Space and astronomy news
The folk at JPL have kindly put together an animation of the gigantic Martian dust devil spotted by the Mars Reconnaissance Orbiter. The dust devil is roughly 20 kilometers (12 miles) high, churning through the Amazonis Planitia region of northern Mars, and this shows what the tall but thin dust devil would look like if you were observing it as you hovered around in your Mars helicopter or balloon.
[/caption]
Recent images from ESA’s Mars Express spacecraft reveal long rows of crater-like depressions lining the flanks of ancient Martian volcanoes located in the planet’s vast Tharsis region. Rather than being the result of impact events, these “pit chains” were likely caused by underground lava flows — and could be a prime location for look for life.
Like similar features found on Earth, lava tubes on Mars are the result of rivers of magma that carved channels beneath the surface. When these channels empty out, a hollow tube is left. If the roof of a particularly large tube is near the surface the roof can eventually collapse, creating a surface depression… or, in some cases, opening up to the surface entirely.
Even though volcanism on Mars isn’t currently active — the last eruptions probably took place at least over a million years ago — the features left by volcanic activity are still very much present today and likely well-preserved beneath the Martian surface.
Shielded from harsh solar and cosmic radiation, the interior of such lava tubes could provide a safe haven for microbial life — especially if groundwater had found its way inside at some point.
Even though the surface of Mars can receive 250 times the radiation levels found on Earth, the layers of soil and rock surrounding the tubes can provide adequate protection for life, whether it be ancient Martian microbes or future explorers from Earth.
Of course, water and protection from radiation aren’t the only factors necessary for life. There also needs to be some source of heat. Fortunately, the pit chains imaged by Mars Express happen to be within one of the most volcano-laden areas of the Red Planet, a region called the Arcadia quadrangle. Within this area exist some of the largest volcanoes on Mars — and the Tractus Catena pits are located right in the middle of them.
If a heat source were ever to have been beneath the surface of Mars, there would be a good chance it would have been here.
And if our own planet is any measure of such things, where there’s heat and water there is often some form of life — however extreme the conditions may be.
“I’d like to see us land ON a volcano,” Dr. Tracy Gregg, a volcanologist with the University of Buffalo, had once told Universe Today back in 2004. “Right on the flanks. Often the best place to look for evidence of life on any planet is near volcanoes.”
“That may sound counterintuitive, but think about Yellowstone National Park , which really is nothing but a huge volcano,” Gregg elaborated. “Even when the weather in Wyoming is 20 below zero, all the geysers, which are fed by volcanic heat, are swarming with bacteria and all kinds of happy little things cruising around in the water. So, since we think that the necessary ingredients for life on Earth were water and heat, we are looking for the same things on Mars.”
As far as any remaining geothermal activity still happening beneath the Martian surface?
“I strongly suspect there are still molten (or at least mushy) magma bodies beneath the huge Tharsis volcanoes,” Gregg had said. (Read the full article here.)
On Earth, lava tubes, caves and underground spaces of all kinds harbor life, often specialized forms that are found no place else. Could this be (or have once been) the case on Mars as well? Only future exploration will tell. Until then, places like Tractus Catena will remain on scientists’ short list of places to look.
Read more on the ESA website here.
[/caption]
The past several evenings, Venus has been snuggling up to one of the most famous star clusters, the Pleiades. Universe Today readers have taken some beautiful images of that event, and they have generously shared them with us. Above is John Chumack’s stunning view from Ohio in the US; see below for more images from around the world!
The Pleiades, also known at the Seven Sisters, is a beautiful bright blue open star cluster 440 light years from Earth. Only once every eight years does this conjunction take place.
John Anton took this pretty image from New Jersey in the US. “It was a beautiful sight,” he said.
Astronomers say that the relative tightness of the cluster indicates this is a young group of stars, and the member stars were formed about 100 million years ago and will probably travel together through space as a bound cluster for another 250 million years before the gravity of the Milky Way breaks up the cluster into individual field stars.
