Bar-headed geese in India


Photo Credit: Abhinav Singhai. Visit Abhinav Singhai's Flickr page

Photo Credit: Abhinav Singhai. Visit his Flickr page



EarthSky Facebook friend Abhinav Singhai in India captured this evocative shot of bar-headed geese over Basai Wetlands, a well-known destination for birders near Delhi, India. He said there were hundreds of geese over the wetlands that day.


Thank you, Abhihav!


The bar-headed goose is a fascinating bird, by the way, and one of the world’s highest-flying birds. It’s been heard flying across Mount Makalu – the fifth highest mountain on Earth at 8,481 meters (27,825 ft). The British explorer George Lowe is said to have reported seeing bar-headed geese flying over Mount Everest – 8,848 meters (29,029 ft)! You’ll find mention of Lowe’s tale about the geese here.


According to Wikipedia, the bar-headed goose is:



… a goose that breeds in Central Asia in colonies of thousands near mountain lakes and winters in South Asia, as far south as peninsular India …


The bird is pale grey and is easily distinguished from any of the other grey geese of the genus Anser by the black bars on its head.



A Bar-headed Goose in St James's Park, London, England. Photo by DAVID ILIFF. License: CC-BY-SA 3.0 via Wikipedia.

A Bar-headed Goose in St James’s Park, London, England. Photo by DAVID ILIFF. License: CC-BY-SA 3.0 via Wikipedia.



Bottom line: A beautiful shot of bar-headed geese flying over a wetlands in India in November 2014. Photo by Abhinav Singhai.






from EarthSky http://earthsky.org/todays-image/bar-headed-geese-in-india

Photo Credit: Abhinav Singhai. Visit Abhinav Singhai's Flickr page

Photo Credit: Abhinav Singhai. Visit his Flickr page



EarthSky Facebook friend Abhinav Singhai in India captured this evocative shot of bar-headed geese over Basai Wetlands, a well-known destination for birders near Delhi, India. He said there were hundreds of geese over the wetlands that day.


Thank you, Abhihav!


The bar-headed goose is a fascinating bird, by the way, and one of the world’s highest-flying birds. It’s been heard flying across Mount Makalu – the fifth highest mountain on Earth at 8,481 meters (27,825 ft). The British explorer George Lowe is said to have reported seeing bar-headed geese flying over Mount Everest – 8,848 meters (29,029 ft)! You’ll find mention of Lowe’s tale about the geese here.


According to Wikipedia, the bar-headed goose is:



… a goose that breeds in Central Asia in colonies of thousands near mountain lakes and winters in South Asia, as far south as peninsular India …


The bird is pale grey and is easily distinguished from any of the other grey geese of the genus Anser by the black bars on its head.



A Bar-headed Goose in St James's Park, London, England. Photo by DAVID ILIFF. License: CC-BY-SA 3.0 via Wikipedia.

A Bar-headed Goose in St James’s Park, London, England. Photo by DAVID ILIFF. License: CC-BY-SA 3.0 via Wikipedia.



Bottom line: A beautiful shot of bar-headed geese flying over a wetlands in India in November 2014. Photo by Abhinav Singhai.






from EarthSky http://earthsky.org/todays-image/bar-headed-geese-in-india

Sun in constellation Ophiuchus November 30 to December 18


If you could see the stars during the daytime, you’d see the sun shining in front of the border of the constellations Ophiuchus and Scorpius today. At about this time each year, the sun passes out of Scorpius to enter Ophiuchus. Like Scorpius, Ophiuchus is a constellation of the Zodiac, and every year the sun passes in front of Ophiuchus from about November 29 until December 18.


This year, in 2014, the sun enters the constellation Ophiuchus on November 30, at 1:00 a.m. CST in the central U.S. By Universal Time, that’s 7:00 on November 30.


How do I translate Universal Time into my time?



You can’t see the constellation Ophiuchus when the sun lies in front of it. But, each Northern Hemisphere summer, you’ll find this constellation to the north of the bright star Antares in the constellation Scorpius.



Need the perfect gift? Check out these 2015 moon calendars.


The ecliptic – which translates on our sky’s dome as the sun’s annual path in front of the background stars – actually passes through 13 constellations, although this is not commonly known. After all, when you read the horoscope in the daily newspaper or a monthly magazine, you see only 12 constellations, or signs, mentioned. No one ever claims to be an Ophiuchus. There are the 12 traditional zodiacal constellations. But the sun passes through Ophiuchus as surely as it does the others.


Today’s constellation boundaries were drawn out by the International Astronomical Union in the 1930s.


Look at the chart carefully, and you’ll see that the border between Ophiuchus and the constellation Scorpius for the most part lies just south of, or below, the ecliptic. In ancient times, the Ophuichus-Scorpius border was likely placed to the north of, or above, the ecliptic. Had the International Astronomical Union placed its constellation boundary where the ancients might have, the sun’s annual passing in front of Scorpius would be from about November 23 till December 18, not November 23 to November 30.


Bottom line: As seen from Earth, the sun passes in front of the constellation Ophiuchus each year from about November 30 to December 18.


Birthday late November to middle December? Here’s your constellation






from EarthSky http://earthsky.org/tonight/sun-in-ophiuchus-november-30-to-december-18

If you could see the stars during the daytime, you’d see the sun shining in front of the border of the constellations Ophiuchus and Scorpius today. At about this time each year, the sun passes out of Scorpius to enter Ophiuchus. Like Scorpius, Ophiuchus is a constellation of the Zodiac, and every year the sun passes in front of Ophiuchus from about November 29 until December 18.


This year, in 2014, the sun enters the constellation Ophiuchus on November 30, at 1:00 a.m. CST in the central U.S. By Universal Time, that’s 7:00 on November 30.


How do I translate Universal Time into my time?



You can’t see the constellation Ophiuchus when the sun lies in front of it. But, each Northern Hemisphere summer, you’ll find this constellation to the north of the bright star Antares in the constellation Scorpius.



Need the perfect gift? Check out these 2015 moon calendars.


The ecliptic – which translates on our sky’s dome as the sun’s annual path in front of the background stars – actually passes through 13 constellations, although this is not commonly known. After all, when you read the horoscope in the daily newspaper or a monthly magazine, you see only 12 constellations, or signs, mentioned. No one ever claims to be an Ophiuchus. There are the 12 traditional zodiacal constellations. But the sun passes through Ophiuchus as surely as it does the others.


Today’s constellation boundaries were drawn out by the International Astronomical Union in the 1930s.


Look at the chart carefully, and you’ll see that the border between Ophiuchus and the constellation Scorpius for the most part lies just south of, or below, the ecliptic. In ancient times, the Ophuichus-Scorpius border was likely placed to the north of, or above, the ecliptic. Had the International Astronomical Union placed its constellation boundary where the ancients might have, the sun’s annual passing in front of Scorpius would be from about November 23 till December 18, not November 23 to November 30.


Bottom line: As seen from Earth, the sun passes in front of the constellation Ophiuchus each year from about November 30 to December 18.


Birthday late November to middle December? Here’s your constellation






from EarthSky http://earthsky.org/tonight/sun-in-ophiuchus-november-30-to-december-18

M33: Triangulum Galaxy


How to find it


Although long-exposure photographs show the Triangulum galaxy (Messier 33) as a pinwheel of swarming suns, this face-on spiral galaxy looks rather lackluster in binoculars or even the telescope. The Triangulum galaxy has a low surface brightness that makes this faint object a major challenge, with or without optics.


Have you ever seen the Great Andromeda Galaxy (Messier 31)? If not, try finding the Andromeda galaxy before you take on the Triangulum galaxy. Shining 8 to 9 times more brightly than the Triangulum galaxy, the Andromeda galaxy is the most distant object that you can easily see with the unaided eye. Fortunately, the Triangulum and Andromeda galaxies are a relatively close 15 degrees apart. (For reference, a fist-width at an arm length approximates 10 degrees.)


Star-hop to the Andromeda galaxy to orient yourself to the Triangulum galaxy. As seen on the sky chart, the star Mirach stands about midway between the two galaxies. Our Andromeda galaxy sky chart shows you how to star-hop to the Andromeda galaxy. Once you’ve found it, the Andromeda galaxy and Mirach point in the general direction of the Triangulum galaxy.


The constellation Triangulum


Learn the constellation Triangulum, the small triangle made of three rather faint yet visible stars. Look eastward on some autumn evening, placing the star Alpha Triangulum at about the “7 o’clock” position in your binoculars. The Triangulum galaxy appears at the opposite side of the binouclar field, somewhere around 1 or 2 o’clock.


Now for a word of warning: even if you’re staring right at the Triangulum galaxy, it’s still possible to miss it. You won’t see the galaxy’s stars at all. Sometimes, this galaxy looks almost transparent, like a water spot on a window. The small blob in your binocular field might resemble an unwashed spot on an otherwide clean window. If you’ve never seen this deep-sky object before, it’s hard to know what to look for. Once you finally spot the Triangulum galaxy, you may wonder how you overlooked it so easily so many times before.


