Space and astronomy news
A very creative and stunning use of perspective, timing and distance! BASE jumper Dean Potter walks a highline at Cathedral Peak in Yosemite National Park just as the Moon rises. This was shot with a zoom lens from over a mile away, and is part of a bigger project for National Geographic called The Man Who Can Fly.
Moonwalk from Bryan Smith on Vimeo.
This week’s Carnival of Space is hosted by Brian Wang at Next Big Future.
Click here to read Carnival of Space #283.
And if you’re interested in looking back, here’s an archive to all the past Carnivals of Space. If you’ve got a space-related blog, you should really join the carnival. Just email an entry to [email protected], and the next host will link to it. It will help get awareness out there about your writing, help you meet others in the space community – and community is what blogging is all about. And if you really want to help out, sign up to be a host. Send an email to the above address.
Spring, Summer, Autumn and Winter. These are the seasons we experience here on Earth as our planet completes an orbit around the Sun. But what’s going on? Why do we experience such different temperatures and weather over the course of 365 days? Do other planets experience the seasons like we do?
Click here to download the episode.
Or subscribe to: astronomycast.com/podcast.xml with your podcatching software.
“Seasons” on the Astronomy Cast website, with shownotes and transcript.
And the podcast is also available as a video, as Fraser and Pamela now record Astronomy Cast as part of a Google+ Hangout:
What a great shot of the Seven Sisters! M45, or the Pleiades is a cluster of stars that contains hundreds of stars, but just a handful are commonly visible to the unaided eye. The stars in the Pleiades are thought to have formed together around 100 million years ago, making them 1/50th the age of our Sun, and they lie about 450 light years from Earth. Chuck Manges, (astrochuck on Flickr) took this image on January 5, 2013 with a QHY9M camera and an Orion ED102CF telescope, and processed it in Photoshop. Gorgeous!
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.
Artist’s concept of brown dwarf 2MASSJ22282889-431026 (NASA/JPL-Caltech)
The complex weather patterns within the atmosphere of a rapidly-rotating brown dwarf have been mapped in the highest detail ever by researchers using the infrared abilities of NASA’s Spitzer and Hubble space telescopes… talk about solar wind!
Sometimes referred to as failed stars, brown dwarfs form from condensing gas and dust like regular stars but never manage to gather enough mass to ignite full-on hydrogen fusion in their cores. As a result they more resemble enormous Jupiter-like planets, radiating low levels of heat while possessing bands of wind-driven eddies in their upper atmospheric layers.
Although brown dwarfs are by their nature very dim, and thus difficult to observe in visible wavelengths of light, their heat can be detected by Hubble and the Spitzer Space Telescope — both of which can “see” just fine in near- and far-infrared, respectively.
Led by researchers from the University of Arizona, a team of astronomers used these orbiting observatories on July 7, 2011 to measure the light curves from a brown dwarf named 2MASSJ22282889-431026 (2M2228 for short.) What they found was that while 2M2228 exhibited periodic brightening in both near- and far-infrared over the course of its speedy 1.43-hour rotation, the amount and rate of brightening varied between the different wavelengths detected by the two telescopes.
“With Hubble and Spitzer, we were able to look at different atmospheric layers of a brown dwarf, similar to the way doctors use medical imaging techniques to study the different tissues in your body.”
– Daniel Apai, principal investigator, University of Arizona
This unexpected variance — or phase shift — most likely indicates different layers of cloud material and wind velocities surrounding 2M2228, swirling around the dwarf star in very much the same way as the stormy cloud bands seen on Jupiter or Saturn.
But while the clouds on Jupiter are made of gases like ammonia and methane, the clouds of 2M2228 are made of much more unusual stuff.
“Unlike the water clouds of Earth or the ammonia clouds of Jupiter, clouds on brown dwarfs are composed of hot grains of sand, liquid drops of iron, and other exotic compounds,” said Mark Marley, a research scientist at NASA’s Ames Research Center and co-author of the paper. “So this large atmospheric disturbance found by Spitzer and Hubble gives a new meaning to the concept of extreme weather.”
