This image from NASA’s Chandra X-ray Observatory shows the center of our Galaxy, with a supermassive black hole known as Sagittarius A* (Sgr A* for short) in the center. Using intermittent observations over several years, Chandra has detected X-ray flares about once a day from Sgr A*. The flares have also been seen in infrared data from ESO’s Very Large Telescope in Chile.
A new study provides a possible explanation for the mysterious flares. The suggestion is that there is a cloud around Sgr A* containing hundreds of trillions of asteroids and comets , which have been stripped from their parent stars. The panel on the left is an image containing nearly a million seconds of Chandra observing of the region around the black hole, with red representing low-energy X-rays, green as medium-energy X-rays, and blue being the highest.
An asteroid that undergoes a close encounter with another object, such as a star or planet, can be thrown into an orbit headed towards Sgr A*, as seen in a series of artist’s illustrations beginning with the top-right panel. If the asteroid passes within about 100 million miles of the black hole, roughly the distance between the Earth and the Sun, it would be torn into pieces by the tidal forces from the black hole (middle-right panel).
These fragments would then be vaporized by friction as they pass through the hot, thin gas flowing onto Sgr A*, similar to a meteor heating up and glowing as it falls through Earth’s atmosphere. A flare is produced (bottom-right panel) and eventually the remains of the asteroid are swallowed by the black hole. … (Chandra)
Tag Archives: iss
Why we hate computers
A computer programming error doomed Russia’s Phobos-Grunt Mars spacecraft, a government board investigating the accident has determined.
In a report to be presented to Russian deputy prime minister Dmitry Rogozin on Tuesday, investigators concluded that the primary cause of the failure was “a programming error which led to a simultaneous reboot of two working channels of an onboard computer,” RIA Novosti reports.
The Phobos-Grunt spacecraft was launched on Nov. 9 on a mission to return soil samples from the Martian moon Phobos. But the probe never got out of Earth orbit due to a propulsion system failure.
Accusations that U.S. radars were responsible for the failure proved false, investigators said.
“A series of tests showed that the electronics similar to those onboard the Phobos-Grunt had withstood the highest possible level of electromagnetic radiation,” RIA Novosti reported.
Likewise, cosmic rays and/or defective electronics are not the leading suspects behind Phobos-Grunt’s demise.
The spacecraft fell back to Earth on Jan. 15. (Discovery)
Come fly (fast) with me
Time-lapse video from the ISS on Jan. 30, 2012. These sequences of frames were taken at the rate of one frame per second, therefore the slower speed of the video represents nearly the true speed of the International Space Station.
This video was taken by the crew of Expedition 30 on board the International Space Station. The sequence of shots was taken January 30, 2012 from 06:13:36 to 06:23:09 GMT, on a pass from northern Mexico to northwest New Brunswick. This video begins looking northeast over Texas, where cities like San Antonio, Houston, and the Dallas/Fort Worth area can be seen. Continuing northeast over the Great Plains states, cities like Oklahoma City, Kansas City, and St. Louis can be easily distinguished. The pass continues over the familiar shape of the Michigan Peninsula, with Chicago at the south edge of Lake Michigan. As the ISS continues northeast, the Aurora Borealis can be seen over Canada. (JMajorLITD)
Return of the droid
The unpiloted ISS Progress 45 supply vehicle departs from the International Space Station at 5:10 p.m. (EST) on Jan. 23, 2012. Filled with trash and discarded items, Progress 45 was later deorbited, subsequently burning up in Earth’s atmosphere. The departure of Progress 45 clears the way for the next unpiloted supply ship, Progress 46, which is set to launch at 6:06 p.m. (EST) on Jan. 25 (5:06 a.m. Baikonur time Jan. 26) from the Baikonur Cosmodrome in Kazakhstan bringing 2.9 tons of food, fuel and supplies for the residents of the space station. … (SpaceRef)
Clean. Very clean.
Mars may have been arid for more than 600 million years, making it too hostile for any life to survive on the planet’s surface, according to researchers who have been carrying out the painstaking task of analysing individual particles of Martian soil. Dr Tom Pike, from Imperial College London, will discuss the team’s analysis at a European Space Agency (ESA) meeting on 7 February 2012. The researchers have spent three years analysing data on Martian soil that was collected during the 2008 NASA Phoenix mission to Mars. Phoenix touched down in the northern arctic region of the planet to search for signs that it was habitable and to analyse ice and soil on the surface.
The results of the soil analysis at the Phoenix site suggest the surface of Mars has been arid for hundreds of millions of years, despite the presence of ice and the fact that previous research has shown that Mars may have had a warmer and wetter period in its earlier history more than three billion years ago. The team also estimated that the soil on Mars had been exposed to liquid water for at most 5,000 years since its formation billions of years ago. They also found that Martian and Moon soil is being formed under the same extremely dry conditions. …(SpaceRef)
Kepler sleuthing on
NASA’s Kepler mission has discovered 11 new planetary systems hosting 26 confirmed planets. These discoveries nearly double the number of verified planets and triple the number of stars known to have more than one planet that transits, or passes in front of, the star. Such systems will help astronomers better understand how planets form.
The planets orbit close to their host stars and range in size from 1.5 times the radius of Earth to larger than Jupiter. Fifteen are between Earth and Neptune in size. Further observations will be required to determine which are rocky like Earth and which have thick gaseous atmospheres like Neptune. The planets orbit their host star once every six to 143 days. All are closer to their host star than Venus is to our sun. … (NASA)
Ice fiesta on Vesta?
Though generally thought to be quite dry, roughly half of the giant asteroid Vesta is expected to be so cold and to receive so little sunlight that water ice could have survived there for billions of years, according to the first published models of Vesta’s average global temperatures and illumination by the sun.
“Near the north and south poles, the conditions appear to be favorable for water ice to exist beneath the surface,” says Timothy Stubbs of NASA’s Goddard Space Flight Center in Greenbelt, Md., and the University of Maryland, Baltimore County. Stubbs and Yongli Wang of the Goddard Planetary Heliophysics Institute at the University of Maryland published the models in the January 2012 issue of the journal Icarus. The models are based on information from telescopes including NASA’s Hubble Space Telescope. …(NASA)





