Universe Today

December 9, 2013December 23, 2015 by Nancy Atkinson

And the Coldest Place on Earth Is …

With remote-sensing satellites, scientists have found the coldest places on Earth, just off a ridge in the East Antarctic Plateau. The coldest of the cold temperatures dropped to minus 135.8 F (minus 93.2 C) -- several degrees colder than the previous record. Image Credit: Ted Scambos, National Snow and Ice Data Center.

What is the coldest place on Earth? Scientists say it’s a place so cold that ordinary mercury or alcohol thermometers won’t work there. If you were there, every breath would be painful, your clothing would crackle every time you moved, and if you threw hot water into the air, it would fall to the ground as tiny shards of ice. At this place, the new record of minus 136 F (minus 93.2 C) was set on Aug. 10, 2010. Researchers analyzed data from several satellite instruments and found the coldest place on Earth in the past 32 years is … a high ridge in Antarctica between Dome Argus and Dome Fuji, two summits on the ice sheet known as the East Antarctic Plateau. Temperatures in several hollows were found to dip to the new record.

“We had a suspicion this Antarctic ridge was likely to be extremely cold,” said Ted Scambos, from the National Snow and Ice Data Center in Boulder, Colorado. “With the launch of Landsat 8, we finally had a sensor capable of really investigating this area in more detail.”

This beats out the previous low of minus 128.6 F (minus 89.2 C), set in 1983 at the Russian Vostok Research Station in East Antarctica. The coldest permanently inhabited place on Earth is northeastern Siberia, where temperatures in the towns of Verkhoyansk and Oimekon dropped to a bone-chilling 90 degrees below zero Fahrenheit (minus 67.8 C) in 1892 and 1933, respectively.

Scambos and his team made the discovery while analyzing the most detailed global surface temperature maps to date, developed with data from remote sensing satellites. The new findings were reported at the American Geophysical Union meeting in San Francisco.

The pursuit to find the coldest place on Earth started when the researchers were studying large snow dunes, sculpted and polished by the wind, on the East Antarctic Plateau. When the scientists looked closer, they noticed cracks in the snow surface between the dunes, possibly created when wintertime temperatures got so low the top snow layer shrunk. This led scientists to wonder what the temperature range was, and prompted them to hunt for the coldest places using data from two types of satellite sensors.

They used data from the Moderate Resolution Imaging Spectroradiometer (MODIS) instruments on NASA’s Terra and Aqua satellites and the Advanced Very High Resolution Radiometer (AVHRR) on several National Oceanic and Atmospheric Administration satellites. These sensitive instruments can pick up thermal radiation emitted from Earth’s surface, even in areas lacking much heat.

Using these sensors to scan the East Antarctic Plateau, Scambos detected extremely cold temperatures on a 620-mile stretch of the ridge at high elevations between Argus and Fuji, and even colder temperatures lower elevations in pockets off the ridge. Then, with the higher resolution of the Thermal Infrared Sensor (TIRS) aboard Landsat 8, the research team pinpointed the record-setting pockets.

The team compared the sites to topographic maps to explore how it gets so cold. Already cold temperatures fall rapidly when the sky clears. If clear skies persist for a few days, the ground chills as it radiates its remaining heat into space. This creates a layer of super-chilled air above the surface of the snow and ice. This layer of air is denser than the relatively warmer air above it, which causes it to slide down the shallow slope of domes on the Antarctic plateau. As it flows into the pockets, it can be trapped, and the cooling continues.

“By causing the air to be stationary for extended periods, while continuing to radiate more heat away into space, you get the absolute lowest temperatures we’re able to find,” Scambos said. “We suspected that we would be looking for one magical site that got extremely cold, but what we found was a large strip of Antarctica at high altitude that regularly reached these record low temperatures.”

Source: NASA

December 9, 2013December 23, 2015 by Nancy Atkinson

See What the Moon Will Look Like in All of 2014 in Just 5 Minutes

The Moon, via the Scientific Visualization Studio.

Here’s how the Moon will look to us on Earth during the entire year of 2014. Using data from the Lunar Reconnaissance Orbiter, the Goddard Space Flight Center Scientific Visualization Studio can project how the Moon will appear, and compresses one month into 24 seconds and a year to about 5 minutes. Above is the video where Celestial north is up, corresponding to the view from the northern hemisphere, and below is how the Moon will look from the southern hemisphere.

