin?

Image via NASA.gov

Earth spins on its axis once in every 24-hour day. At Earth’s equator, the speed of Earth’s spin is about 1,000 miles per hour (1,600 kph). The day-night has carried you around in a grand circle under the stars every day of your life, and yet you don’t feel Earth spinning. Why not? It’s because you and everything else – including Earth’s oceans and atmosphere – are spinning along with the Earth at the same constant speed.

It’s only if Earth stopped spinning, suddenly, that we’d feel it. Then it would be a feeling similar to riding along in a fast car, and having someone slam on the brakes!

Think about riding in a car or flying in a plane. As long as the ride is going smoothly, you can almost convince yourself you’re not moving. A jumbo jet flies at about 500 miles per hour (about 800 km per hour), or about half as fast as the Earth spins at its equator. But, while you’re riding on that jet, if you close your eyes, you don’t feel like you’re moving at all. And when the flight attendant comes by and pours coffee into your cup, the coffee doesn’t fly to the back of the plane. That’s because the coffee, the cup and you are all moving at the same rate as the plane.

Now think about what would happen if the car or plane wasn’t moving at a constant rate, but instead speeding up and slowing down. Then, when the flight attendant poured your coffee … look out!

If you're drinking coffee in a steadily moving car or airplane, no problem. But if the car or plane speeds up or slows down, your coffee sloshes and maybe spills. Likewise, as long as Earth spins steadily, we can't feel it move. Image by H.C. Mayer and R. Krechetnikov, via Science.

If you’re drinking coffee in a steadily moving car or airplane, no problem. But if the car or plane speeds up or slows down, your coffee sloshes and maybe spills. Likewise, as long as Earth spins steadily, we can’t feel it move. Image by H.C. Mayer and R. Krechetnikov, via Science.

Earth is moving at a fixed rate, and we’re all moving along with it, and that’s why we don’t feel Earth’s spin. If Earth’s spin were suddenly to speed up or slow down, you would definitely feel it.

The constant spin of the Earth had our ancestors pretty confused about the true nature of the cosmos. They noticed that the stars, and the sun and the moon, all appeared to move above the Earth. Because they couldn’t feel Earth move, they logically interpreted this observation to mean that Earth was stationary and “the heavens” moved above us.

With the notable exception of the early Greek scientist Aristarchus, who first proposed a heliocentric (sun-centered) model of the universe hundreds of years B.C.E., the world’s great thinkers upheld the geocentric (Earth-centered) idea of the cosmos for many centuries.

It wasn’t until the 16th Century that the heliocentric model of Copernicus began to be discussed and understood. While not without errors, Copernicus’ model eventually convinced the world that Earth spun on its axis beneath the stars … and also moved in orbit around the sun.

Sky wheeling around Polaris, the North Star.

A time exposure of the northern sky, revealing the apparent motion of all the stars around Polaris. In fact, this apparent motion is due to Earth’s spin. Image via Shutterstock

Bottom line: We don’t feel Earth rotating on its axis because Earth spins steadily – and moves at a constant rate in orbit around the sun – carrying you as a passenger right along with it.



from EarthSky http://bit.ly/2ET0Smj

Image via NASA.gov

Earth spins on its axis once in every 24-hour day. At Earth’s equator, the speed of Earth’s spin is about 1,000 miles per hour (1,600 kph). The day-night has carried you around in a grand circle under the stars every day of your life, and yet you don’t feel Earth spinning. Why not? It’s because you and everything else – including Earth’s oceans and atmosphere – are spinning along with the Earth at the same constant speed.

It’s only if Earth stopped spinning, suddenly, that we’d feel it. Then it would be a feeling similar to riding along in a fast car, and having someone slam on the brakes!

Think about riding in a car or flying in a plane. As long as the ride is going smoothly, you can almost convince yourself you’re not moving. A jumbo jet flies at about 500 miles per hour (about 800 km per hour), or about half as fast as the Earth spins at its equator. But, while you’re riding on that jet, if you close your eyes, you don’t feel like you’re moving at all. And when the flight attendant comes by and pours coffee into your cup, the coffee doesn’t fly to the back of the plane. That’s because the coffee, the cup and you are all moving at the same rate as the plane.

Now think about what would happen if the car or plane wasn’t moving at a constant rate, but instead speeding up and slowing down. Then, when the flight attendant poured your coffee … look out!