While it might seem strange to think about weather on a star, remember that brown dwarfs are much more gas planet-like than “real” stars. Although the temperatures of 1,100–1,600 ºF (600–700 ºC) found on 2M2228 might sound searingly hot, it’s downright chilly compared to even regular stars like our Sun, which has an average temperature of nearly 10,000 ºF (5,600 ºC). Different materials gather at varying layers of its atmosphere, depending on temperature and pressure, and can be penetrated by different wavelengths of infrared light — just like gas giant planets.
“What we see here is evidence for massive, organized cloud systems, perhaps akin to giant versions of the Great Red Spot on Jupiter,” said Adam Showman, a theorist at the University of Arizona involved in the research. “These out-of-sync light variations provide a fingerprint of how the brown dwarf’s weather systems stack up vertically. The data suggest regions on the brown dwarf where the weather is cloudy and rich in silicate vapor deep in the atmosphere coincide with balmier, drier conditions at higher altitudes — and vice versa.”
The team’s results were presented today, January 8, during the 221st meeting of the American Astronomical Society in Long Beach, CA.
Read more on the Spitzer site, and find the team’s paper in PDF form here.
Inset image: the anatomy of a brown dwarf’s atmosphere (NASA/JPL).
Astronomers have found what may be considered a piece of a galactic skeleton; a dark structure of gas and dust that might provide a backbone on which one of the spiral arms extend from the central bar of the Milky Way galaxy.
“This ‘bone’ is likely made from high density gas — the type that forms stars — and while the feature that we see is a sinuous distinction you get from dust, there is a huge amount of gas,” said Alyssa Goodman of the Harvard-Smithsonian Center for Astrophysics (CfA) at a press conference at the American Astronomical Society meeting in Long Beach, California today. “But we just don’t know yet what it is.”
While this is the first time such a structure has been seen in our own galaxy, other spiral galaxies seemingly display internal “endoskeletons.” Observations, especially at infrared wavelengths of light, have found long skinny features jutting between galaxies’ spiral arms. These relatively straight structures are much less massive than the curving spiral arms.
Goodman said that since we view the Milky Way from the inside, its exact structure is difficult to determine, but it is thought to have a central bar and two major spiral arms that wrap around its disk.
A team of astronomers first spotted the galactic bone while studying a dust cloud nicknamed “Nessie,” since its shape is reminiscent of the Loch Ness monster. The central part of the “Nessie” bone was discovered in Spitzer Space Telescope data in 2010 by James Jackson (Boston University). With further analysis, Goodman’s team determined the dark cloud goes way beyond the original section that was first found, and is as much as eight times longer than Jackson’s original sighting.
Radio emissions from molecular gas show that the feature is not a chance projection of material on the sky, but instead a real feature. Not only is “Nessie” in the galactic plane, but also it extends much longer than anyone anticipated. This slender bone of the Milky Way is more than 300 light-years long but only 1 or 2 light-years wide. It contains about 100,000 suns’ worth of material, and now looks more like a cosmic snake.
“This bone is much more like a fibula – the long skinny bone in your leg – than it is like the tibia, or big thick leg bone,” Goodman said.
It lies along the plane of the Milky Way, and since our vantage point is just above the the plane, Goodman and her team are hopeful that the skeleton may be able to be mapped.
“It’s possible that the ‘Nessie’ bone lies within a spiral arm, or that it is part of a web connecting bolder spiral features. Our hope is that we and other astronomers will find more of these features, and use them to map the skeleton of the Milky Way in 3-D,” she said.
The team’s paper is not quite finished yet, but it is online on the new open source scientific collaboration site, Authorea.
For more information, visit http://milkywaybones.org.
The Cassini spacecraft has been getting some strange data from Saturn’s moon Titan, and scientists will soon test out whether there might be “icebergs” of sorts, blocks of hydrocarbon ice floating on the surface of the lakes and seas of liquid hydrocarbon.
“One of the most intriguing questions about these lakes and seas is whether they might host an exotic form of life,” said Jonathan Lunine, a paper co-author and Cassini interdisciplinary Titan scientist at Cornell University, Ithaca, N.Y. “And the formation of floating hydrocarbon ice will provide an opportunity for interesting chemistry along the boundary between liquid and solid, a boundary that may have been important in the origin of terrestrial life.”
