January 26, 2011
New Galaxy Discovered 13.2 Billion Light Years Away
Astronomers have discovered a galaxy so far away that its light has taken 13.2 billion years to reach Earth.
The cluster of stars, dust and gas was spotted by NASA's Hubble space telescope as it orbited Earth.The galaxy is so far away that scientists are observing it at a time when the universe was in its infancy, just 480 million years after the Big Bang.
Dr. Garth Illingworth, professor of astronomy at the University of California Santa Cruz, said "We're getting back very close to the first galaxies which we think formed around 200 or 300million years after the Big Bang."
The light from stars close by takes just a few years to reach the Earth. But light from distant stars and galaxies takes millions or billions of years to travel across space.
The new galaxy was detected by using Hubble's eight-foot wide mirror and Wide Field Planetary Camera 3, which is a device that was fitted to the spacecraft in 2009.
The researchers reported in the journal Nature that the newly discovered galaxy is just one hundredth the size of our own Milky Way galaxy
The galaxy is 13.2 billion light years away, or 80 sextillion miles, which is 80 followed by 21 zeroes.
The researchers also found three other ancient galaxies from a similar era.
However, they will have to wait for the launch of Hubble's replacement, the James Webb Telescope to find even older galaxies.
The astronomers were also able to see dramatic changes in the way galaxies formed when the universe was still young.
The rate of star birth in the universe increased ten-fold during the period between 480 to 650 million years after the Big Bang.
Illingworth said "This is an astonishing increase in such a short period - just one percent of the current age of the universe."
"Our previous searches had found 47 galaxies at somewhat later times when the universe was about 650 million years old. However, we could only find one galaxy candidate just 170million years earlier. The universe was changing very quickly in a short amount of time."
Scientists determine the distance of a galaxy by studying the wavelength of their light reaching the Earth.
Most of the light from distant galaxies falls in the infra-red spectrum because its wavelength has been stretched by the expansion of the universe.
Image Caption: The farthest and one of the very earliest galaxies ever seen in the universe appears as a faint red blob in this ultra-deep"“field exposure taken with NASA's Hubble Space Telescope. This is the deepest infrared image taken of the universe. Based on the object's color, astronomers believe it is 13.2 billion light-years away. (Credit: NASA, ESA, G. Illingworth (University of California, Santa Cruz), R. Bouwens (University of California, Santa Cruz, and Leiden University), and the HUDF09 Team)
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