Science


At a distance of about 2.7 million light-years, the Triangulum galaxy might be a satellite galaxy of the Andromeda galaxy. The diameter of the Triangulum galaxy is about 50,000 light-years, or about one-half that of our Milky Way. After the Milky Way and Andromeda galaxies, the Triangulum galaxy ranks as the third largest of the few dozen galaxies inhabiting our Local Group of Galaxies.






from EarthSky http://earthsky.org/clusters-nebulae-galaxies/triangulum-galaxy-m33-a-binocular-challenge

How to find it


Although long-exposure photographs show the Triangulum galaxy (Messier 33) as a pinwheel of swarming suns, this face-on spiral galaxy looks rather lackluster in binoculars or even the telescope. The Triangulum galaxy has a low surface brightness that makes this faint object a major challenge, with or without optics.


Have you ever seen the Great Andromeda Galaxy (Messier 31)? If not, try finding the Andromeda galaxy before you take on the Triangulum galaxy. Shining 8 to 9 times more brightly than the Triangulum galaxy, the Andromeda galaxy is the most distant object that you can easily see with the unaided eye. Fortunately, the Triangulum and Andromeda galaxies are a relatively close 15 degrees apart. (For reference, a fist-width at an arm length approximates 10 degrees.)


Star-hop to the Andromeda galaxy to orient yourself to the Triangulum galaxy. As seen on the sky chart, the star Mirach stands about midway between the two galaxies. Our Andromeda galaxy sky chart shows you how to star-hop to the Andromeda galaxy. Once you’ve found it, the Andromeda galaxy and Mirach point in the general direction of the Triangulum galaxy.


The constellation Triangulum


Learn the constellation Triangulum, the small triangle made of three rather faint yet visible stars. Look eastward on some autumn evening, placing the star Alpha Triangulum at about the “7 o’clock” position in your binoculars. The Triangulum galaxy appears at the opposite side of the binouclar field, somewhere around 1 or 2 o’clock.


Now for a word of warning: even if you’re staring right at the Triangulum galaxy, it’s still possible to miss it. You won’t see the galaxy’s stars at all. Sometimes, this galaxy looks almost transparent, like a water spot on a window. The small blob in your binocular field might resemble an unwashed spot on an otherwide clean window. If you’ve never seen this deep-sky object before, it’s hard to know what to look for. Once you finally spot the Triangulum galaxy, you may wonder how you overlooked it so easily so many times before.


Science


At a distance of about 2.7 million light-years, the Triangulum galaxy might be a satellite galaxy of the Andromeda galaxy. The diameter of the Triangulum galaxy is about 50,000 light-years, or about one-half that of our Milky Way. After the Milky Way and Andromeda galaxies, the Triangulum galaxy ranks as the third largest of the few dozen galaxies inhabiting our Local Group of Galaxies.






from EarthSky http://earthsky.org/clusters-nebulae-galaxies/triangulum-galaxy-m33-a-binocular-challenge

News digest – obesity and diets, the immune system, stats galore and more

Newspapers


  • In another big week for research on the immune system and cancer, the journal Nature published five separate papers on the subject. And one of those papers looking at bladder cancer caught the eye of the BBC, Mail Online and the Telegraph. We also covered the studies on our news feed.

  • New estimates revealed that almost half a million new cancer cases worldwide in adults each year are linked to excess bodyweight. We covered this, and here’s the Mail Online and the Telegraph’s take on the findings.

  • Continuing with statistics, a new study found that, although things are improving, the UK cancer survival still lags behind the best in the world – particularly for lung cancer. The Guardian has more.

  • And in even more stats news, smoking rates in Britain have more than halved in the last 40 years. Look at the data in our news report, and the Mail Online had this take.

  • US researchers discovered that the presence of particular genetic faults in the DNA of blood cells may be an indicator for the development of blood cancers later in life. TIME has more on this.

  • The BBC took a graphic look at the changing face of Australian cigarette packing.

  • This piece in the Independent, by GP Margaret McCartney, discussed the importance of end-of-life care.

  • The Mail Online covered a new trial looking to test an advanced imaging technique that could help diagnose prostate cancer.

  • This article in The Conversation debunks the hype around research on cannabis and cancer.

  • This overhyped article appeared in the Telegraph following some interesting early research looking to develop a ‘breath test’ for lung cancer. It’s still too early to say if this could be used to diagnose people earlier.


And finally


New research sparked a couple of news reports on the perceived health benefits of the 5:2 diet and claims it could prevent diseases like Alzheimer’s and cancer. But the study actually found there’s not enough evidence to reach make those conclusions. Read this NHS Choices article for a more balanced analysis.







from Cancer Research UK - Science blog http://feedproxy.google.com/~r/cancerresearchuk/SHhE/~3/x6KzXF4iAzc/
Newspapers


  • In another big week for research on the immune system and cancer, the journal Nature published five separate papers on the subject. And one of those papers looking at bladder cancer caught the eye of the BBC, Mail Online and the Telegraph. We also covered the studies on our news feed.

  • New estimates revealed that almost half a million new cancer cases worldwide in adults each year are linked to excess bodyweight. We covered this, and here’s the Mail Online and the Telegraph’s take on the findings.

  • Continuing with statistics, a new study found that, although things are improving, the UK cancer survival still lags behind the best in the world – particularly for lung cancer. The Guardian has more.

  • And in even more stats news, smoking rates in Britain have more than halved in the last 40 years. Look at the data in our news report, and the Mail Online had this take.

  • US researchers discovered that the presence of particular genetic faults in the DNA of blood cells may be an indicator for the development of blood cancers later in life. TIME has more on this.

  • The BBC took a graphic look at the changing face of Australian cigarette packing.

  • This piece in the Independent, by GP Margaret McCartney, discussed the importance of end-of-life care.

  • The Mail Online covered a new trial looking to test an advanced imaging technique that could help diagnose prostate cancer.

  • This article in The Conversation debunks the hype around research on cannabis and cancer.

  • This overhyped article appeared in the Telegraph following some interesting early research looking to develop a ‘breath test’ for lung cancer. It’s still too early to say if this could be used to diagnose people earlier.


And finally


New research sparked a couple of news reports on the perceived health benefits of the 5:2 diet and claims it could prevent diseases like Alzheimer’s and cancer. But the study actually found there’s not enough evidence to reach make those conclusions. Read this NHS Choices article for a more balanced analysis.







from Cancer Research UK - Science blog http://feedproxy.google.com/~r/cancerresearchuk/SHhE/~3/x6KzXF4iAzc/

A famous variable star in the constellation Cepheus


Tonight … come to know Delta Cephei, a famous variable star in the constellation Cepheus. With clock-like precision, this rather faint star doubles in brightness every 5.36 days. You can see the brightness change best if you contrast this star to others nearby.


The constellation Cepheus requires a dark sky to be seen, so it’ll be more obvious after moonset tonight. But if you can spot this constellation, you might be able to find the variable star. You’ll find it high in your northern sky on November and December evenings. The pattern of stars in Cepheus resembles a stick house, the kind we all drew as children. The variable star – Delta Cephei – is located near the bottom corner of the house pattern.



Black Friday to Cyber Monday! 50% off your 2015 EarthSky Lunar Calendar today!


Cepheid variable stars are a class of stars named in honor of Delta Cephei. They are known as pulsating variables. The image at right is what astronomers call a “light curve” of a variable star. Each point represents the brightness of the star at a particular time. You can see that the star’s brightness changes in a regular way over a period of days.


The brightness of a Cepheid variable star changes because the star is actually expanding and contracting in size. The radius of a Cepheid variable star changes by several million kilometers (30%) as the star expands and shrinks. There is a very precise relationship between a Cepheid variable’s luminosity, or true brightness, and pulsation period. The greater the intrinsic brightness of the star, the longer the period. For that reason, these variable stars serve as standard candles – in other words, their true brightness is known, so astronomers can see how bright they look to measure the distances to the stars – and hence to faraway galaxies.


Now look again at the chart showing the constellations Cepheus the King and Cassiopeia the Queen at the top of this page. In the actual sky, the two stars near Delta Cephei – Epsilon Cephei and Zeta Cephei – mark the low and high ends of Delta Cephei’s brightness scale. At its faintest, the variable star Delta Cephei is as dim as the fainter star, Epsilon Cephei. At its brightest, Delta Cephei matches the brightness of Zeta Cephei.


Cepheid variable stars enabled the astronomer Edwin Hubble to figure out that the Andromeda galaxy lies outside the bounds of our local galaxy, the Milky Way.


Bottom line: Delta Cephei is a famous variable star in the constellation Cepheus. With clock-like precision, this rather faint star doubles in brightness every 5.36 days.