“An old SLR 70-210mm zoom lens on my DMC-G10. 5 second exposure, 1600 ISO. Tree illuminated partly by a neighbours light and partly by the built in flash on the camera,” says Dave Liddicott.
Sirrka Stephens from Norway took her image using a Panasonic Lumix DMC-F62, Leica 35mm, 30 sec., f/2.8, ISO 80, rotated to the left.
“Space Weed” from Beirut, Lebanon took this image on April 3, 2012. “2 second exposure, ISO 1600, f 5.9, Stack of 40 images and 18 dark frames, Level correction in Photoshop,” Space Weed reports.
Tavi Greiner on the east coast of the US took this lovely image on April 2, 2012.
Another beautiful view from Austin Russie. “A luminous Venus passes directly between Earth and an elusive cluster of stars known as the Pleiades,” he says.
Laurent Laveder from France sent in this unusual image showing the shifting of Venus in the Pleiades in two hours’ time.
The final image is by Miguel Claro from Portugal, who can be seen enjoying the stars with binoculars “in a peaceful moment,” he said.
There are more images on UT’s Flick page, so check them out!
Want to get your astrophoto featured on Universe Today? Join our Flickr group, post in our Forum 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.
Editor’s note: Apologies for the irregular formatting of this article — we’re working to fix it!
[/caption]
Located at the southermost point on Earth, the 280-ton, 10-meter-wide South Pole Telescope has helped astronomers unravel the nature of dark energy and zero in on the actual mass of neutrinos — elusive subatomic particles that pervade the Universe and, until very recently, were thought to be entirely without measureable mass.
The NSF-funded South Pole Telescope (SPT) is specifically designed to study the secrets of dark energy, the force that purportedly drives the incessant (and apparently still accelerating) expansion of the Universe. Its millimeter-wave observation abilities allow scientists to study the Cosmic Microwave Background (CMB) which pervades the night sky with the 14-billion-year-old echo of the Big Bang.
Overlaid upon the imprint of the CMB are the silhouettes of distant galaxy clusters — some of the most massive structures to form within the Universe. By locating these clusters and mapping their movements with the SPT, researchers can see how dark energy — and neutrinos — interact with them.
“Neutrinos are amongst the most abundant particles in the universe,” said Bradford Benson, an experimental cosmologist at the University of Chicago’s Kavli Institute for Cosmological Physics. “About one trillion neutrinos pass through us each second, though you would hardly notice them because they rarely interact with ‘normal’ matter.”
If neutrinos were particularly massive, they would have an effect on the large-scale galaxy clusters observed with the SPT. If they had no mass, there would be no effect.
The SPT collaboration team’s results, however, fall somewhere in between.
Even though only 100 of the 500 clusters identified so far have been surveyed, the team has been able to place a reasonably reliable preliminary upper limit on the mass of neutrinos — again, particles that had once been assumed to have no mass.
Previous tests have also assigned a lower limit to the mass of neutrinos, thus narrowing the anticipated mass of the subatomic particles to between 0.05 – 0.28 eV (electron volts). Once the SPT survey is completed, the team expects to have an even more confident result of the particles’ masses.
“With the full SPT data set we will be able to place extremely tight constraints on dark energy and possibly determine the mass of the neutrinos,” said Benson.
“We should be very close to the level of accuracy needed to detect the neutrino masses,” he noted later in an email to Universe Today.
Such precise measurements would not have been possible without the South Pole Telescope, which has the ability due to its unique location to observe a dark sky for very long periods of time. Antarctica also offers SPT a stable atmosphere, as well as very low levels of water vapor that might otherwise absorb faint millimeter-wavelength signals.
“The South Pole Telescope has proven to be a crown jewel of astrophysical research carried out by NSF in the Antarctic,” said Vladimir Papitashvili, Antarctic Astrophysics and Geospace Sciences program director at NSF’s Office of Polar Programs. “It has produced about two dozen peer-reviewed science publications since the telescope received its ‘first light’ on Feb. 17, 2007. SPT is a very focused, well-managed and amazing project.”
