Space and astronomy news
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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”
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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.
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We’ve all dreamed of having a flying car, but two companies are working to make this dream a reality. The latest in flying car designs is the Personal Air and Land Vehicle (PAL-V) One, which is advertised as going from high performance sports car to flying car in just minutes. Based in the Netherlands, the PAL-V company says this is “the ultimate vehicle to go wherever and whenever you want to, easily overcoming all sorts of barriers. Now you can leave home and fly-drive to almost any destination! Avoid traffic jams and cross lakes, fjords, rivers or mountain ranges like an eagle.”
Sign me up!
See a video of the PAL-V in flight, below.
While the PAL-V is designed more like a helicopter, another flying car prototype we reported on, the Terrafugia Transition, operates more like a airplane. Terrafugia recently completed its first test flight, and sells for about $250,000. The PAL-V One does not yet have listed price, but likely would be in a similar price range. Both companies hope to bring their products to market soon, with Terrafugia targeting a late 2012 release date, and PAL-V aiming for 2014.
PAL-V uses gyroplane technology for flying, with rotors that fold up when you want to drive the vehicle on land. It can fly to an altitude of 4,000 feet (considerably lower than the 30,000 to 50,000 feet where commercial jets fly), and owners would need to have a Sport Pilot’s certificate in order to fly the PAL-V One.
For more info, see the PAL-V website.
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Earth just doesn’t make crust like it used to… at least, not according to new research by a team of scientists in the UK.
Researchers with the Universities of Bristol, St Andrews and Portsmouth have studied elements trapped within zircon samples gathered from all over the planet to peer billions of years back in time at how Earth’s crust was being produced.
Zircon, a mineral found in granite, can be dated with precision and is thus an accurate measure for geologic timescales.
What they found was that 65% of our planet’s current crust had already existed 3 billion years ago. Since rocks older than 2.5 billion years are rare on Earth today, this means that some process began to take place that either reworked — or destroyed — a large portion of the older crust, and changed how new crust was formed.
During the first 1.5 billion years of Earth’s history, the team reports, the rate of crust formation was high — approximately 3 cubic kilometers was added to the continents each year. After that the rate dropped substantially, falling to about 0.8 cubic kilometers per year for the next 3 billion years — right up to the present day.
The cause is yet unknown, but it may be the result of the onset of plate tectonics driven by subduction — the process by which sections of Earth’s crust (“plates”) slide beneath other sections, sinking into the underlying mantle to be liquefied into magma by pressure and heat. New crust is created when the magma rises again where the plates separate… Earth’s current “conveyor belt” of crust formation.
Whatever process was in place prior to 3 billion years ago, it was much more efficient at creating crust.
“Such a sharp decrease in the crustal growth rate about 3 billion years ago indicates a dramatic change in the way the continental crust was generated and preserved,” said Dr. Bruno Dhuime of the University of Bristol’s School of Earth Sciences. “This change may in turn be linked to the onset of subduction-driven plate tectonics and discrete subduction zones as observed at the present day. The next challenge is to determine which tectonic regime shaped the Earth’s crust in the planet’s first 1.5 billion years before this change.”
The team’s paper “A Change in the Geodynamics of Continental Growth 3 Billion Years Ago” (Bruno Dhuime, Chris J. Hawkesworth, Peter A. Cawood, Craig D. Storey) was published March 16 in Science.
Read more on the University of Bristol’s press release here.
There’s a nice meetup in the heavens tonight: bright Venus is snuggling up to one of the most famous star clusters, the Pleiades. The Slooh Space Camera is broadcasting a live, real-time feed of the most famous star cluster in the heavens, the Pleiades, meeting up with our nearest and brightest planetary neighbor, Venus. Slooh’s coverage will begin on Wednesday, April 4th starting at 1:30 PM PDT / 4:30 PM EDT / 20:30 UT. (This was originally scheduled for April 3rd, but was rescheduled due to high humidity at Canary Islands observatory off the coast of Africa.) The broadcast can be watched here, or accessed at Slooh’s homepage or by visiting Slooh’s G+ page, where you will be able to see the panel interact live via G+ Hangouts On Air.
If skies are clear, you can see the conjunction for yourself by looking toward the west in the constellation Taurus, after sunset, using binoculars. If you can get images of the event, we’ll post views of them. Share them on Universe Today’s Flickr page.
Continue reading “Watch Live Webcast of Venus-Pleiades Conjunction April 4, 2012”
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With NASA’s tight budget, there were concerns that some of the agency’s most successful astrophysics missions might not be able to continue. Anxieties were rampant about one mission in particular, the very fruitful exoplanet-hunting Kepler mission, as several years of observations are required in order for Kepler to confirm a repeated orbit as a planet transits its star. But today, after a long awaited Senior Review of nine astrophysics missions, surprisingly all have received funding to continue at least through 2014, with several mission extensions, including Kepler.
“Ad Astra… Kepler mission extended through FY16! We are grateful & ecstatic!” the @NASAKepler Twitter account posted today.
Additionally, missions such as Hubble, Fermi and Swift will receive continued funding. The only mission that took a hit was the Spitzer infrared telescope, which – as of now — will be closed out in 2015, which is sooner than requested.
The Senior Review of missions takes place every two years, with the goal assisting NASA to optimize the scientific productivity of its operating missions during their extended phase. In the Review, missions are ranked as which are most successful; previous Senior Reviews led to the removal of funding for the weakest 10-20% of extended missions, some of which had partial instrument failures or significantly reduced capabilities.
But this year’s review found all the astrophysics mission to be successful.