Titan is the only other body besides Earth in our solar system with stable bodies of liquid on its surface. But it is too cold on Titan for water to be liquid, so hydrocarbons like ethane and methane fill lakebeds and seas there, and scientists have determined there is even a likely cycle of precipitation and evaporation that involves hydrocarbons.
Ethane and methane are organic molecules, which scientists think can be building blocks for the more complex chemistry from which life arose.
Cassini has seen a vast network of these hydrocarbon seas cover Titan’s northern hemisphere, while a more sporadic set of lakes are in the southern hemisphere.
It has long been thought that lakes or seas dotted Titan, ever since Voyager 1 and 2 flew past the Saturn system in the early 1980’s. But with Titan’s thick atmosphere, direct evidence was not obtained until 1995 during observations from the Hubble Space Telescope. The Cassini mission has imaged and mapped many of these bodies of liquids on Titan.
The Cassini spacecraft has been getting mixed readings in the reflectivity of the surfaces of lakes on Titan. A smooth surface or liquids dotted with chunks of ice could be a possibility explanation for the readings.
Up to this point, Cassini scientists assumed that Titan lakes would not have floating ice, because solid methane is denser than liquid methane and would sink. But a new model considers the interaction between the lakes and the atmosphere, resulting in different mixtures of compositions, pockets of nitrogen gas, and changes in temperature. The result, scientists found, is that winter ice will float in Titan’s methane-and-ethane-rich lakes and seas if the temperature is below the freezing point of methane — minus 297 degrees Fahrenheit (90.4 kelvins). The scientists realized all the varieties of ice they considered would float if they were composed of at least 5 percent “air,” which is an average composition for young sea ice on Earth. (“Air” on Titan has significantly more nitrogen than Earth air and almost no oxygen.)
If the temperature drops by just a few degrees, the ice will sink because of the relative proportions of nitrogen gas in the liquid versus the solid. Temperatures close to the freezing point of methane could lead to both floating and sinking ice – that is, a hydrocarbon ice crust above the liquid and blocks of hydrocarbon ice on the bottom of the lake bed. Scientists haven’t entirely figured out what color the ice would be, though they suspect it would be colorless, as it is on Earth, perhaps tinted reddish-brown from Titan’s atmosphere.
“We now know it’s possible to get methane-and-ethane-rich ice freezing over on Titan in thin blocks that congeal together as it gets colder — similar to what we see with Arctic sea ice at the onset of winter,” said Jason Hofgartner, first author on the paper and a Natural Sciences and Engineering Research Council of Canada scholar at Cornell. “We’ll want to take these conditions into consideration if we ever decide to explore the Titan surface some day.”
Cassini’s radar instrument will be able to test this model by watching what happens to the reflectivity of the surface of these lakes and seas. A hydrocarbon lake warming in the early spring thaw, as the northern lakes of Titan have begun to do, may become more reflective as ice rises to the surface. This would provide a rougher surface quality that reflects more radio energy back to Cassini, making it look brighter. As the weather turns warmer and the ice melts, the lake surface will be pure liquid, and will appear to the Cassini radar to darken.
“Cassini’s extended stay in the Saturn system gives us an unprecedented opportunity to watch the effects of seasonal change at Titan,” said Linda Spilker, Cassini project scientist at NASA’s Jet Propulsion Laboratory, Pasadena, Calif. “We’ll have an opportunity to see if the theories are right.”
Source: NASA/JPL
Intense wild fires, or bush fires as they are called in Australia, are burning out of control across southeast Australia with authorities describing the condition as “catastrophic.” The huge fires were easily visible from the International Space Station on Tuesday and onboard, Canadian astronaut Chris Hadfield has been watching from above.
See more of his images below:
Officials say more than 130 fires, many uncontained, are burning in the heavily populated New South Wales state, where dry conditions are fueling the fires as temperatures reached 45 degrees and wind gusts reached more than 100 kilometers per hour.