The team’s findings were presented by Bradford Benson at the American Physical Society meeting in Atlanta on April 1.
[/caption]
The mysterious galaxy Centaurus A is a great place to study the extreme processes that occur near super-massive black holes, scientists say, and this beautiful new image from the combined forces of the Herschel Space Observatory and the XMM-Newton x-ray satellite reveals energetic processes going on deep in the galaxy’s core. This beautiful image tells a tale of past violence that occurred here.
The twisted disc of dust near the galaxy’s heart shows strong evidence that Centaurus A underwent a cosmic collision with another galaxy in the distant past. The colliding galaxy was ripped apart to form the warped disc, and the formation of young stars heats the dust to cause the infrared glow.
This multi-wavelength view of Centaurus A shows two massive jets of material streaming from a immense black hole in the center. When observed by radio telescopes, the jets stretch for up to a million light years, though the Herschel and XMM-Newton results focus on the inner regions.
At a distance of around 12 million light years from Earth, Centaurus A is the closest large elliptical galaxy to our own Milky Way.
“Centaurus A is the closest example of a galaxy to us with massive jets from its central black hole,” said Christine Wilson of McMaster University, Canada, who is leading the study of Centaurus A with Herschel. “Observations with Herschel, XMM-Newton and telescopes at many other wavelengths allow us to study their effects on the galaxy and its surroundings.”
Find more information on this image at ESA’s website.
[/caption]
Last month, we were excited to share an image of a twister on Mars that lofted a twisting column of dust more than 800 meters (about a half a mile) high. We now know that’s nothin’ — just peanuts, chump change, hardly worth noticing. The Mars Reconnaissance Orbiter has now spotted a gigantic Martian dust devil roughly 20 kilometers (12 miles) high, churning through the Amazonis Planitia region of northern Mars. The HiRISE camera (High Resolution Imaging Science Experiment) captured the event on March 14, 2012. Scientists say that despite its height, the plume is just 70 meters (70 yards) wide.
Yikes! After seeing trucks thrown about by the tornadoes in Dallas yesterday, it makes you wonder how the MER rovers and even the Curiosity rover would fare in an encounter with a 20-km high twister.
The image was taken during late northern spring, two weeks short of the northern summer solstice, a time when the ground in the northern mid-latitudes is being heated most strongly by the sun.
Dust devils are spinning columns of air, made visible by the dust they pull off the ground. Unlike a tornado, a dust devil typically forms on a clear day when the ground is heated by the sun, warming the air just above the ground. As heated air near the surface rises quickly through a small pocket of cooler air above it, the air may begin to rotate, if conditions are just right.
Obviously, conditions were more than just right to create such a whopper.
Source: JPL
If you’ve fallen for the enchantment of a night out watching the stars, you’ll relate to and revere in this new timelapse video.
“This timelapse production is a tribute to all skygazers around the world who enjoy exploring the night sky with their telescopes,” said Babak Tafreshi, an astronomer, journalist and director of The World at Night (TWAN). “I’m happy to release this in April 2012 in celebration of the Global Astronomy Month, an international program of Astronomers Without Borders in partnership with world-wide astronomy centers and clubs.”
Continue reading “Timelapse: A Tribute to Sky Gazers”
[/caption]
Obama is definitely going for the geek vote with this image, which actress Nichelle Nichols posted on her Twitter account. As one commenter mentioned, the Birthers will probably now claim Obama was born on Vulcan.
NASA’s Solar Dynamics Observatory captured this video on March 27 – 28 of two large areas of “dark” plasma on the Sun’s limb, twisting and spiraling in our star’s complex magnetic field. The southern region bears an uncanny resemblance to three figures swaying to some spooky, unheard music… a real “danse macabre” on the Sun!