If you're drinking coffee in a steadily moving car or airplane, no problem. But if the car or plane speeds up or slows down, your coffee sloshes and maybe spills. Likewise, as long as Earth spins steadily, we can't feel it move. Image by H.C. Mayer and R. Krechetnikov, via Science.

If you’re drinking coffee in a steadily moving car or airplane, no problem. But if the car or plane speeds up or slows down, your coffee sloshes and maybe spills. Likewise, as long as Earth spins steadily, we can’t feel it move. Image by H.C. Mayer and R. Krechetnikov, via Science.

Earth is moving at a fixed rate, and we’re all moving along with it, and that’s why we don’t feel Earth’s spin. If Earth’s spin were suddenly to speed up or slow down, you would definitely feel it.

The constant spin of the Earth had our ancestors pretty confused about the true nature of the cosmos. They noticed that the stars, and the sun and the moon, all appeared to move above the Earth. Because they couldn’t feel Earth move, they logically interpreted this observation to mean that Earth was stationary and “the heavens” moved above us.

With the notable exception of the early Greek scientist Aristarchus, who first proposed a heliocentric (sun-centered) model of the universe hundreds of years B.C.E., the world’s great thinkers upheld the geocentric (Earth-centered) idea of the cosmos for many centuries.

It wasn’t until the 16th Century that the heliocentric model of Copernicus began to be discussed and understood. While not without errors, Copernicus’ model eventually convinced the world that Earth spun on its axis beneath the stars … and also moved in orbit around the sun.

Sky wheeling around Polaris, the North Star.

A time exposure of the northern sky, revealing the apparent motion of all the stars around Polaris. In fact, this apparent motion is due to Earth’s spin. Image via Shutterstock

Bottom line: We don’t feel Earth rotating on its axis because Earth spins steadily – and moves at a constant rate in orbit around the sun – carrying you as a passenger right along with it.



from EarthSky http://bit.ly/2ET0Smj

Red sunset from Italy’s Mount Etna

“A ‘burned’ sunset,” wrote Giuseppe Pappa on December 27.

Europe’s most active volcano – Mount Etna on the east coast of Sicily, Italy – began its newest eruption on Christmas Eve 2018. Giuseppe Pappa in Sicily posted the two photos on this page to EarthSky Facebook on December 27. Thanks for sharing, Giuseppe! Read more: Mount Etna volcano eruption and earthquake cause Christmas chaos

A December 27 photo of Mount Etna from Giuseppe Pappa. Click here to go to an interactive version of this photo.

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



from EarthSky http://bit.ly/2Srcwc2

“A ‘burned’ sunset,” wrote Giuseppe Pappa on December 27.

Europe’s most active volcano – Mount Etna on the east coast of Sicily, Italy – began its newest eruption on Christmas Eve 2018. Giuseppe Pappa in Sicily posted the two photos on this page to EarthSky Facebook on December 27. Thanks for sharing, Giuseppe! Read more: Mount Etna volcano eruption and earthquake cause Christmas chaos

A December 27 photo of Mount Etna from Giuseppe Pappa. Click here to go to an interactive version of this photo.

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



from EarthSky http://bit.ly/2Srcwc2

Moon and Spica on December 29 and 30

These next few mornings – December 29 and 30, 2018 – people around the world will see the moon in the vicinity of Spica, the constellation Virgo’s one and only 1st-magnitude star.

As seen from around the world, the moon will be at or near its last quarter phase on the morning of December 29. At last quarter, the moon appears half-illuminated in sunshine and half-immersed in the moon’s own shadow. The lit side of the waning moon always points eastward – or in the direction of sunrise.

Relative to the backdrop stars of the zodiac, the moon travels its own angular diameter of about one-half degree eastward per hour, or approximately 13 degrees eastward per day. For that reason the moon will be closer to Spica on December 30 than it’ll be on December 29.

On the last morning of the year – December 31, 2018 – watch for the moon to line up with the planets Venus, Jupiter and Mercury. Read more.

The last quarter moon happens on December 29 at 9:34 UTC. At U.S. time zones, that places the time of the last quarter moon on December 29 at 5:34 a.m. EDT, 4:34 a.m. CDT, 3:34 a.m. MDT and 2:34 a.m. PDT.

By definition, and in the language of astronomy, the moon at its last quarter phase is at west quadrature – 90 degrees west of the sun in geocentric ecliptic longitude. Technically speaking, the last quarter moon is not exactly 50% illuminated at west quadrature, although the lunar disk certainly looks half lit to the eye. Depending on the month, the illuminated portion of last quarter moon varies from 50.117% to 50.138%.