Easily locate stars and constellations during any day and time with EarthSky’s Planisphere.






from EarthSky http://ift.tt/1rEXMHE

Tonight … come to know Delta Cephei, a famous variable star in the constellation Cepheus. With clock-like precision, this rather faint star doubles in brightness every 5.36 days. You can see the brightness change best if you contrast this star to others nearby.


The constellation Cepheus requires a dark sky to be seen, so it’ll be more obvious after moonset tonight. But if you can spot this constellation, you might be able to find the variable star. You’ll find it high in your northern sky on November and December evenings. The pattern of stars in Cepheus resembles a stick house, the kind we all drew as children. The variable star – Delta Cephei – is located near the bottom corner of the house pattern.



Black Friday to Cyber Monday! 50% off your 2015 EarthSky Lunar Calendar today!


Cepheid variable stars are a class of stars named in honor of Delta Cephei. They are known as pulsating variables. The image at right is what astronomers call a “light curve” of a variable star. Each point represents the brightness of the star at a particular time. You can see that the star’s brightness changes in a regular way over a period of days.


The brightness of a Cepheid variable star changes because the star is actually expanding and contracting in size. The radius of a Cepheid variable star changes by several million kilometers (30%) as the star expands and shrinks. There is a very precise relationship between a Cepheid variable’s luminosity, or true brightness, and pulsation period. The greater the intrinsic brightness of the star, the longer the period. For that reason, these variable stars serve as standard candles – in other words, their true brightness is known, so astronomers can see how bright they look to measure the distances to the stars – and hence to faraway galaxies.


Now look again at the chart showing the constellations Cepheus the King and Cassiopeia the Queen at the top of this page. In the actual sky, the two stars near Delta Cephei – Epsilon Cephei and Zeta Cephei – mark the low and high ends of Delta Cephei’s brightness scale. At its faintest, the variable star Delta Cephei is as dim as the fainter star, Epsilon Cephei. At its brightest, Delta Cephei matches the brightness of Zeta Cephei.


Cepheid variable stars enabled the astronomer Edwin Hubble to figure out that the Andromeda galaxy lies outside the bounds of our local galaxy, the Milky Way.


Bottom line: Delta Cephei is a famous variable star in the constellation Cepheus. With clock-like precision, this rather faint star doubles in brightness every 5.36 days.


Easily locate stars and constellations during any day and time with EarthSky’s Planisphere.






from EarthSky http://ift.tt/1rEXMHE

NASA is tracking a gargantuan iceberg, escaped from Antarctica


Earth Observatory's first look (above) at B31 following the Southern Hemisphere winter was acquired by the Moderate Resolution Imaging Spectroradiometer (MODIS) on the Aqua satellite on November 22, 2014.

A first look at Antarctic iceberg B31, following the Southern Hemisphere winter. NASA’s Aqua satellite captured this image on November 22, 2014.



Winter has lifted from Antarctica’s Pine Island Bay, so that passing satellites can once again acquire sunlit views of massive iceberg B31 as it drifts in the Amundsen Sea. NASA has been tracking this iceberg – an ice island, really – since it separated from the front of Antarctica’s Pine Island Glacier a year ago (November 2013). It’s 240 square miles (over 600 square kilometers), in contrast to about 23 square miles for New York’s Manhattan Island. When southern winter fell around May 2014, darkness came to this region of Earth and the iceberg could not be seen for six months. It was thought then it would likely be swept up in the swift currents of the Southern Ocean, but, for now, it’s still in the Amundsen Sea – moving west – free now of surrounding debris and sea ice. Scientists expect that the berg will continue moving west.


Last April, just before winter darkness fell in Antarctica, Kelly Brunt, a glaciologist at NASA’s Goddard Space Flight Center, noted:



Iceberg calving is a very normal process. However, the detachment rift, or crack, that created this iceberg was well upstream of the 30-year average calving front of Pine Island Glacier, so this a region that warrants monitoring.



Pine Island Glacier itself – the source of the massive iceberg – has been the subject of intense study in the past several decades. Scientists speak of this glacier as the weak underbelly of the West Antarctic Ice Sheet. The glacier has been thinning and draining rapidly and may be one of the largest contributors to sea level rise. Read more: As ocean warms, Antarctica’s Pine Island Glacier thaws


Large icebergs like this one pose a danger to ships. Our modern shipboard technologies – radar and warning systems – can’t always prevent accidents. For example, in 2007, the MS Explorer, an Antarctic cruise ship, sank after striking an iceberg near the South Shetland Islands. Read more at CBS News.


Read more the images of B31 from NASA Visible Earth


B31 is a huge ice island, currently floating in the Admunsen Sea. It's excepted to cross into the Southern Ocean soon. Credit: NASA images by Jeff Schmaltz, LANCE/EOSDIS Rapid Response. Caption by Michael Carlowicz.

B31 is a huge ice island, 20 miles (33 kilometers) by 12 miles (20 kilometers). Image via Jeff Schmaltz, LANCE/EOSDIS Rapid Response.



The ice island B31 - __ square miles in diameter (over 600 square kilometers) - broke away from Pine Island Glacier in November 2013.

The ice island B31 broke away from Pine Island Glacier in early November, 2013.



NASA has been using at least two satellites to track the massive floating ice chunk.

Over the course of five months of Antarctic spring and summer – in late 2013 and early 2014 – NASA used both its Terra and Aqua satellites to capture images of the massive floating ice chunk. One of the scientists involved, Grant Bigg of the University of Sheffield, said his team was busy doing research on local ocean currents to try to explain the iceberg’s motion properly. He said, “It has been surprising how there have been periods of almost no motion, interspersed with rapid flow. There were a couple of occasions early on when there might have been partial grounding or collisions with the seafloor, as B31 bounced from one side of the Bay to the other.”



In the coming months, B31 is expected to leave the Amundsen Bay and enter the waters of the Southern Ocean. Since southern winter is approaching, it'll be dark over that area, and the iceberg will be harder to track.

This image was acquired in April, 2014, during Antarctica’s autumn. Since about that time, the iceberg has been impossible to track visually. However, as of November 2014, NASA is tracking the iceberg again with the return of summer to Antarctica.



Bottom line: NASA is tracking the huge iceberg B31, which broke away from Antarctica’s Pine Island Glacier in November, 2013. Winter is now over in the southern part of the world, and acquired its first image in six months of B31 on November 22, 2014.






from EarthSky http://ift.tt/1gXYlRy

Earth Observatory's first look (above) at B31 following the Southern Hemisphere winter was acquired by the Moderate Resolution Imaging Spectroradiometer (MODIS) on the Aqua satellite on November 22, 2014.

A first look at Antarctic iceberg B31, following the Southern Hemisphere winter. NASA’s Aqua satellite captured this image on November 22, 2014.



Winter has lifted from Antarctica’s Pine Island Bay, so that passing satellites can once again acquire sunlit views of massive iceberg B31 as it drifts in the Amundsen Sea. NASA has been tracking this iceberg – an ice island, really – since it separated from the front of Antarctica’s Pine Island Glacier a year ago (November 2013). It’s 240 square miles (over 600 square kilometers), in contrast to about 23 square miles for New York’s Manhattan Island. When southern winter fell around May 2014, darkness came to this region of Earth and the iceberg could not be seen for six months. It was thought then it would likely be swept up in the swift currents of the Southern Ocean, but, for now, it’s still in the Amundsen Sea – moving west – free now of surrounding debris and sea ice. Scientists expect that the berg will continue moving west.


Last April, just before winter darkness fell in Antarctica, Kelly Brunt, a glaciologist at NASA’s Goddard Space Flight Center, noted:



Iceberg calving is a very normal process. However, the detachment rift, or crack, that created this iceberg was well upstream of the 30-year average calving front of Pine Island Glacier, so this a region that warrants monitoring.



Pine Island Glacier itself – the source of the massive iceberg – has been the subject of intense study in the past several decades. Scientists speak of this glacier as the weak underbelly of the West Antarctic Ice Sheet. The glacier has been thinning and draining rapidly and may be one of the largest contributors to sea level rise. Read more: As ocean warms, Antarctica’s Pine Island Glacier thaws


Large icebergs like this one pose a danger to ships. Our modern shipboard technologies – radar and warning systems – can’t always prevent accidents. For example, in 2007, the MS Explorer, an Antarctic cruise ship, sank after striking an iceberg near the South Shetland Islands. Read more at CBS News.


Read more the images of B31 from NASA Visible Earth


B31 is a huge ice island, currently floating in the Admunsen Sea. It's excepted to cross into the Southern Ocean soon. Credit: NASA images by Jeff Schmaltz, LANCE/EOSDIS Rapid Response. Caption by Michael Carlowicz.

B31 is a huge ice island, 20 miles (33 kilometers) by 12 miles (20 kilometers). Image via Jeff Schmaltz, LANCE/EOSDIS Rapid Response.



The ice island B31 - __ square miles in diameter (over 600 square kilometers) - broke away from Pine Island Glacier in November 2013.

