A Galaxy from the Universe's Dark Ages -13 Billion Light Years Distant
Space is big. Like, really big (and here we'll deviate from the Hitchhikers Guide), so unimaginably vast that even light can take a long time to get around the place. This turns the sky into a live-action cross section of history - we might see everything right now, but the further away something is the longer that light took to reach us and the further back in time what we see now actually happened. And it's hard to go much further back than the snappily titled A1689-zD1, a galaxy whose light has spent almost all of time itself getting to us.
The galaxy is thirteen billion light-years away, and don't worry if that seems like a ridiculously huge distance, because it is. The universe itself is only about thirteen point seven billion years old, so do the megascale mathematics and you see that this is almost at the limit of how insanely far away something could be and still ever be seen. A1689-zD1 is thought to be one of the first galaxies, the earliest star group formations which began to illuminate the vast (boring) clouds of cold hydrogen that made up the universe about half a million years after the big bang. Pretty impressive work for a (galactic) infant.
Recorded by the Hubble telescope, this is probably the most effort that's ever been expended taking a baby photo. The images were recorded using a combination of man-made machinery and the heavens themselves - the satellite's "NICMOS" system (Near Infrared Camera and Multi-Object Spectrometer) recorded light gravitationally lensed by the mega-massive cluster of galaxies known as Abell 1689. The brain-blowing bulk of the gigantic Abell cluster bends spacetime around it, focussing the faint light from the faraway target towards the sensitive satellite detectors. Which is an optical add-on that makes even the most expensive Zeiss telephoto lens look like a blurry cameraphone.
Hubble has allowed scientists to develop an entire parenting manual for galactic structure, observing galaxies at different distances (and so different ages) throughout the sky. But like all those who go through photo albums, they have a soft spot for the infants - they are already making plans to get better images of baby A1689-zD1, including future satellites and radio telescopes. Expect to hear more about this literally historical find.
Posted by Luke McKinney.
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A light year is a measurement of distance not time right? Was the rate of expansion in the big bang theory no faster than the speed of light? If the Big bang theory is true with an expansion from a small point, wouldn't there be other galaxies closer to this one in the picture?
Posted by: Bob Dickerson | July 07, 2009 at 07:23 AM