“These nine missions comprise an extremely strong ensemble to enter the Senior Review process and we find that all are making very significant scientific contributions,” the Review committee wrote in their report.
Here’s a rundown of the missions and how their funding was affected by the Senior Review:
• The Hubble Space Telescope will continue at the currently funded levels.
• Chandra will also continue at current levels, but its Guest Observer budget will actually be increased to account for decreases in Fiscal Year 2011.
• Fermi operations are extended through FY16, with a 10 percent per year reduction starting in FY14.
• Swift and Kepler mission operations are extended through FY16, including funding for data analysis.
• Planck will support one year extended operations of the Low Frequency Instrument (LFI).
• Spitzer’s operations are extended through FY14 with closeout in FY15.
• U.S. science support of Suzaku is extended to March 2015.
• Funding for U.S. support of XMM-Newton is extended through March 2015.
NASA says that all FY15-FY16 decisions are for planning purposes and they will be revisited in the 2014 Senior Review.
Some lucky sixth-, seventh- and eigth-graders at the O. Henry Middle School in Austin, Texas got the chance to chat with Expedition 30 astronauts Dan Burbank, Don Pettit and Andre Kuipers aboard the International Space Station today, getting answers to their questions about life in orbit. The video was shared by NASA TV shortly after. Enjoy!
Credit: NASA
Astronomers using NASA’s Fermi Gamma-Ray Space Telescope have been looking for evidence of suspected types of dark matter particles within faint dwarf galaxies near the Milky Way — relatively “boring” galaxies that have little activity but are known to contain large amounts of dark matter. The results?
These aren’t the particles we’re looking for.
80% of the material in the physical Universe is thought to be made of dark matter — matter that has mass and gravity but does not emit electromagnetic energy (and is thus invisible). Its gravitational effects can be seen, particularly in clouds surrounding galaxies where it is suspected to reside in large amounts. Dark matter can affect the motions of stars, galaxies and even entire clusters of galaxies… but when it all comes down to it, scientists still don’t really know exactly what dark matter is.
Possible candidates for dark matter are subatomic particles called WIMPs (Weakly Interacting Massive Particles). WIMPs don’t absorb or emit light and don’t interact with other particles, but whenever they interact with each other they annihilate and emit gamma rays.
If dark matter is composed of WIMPs, and the dwarf galaxies orbiting the Milky Way do contain large amounts of dark matter, then any gamma rays the WIMPs might emit could be detected by NASA’s Fermi Gamma-Ray Space Telescope.
After all, that’s what Fermi does.
Ten such galaxies — called dwarf spheroids — were observed by Fermi’s Large-Area Telescope (LAT) over a two-year period. The international team saw no gamma rays within the range expected from annihilating WIMPs were discovered, thus narrowing down the possibilities of what dark matter is.
“In effect, the Fermi LAT analysis compresses the theoretical box where these particles can hide,” said Jennifer Siegal-Gaskins, a physicist at the California Institute of Technology in Pasadena and a member of the Fermi LAT Collaboration.
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So rather than a “failed experiment”, such non-detection means that for the first time researchers can be scientifically sure that WIMP candidates within a specific range of masses and interaction rates cannot be dark matter.
(Sometimes science is about knowing what not to look for.)
A paper detailing the team’s results appeared in the Dec. 9, 2011, issue of Physical Review Letters. Read more on the Fermi mission page here.
Landing large payloads on Mars — large enough to bring humans to the Red Planet’s surface — is still beyond our capability. “There’s too much atmosphere on Mars to land heavy vehicles like we do on the moon, using propulsive technology completely,” said Rob Manning, Chief Engineer for the Mars Exploration Directorate, in an article we wrote a few years ago about the problems of landing on Mars “and there’s too little atmosphere to land like we do on Earth. Mars atmosphere provides an ugly, grey zone.”
The best hope on the horizon for making the human missions to Mars possible are supersonic decelerators that are now being developed. This new technology will hopefully be able to slow larger, heavier landers from the supersonic speeds of atmospheric entry to subsonic ground-approach speeds. NASA’s Low Density Supersonic Decelerator (LDSD) program is testing out some of these new devices and recently performed a trial run on a rocket sled test to replicate the forces a supersonic spacecraft would experience prior to landing. The sled tests will see how inflatable and parachute decelerators work to slow spacecraft prior to landing and allow NASA to increase landed payload masses, as well as improve landing accuracy and increase the altitude of safe landing-sites.
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Three devices are being developed: two different sizes of supersonic inflatable aerodynamic decelerators and super-huge parachutes. The supersonic inflatable decelerators are very large, durable, balloon-like pressure vessels that inflate around the entry vehicle and slow it from Mach 3.5 or greater to Mach 2. These decelerators are being developed in 6-meter-diameter and 9-meter-diameters.
The large parachute is 30 meters in diameter, and it will further slow the entry vehicle from Mach 2 to subsonic speeds. All three devices will be the largest of their kind ever flown at speeds several times greater than the speed of sound.
Together, these new drag devices can increase payload delivery to the surface of Mars from our current capability of 1.5 metric tons to 2 to 3 metric tons, depending on which inflatable decelerator is used in combination with the parachute. They will increase available landing altitudes by 2-3 kilometers, increasing the accessible surface area we can explore. They also will improve landing accuracy from a margin of 10 kilometers to just 3 kilometers. All these factors will increase the capabilities and robustness of robotic and human explorers on Mars.
NASA is now testing these devices on rocket sleds and later will conduct tests high in Earth’s stratosphere, simulating entry into Mars’ thin atmosphere. The first supersonic flight tests are set for 2013 and 2014.