Galaxies 'formed much earlier than thought'
Using NASA telescopes, astronomers have discovered a distant galaxy with stars that began forming just 200 million years after the big bang.world Updated: Apr 13, 2011 11:22 IST
Using NASA telescopes, astronomers have discovered a distant galaxy with stars that began forming just 200 million years after the big bang.
The finding could shed new light on the formation of the first galaxies, as well as on the evolution of the early Universe.
NASA's Hubble Space Telescope was the first to spot the newfound galaxy. Detailed observations from the W M Keck Observatory on Mauna Kea in Hawaii revealed the observed light dates to when the universe was only 950 million years old; the universe formed about 13.7 billion years ago.
Infrared data from both Hubble and NASA's Spitzer Space Telescope revealed the galaxy's stars are quite mature, having formed when the universe was just a toddler at 200 million years old.
"This challenges theories of how soon galaxies formed in the first years of the universe. It could even help solve the mystery of how the hydrogen fog that filled the early universe was cleared," said lead author Johan Richard of the Centre de Recherche Astronomique de Lyon, Universite Lyon 1 in France.
This galaxy is not the most distant ever observed, but it is one of the youngest to be observed with such clarity.
Normally, galaxies like this one are extremely faint and difficult to study, but, in this case, nature has provided the astronomers with a cosmic magnifying glass. The galaxy's image is being magnified by the gravity of a massive cluster of galaxies parked in front of it, making it appear 11 times brighter. This phenomenon is called gravitational lensing.
"Without this big lens in space, we could not study galaxies this faint with currently available observing facilities," said co-author Eiichi Egami of the University of Arizona in Tucson.
The findings may help explain how the early universe became "reionized."
NASA's James Webb Space Telescope (JWST), scheduled to launch later this decade, will be able to see these faint galaxies lacking magnification. A successor to Hubble and Spitzer, JWST will see infrared light from the missing population of early galaxies. As a result, the mission will reveal some of our universe's best-kept secrets.
"Seeing a galaxy as it appeared near the beginning of the universe is an awe-inspiring feat enabled by innovative technology and the fortuitous effect of gravitational lensing," said Jon Morse, NASA's Astrophysics Division director at the agency's headquarters in Washington.
"Observations like this open a window across space and time, but more importantly, they inspire future work to one day peer at the stars that lit up the universe following the big bang," he added.
The study will be published in the Monthly Notices of the Royal Astronomical Society.