While the Moon always keeps the same face to us, it’s not exactly the same face. Because of the tilt in its axis and shape of its orbit, we see the Moon from slightly different angles over the course of a month, and the year. Normally, we don’t see how the Moon “wobbles” in its orbit, but seeing the Moon’s year this quickly, we can see the changes in libration, and axis tilt — as well as the most noticeable changes, the Moon’s phases.

Find out more at this SVS page, where you can also “Dial a Moon” — put in a specific date and see how the Moon will look on that day.

Universe Today also has a great app for your iPhone or Android that can also show you how the Moon will look any day in the past or present.

We also have a full list of the Moon phases and full Moon/New Moon dates here.

December 9, 2013December 23, 2015 by Nancy Atkinson

Astrophoto: Zodiacal Light at Dawn

The morning zodiacal as seen from near Rodeo, New Mexico, looking east at 5:00 am December 6, 2013. Credit and copyright: Alan Dyer/Amazing Sky Photography.

Sometimes, if you are lucky, dawn comes before the dawn. The zodiacal light – or false dawn, as it is sometimes called – is an ethereal light extending up from the horizon, sometimes seen about an hour before sunrise or an hour after sunset. At one time, it was thought this was an atmospheric phenomenon, but it’s more cosmic than that! Zodiacal light is sunlight reflecting off dust grains in space. These dust grains are likely left over from the same process that created Earth and the other planets of our solar system 4.5 billion years ago.

Alan Dyer captured this beautiful view of the zodiacal light on a recent trip to New Mexico. If you look closely you can see some other cosmic phenomena as well: “Mars is above centre and Saturn is just rising over the mountain ridge,” Alan wrote on Flickr. “Comet Lovejoy C/2013 R1 is at far left. The image includes the position (left of centre, above the mountains left of the Zodiacal Light) where Comet ISON (C/2012 S2) would have been had it survived passage around the Sun.”

See more of Alan’s great work at his Flickr page or his website, Amazing Sky Photography.

Want to get your astrophoto featured on Universe Today? Join our Flickr group or send us your images by email (this means you’re giving us permission to post them). Please explain what’s in the picture, when you took it, the equipment you used, etc.

December 9, 2013December 28, 2015 by Fraser Cain

Astronomy Cast Ep. 325: Cold Fusion

The Universe is filled with hot fusion, in the cores of stars. And scientists have even been able to replicate this stellar process in expensive experiments. But wouldn’t it be amazing if you could produce energy from fusion without all that equipment, and high temperatures and pressures? Pons and Fleischmann announced exactly that back in 1989, but things didn’t quite turn out as planned…

Continue reading “Astronomy Cast Ep. 325: Cold Fusion”

December 9, 2013December 23, 2015 by Evan Gough

Book Review and Giveaway: The Constellation Observing Atlas

Here is another giveaway just in time for the holidays: The Constellation Observing Atlas by Grant Privett and Kevin Jones. Springer and Universe Today are giving away free copies to two lucky Universe Today readers.

Review by: Evan Gough

The night sky is vast and full of wonders, and binoculars or a telescope can bring these wonders into view. The planets and the moon are easy to find, but after that, the rest of the objects in the night sky can be challenging to locate. “The Constellation Observing Atlas,” by Grant Privett and Kevin Jones, will guide you around the night sky, and help you find the most interesting objects.

This atlas uses the patterns of the constellations to cut the sky up into bite-sized pieces, giving the amateur observer an easy to use method for exploring the night sky. “The Constellation Observing Atlas” has a section for each one of the eighty-eight constellations recognized by the International Astronomical Union, from Andromeda to Vulpecula.

General information about each constellation is included, followed by the history of its name and mapping, any notable double and variable stars are mentioned and any deep sky objects that reside in or near the constellation are listed. Along with some nice images, “The Constellation Observing Atlas” also has detailed maps of each constellation which helps make the observing process straightforward.

The book is well laid out, and the amount of information for each constellation is just right. The maps are detailed and helpful and I found the history sections very interesting and amusing. The authors don’t mind having a little fun at the ancient’s expense for some of their comical constellation choices and the convoluted myths behind them, and who can blame them? Many of the constellations are just vague clumps and arrangements of stars in which the ancients somehow saw their most powerful gods, mythical creatures, and heroes.

