Cosmic Explosions Show the Way to the Farthest Reaches of the Universe
Put on your Spock ears, star gazers. An explosion in what may be one of the oldest galaxies in the universe is making headlines today.
Back in 2009, NASA’s Swift Satellite captured a gamma-ray burst an estimated 13.14 billion light years away. That’s much farther than any previously known galaxy, quasar, or other celestial object.
The burst, affectionately called GRB 090429B, was discovered by a team of international scientists led by Antonino Cucchiara, a graduate student at the University of Pennsylvania at the time, and now working on his doctorate at UC Berkeley.
Three years later, Cucchiara’s team has finally published their findings in the Astrophysical Journal [pdf].
Cucchiara discovered the burst early in the morning of April 29, 2009. It lasted less than 10 seconds. The burst is now in competition to be named the furthest object in the universe. The other bursts up for consideration were discovered more recently — one in 2010 by a group of observers at Observatoire de Paris (at 13.07 billion light years away), and the other in 2011 by a team at U.C. Santa Cruz (between 13.11 to 13.28 billion light years away). Those scientists are still studying the distance of those bursts, so for now, Cucchiara’s gamma-ray burst at an estimated 13.14 billion light years away is considered the farthest object in the universe.
That’s great, but what the heck is a gamma-ray burst?
Gamma-ray bursts happen when a massive star dies, and the core of the star collapses into a black hole. As the black hole consumes the star’s outer layers it emits two powerful jets made up of gamma photons and other material, which creates a short and brilliant burst of light known as a gamma-ray burst. Confused? For the visual learners in the audience, the University of Pennsylvania website has an animated NASA video showing how GRB 090429B — the gammy-ray burst making news today — likely occurred.
If GRB 090429B really is 13.4 billion light years away, then scientists estimate that it exploded when the universe was 520 million years old and could have resided in one of the very first galaxies in the universe. That’s according to Derek Fox, associate professor of astronomy and astrophysics at Penn State and a co-author of the paper presented today.
“Beyond the possible cosmic distance record, GRB 090429B illustrates how gamma-ray bursts can be used to reveal the locations of massive stars in the early universe and to track the processes of early galaxy and star formation that eventually led to the galaxy-rich cosmos we see around us today,” Fox wrote.
But stay tuned…NASA’s forthcoming James Webb Space Telescope, due to launch in 2014, will help scientists investigate the first galaxies that formed after the Big Bang.