NASA's Hubble and Spitzer space telescopes have discovered the most distant galaxy identified so far in the universe.
Appearing in images as a diminutive blob, the galaxy is 13.3 billion light years away and only a tiny fraction of the size of the Milky Way. Due to the time it takes light to travel through space, the images seen from Earth now show what the galaxy looked like when the universe was just 420 million years old, according to a press statement released from NASA.
The newly discovered galaxy, named MACS0647-JD, was observed 420 million years after the so-called Big Bang, the theorized beginning of the universe, and its light has traveled 13.3 billion years to reach Earth.
The discovery is the latest from a program that uses naturally occuring "zoom lenses" to reveal distant galaxies in the early universe. The Cluster Lensing And Supernova Survey with Hubble (CLASH), an international group led by Marc Postman of the Space Telescope Science Institute in Baltimore, is using large galaxy clusters as cosmic telescopes to magnify distant galaxies behind them.
The cluster's gravity boosted the light from the faraway galaxy, making the images appear about eight, seven, and two times brighter than they otherwise would.
"This cluster does what no manmade telescope can do. Without the magnification, it would require a Herculean effort to observe this galaxy," says Postman.
According to NASA, MACS0647-JD is so small it may be in the first steps of forming a larger galaxy. Analysis indicates the galaxy is less than 600 light-years wide. Based on observations of somewhat closer galaxies, astronomers estimate that a typical galaxy of a similar age should be about 2,000 light-years wide.
For comparison, the Large Magellanic Cloud, a dwarf galaxy companion to the Milky Way, is 14,000 light-years wide. The Milky Way is 150,000 light-years across.
"This object may be one of many building blocks of a galaxy,"said the study's lead author, Dan Coe of the Space Telescope Science Institute. "Over the next 13 billion years, it may have dozens, hundreds, or even thousands of merging events with other galaxies and galaxy fragments."
The study will appear in the Dec. 20 issue of The Astrophysical Journal.