The oldest galaxy ever seen? (Courtesy: NASA)
By Hamish Johnston
What will astronomers see when NASA launches the James Webb Space Telescope (JWST) in 2014? That question kept cropping up a few weeks ago at the 217th meeting of the American Astronomical Society in Seattle.
With it’s huge mirror – 2.5 times bigger than Hubble’s – the JWST should be able to spot faint and distant galaxies that formed just a few hundred million years after the Big Bang.
But thanks to a recent upgrade, Hubble has also managed to spy some of these ancient galaxies, providing a preview of things to come from the JWST.
The results are published today in Nature and include the discovery of what just might be the most distant, and therefore oldest, galaxy ever seen. Astronomers believe it is13.2 billion light-years away, which means that light from the galaxy began its journey to Earth just 480 million years after the Big Bang.
Garth Illingworth of the University of California, Santa Cruz, said of the galaxy: “We’re getting back very close to the first galaxies, which we think formed around 200 to 300 million years after the Big Bang”.
Using Hubble’s Wide Field Planetary Camera 3 (WFC3), the researchers studied galaxies over a period from about 480 to 650 million years after the Big Bang. They were amazed to find that the number of stars being created in the universe increased by a factor of 10 during this relatively short time period.
“This is an astonishing increase in such a short period, just 1% of the current age of the universe,” said Illingworth.
Hubble found a similar rapid increase in the number of galaxies over the same time period.
The findings provide astrophysicists with tantalizing clues about how stars and galaxies formed in the early universe – but researchers will likely have to wait until the launch of the JWST before this trickle of information becomes a flood.