The ice island B31 broke away from Pine Island Glacier in early November, 2013.



NASA has been using at least two satellites to track the massive floating ice chunk.

Over the course of five months of Antarctic spring and summer – in late 2013 and early 2014 – NASA used both its Terra and Aqua satellites to capture images of the massive floating ice chunk. One of the scientists involved, Grant Bigg of the University of Sheffield, said his team was busy doing research on local ocean currents to try to explain the iceberg’s motion properly. He said, “It has been surprising how there have been periods of almost no motion, interspersed with rapid flow. There were a couple of occasions early on when there might have been partial grounding or collisions with the seafloor, as B31 bounced from one side of the Bay to the other.”



In the coming months, B31 is expected to leave the Amundsen Bay and enter the waters of the Southern Ocean. Since southern winter is approaching, it'll be dark over that area, and the iceberg will be harder to track.

This image was acquired in April, 2014, during Antarctica’s autumn. Since about that time, the iceberg has been impossible to track visually. However, as of November 2014, NASA is tracking the iceberg again with the return of summer to Antarctica.



Bottom line: NASA is tracking the huge iceberg B31, which broke away from Antarctica’s Pine Island Glacier in November, 2013. Winter is now over in the southern part of the world, and acquired its first image in six months of B31 on November 22, 2014.






from EarthSky http://ift.tt/1gXYlRy

Is it true that Jupiter protects Earth?


Here’s a question we get regularly:



Is it true that Jupiter could be considered our friendliest planet because – without Jupiter – comets would be more likely to hit us?



The answer is yes … and no. Some astronomers believe that one reason Earth is habitable is that the gravity of Jupiter does help protect us from some comets. Long-period comets, in particular, enter the solar system from its outer reaches. Jupiter’s gravity is thought to sling most of these fast-moving ice balls out of the solar system before they can get close to Earth. So long-period comets are thought to strike Earth only on very long timescales of millions or tens of millions of years. Without Jupiter nearby, long-period comets would collide with our planet much more frequently.


In addition, in recent decades, astronomers have been able to see signs of comets that have crashed into Jupiter. There was Comet Shoemaker-Levy 9 in 1994. And, in 2009, astronomers observed a dark gash in one side of the giant planet, likely caused by a comet.


A NASA Hubble Space Telescope image of Comet Shoemaker-Levy 9, taken on May 17, 1994. At this point, the comet had broken into 21 icy fragments stretched stretched across 1.1 million kilometers (710 thousand miles) of space, or 3 times the distance between Earth and moon. When this picture was taken, these fragments were on a mid-July collision course with the gas giant planet Jupiter.

A NASA Hubble Space Telescope image of Comet Shoemaker-Levy 9, taken on May 17, 1994. At this point, the comet had broken into 21 icy fragments stretched stretched across 1.1 million kilometers (710 thousand miles) of space, or 3 times the distance between Earth and moon. When this picture was taken, these fragments were on a mid-July collision course with the gas giant planet Jupiter. Image via Wikimedia Commons.



Brown spots mark the places where fragments of Comet Shoemaker-Levy 9 tore through Jupiter's atmosphere in July 1994. Image and caption via Wikimedia Commons.

Taking one for the team? Brown spots mark the places where fragments of Comet Shoemaker-Levy 9 tore through Jupiter’s atmosphere in July 1994. Image and caption via Wikimedia Commons.



In 2009, amateur astronomer Anthony Wesley noticed a dark mark on Jupiter. It turned out to be a scar from a comet impact. Read more about the 2009 impact on Jupiter here.

In 2009, amateur astronomer Anthony Wesley noticed a dark mark on Jupiter. It turned out to be a scar from an impact with some object, presumably a comet. Read more about the 2009 impact on Jupiter here.



But Jupiter creates both good and bad conditions for earthly life. Consider that its powerful gravity prevented space rocks orbiting near it from coalescing into a planet, and that’s why our solar system today has an asteroid belt, consisting of hundreds of thousands of small flying chunks of debris.


Today, Jupiter’s gravity continues to affect the asteroids – only now it nudges some asteroids toward the sun, where they have the possibility of colliding with Earth.


Another interesting story comes from several centuries ago. The late Brian G. Marsden, former director of the the International Astronomical Union’s Central Bureau for Astronomical Telegrams, related it to Dennis Overbye of the New York Times in 2009, shortly after the dark gash appeared on Jupiter. It’s rare for a comet to come within 1 astronomical unit of Earth (that is, one Earth-sun distance, 92 million miles, or about 150 million kilometers). But, in the year 1770, a Comet Lexell streaked past Earth at a distance of only a million miles. Dr. Marsden told Overbye that:



… the comet had come streaking in from the outer solar system three years earlier and passed close to Jupiter, which diverted it into a new orbit and straight toward Earth.


The comet made two passes around the sun and in 1779 again passed very close to Jupiter, which then threw it back out of the solar system.


‘It was as if Jupiter aimed at us and missed,’ said Dr. Marsden.



So is Jupiter Earth’s protector? The answer is … sometimes!


What’s the difference between comets and asteroids?






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Here’s a question we get regularly:



Is it true that Jupiter could be considered our friendliest planet because – without Jupiter – comets would be more likely to hit us?



The answer is yes … and no. Some astronomers believe that one reason Earth is habitable is that the gravity of Jupiter does help protect us from some comets. Long-period comets, in particular, enter the solar system from its outer reaches. Jupiter’s gravity is thought to sling most of these fast-moving ice balls out of the solar system before they can get close to Earth. So long-period comets are thought to strike Earth only on very long timescales of millions or tens of millions of years. Without Jupiter nearby, long-period comets would collide with our planet much more frequently.


In addition, in recent decades, astronomers have been able to see signs of comets that have crashed into Jupiter. There was Comet Shoemaker-Levy 9 in 1994. And, in 2009, astronomers observed a dark gash in one side of the giant planet, likely caused by a comet.


A NASA Hubble Space Telescope image of Comet Shoemaker-Levy 9, taken on May 17, 1994. At this point, the comet had broken into 21 icy fragments stretched stretched across 1.1 million kilometers (710 thousand miles) of space, or 3 times the distance between Earth and moon. When this picture was taken, these fragments were on a mid-July collision course with the gas giant planet Jupiter.

A NASA Hubble Space Telescope image of Comet Shoemaker-Levy 9, taken on May 17, 1994. At this point, the comet had broken into 21 icy fragments stretched stretched across 1.1 million kilometers (710 thousand miles) of space, or 3 times the distance between Earth and moon. When this picture was taken, these fragments were on a mid-July collision course with the gas giant planet Jupiter. Image via Wikimedia Commons.



Brown spots mark the places where fragments of Comet Shoemaker-Levy 9 tore through Jupiter's atmosphere in July 1994. Image and caption via Wikimedia Commons.

Taking one for the team? Brown spots mark the places where fragments of Comet Shoemaker-Levy 9 tore through Jupiter’s atmosphere in July 1994. Image and caption via Wikimedia Commons.



In 2009, amateur astronomer Anthony Wesley noticed a dark mark on Jupiter. It turned out to be a scar from a comet impact. Read more about the 2009 impact on Jupiter here.

In 2009, amateur astronomer Anthony Wesley noticed a dark mark on Jupiter. It turned out to be a scar from an impact with some object, presumably a comet. Read more about the 2009 impact on Jupiter here.



But Jupiter creates both good and bad conditions for earthly life. Consider that its powerful gravity prevented space rocks orbiting near it from coalescing into a planet, and that’s why our solar system today has an asteroid belt, consisting of hundreds of thousands of small flying chunks of debris.


Today, Jupiter’s gravity continues to affect the asteroids – only now it nudges some asteroids toward the sun, where they have the possibility of colliding with Earth.


Another interesting story comes from several centuries ago. The late Brian G. Marsden, former director of the the International Astronomical Union’s Central Bureau for Astronomical Telegrams, related it to Dennis Overbye of the New York Times in 2009, shortly after the dark gash appeared on Jupiter. It’s rare for a comet to come within 1 astronomical unit of Earth (that is, one Earth-sun distance, 92 million miles, or about 150 million kilometers). But, in the year 1770, a Comet Lexell streaked past Earth at a distance of only a million miles. Dr. Marsden told Overbye that:



… the comet had come streaking in from the outer solar system three years earlier and passed close to Jupiter, which diverted it into a new orbit and straight toward Earth.


The comet made two passes around the sun and in 1779 again passed very close to Jupiter, which then threw it back out of the solar system.


‘It was as if Jupiter aimed at us and missed,’ said Dr. Marsden.



So is Jupiter Earth’s protector? The answer is … sometimes!


What’s the difference between comets and asteroids?






from EarthSky http://ift.tt/QDGsx4

Good morning!



.

Photo by Daniel Levy Photography. Thank you Daniel!


