Telstra has revealed the addition of almost one million new mobile services in the six months to December 2011, but Sensis revenues plummeted 24 percent in 12 months.
NASA’s hunt to find the supernova remnant began in 1985 when astronomers, led by Green, used the VLA, located in New Mexico, U.S.A., viewed a bright radio source (an object that emits huge amounts of radio waves) near the center of the Milky Way galaxy.
At this time, they thought the radio source, which is often the result of a supernova, had exploded between 400 and 1,000 years ago.
In 2007, astronomers using Chandra found that this same supernova remnant was much younger than previously thought. This change in age was due to images that showed the remnant was growing faster than first thought—in fact, about 16% faster.
Thus, the age of the supernova remnant was thought to be much less than first thought. Observations made by astronomers using the VLA in 2008 verified the fast growth and, thus, estimated the age of the remnant at about 140 years—or about the year 1868.
These astronomers also found that the supernova was expanding out at about 35 million miles per hour (56 million kilometer per hour)—approximately equal to 5% of the speed of light.
Actually, the explosion occurred about 25,000 years ago (and at about 25,000 light-years from Earth), but the radio waves and x-rays seen by VLA and Chandra are just now getting here to Earth.
Radio waves and x-rays, along with all other types of radiation, travel at the speed of light, which is approximately 186,282 miles per second (about 300,000 kilometers per second). Radiation travels about 5.88 x 1012 miles per year (9.46 x 1012 kilometers per year)—about 6 trillion miles, or 10 trillion kilometers, over the span of one Earth-year while traveling in the vacuum of space.
Therefore, G1.9+0.3 is the youngest supernova remnant in the Milky Way galaxy. This discovery is considered very important to astronomers because it will allow them to learn more about how stars explode and what happens to them after they explode.
The results of the discovery of G1.9+0.3 by the astronomers with VLA and Chandra will appear in a future issue of The Astrophysics Journal Letters.
The paper currently appears at the arxiv.org website under the title "The Youngest Galactic Supernova Remnant: G1.9+0.3," with authors S.P. Reynolds, K.J. Borkowski, D.A. Green, U. Hwang, I. Harrus, and R. Petre.
David Bass
| For the fourth year in a row, IDC has placed content security provider Websense (NASDAQ: WBSN) at the top of the IDC Worldwide Web Security 2011 –…
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