Like many Universe Today readers, I’m interested in all things astronomy and space, but I’m far from an expert observer. “The Constellation Observing Atlas” tries to make the night sky accessible for amateurs like myself, and it works. You simply locate a constellation in the sky, check the book for interesting viewing targets, point your ‘scope around, and have some fun. Some of the stars and deep sky objects will be challenging to find, and the authors give detailed information for finding these elusive targets.

In my part of the world, winter has come and I’m in store for some clear, cold, crisp nights. There should be some great observing conditions ahead, with Orion prominent in the night sky. I’m looking forward to using “The Constellation Observing Atlas” to expand my observing. The authors have done a good job of being informative and fun, and I highly recommend this book to amateur and novice observers. It makes the wonders of the night sky accessible, one constellation at a time.

In order to be entered into the giveaway drawing, just put your email address into the box at the bottom of this post (where it says “Enter the Giveaway”) before Monday, December 16th, 2013. We’ll send you a confirmation email, so you’ll need to click that to be entered into the drawing.

Don’t want to wait to see if you won? Get your copy in time for Christmas from Amazon.com

December 9, 2013December 23, 2015 by Nancy Atkinson

Take a Virtual Spin Around Mars’ North Pole

An image from ESA's Mars Express taken in May of 2010 shows the north pole of Mars during the red planet's summer solstice. All the carbon dioxide ice has gone, leaving just a bright cap of water ice. Credit: ESA.

Get a satellite’s-eye view of the Martian north pole in this new animation from the Mars Express spacecraft, using data from the Mars Advanced Radar for Subsurface and Ionospheric Sounding instrument, MARSIS. This instrument allows for studying the surface heights, providing a 3-D view of the Mars’ north pole.

You can see the prominent gap in the ice cap, which is a 318 km-long, 2 km-deep chasm called Chasma Boreale.

In all, the ice cap has a diameter of about 1000 km and consists of many thin layers of ice mixed with dust that extend to a depth of around 2 km below the cap.

ESA says the layers result from variations in the orbit and rotation of Mars that affect the amount of sunlight received at the poles, and thus the amount of melting and deposition of materials over time. Meanwhile, strong prevailing winds are thought to be responsible for shaping the spiral troughs.

The MARSIS instrument works by sending low-frequency radio waves towards the surface of Mars, and they are reflected back to the spacecraft from the planet’s surface. The strength and timing of the radar echoes are a gauge of the depths of different types of interfaces, such as between rock, water or ice.

Video credit: ESA/ASI/NASA/JPL/La Sapienza University/INAF (A. Frigeri)

December 9, 2013April 26, 2016 by Elizabeth Howell

‘Glowing Wreck Of A Star’ Reveals Cosmic Cannibalism

Composite image of Circinus X-1, which is about 24,000 light-years from Earth in the constellation Circinus. Credit: X-ray: NASA/CXC/Univ. of Wisconsin-Madison/S. Heinz et al; Optical: DSS; Radio: CSIRO/ATNF/ATCA

Circinus X-1 may look like a serene place from a distance, but in reality this gassy nebula is quite a busy spot. Embedded in the nebula is the neutron star that is also a leftover of the supernova that produced the gas. Not only that, but the neutron star is still locked on to a companion and is in fact “cannibalizing” it, astronomers said.

The “glowing wreck of a star”, as the team called it, is exciting because it demonstrates what systems look like in the first stages after an explosion. The nebula is an infant in cosmic terms, with an upper limit to its age of just 4,500 years. To put that in human terms, that’s around the time of the first civilizations (such as in Mesopotamia).

“The fact that we have this remnant along with the neutron star and its companion means we can test all kinds of things,” stated Sebastian Heinz, an astronomy professor at the University of Wisconsin-Madison who led the research.

“Our observations solve a number of puzzles both about this object and the way that neutron stars evolve after they are born. For example, the unusual elliptical orbit on which these two stars swing around each other is exactly what you would expect for a very young X-ray binary.”

X-ray binaries are typically made up of a black hole or a neutron star that is locked on to a “normal” companion star such as that of our sun. That star won’t stay normal forever, however, as it’s being subject to very intense gravity from the black hole or neutron star. Its starstuff is being pulled off, heated, and then emitting radiation in X-rays that are easily trackable across the universe.