You can see more of Daniel’s photos here






from EarthSky http://ift.tt/1FArKxf


.

Photo by Daniel Levy Photography. Thank you Daniel!


You can see more of Daniel’s photos here






from EarthSky http://ift.tt/1FArKxf

Neptune near moon on November 28



Photo of Neptune taken by Voyager 2 spacecraft in August 1989



Tonight … don’t expect to see Neptune, even though (because!) it’s close to the waxing gibbous moon. Neptune – eighth planet out from the sun and outermost of the major planets according to the International Astronomical Union – is the only major planet in our solar system that you absolutely can’t see with the unaided eye. The even-more-distant dwarf planet Pluto isn’t visible to the unaided eye, either, of course. On November 28, 2914, Neptune shines in front of the constellation Aquarius, and near the star Sigma Aquarii (chart of Aquarius below). Neptune is also close to the ecliptic – the path the planets follow in front of the constellations of the Zodiac. Because of the moonlit glare, you probably won’t see much of Aquarius tonight. What will you see? Only the moon shining in all its splendor. You can gaze at it and imagine Neptune nearby.


Although the moon and Neptune are close together on the sky’s dome tonight, they’re nowhere close in space. The moon resides about 1.2 light-seconds from Earth, whereas Neptune looms way out there at over four light-hours away. In other words, Neptune is over 12,000 times farther away than the moon in tonight’s sky.


Once the moon leaves the evening sky, starting the second week in December, Aquarius will easy to spot in a dark country sky. Then, if you’re armed with a telescope or powerful binoculars and a good sky chart, you might be able to glimpse Neptune.


Happy Black Friday! EarthSky lunar calendars 50% off Friday to Monday.


View larger We have labeled Sigma Aquarii (abbreviated Sigma) on the above sky chart. It's a 5th-magnitude star, which is dimly visible to the unaided eye in a dark sky.

View larger | Star chart of constellation Aquarius. We’ve labeled the star Sigma Aquarii (abbreviated Sigma). It’s a 5th-magnitude star, meaning it’s only dimly visible to the unaided eye in a dark sky.



For a stellar reference, learn how to star-hop to Sigma Aquarii, your guide star to Neptune. Neptune demands high-quality binoculars or a telescope, patience and a detailed star chart. Look for Neptune and the star Sigma Aquarii to take stage within the same binocular field.


Bottom line: On this November night – November 28, 2014 – use your mind’s eye to envision the solar system’s most distant major planet – Neptune – by tonight’s waxing gibbous moon.


Do you love stargazing? Order your EarthSky Planisphere today!






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Photo of Neptune taken by Voyager 2 spacecraft in August 1989



Tonight … don’t expect to see Neptune, even though (because!) it’s close to the waxing gibbous moon. Neptune – eighth planet out from the sun and outermost of the major planets according to the International Astronomical Union – is the only major planet in our solar system that you absolutely can’t see with the unaided eye. The even-more-distant dwarf planet Pluto isn’t visible to the unaided eye, either, of course. On November 28, 2914, Neptune shines in front of the constellation Aquarius, and near the star Sigma Aquarii (chart of Aquarius below). Neptune is also close to the ecliptic – the path the planets follow in front of the constellations of the Zodiac. Because of the moonlit glare, you probably won’t see much of Aquarius tonight. What will you see? Only the moon shining in all its splendor. You can gaze at it and imagine Neptune nearby.


Although the moon and Neptune are close together on the sky’s dome tonight, they’re nowhere close in space. The moon resides about 1.2 light-seconds from Earth, whereas Neptune looms way out there at over four light-hours away. In other words, Neptune is over 12,000 times farther away than the moon in tonight’s sky.


Once the moon leaves the evening sky, starting the second week in December, Aquarius will easy to spot in a dark country sky. Then, if you’re armed with a telescope or powerful binoculars and a good sky chart, you might be able to glimpse Neptune.


Happy Black Friday! EarthSky lunar calendars 50% off Friday to Monday.


View larger We have labeled Sigma Aquarii (abbreviated Sigma) on the above sky chart. It's a 5th-magnitude star, which is dimly visible to the unaided eye in a dark sky.

View larger | Star chart of constellation Aquarius. We’ve labeled the star Sigma Aquarii (abbreviated Sigma). It’s a 5th-magnitude star, meaning it’s only dimly visible to the unaided eye in a dark sky.



For a stellar reference, learn how to star-hop to Sigma Aquarii, your guide star to Neptune. Neptune demands high-quality binoculars or a telescope, patience and a detailed star chart. Look for Neptune and the star Sigma Aquarii to take stage within the same binocular field.


Bottom line: On this November night – November 28, 2014 – use your mind’s eye to envision the solar system’s most distant major planet – Neptune – by tonight’s waxing gibbous moon.


Do you love stargazing? Order your EarthSky Planisphere today!






from EarthSky http://ift.tt/1vTY66K

Does eating turkey really make you sleepy?


Ah, Thanksgiving Day. You pile your plates with turkey, dressing, two kinds of potatoes, cranberries – all the traditional foods – and dig in. Second helpings? Of course! An hour later, after plenty of food and conversation, you push back and notice you’ve become very, very sleepy. You think, “I’m sleepy because turkey is high in tryptophan.”


Photo credit: Lotus Carroll/Flickr

Photo credit: Lotus Carroll/Flickr



True? Or myth?



The answer is – don’t blame it on the turkey. While it’s a commonly held myth that turkey is especially high in tryptophan – and causes that drowsiness (“turkey coma”) you feel after a big Thanksgiving meal – the reality is that the amount of tryptophan in turkey is comparable to that found in chicken, beef, and other meats. In fact, turkey doesn’t result in higher levels of tryptophan in your blood than other common foods.


So why do you get so sleepy after a big turkey dinner? Post-meal drowsiness on Thanksgiving might have more to do with what else is on your plate – in particular, carbohydrates. A heavy meal rich in carbohydrates increases the production of sleep-promoting melatonin in the brain.


Melatonin is a hormone – produced in the pineal gland – that plays a role in regulating biological rhythms, including sleep. Melatonin is sold as a sleep aid. People often use it to combat jet lag when flying between time zones. Hence, “feast-induced drowsiness” — which many people across the U.S. will feel this afternoon – might be the result of a rich meal high in carbohydrates – not because of the tryptophan in turkey.



And there are other factors in post-Thanksgiving meal drowsiness including, possibly, the amount of fat in the meal (slows down the digestion), alcohol consumption, overeating and just plain tiredness from all the conversation with relatives and friends, plus the work of preparing the meal itself.


By the way, certain foods, such as soybeans, sesame and sunflower seeds, and certain cheeses, are high in tryptophan. Although it is possible these might induce sleepiness if consumed in sufficient quantities, this is not well-studied.


So enjoy your Thanksgiving meal today, and aim for a nap afterwards. Why not? Happy Thanksgiving!


Bottom line: Turkey does contain tryptophan but no more so than chicken, beef, and other meats. The drowsiness you feel after a rich Thanksgiving meal might result from the inclusion of large amounts of carbohydrates (the dressing, rolls, mashed potatoes), which increases the production of sleep-inducing melatonin in the brain. Plus the fats in the meal, alcohol, overeating and just plain tiredness all can have an effect.






from EarthSky http://ift.tt/1ykR5dT

Ah, Thanksgiving Day. You pile your plates with turkey, dressing, two kinds of potatoes, cranberries – all the traditional foods – and dig in. Second helpings? Of course! An hour later, after plenty of food and conversation, you push back and notice you’ve become very, very sleepy. You think, “I’m sleepy because turkey is high in tryptophan.”


Photo credit: Lotus Carroll/Flickr

Photo credit: Lotus Carroll/Flickr



True? Or myth?



The answer is – don’t blame it on the turkey. While it’s a commonly held myth that turkey is especially high in tryptophan – and causes that drowsiness (“turkey coma”) you feel after a big Thanksgiving meal – the reality is that the amount of tryptophan in turkey is comparable to that found in chicken, beef, and other meats. In fact, turkey doesn’t result in higher levels of tryptophan in your blood than other common foods.


So why do you get so sleepy after a big turkey dinner? Post-meal drowsiness on Thanksgiving might have more to do with what else is on your plate – in particular, carbohydrates. A heavy meal rich in carbohydrates increases the production of sleep-promoting melatonin in the brain.


Melatonin is a hormone – produced in the pineal gland – that plays a role in regulating biological rhythms, including sleep. Melatonin is sold as a sleep aid. People often use it to combat jet lag when flying between time zones. Hence, “feast-induced drowsiness” — which many people across the U.S. will feel this afternoon – might be the result of a rich meal high in carbohydrates – not because of the tryptophan in turkey.



And there are other factors in post-Thanksgiving meal drowsiness including, possibly, the amount of fat in the meal (slows down the digestion), alcohol consumption, overeating and just plain tiredness from all the conversation with relatives and friends, plus the work of preparing the meal itself.


