NASA Finds What Could be the Most Distant Galaxy Yet SeenBy: Sean Patterson - September 19, 2012
NASA today announced that it has snapped a picture of what could be the most distant galaxy ever seen.
Using the Spitzer and Hubble space telescopes, astronomers have captured an image of what could be a young galaxy from when the universe was just 500 million years old. The current age of the universe is calculated to be 13.7 billion years old, making the spotted object close to 13.2 billion years old. This galaxy, called MACS 1149-JD, was one of the first galaxies to form.
“This galaxy is the most distant object we have ever observed with high confidence,” said Wei Zheng, a principal research scientist in the department of physics and astronomy at Johns Hopkins University and lead author of a paper on the galaxy sighting that has been published in the journal Nature. “Future work involving this galaxy, as well as others like it that we hope to find, will allow us to study the universe’s earliest objects and how the dark ages ended.”
In the image above, the galaxy appears red because the light traveling from the galaxy has redshifted, or lengthened in wavelength. Astronomers use this redshift, which is the result of the expansion of the universe, to describe cosmic distances. The light from MACS 1149-JD has traveled 13.2 billion light-years before reaching Earth, and has a redshift of 9.6.
To spot the galaxy, astronomers used what is called gravitational lensing. Since even modern telescopes are not sensitive enough to capture an image of an object so old, the gravity of a massive galaxy cluster situated between the Milky Way and MACS 1149-JD was used to magnify the new galaxy’s light, brightening it by around 15 times.
Astronomers estimate that the galaxy was less than 200 million years old when it was viewed. It is small, with only around 1% of the mass of the Milky Way. This fits with currently accepted cosmological models, which show that early galaxies would have been small, then merged to form more sizable, modern galaxies.
(Image courtesy NASA/STScl/JHU)