To be less ambiguous, we could say the moon at the instant that it lies 90 degrees west of the sun is at westquadrature, rather than at last quarter. However, the term last quarter is synonymous with west quadrature, and the term first quarter moon is synonymous with east quadrature.

Not to scale! The illustration shows the moon at dichotomy as seen from Earth, and Earth at quadrature as seen from the moon. The moon resides at the vertex of the right angle. However, when it's the Earth that resides at the vertex of the right angle, then it's moon that's at quadrature as viewed from the Earth, and the Earth that's at dichotomy as seen from the moon.

Not to scale! The illustration shows the moon at dichotomy as seen from Earth, and Earth at quadrature as seen from the moon. The moon resides at the vertex of the right angle. However, when it’s the Earth that resides at the vertex of the right angle, then it’s moon that’s at quadrature as viewed from the Earth, and the Earth that’s at dichotomy as seen from the moon.

The moon is exactly half-illuminated at dichotomy, yet a tiny bit more than half-illuminated at quadrature (quarter moon). The moon always reaches dichotomy (50% illumination) a short while after its first quarter phase; and the moon always reaches its last quarter phase shortly before dichotomy.

When the moon is at quadrature (first or last quarter) in Earth’s sky, then it’s the Earth that’s at dichotomy in the moon’s sky – and vice versa.

Want more? See this cool diagram of dichotomy vs. quadrature via GeoGebra!

Bottom line: On December 29 and 30, 2018, let the waning moon introduce you to Spica, the brightest star in the constellation Virgo the Maiden.



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

These next few mornings – December 29 and 30, 2018 – people around the world will see the moon in the vicinity of Spica, the constellation Virgo’s one and only 1st-magnitude star.

As seen from around the world, the moon will be at or near its last quarter phase on the morning of December 29. At last quarter, the moon appears half-illuminated in sunshine and half-immersed in the moon’s own shadow. The lit side of the waning moon always points eastward – or in the direction of sunrise.

Relative to the backdrop stars of the zodiac, the moon travels its own angular diameter of about one-half degree eastward per hour, or approximately 13 degrees eastward per day. For that reason the moon will be closer to Spica on December 30 than it’ll be on December 29.

On the last morning of the year – December 31, 2018 – watch for the moon to line up with the planets Venus, Jupiter and Mercury. Read more.

The last quarter moon happens on December 29 at 9:34 UTC. At U.S. time zones, that places the time of the last quarter moon on December 29 at 5:34 a.m. EDT, 4:34 a.m. CDT, 3:34 a.m. MDT and 2:34 a.m. PDT.

By definition, and in the language of astronomy, the moon at its last quarter phase is at west quadrature – 90 degrees west of the sun in geocentric ecliptic longitude. Technically speaking, the last quarter moon is not exactly 50% illuminated at west quadrature, although the lunar disk certainly looks half lit to the eye. Depending on the month, the illuminated portion of last quarter moon varies from 50.117% to 50.138%.

To be less ambiguous, we could say the moon at the instant that it lies 90 degrees west of the sun is at westquadrature, rather than at last quarter. However, the term last quarter is synonymous with west quadrature, and the term first quarter moon is synonymous with east quadrature.

Not to scale! The illustration shows the moon at dichotomy as seen from Earth, and Earth at quadrature as seen from the moon. The moon resides at the vertex of the right angle. However, when it's the Earth that resides at the vertex of the right angle, then it's moon that's at quadrature as viewed from the Earth, and the Earth that's at dichotomy as seen from the moon.

Not to scale! The illustration shows the moon at dichotomy as seen from Earth, and Earth at quadrature as seen from the moon. The moon resides at the vertex of the right angle. However, when it’s the Earth that resides at the vertex of the right angle, then it’s moon that’s at quadrature as viewed from the Earth, and the Earth that’s at dichotomy as seen from the moon.

The moon is exactly half-illuminated at dichotomy, yet a tiny bit more than half-illuminated at quadrature (quarter moon). The moon always reaches dichotomy (50% illumination) a short while after its first quarter phase; and the moon always reaches its last quarter phase shortly before dichotomy.

When the moon is at quadrature (first or last quarter) in Earth’s sky, then it’s the Earth that’s at dichotomy in the moon’s sky – and vice versa.

Want more? See this cool diagram of dichotomy vs. quadrature via GeoGebra!

Bottom line: On December 29 and 30, 2018, let the waning moon introduce you to Spica, the brightest star in the constellation Virgo the Maiden.



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