By the way, certain foods, such as soybeans, sesame and sunflower seeds, and certain cheeses, are high in tryptophan. Although it is possible these might induce sleepiness if consumed in sufficient quantities, this is not well-studied.


So enjoy your Thanksgiving meal today, and aim for a nap afterwards. Why not? Happy Thanksgiving!


Bottom line: Turkey does contain tryptophan but no more so than chicken, beef, and other meats. The drowsiness you feel after a rich Thanksgiving meal might result from the inclusion of large amounts of carbohydrates (the dressing, rolls, mashed potatoes), which increases the production of sleep-inducing melatonin in the brain. Plus the fats in the meal, alcohol, overeating and just plain tiredness all can have an effect.






from EarthSky http://ift.tt/1ykR5dT

Crescent moon


Photo credit: Göran Strand

Photo credit: Göran Strand



If you’ve been watching the early evening sky, you know the moon has returned to it. It has appeared in a slim waxing crescent phase over these past evenings. Göran Strand of Sweden captured the crescent moon on Tuesday evening, November 25, 2014. Notice the glow over the unlit part of a crescent moon? It’s called earthshine, and it’s sunlight reflected from Earth’s day onto the moon’s surface.


A big thank you to Göran Strand for sharing his photo with us. You can see more beautiful photos by Göran Strand here






from EarthSky http://ift.tt/1vogRNu

Photo credit: Göran Strand

Photo credit: Göran Strand



If you’ve been watching the early evening sky, you know the moon has returned to it. It has appeared in a slim waxing crescent phase over these past evenings. Göran Strand of Sweden captured the crescent moon on Tuesday evening, November 25, 2014. Notice the glow over the unlit part of a crescent moon? It’s called earthshine, and it’s sunlight reflected from Earth’s day onto the moon’s surface.


A big thank you to Göran Strand for sharing his photo with us. You can see more beautiful photos by Göran Strand here






from EarthSky http://ift.tt/1vogRNu

Second of two lunar perigees in one month on November 27


Tonight’s moon and Mars appear in the evening sky as soon as darkness falls. On this date (November 27, 2014), for the second time this month, the moon swings to perigee – nearest point to Earth in its orbit. The moon last reached perigee on November 3. Because this is the second of two lunar perigees to occur in one calendar month, perhaps we could call the second one a blue moon perigee. Just kidding!


The November 27 perigee finds the moon at 369,827 kilometers (229,800 miles) distant. That’s nearly two thousand kilometers farther than the November 3 perigee, when the moon was 367,879 kilometers (228,589 miles) away.


In fact, the November 27 perigee ranks the most distant lunar perigee of the year. A more distant perigee won’t come again until September 13, 2017 (369,860 kilometers).


On sale! 25% off EarthSky lunar calendars. We’re giving thanks for all of you.


In November 2014, the moon reaches perigee twice: November 3 and November 27. Image credit: NASA

In November 2014, the moon reaches perigee twice: November 3 and November 27. Image credit: NASA



Perigees are nowhere close to equal throughout the year. The closest perigee of 2014 fell on August 10, when the moon swung within 356,896 kilometers of Earth. That’s nearly 13,000 kilometers closer than the farthest perigee of November 27 (369,827 kilometers).


Perigees aligning with the full moon and new moon bring about the year’s closest perigees. The two closest of 2014:



1. August 10, 2014: 356,896 kilometers (full moon)

2. January 1, 2014: 356,923 kilometers (new moon)



Perigees happening in the vicinity of the quarter moons bring about the year’s farthest perigees. The two farthest of 2014:



1. November 27, 2014: 369,827 kilometers (first quarter moon)

2. April 23, 2014: 369,765 kilometers (last quarter moon)



Moon at perigee and apogee 2001 to 2100


Today’s November 27 perigee happens at 23:11 Universal Time. At US time zones, that converts to 6:11 p.m. EST, 5:11 p.m. CST, 4:11 p.m. MST or 3:11 p.m. PST.


Bottom line: For the second time this month, the moon today swings to perigee – nearest point to Earth in its orbit. The moon is at 369,827 kilometers (229,800 miles) distant today, farther from Earth than it will be again until September 13, 2017.


EarthSky astronomy kits are perfect for beginners. Order today from the EarthSky store






from EarthSky http://ift.tt/1rxujK0

Tonight’s moon and Mars appear in the evening sky as soon as darkness falls. On this date (November 27, 2014), for the second time this month, the moon swings to perigee – nearest point to Earth in its orbit. The moon last reached perigee on November 3. Because this is the second of two lunar perigees to occur in one calendar month, perhaps we could call the second one a blue moon perigee. Just kidding!


The November 27 perigee finds the moon at 369,827 kilometers (229,800 miles) distant. That’s nearly two thousand kilometers farther than the November 3 perigee, when the moon was 367,879 kilometers (228,589 miles) away.


In fact, the November 27 perigee ranks the most distant lunar perigee of the year. A more distant perigee won’t come again until September 13, 2017 (369,860 kilometers).


On sale! 25% off EarthSky lunar calendars. We’re giving thanks for all of you.


In November 2014, the moon reaches perigee twice: November 3 and November 27. Image credit: NASA

In November 2014, the moon reaches perigee twice: November 3 and November 27. Image credit: NASA



Perigees are nowhere close to equal throughout the year. The closest perigee of 2014 fell on August 10, when the moon swung within 356,896 kilometers of Earth. That’s nearly 13,000 kilometers closer than the farthest perigee of November 27 (369,827 kilometers).


Perigees aligning with the full moon and new moon bring about the year’s closest perigees. The two closest of 2014:



1. August 10, 2014: 356,896 kilometers (full moon)

2. January 1, 2014: 356,923 kilometers (new moon)



Perigees happening in the vicinity of the quarter moons bring about the year’s farthest perigees. The two farthest of 2014:



1. November 27, 2014: 369,827 kilometers (first quarter moon)

2. April 23, 2014: 369,765 kilometers (last quarter moon)



Moon at perigee and apogee 2001 to 2100


Today’s November 27 perigee happens at 23:11 Universal Time. At US time zones, that converts to 6:11 p.m. EST, 5:11 p.m. CST, 4:11 p.m. MST or 3:11 p.m. PST.


Bottom line: For the second time this month, the moon today swings to perigee – nearest point to Earth in its orbit. The moon is at 369,827 kilometers (229,800 miles) distant today, farther from Earth than it will be again until September 13, 2017.


EarthSky astronomy kits are perfect for beginners. Order today from the EarthSky store






from EarthSky http://ift.tt/1rxujK0

Earth has its own Star-Trek-like invisible shield


Scientists have discovered an invisible shield roughly 7,200 miles above Earth that blocks so-called “killer electrons,” which can fry satellites and degrade space systems during intense solar storms. Illustration by Andy Kale, University of Alberta.

Scientists have discovered an invisible shield roughly 7,200 miles (11,600 km) above Earth that blocks so-called “killer electrons,” which can fry satellites and degrade space systems during intense solar storms. Illustration by Andy Kale, University of Alberta.



In the 1950s, James Van Allen made one of the first major discoveries of the space age when he and his team found Earth’s two Van Allen radiation belts. These doughnut-shaped rings high above Earth are filled with high-energy electrons and protons. They swell and shrink in response to incoming energy disturbances from the sun, as they protect Earth from space radiation and the effects of our sun’s activity. In 2013, Daniel Baker at the University of Colorado Boulder – who received his doctorate under Van Allen – led a team that used data from twin NASA probes to discover a third, transient storage ring between the inner and outer Van Allen radiation belts. Today, Baker announced that his team has found an “extremely sharp” boundary at the inner edge of the outer belt. This boundary layer is Earth’s own invisible Star-Trek-like shield, he said, in that it appears to block ultrafast electrons from moving deeper into Earth’s atmosphere. The journal Nature published a paper on this subject on November 26, 2014.


The newly found boundary layer is roughly 7,200 miles (11,600 km) above Earth’s surface. The Van Allen belts themselves extend up to 25,000 miles (40,000 km) high.

.

This new layer blocks what scientists sometimes call killer electrons, known to whip around Earth at near-light speed, threatening astronauts, frying satellites and degrading space systems during intense solar storms. What the killer electrons don’t do, however, is penetrate down to Earth’s surface. It was originally thought that these highly charged electrons slowly drifted downward into Earth’s upper atmosphere, where they were gradually wiped out by interactions with air molecules. But the impenetrable barrier seen by the twin Van Allen belt spacecraft stops the electrons before they get that far, said Baker, who added:



It’s almost like theses electrons are running into a glass wall in space.


Somewhat like the shields created by force fields on Star Trek that were used to repel alien weapons, we are seeing an invisible shield blocking these electrons.