In Tasmania, an island south of Australia, rescue officials are still trying to locate around 100 residents who have been missing after a fire tore through a village, destroying dozens of homes. You can see images from the Moderate Resolution Imaging Spectroradiometer (MODIS) on NASA’s Terra satellite that were taken on January 7, 2013 at the Earth Observatory website.
Follow Chris Hadfield on Twitter to see more images.
Additional information on the bush fires from Voice of America
A few sunspots are now ‘peppering” the surface of our Sun — Spaceweather.com lists about 12 different sunspot groups today. Yesterday (January 7, 2013), astrophotographer John Chumack stepped outside over his lunch break and captured some cool-looking views of the Sun from his observatory in Ohio, using different filters.
See more below, plus the Solar Dynamics Observatory has a spectacular video of coronal loops on the Sun during January 5 through 7.
The video shows the 171 angstroms channel, which is especially good at showing coronal loops – the arcs extending off of the Sun where plasma moves along the magnetic field lines, said the SDO team. The brightest spots seen here are locations where the magnetic field near the surface is exceptionally strong. The characteristic temperature here is 1 million K (or 1.8 million F).
Many of these loops could fit several Earths inside of them.
Different views from different filters from John Chumack:
See more of John’s work at his website, Galactic Images, or his Flickr page.
This incredible new movie of the Vela pulsar has the unnerving appearance of the Phantom of the Opera – wearing not only a mask, but also a steam-blowing hat like the Tin Man in “The Wizard of Oz.” What you are seeing here are observations from the Chandra X-ray Observatory, showing a fast moving jet of particles produced by a rapidly rotating neutron star. Scientists say these observations may provide new insight into the nature of some of the densest matter in the universe.
The Vela pulsar is about 1,000 light-years from Earth, about 19 km (12 miles) in diameter, and makes a complete rotation in 89 milliseconds. As the pulsar whips around, it spews out a jet of charged particles that race along the pulsar’s rotation axis at about 70 percent of the speed of light. The Chandra data used in the movie were obtained from June to September 2010, and it may suggest the pulsar may be slowly wobbling, or precessing, as it spins. The period of the precession, which is analogous to the slow wobble of a spinning top, is estimated to be about 120 days.
“We think the Vela pulsar is like a rotating garden sprinkler — except with the water blasting out at over half the speed of light,” said Martin Durant of the University of Toronto in Canada, who is the first author of the paper describing these results.
The eight images shown in the movie suggest that the pulsar may be slowly wobbling, or precessing, as it spins. If the evidence for precession of the Vela pulsar is confirmed, it would be the first time that a jet from a neutron star has been found to be wobbling, or precessing, in this way.
One possible cause of precession for a spinning neutron star is that it has become slightly distorted and is no longer a perfect sphere. This distortion might be caused by the combined action of the fast rotation and “glitches”, sudden increases of the pulsar’s rotational speed due to the interaction of the superfluid core of the neutron star with its crust.
A paper describing these results will be published in The Astrophysical Journal on January 10, 2013.
This is the second Chandra movie of the Vela pulsar. The first one, released in 2003, looks like a Halloween Jack-o-lanatern gone wrong:
This movie contains shorter, unevenly spaced observations so that the changes in the jet were less pronounced and the authors did not argue that precession was occurring. However, based on the same data, Avinash Deshpande of Arecibo Observatory in Puerto Rico and the Raman Research Institute in Bangalore, India, and the late Venkatraman Radhakrishnan, argued in a 2007 paper that the Vela pulsar might be precessing.
The Earth also precesses as it spins, with a period of about 26,000 years. In the future Polaris will no longer be the “north star” and other stars will take its place. The period of the Vela precession is much shorter and is estimated to be about 120 days.
The supernova that formed the Vela pulsar exploded over 10,000 years ago. This optical image from the Anglo-Australian Observatory’s UK Schmidt telescope shows the enormous apparent size of the supernova remnant formed by the explosion. The full size of the remnant is about eight degrees across, or about 16 times the angular size of the Moon. The square near the center shows the Chandra image with a larger field-of-view than used for the movie, with the Vela pulsar in the middle.
Source: NASA