While X-ray binaries have been spotted before, seeing one along with a nebula is something special. By comparison, the gas cloud doesn’t stick around for very long — just 100,000 years or so — while the stars can be there for a while longer.

Checking out this star system could not only teach scientists about stellar evolution, but about the nature of neutron stars. One thing puzzling the team right now is why the neutron star has a faint magnetic field, which stands against established theory. Further study will be required to figure out why it isn’t as strong as expected.

Combining observations done with ESO's Very Large Telescope and NASA's Chandra X-ray telescope, astronomers have uncovered the most powerful pair of jets ever seen from a stellar black hole. The black hole blows a huge bubble of hot gas, 1,000 light-years across or twice as large and tens of times more powerful than the other such microquasars. The stellar black hole belongs to a binary system as pictured in this artist's impression. Credit: ESO/L. Calçada — A binary X-ray system with a black hole (right) and companion star. Credit: ESO/L. Calçada

This high-resolution view from NASA’s Chandra X-Ray Telescope and the Australia Telescope Compact Array, however, has revealed some new things.

“I have been perplexed by the unusually strong evolution of the orbit of Circinus X-1 since my graduate-school days,” stated Niel Brandt, an astronomer at Pennsylvania State University who is on the team. “The discovery now of this system’s youth provides a satisfying explanation for why its orbit evolves so strongly — because the system likely still is settling down after its violent birth.”

You can read more in the Dec. 4 publication in The Astrophysical Journal or, in prepublished form, on Arxiv.

Sources: University of Wisconsin-Madison and Pennsylvania State University

December 9, 2013December 23, 2015 by David Dickinson

Get Ready for the 2013 Geminid Meteor Shower

The rising radiant of the Geminids-Looking east at 9PM local from latitude 30 degrees north. (Credit-Stellarium).

One of the best annual meteor showers occurs this coming weekend.

The 2013 Geminid meteors peak this coming Saturday on December 14^th. This shower has a broad maximum, assuring that observers worldwide get a good look. In 2013, the maximum for the Geminids is forecast to span from 13:00 Universal Time (UT) on Friday, December 13^th to 10:00UT/5:00AM EST on Saturday, December 14^th, with a projected maximum centered a few hours earlier at 2:00 UT Saturday morning.

This is good news for observers spanning both sides of the Atlantic, who should be well placed to catch the event. Keep in mind, meteor showers often peak hours before or after predictions… we certainly don’t know everything that a given meteor stream might have in store!

An all-sky composite of the 2008 Geminid meteor shower. (Credit: NASA/MSFC/Bill Cooke, NASA's Meteoroid Environment Office). — An all-sky composite of the 2008 Geminid meteor shower. (Credit: NASA/MSFC/Bill Cooke, NASA’s Meteoroid Environment Office).

But the time to start watching is now. We’ve already seen a few early Geminids this past weekend, and this shower is notable for showing early activity for northern hemisphere observers before local midnight. This is because the radiant, or the direction that the meteors seem to emanate from lies at a high northern declination of 33 degrees north near the star Castor, also known as Alpha Geminorum.

The typical Zenithal Hourly Rate for the Geminids is 80-120, or about 1 to 2 per minute. Keep in mind, the ZHR is an ideal rate, assuming dark skies, with the radiant positioned directly overhead. Most observers will see significantly less activity.

The 2013 Geminids also have to contend with the waxing gibbous Moon, which reaches Full just 3 days after the shower’s expected maximum. This will give observers a dwindling window between moonset and the start of dawn twilight to catch the Geminids at their best.

We always thought that the Geminids had a bit of an undeserved PR problem among annual showers. This no doubt stems from the fact that they arrive in the chilly month of December, a time when fingers go numb, camera batteries die, and conducting a vigil for meteors is challenging.

A 2012 Geminid captured by the author from Mars Hill. North Carolina. — A 2012 Geminid captured by the author from Mars Hill, North Carolina.