Read more about the newly discovered invisible shield in the Van Allen belts from University of Colorado Boulder


Bottom line: Scientists led by Daniel Baker at the University of Colorado Boulder – using data from the twin Van Allen Probes launched by NASA in 2012 – studying Earth’s Van Allen belts have found an invisible shield that blocks ultrafast electrons from moving deeper into Earth’s atmosphere.






from EarthSky http://ift.tt/1vP6R24

Scientists have discovered an invisible shield roughly 7,200 miles above Earth that blocks so-called “killer electrons,” which can fry satellites and degrade space systems during intense solar storms. Illustration by Andy Kale, University of Alberta.

Scientists have discovered an invisible shield roughly 7,200 miles (11,600 km) above Earth that blocks so-called “killer electrons,” which can fry satellites and degrade space systems during intense solar storms. Illustration by Andy Kale, University of Alberta.



In the 1950s, James Van Allen made one of the first major discoveries of the space age when he and his team found Earth’s two Van Allen radiation belts. These doughnut-shaped rings high above Earth are filled with high-energy electrons and protons. They swell and shrink in response to incoming energy disturbances from the sun, as they protect Earth from space radiation and the effects of our sun’s activity. In 2013, Daniel Baker at the University of Colorado Boulder – who received his doctorate under Van Allen – led a team that used data from twin NASA probes to discover a third, transient storage ring between the inner and outer Van Allen radiation belts. Today, Baker announced that his team has found an “extremely sharp” boundary at the inner edge of the outer belt. This boundary layer is Earth’s own invisible Star-Trek-like shield, he said, in that it appears to block ultrafast electrons from moving deeper into Earth’s atmosphere. The journal Nature published a paper on this subject on November 26, 2014.


The newly found boundary layer is roughly 7,200 miles (11,600 km) above Earth’s surface. The Van Allen belts themselves extend up to 25,000 miles (40,000 km) high.

.

This new layer blocks what scientists sometimes call killer electrons, known to whip around Earth at near-light speed, threatening astronauts, frying satellites and degrading space systems during intense solar storms. What the killer electrons don’t do, however, is penetrate down to Earth’s surface. It was originally thought that these highly charged electrons slowly drifted downward into Earth’s upper atmosphere, where they were gradually wiped out by interactions with air molecules. But the impenetrable barrier seen by the twin Van Allen belt spacecraft stops the electrons before they get that far, said Baker, who added:



It’s almost like theses electrons are running into a glass wall in space.


Somewhat like the shields created by force fields on Star Trek that were used to repel alien weapons, we are seeing an invisible shield blocking these electrons.



Read more about the newly discovered invisible shield in the Van Allen belts from University of Colorado Boulder


Bottom line: Scientists led by Daniel Baker at the University of Colorado Boulder – using data from the twin Van Allen Probes launched by NASA in 2012 – studying Earth’s Van Allen belts have found an invisible shield that blocks ultrafast electrons from moving deeper into Earth’s atmosphere.






from EarthSky http://ift.tt/1vP6R24

Hangout with astrophysicists to discuss film Interstellar. Watch here



Today – November 26, 2014 – at 12 p.m. Pacific (2 Central, 3 Eastern, 2000 UTC), the Kavli Foundation will host a fun Google+ hangout on the science of the blockbuster film “Interstellar.”


Three astrophysicists will answer viewers’ questions about black holes, relativity and gravity, separating the movie’s science facts from its science fiction.


More details: http://bit.ly/11UGbQc


By the way, if the time for the Hangout has passed, come back to this space soon. We’ll be posting the video of the event as soon as it’s available.


Bottom line: Ever wanted to hang out with astrophysicists? Now is your chance. G+ hangout today to talk about the film Interstellar.






from EarthSky http://ift.tt/1vODMDG


Today – November 26, 2014 – at 12 p.m. Pacific (2 Central, 3 Eastern, 2000 UTC), the Kavli Foundation will host a fun Google+ hangout on the science of the blockbuster film “Interstellar.”


Three astrophysicists will answer viewers’ questions about black holes, relativity and gravity, separating the movie’s science facts from its science fiction.


More details: http://bit.ly/11UGbQc


By the way, if the time for the Hangout has passed, come back to this space soon. We’ll be posting the video of the event as soon as it’s available.


Bottom line: Ever wanted to hang out with astrophysicists? Now is your chance. G+ hangout today to talk about the film Interstellar.






from EarthSky http://ift.tt/1vODMDG

Using supermassive black holes to measure cosmic distances



“Eye of Sauron,” an actively growing supermassive black hole at the center of the galaxy called NGC 4151. Read more about this image



How do we know the distances across space? Astronomers start with an actual measurement of nearby stars via stellar parallax and use a stepping stone method to estimate the vast distances beyond the closest stars. It’s impressive, but the method is full of guesstimates, and thus cosmic distances are known to be uncertain. Now researchers from the Niels Bohr Institute at the University of Copenhagen say they’ve demonstrated that precise distances can be measured using supermassive black holes. The scientific journal Nature published their results, which they announced today (November 26, 2014).


To probe the usefulness of this method, the researchers used the central region of an active galaxy called NGC 4151. Its central region is the famous Eye of Sauron – not the one from Lord of the Rings, but a realm of space surely as formidable: a supermassive black hole at the center of NGC 4151, which we – at our great distance across space – see as still active. IN other words, unlike the dormant supermassive black hole at the center of our own Milky Way galaxy, the supermassive black hole in NGC 4151 still accretes – or accumulate – matter via gas clouds surrounding it. The researchers say it’s this process of accretion that makes it possible to measure the distance to the galaxy.


Darach Watson of the Dark Cosmology Center at the Niels Bohr Institute and study leader Sebastian Hönig, who now works at the University of Southampton in the U.K., worked together to obtain these results. Watson explained:



When the gas falls in towards the black hole, it is heated up and emits ultraviolet radiation. The ultraviolet radiation heats a ring of dust, which orbits the black hole at a large distance, and this heats the dust causing it to emit infrared radiation.


Using telescopes on Earth, we can now measure the time delay between the ultraviolet light from the black hole and the subsequent infrared radiation emitted from the dust cloud. The time difference is about 30 days, and because we know the speed of light, we can calculate the real physical distance between the black hole and the encircling dust.



He said that by combining the light from the two 10-meter Keck telescopes on Mauna Kea on Hawaii using a method called interferometry, his team was able make the two Keck telescopes act in a way that was equivalent to one telescope with a perfect 85-meter diameter mirror. According to their press release, that gave the two Keck telescopes:



… a hundred times better resolution than the Hubble Space Telescope — and allows them to measure the angle the dust ring makes in the sky, (about twelve millionth of a degree).



Then the researchers combined data about the angular size of the dust ring on the sky’s dome with the physical size of 30 light-days, to find the distance to the supermassive black hole in NGC 4151. Watson said:



We calculated the distance to be 62 million light-years. The previous calculations based on redshift (a change in the wavelength of the light due to the velocity of the object away from us) were between 13 million and 95 million light-years, so we have gone from a great deal of uncertainty to now being able to determine the precise distance. This is very significant for astronomical calculations of cosmic scale distances.



Here is the entire galaxy NGC 4151. It's located toward the constellation Canes Venatici. Image via David W. Hogg, Michael R. Blanton, and the Sloan Digital Sky Survey Collaboration.

Here is the entire galaxy NGC 4151. It’s located in the direction to what we see as the constellation Canes Venatici. Image via David W. Hogg, Michael R. Blanton, and the Sloan Digital Sky Survey Collaboration.



Watson said he and Sebastian Hönig were both



… thrilled with the results.


The process was almost magical. The most important thing about measuring distance is high precision — how accurate is the method. We knew that if we could get the uncertainty down to about 10 percent, it would be significant, but we had no idea that it was possible. When we first realized that we could carry out this measurement, we knew that the precision of the measurements of the angular size using interferometry and the physical size based on the time delay were both only about 30 percent. Normally, when you combine two such numbers, the accuracy of the ratio is worse, so we expected an overall accuracy of 40 percent or so. But that was not what happened. It turned out that the greatest uncertainty in both measurements was the distribution of the brightness across the dust ring. And it was the same in both measurements, so when we took the ratio, the uncertainties cancelled — simply disappeared. Sebastian Hönig, after making the first calculation, came to me and said: ‘You’ll never believe what the precision is, guess!’ Usually in science you fight so hard to get something to fit or work properly. But every so often — very rarely, something magical happens — it’s like a gift and everything just falls into place. That is what happened here.