Continue reading “Dark Figures Do An Eerie Dance On The Sun”
[/caption]
Supernova explosions and the jets of a monstrous black hole are scattering one galaxy’s star-making gas, driving a dramatic transformation from spiral galactic youth to elderly elliptical, according to a new study of a recently merged galaxy. Cool gas, the fuel from which new stars form, is essential to the youth and vigor of a galaxy. But supernova explosions can start the decline in star formation, and then shock waves from the supermassive black hole finish the job, turning spiral galaxies to “red and dead” ellipticals.
Astronomers think they have identified a recently merged galaxy, NGC 3801, where this gas loss has just gotten underway. Using ultraviolet observations from NASA’s Galaxy Evolution Explorer (GALEX) and a host of other instruments, the new findings fill an important gap in the current understanding of galactic evolution.
“We have caught a galaxy in the act of destroying its gaseous fuel for new stars and marching toward being a red-and-dead type of galaxy,” said Ananda Hota, lead author of a new paper in the Monthly Notices of the Royal Astronomical Society. “We have found a crucial missing piece to connect and solve the puzzle of this phase of galaxy evolution.”
It has long been known that gas-rich spiral galaxies like our Milky Way smash together to create elliptical galaxies such as the one observed in the study. These big, round galaxies have very little star formation.
The supermassive black holes that reside in the centers of galaxies can flare up when engorged by gas during galactic mergers. As a giant black hole feeds, colossal jets of matter shoot out from it, giving rise to what is known as an active galactic nucleus. According to theory, shock waves from these jets heat up and disperse the reservoirs of cold gas in elliptical galaxies, thus preventing new stars from taking shape.
NGC 3801 shows signs of such a process. This galaxy is unique in that evidence of a past merger is clearly seen, and the shock waves from the central black hole’s jets have started to spread out very recently. The researchers used the Galaxy Evolution Explorer to determine the age of the galaxy’s stars and decipher its evolutionary history. The ultraviolet observations show that NGC 3801’s star formation has petered out over the last 100 to 500 million years, demonstrating that the galaxy has indeed begun to leave behind its youthful years. The lack of many big, new, blue stars makes NGC 3801 look yellowish and reddish in visible light, and thus middle-aged.
What’s causing the galaxy to age and make fewer stars? The short-lived blue stars that formed right after it merged with another galaxy have already blown up as supernovae. Data from NASA’s Hubble Space Telescope revealed that those stellar explosions have triggered a fast outflow of heated gas from NGC 3801’s central regions. That outflow has begun to banish the reserves of cold gas, and thus cut into NGC 3801’s overall star making.
Some star formation is still happening in NGC 3801, as shown in ultraviolet wavelengths observed by the Galaxy Evolution Explorer, and in infrared wavelengths detected by NASA’s Spitzer Space Telescope. But that last flicker of youth will soon be extinguished by colossal shock waves from the black hole’s jets, seen in X-ray light by NASA’s Chandra X-ray Observatory. These blast waves are rushing outward from the galactic center at a velocity of nearly two million miles per hour (nearly 900 kilometers per second). The waves will reach the outer portions of NGC 3801 in about 10 million years, scattering any remaining cool hydrogen gas and rendering the galaxy truly red and dead.
Astronomers think the transition captured early-on in the case of NGC 3801 — from the merger of gas-rich galaxies to the rise of an old-looking elliptical — happens very quickly on cosmic time scales.
“The quenching of star formation by feedback from the active galactic nucleus probably occurs in just a billion years. That’s not very long compared to the 10-billion-year age of a typical big galaxy,” said Hota. “The explosive shock wave event caused by the central black hole is so powerful that it can dramatically change the future course of the evolution of an entire galaxy.”
Additional observations for the study in optical light come from the Sloan Digital Sky Survey and in radio using the Very Large Array in New Mexico.
Hota is an astronomer in Pune, India, conducted the study as a post-doctoral research fellow at the Institute of Astronomy & Astrophysics at Academia Sinica in Taipei, Taiwan.