This shower is an interesting one though, with an equally interesting history and source. The Geminids were first identified as a distinct meteor shower by R.P. Greg of Manchester UK in 1862, and the estimated ZHR rose from about 20 to 80 through the 20^th century. The parent source of the Geminids remained unknown until 1983, when astronomer Fred Whipple linked them to the strange “rock-comet” body 3200 Phaethon. An Apollo asteroid also thought to be a member of the Pallas family of asteroids, 3200 Phaethon seems to be shedding enough material to produce the annual Geminid meteor shower. This makes the annual shower rare as one not produced by a comet. It’s worth noting that 3200 Phaethon also passes extremely close – 0.14 AU – from the Sun at perihelion, and gets periodically “baked” during each 1.4 year passage.

In the 21^st century, rates for the Geminids have stayed above a ZHR of 120, currently the highest of any annual shower. It’s worth noting that an extrapolated ZHR of almost 200 were seen in 2011 when the Moon was at an equally unfavorable waning gibbous phase! The Geminids always produce lots of fireballs, capable of being seen even under moonlit skies.

There are also two other showers currently active to watch for this week. One is the Ursid meteors, which radiate from the Little Dipper (Ursa Minor) with a peak ZHR of 10-50 occurring on December 22^nd. Also, keep an eye out for Andromedid meteors this week, a defunct shower that may be making a comeback. The source of several great meteor storms in the late 19^th century, the Andromedid parent source is the shattered comet formerly known as 3D/Biela.

An early Geminid crosses pathes with Comet 2013 R1 Lovejoy. (Credit: Jason Hullinger). — An early Geminid crosses paths with Comet 2013 R1 Lovejoy. (Credit: Jason Hullinger).

Though the Geminids appear to radiate from the constellation Gemini, they can appear anywhere in the sky. Tracing the path back can determine the source constellation and the “membership” of a given meteor. Random meteors not associated with any identified shower are known as “sporadics.” Block that pesky light-polluting Moon behind a building or hill to optimize your chances of catching sight of a meteor. Employing a friend or two to watch in different directions will also maximize the number seen. The International Meteor Organization always welcomes reports from observers… this is real science that you can contribute to using nothing more sophisticated than your eyes!

The Geminids are medium-speed meteors with an average atmospheric velocity of about 35 kilometres per second, often leaving long, glowing trails worth examining with a pair of binoculars. You might note an apparent surge in speed to this shower past local midnight, as your vantage point turns into the oncoming shower, adding the velocity of the Earth to the approaching Geminids.

Photographing meteors is fun and easy to do; all you’ll need is a DSLR camera mounted on a tripod. Take several manual setting exposures to get the combination of ISO,F-stop, and shutter speed correct for your local sky conditions. Then simply set the focus to infinity, and use the widest field of view possible. Catching meteors is surreptitious, as they can appear anywhere – and at any time – in the sky. Be sure to thoroughly review those images afterwards… nearly every meteor we’ve caught photographically went unnoticed during observation!

Also, remember that cold weather plus long exposure times can conspire to drain camera batteries in a hurry. Be sure to keep a spare set of charged batteries ready to go in a warm pocket!

How powerful will the Geminids become? Are we in for a “return of the Andromedids” moving towards 2014? One thing is for sure: you won’t see any meteors if you don’t try. So be sure to get out there, pour a mug of your favorite warming beverage, and don’t miss the 2013 Geminid meteor shower!

– Got meteors? Be sure and tweet ‘em to #Meteorwatch.

– Be sure to send those pics of Geminids and more in to Universe Today.

December 9, 2013December 23, 2015 by Elizabeth Howell

This Spooky X-Ray ‘Hand’ Demonstrates A Pulsar Star Mystery

This X-ray nebula appears to look like a human hand. The ghostly shape comes courtesy of a pulsar star called PSR B1509-58 (B1509 for short) that is just 12 miles or 19 kilometers in diameter. The nebula itself is 150 light-years across. Image taken by NASA's Chandra X-ray Observatory. Credit: NASA/CXC/CfA/P. Slane et al.

That spooky hand in the image above is producing questions for scientists. While the shape only coincidentally looks like a human hand, scientists are still trying to figure out how a small star produced such a large shape visible in X-rays.

Pulsar star PSR B1509-58 (or B1509 for short) is a 12-mile (19-kilometer) remnant of a much larger star that exploded and left behind a quickly spinning neutron star. Energy leaves mostly via neutrino (or neutral particle) emission, with a bit more coming out via beta decay, or a radioactive process where charged particles leave from atoms.