The two Keck 10-meter (33 feet) telescopes. Image via NASA/JPL

The two Keck 10-meter (33 feet) telescopes. The black hole researchers used these two telescopes in a way that made them act equivalently to one telescope with a perfect 85-meter diameter mirror. Image via NASA/JPL



Bottom line: Niels Bohr Institute at the University of Copenhagen say they’ve demonstrated that precise distances can be measured using supermassive black holes. They used the famous “Eye of Sauron” an active supermassive black hole at the core of a distant galaxy called NGC 4151. Researchers measured the black hole’s distance at 62 million light-years.






from EarthSky http://ift.tt/1yhGOiw


“Eye of Sauron,” an actively growing supermassive black hole at the center of the galaxy called NGC 4151. Read more about this image



How do we know the distances across space? Astronomers start with an actual measurement of nearby stars via stellar parallax and use a stepping stone method to estimate the vast distances beyond the closest stars. It’s impressive, but the method is full of guesstimates, and thus cosmic distances are known to be uncertain. Now researchers from the Niels Bohr Institute at the University of Copenhagen say they’ve demonstrated that precise distances can be measured using supermassive black holes. The scientific journal Nature published their results, which they announced today (November 26, 2014).


To probe the usefulness of this method, the researchers used the central region of an active galaxy called NGC 4151. Its central region is the famous Eye of Sauron – not the one from Lord of the Rings, but a realm of space surely as formidable: a supermassive black hole at the center of NGC 4151, which we – at our great distance across space – see as still active. IN other words, unlike the dormant supermassive black hole at the center of our own Milky Way galaxy, the supermassive black hole in NGC 4151 still accretes – or accumulate – matter via gas clouds surrounding it. The researchers say it’s this process of accretion that makes it possible to measure the distance to the galaxy.


Darach Watson of the Dark Cosmology Center at the Niels Bohr Institute and study leader Sebastian Hönig, who now works at the University of Southampton in the U.K., worked together to obtain these results. Watson explained:



When the gas falls in towards the black hole, it is heated up and emits ultraviolet radiation. The ultraviolet radiation heats a ring of dust, which orbits the black hole at a large distance, and this heats the dust causing it to emit infrared radiation.


Using telescopes on Earth, we can now measure the time delay between the ultraviolet light from the black hole and the subsequent infrared radiation emitted from the dust cloud. The time difference is about 30 days, and because we know the speed of light, we can calculate the real physical distance between the black hole and the encircling dust.



He said that by combining the light from the two 10-meter Keck telescopes on Mauna Kea on Hawaii using a method called interferometry, his team was able make the two Keck telescopes act in a way that was equivalent to one telescope with a perfect 85-meter diameter mirror. According to their press release, that gave the two Keck telescopes:



… a hundred times better resolution than the Hubble Space Telescope — and allows them to measure the angle the dust ring makes in the sky, (about twelve millionth of a degree).



Then the researchers combined data about the angular size of the dust ring on the sky’s dome with the physical size of 30 light-days, to find the distance to the supermassive black hole in NGC 4151. Watson said:



We calculated the distance to be 62 million light-years. The previous calculations based on redshift (a change in the wavelength of the light due to the velocity of the object away from us) were between 13 million and 95 million light-years, so we have gone from a great deal of uncertainty to now being able to determine the precise distance. This is very significant for astronomical calculations of cosmic scale distances.



Here is the entire galaxy NGC 4151. It's located toward the constellation Canes Venatici. Image via David W. Hogg, Michael R. Blanton, and the Sloan Digital Sky Survey Collaboration.

Here is the entire galaxy NGC 4151. It’s located in the direction to what we see as the constellation Canes Venatici. Image via David W. Hogg, Michael R. Blanton, and the Sloan Digital Sky Survey Collaboration.



Watson said he and Sebastian Hönig were both



… thrilled with the results.


The process was almost magical. The most important thing about measuring distance is high precision — how accurate is the method. We knew that if we could get the uncertainty down to about 10 percent, it would be significant, but we had no idea that it was possible. When we first realized that we could carry out this measurement, we knew that the precision of the measurements of the angular size using interferometry and the physical size based on the time delay were both only about 30 percent. Normally, when you combine two such numbers, the accuracy of the ratio is worse, so we expected an overall accuracy of 40 percent or so. But that was not what happened. It turned out that the greatest uncertainty in both measurements was the distribution of the brightness across the dust ring. And it was the same in both measurements, so when we took the ratio, the uncertainties cancelled — simply disappeared. Sebastian Hönig, after making the first calculation, came to me and said: ‘You’ll never believe what the precision is, guess!’ Usually in science you fight so hard to get something to fit or work properly. But every so often — very rarely, something magical happens — it’s like a gift and everything just falls into place. That is what happened here.



The two Keck 10-meter (33 feet) telescopes. Image via NASA/JPL

The two Keck 10-meter (33 feet) telescopes. The black hole researchers used these two telescopes in a way that made them act equivalently to one telescope with a perfect 85-meter diameter mirror. Image via NASA/JPL



Bottom line: Niels Bohr Institute at the University of Copenhagen say they’ve demonstrated that precise distances can be measured using supermassive black holes. They used the famous “Eye of Sauron” an active supermassive black hole at the core of a distant galaxy called NGC 4151. Researchers measured the black hole’s distance at 62 million light-years.






from EarthSky http://ift.tt/1yhGOiw

Another reason to be thankful for turkey


Photo credit: Brigham Young University

Photo credit: Brigham Young University



Here’s another reason to appreciate turkey this Thanksgiving: According to researchers, the biological machinery needed to produce a potentially life-saving antibiotic is found in turkeys.


Brigham Young University microbiologist Joel Griffitts and his team are exploring how the turkey-born antibiotic comes to be. Griffitts said:



Our research group is certainly thankful for turkeys. The good bacteria we’re studying has been keeping turkey farms healthy for years and it has the potential to keep humans healthy as well.



That’s because the good bacteria in turkeys, Strain 115 as scientists know it, produces an antibiotic called MP1 — a known killer that could target staph infections, strep throat, severe gastrointestinal diseases and roughly half of all infectious bacteria. This antibiotic, however, is not in widespread use because of its complex structure.


The research team has been working to identify exactly how Strain 115 makes this antibiotic, and how it manages to do so without killing itself.


Bottom line: Be thankful for turkeys this Thanksgiving! An antibiotic to target staph infections and strep comes from good bacteria in turkeys, say researchers.


Read more from Brigham Young University






from EarthSky http://ift.tt/1Cg8Ija

Photo credit: Brigham Young University

Photo credit: Brigham Young University



Here’s another reason to appreciate turkey this Thanksgiving: According to researchers, the biological machinery needed to produce a potentially life-saving antibiotic is found in turkeys.


Brigham Young University microbiologist Joel Griffitts and his team are exploring how the turkey-born antibiotic comes to be. Griffitts said:



Our research group is certainly thankful for turkeys. The good bacteria we’re studying has been keeping turkey farms healthy for years and it has the potential to keep humans healthy as well.



That’s because the good bacteria in turkeys, Strain 115 as scientists know it, produces an antibiotic called MP1 — a known killer that could target staph infections, strep throat, severe gastrointestinal diseases and roughly half of all infectious bacteria. This antibiotic, however, is not in widespread use because of its complex structure.


The research team has been working to identify exactly how Strain 115 makes this antibiotic, and how it manages to do so without killing itself.


Bottom line: Be thankful for turkeys this Thanksgiving! An antibiotic to target staph infections and strep comes from good bacteria in turkeys, say researchers.


Read more from Brigham Young University






from EarthSky http://ift.tt/1Cg8Ija

Video: Young volcanoes on the moon



Back in 1971, Apollo 15 astronauts orbiting the moon photographed something very odd. Researchers called it “Ina,” and it looked like the aftermath of a volcanic eruption.


There’s nothing odd about volcanoes on the moon, per se. Much of the moon’s ancient surface is covered with hardened lava. The main features of the “man in the moon,” in fact, are old basaltic flows deposited billions of years ago when the Moon was wracked by violent eruptions. The strange thing about Ina was its age.


Planetary scientists have long thought that lunar volcanism came to an end about a billion years ago, and little has changed since. Yet Ina looked remarkably fresh. For more than 30 years Ina remained a mystery.


Turns out, the mystery is bigger than anyone imagined. Using NASA’s Lunar Reconnaissance Orbiter, a team of researchers has found 70 landscapes similar to Ina. They call them “irregular mare patches” or IMPs for short.


Read more from NASA






from EarthSky http://ift.tt/1vihAi1


Back in 1971, Apollo 15 astronauts orbiting the moon photographed something very odd. Researchers called it “Ina,” and it looked like the aftermath of a volcanic eruption.


There’s nothing odd about volcanoes on the moon, per se. Much of the moon’s ancient surface is covered with hardened lava. The main features of the “man in the moon,” in fact, are old basaltic flows deposited billions of years ago when the Moon was wracked by violent eruptions. The strange thing about Ina was its age.


Planetary scientists have long thought that lunar volcanism came to an end about a billion years ago, and little has changed since. Yet Ina looked remarkably fresh. For more than 30 years Ina remained a mystery.


Turns out, the mystery is bigger than anyone imagined. Using NASA’s Lunar Reconnaissance Orbiter, a team of researchers has found 70 landscapes similar to Ina. They call them “irregular mare patches” or IMPs for short.


Read more from NASA






from EarthSky http://ift.tt/1vihAi1