26th January 2011
The Hubble Telescope is a time machine. It not only coaxes galaxies into view from billions of light years across the universe, it also looks back billions of years in time. All because light has a finite speed (186,000 miles per sec). In fact any telescope is a time machine, even your eyes for that matter when you look at the night sky. If you look at the Moon you’re looking 1.3 seconds into the past as it takes the light that time to reach us. Glance over to M31, the Andromeda Galaxy and you’re looking 2.5 million years into the past. You are seeing it how it looked all that time ago because the light from its stars has taken 2.5 million years to cross the gulf of space, and enter your eyes.
Well this time the Hubble Space Telescope has peered even further back than ever before into the depths of space and time, to come up with the most distant galaxy ever seen. The previous record breaking galaxy (UDFy-38135539) was uncovered in October 2010. This was an image of a star system over 13 billion light years away, from a time around 600 million years after the Big Bang. Impressive? Yes, totally! But this time astronomers have burrowed another 120-150 million years further back, towards the start of everything.
This new image shows a baby galaxy (UDFj-39546284), it is 500 million times fainter than the faintest star visible to the naked the eye, and is 13.2 billion light years away. This distance puts it at a mere 480 million years after the birth of the universe itself. This smudge of light is an embryo star city, a hundredth of the size of the Milky Way, and contains hot young stars. It is on a growth spurt, increasing in size much faster than large modern galaxies like our own Galaxy.
At this time in the infant universe, galaxy formation was on full throttle, and the number of star systems in existence increased rapidly over the next few hundred million years. These proto-galaxies slowly came together under mutual gravity, to eventually assemble into the large majestic spirals and ellipticals we see populating the cosmos today.
Just how far back can we go? How much nearer to the Big Bang can we get, 200 million years, 100? What does the very early cosmos look like? The new James Webb Space Telescope due to take over from Hubble is primed for the infra red part of the spectrum. This makes it perfect for hunting down the very, very earliest star systems to emerge out of the chaos of the birth of the universe.
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