Using a new model, scientists found that so much energy comes out from neutrino emission that there shouldn’t be enough left for the beta decay to set off the X-rays you see here in this image, or in other situations. Yet it’s still happening. And that’s why they’re hoping to take a closer look at the situation.

Artist's conception of a neutron star flare. Credit: University of California Santa Cruz — Artist’s conception of a neutron star flare. Credit: University of California Santa Cruz

“Scientists are intrigued by what exactly powers these massive explosions, and understanding this would yield important insights about the fundamental forces in nature, especially on the astronomical/cosmological scale,” stated Peter Moller, who is with the theoretical division of Los Alamos National Laboratory and participated in the research.

Preliminary studies indicate that to better understand what’s happening on the surface of these objects, computer models must endeavor to “describe the shape of each individual nuclide” (or atom that has a certain number of protons and neutrons in its nucleus). That’s because not all of these nuclides are simple spheres.

Using facilities at Los Alamos, scientists created databases with different types of nuclides that had various beta-decay properties. They then plugged this into a Michigan State University model of neutron stars to see what energy was released as the stars accrete or come together.

Accretion can cause neutron stars to flare violently

The results stood against what was a “common assumption”, the scientists stated, that the radioactive action would be enough to power the X-rays. They urge more study on this front, especially using a proposed Facility for Rare Isotope Beams that would be built at Michigan State, using funding from the U.S. Department of Energy Office of Science. FRIB project participants are hoping that will be ready in the 2020s.

You can read more about the research in the Dec. 1 edition of Nature. It was led by Hendrik Schatz, a professor at the National Superconducting Cyclotron Laboratory at Michigan State.

Source: Los Alamos National Laboratory

December 9, 2013March 14, 2017 by Fraser Cain

Why Does the Moon Shine?

We enjoy the light from the Sun during the day, and then the comforting glow of the Moon at night. But the light coming from the Moon is an illusion. As you know, you’re actually seeing the reflected light from the Sun, bouncing off the Moon which acts like a mirror. A really terrible mirror.

When astronauts walked on the surface, they reported that it was dark grey, the color of pavement. Because of its dark color and bumpy surface, it only reflects about 12% of the light that hits it. Additionally, the amount of light we get from the Moon depends on the point of its orbit.

During its first and last quarters, the Moon is half illuminated, but it’s only 8% as bright when it’s full. Just imagine the surface when its only partly illuminated. With the Sun at a steep angle, the mountains cast long shadows. This makes the lunar surface much darker than when it’s directly illuminated.

During the full Moon, it’s so bright that it obscures fainter objects in the night sky. Many astronomers put their telescopes away during this phase, and wait for it to go away. When the Moon is highly illuminated, it reflects so much light we can even see it during the day.

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The brightness of the daytime sky completely washes out the light from the stars, but the Moon is even brighter, and so we can can see it in the sky during the day. The Moon follows an elliptical orbit around the Earth, changing its distance and brightness quite a bit. When it is at its closest point, and it’s full, this is known as a supermoon. This Moon can be 20% brighter than normal.

You’ve probably experienced how the Moon can cast shadows. In fact, there are three objects in the sky that can cast shadows. The Sun, of course, the Moon… and Venus.

Venus is the next brightest object in the sky, after the Moon. It reflects 65% of the sunlight that hits it. Every few months, Venus reaches its brightest time – that’s when you can see your shadow. On a night with no Moon, head far away from city lights. Let your eyes adjust and watch as your hand casts a shadow on a white piece of paper, illuminated only by Venus.

One last thought on reflected light.We talked about how bad a mirror the Moon is, reflecting only 12% of the light that hits it. That’s nothing. Saturn’s moon Enceladus, on the other hand, reflects about 99% of the light that falls on it. If astronauts ever get the chance to walk on the surface of Enceladus, it’ll feel like freshly fallen snow.

We have written many articles about the Moon for Universe Today. Here are some interesting facts about the Moon, and here are some Earth and Moon photos.

If you’d like more info on the Moon, check out NASA’s Solar System Exploration Guide on the Moon, and here’s a link to NASA’s Lunar and Planetary Science page.

We’ve also recorded an entire episode of Astronomy Cast all about the Moon. Listen here, Episode 113: The Moon, Part 1.

References:
http://lunarscience.nasa.gov/kids/moonshine
http://www-istp.gsfc.nasa.gov/stargaze/Smoon.htm