NASA satellite spots oldest, most distant cosmic explosion
- 29 April, 2009 07:31
Using a NASA satellite, astronomers have gotten a glimpse of the oldest object in the universe that humans have ever seen.
NASA announced Tuesday that its Swift satellite and a global team of astronomers have detected a 10-second, gamma-ray burst (see video) from a star that died when the universe was just a baby. The burst, called the "most distant cosmic explosion ever seen", happened when the universe was only 630 million years old.
Scientists estimate that the universe is now some 13.73 billion years old.
The Swift satellite first detected the gamma-ray burst at 3:55 a.m. EDT on Thursday, April 23. The orbiter automatically swung itself around to bring its ultraviolet/optical and X-ray telescopes into line to capture the event, according to NASA.
"Swift was designed to catch these very distant bursts," said Swift lead scientist Neil Gehrels, in a statement. "The incredible distance to this burst exceeded our greatest expectations. It was a true blast from the past."
Derek Fox, an assistant professor of astronomy at Pennsylvania State University reported that the gamma rays probably were emitted as the star was dying and as a black hole was forming. It was a death and birth in one of the universe's "earliest stellar generations," he added.
Gamma-ray bursts, according to NASA, are the brightest explosions ever seen. As massive stars run out of nuclear fuel, their cores collapse into black holes and gas jets are blown out into space. When the jets hit gas that already had been expelled from the dying star, it heats up and creates short-lived bursts of illumination in many wavelengths.
"Burst afterglows provide us with the most information about the exploded star and its environs," said Nial Tanvir at the University of Leicester in the U.K. "But because afterglows fade out so fast, we must target them quickly."
NASA reported that shortly after the Swift satellite detected the burst, telescopes around the world turned their attention to the gamma-rays, trying to catch glimpses of it at various wave lengths.
Earlier this month, NASA reported that its Ice, Cloud and Land Elevation Satellite, known as ICESat, detected that the Earth's arctic sea ice, which acts as the world's air conditioner, continued to shrink this winter as the ice cap grew thinner.
And next month, space shuttle Atlantis is scheduled to lift off on a mission to maintain and update the Hubble Space Telescope.