Aug. 29, 2013 — Astronomers using NASA’s Chandra X-ray Observatory have taken a major step in explaining why material around the giant black hole at the center of the Milky Way Galaxy is extraordinarily faint in X-rays. This discovery holds important implications for understanding black holes.
New Chandra images of Sagittarius A* (Sgr A*), which is located about 26,000 light-years from Earth, indicate that less than 1 percent of the gas initially within Sgr A*’s gravitational grasp ever reaches the point of no return, also called the event horizon. Instead, much of the gas is ejected before it gets near the event horizon and has a chance to brighten, leading to feeble X-ray emissions.
These new findings are the result of one of the longest observation campaigns ever performed with Chandra. The spacecraft collected five weeks’ worth of data on Sgr A* in 2012. The researchers used this observation period to capture unusually detailed and sensitive X-ray images and energy signatures of super-heated gas swirling around Sgr A*, whose mass is about 4 million times that of the sun.
This image of the moon was generated by data collected by NASA’s Moon Mineralogy Mapper on the Indian Space Research Organization’s Chandrayaan-1 mission. It is a three-color composite of reflected near-infrared radiation from the sun, and illustrates the extent to which different materials are mapped across the side of the moon that faces Earth. Image credit: ISRO/NASA/JPL-Caltech/Brown Univ./USGS
› Full image and caption
August 28, 2013
PASADENA – NASA-funded lunar research has yielded evidence of water locked in mineral grains on the surface of the moon from an unknown source deep beneath the surface. Using data from NASA’s Moon Mineralogy Mapper (M3) instrument aboard the Indian Space Research Organization’s Chandrayaan-1 spacecraft, scientists remotely detected magmatic water, or water that originates from deep within the moon’s interior, on the surface of the moon.
The findings, published Aug. 25 in Nature Geoscience, represent the first detection of this form of water from lunar orbit. Earlier studies had shown the existence of magmatic water in lunar samples returned during NASA’s Apollo program.
M3 imaged the lunar impact crater Bullialdus, which lies near the lunar equator. Scientists were interested in studying this area because they could better quantify the amount of water inside the rocks due to the crater’s location and the type of rocks it held. The central peak of the crater is made up of a type of rock that forms deep within the lunar crust and mantle when magma is trapped underground.
Voyager 1 appears to have at long last left our solar system and entered interstellar space, says a University of Maryland-led team of researchers
Carrying Earthly greetings on a gold plated phonograph record and still-operational scientific instruments — including the Low Energy Charged Particle detector designed, built and overseen, in part, by UMD’s Space Physics Group — NASA’s Voyager 1 has traveled farther from Earth than any other human-made object. And now, these researchers say, it has begun the first exploration of our galaxy beyond the Sun’s influence.
“It’s a somewhat controversial view, but we think Voyager has finally left the Solar System, and is truly beginning its travels through the Milky Way,” says UMD research scientist Marc Swisdak, lead author of a new paper published online this week in The Astrophysical Journal Letters. Swisdak and fellow plasma physicists James F. Drake, also of the University of Maryland, and Merav Opher of Boston University have constructed a model of the outer edge of the Solar System that fits recent observations, both expected and unexpected.
Read more: http://www.sciencedaily.com/releases/2013/08/130815133726.htm
View the panorama here:
May 30, 2013 — Detailed analysis and review have borne out researchers’ initial interpretation of pebble-containing slabs that NASA’s Mars rover Curiosity investigated last year: They are part of an ancient streambed.
The rocks are the first ever found on Mars that contain streambed gravels. The sizes and shapes of the gravels embedded in these conglomerate rocks — from the size of sand particles to the size of golf balls — enabled researchers to calculate the depth and speed of the water that once flowed at this location.
“We completed more rigorous quantification of the outcrops to characterize the size distribution and roundness of the pebbles and sand that make up these conglomerates,” said Rebecca Williams of the Planetary Science Institute, Tucson, Ariz., lead author of a report about them in the journal Science this week. “We ended up with a calculation in the same range as our initial estimate last fall. At a minimum, the stream was flowing at a speed equivalent to a walking pace — a meter, or three feet, per second — and it was ankle-deep to hip-deep.”
By Clay Dillow Posted 05.24.2013
Giant storms on Saturn: Nasa captures incredible view of ‘rose’ hurricane 20 times bigger than any on Earth
- Hurricane’s eye is about 1,250 miles (2,000 kilometers) wide, 20 times larger than the average hurricane eye on Earth
- Hurricane swirls inside a large, mysterious, six-sided weather pattern known as the hexagon
By MARK PRIGG
PUBLISHED: 17:40 GMT, 29 April 2013 | UPDATED: 18:49 GMT, 29 April 2013
At first glance, it resembles a giant rose, surrounded by green foliage.
However, in fact this is a huge, violent storm of the surface of Saturn – and one that has been brewing for years
In high-resolution pictures and video, scientists say the hurricane’s eye is about 1,250 miles (2,000 kilometers) wide, 20 times larger than the average hurricane eye on Earth.
Thin, bright clouds at the outer edge of the hurricane are traveling 330 mph(150 meters per second). The hurricane swirls inside a large, mysterious, six-sided weather pattern known as the hexagon.
‘We did a double take when we saw this vortex because it looks so much like a hurricane on Earth,’ said Andrew Ingersoll, a Cassini imaging team member at the California Institute of Technology in Pasadena.
‘But there it is at Saturn, on a much larger scale, and it is somehow getting by on the small amounts of water vapor in Saturn’s hydrogen atmosphere.’
Scientists will be studying the hurricane to gain insight into hurricanes on Earth, which feed off warm ocean water.