A Galactic Distance Record


The recently discovered galaxy MACS0647-JD was observed 420 million years after the Big Bang when the universe was 3 percent of its present age. Its light has traveled 13.3 billion years to reach Earth. The inset at left shows a close-up of the young dwarf galaxy.

This find is the latest discovery by a program that uses natural gravity lenses to find galaxies in the early universe. The Cluster Lensing And Supernova Survey with Hubble (CLASH) is using gravitational lensing by massive galaxy clusters as cosmic telescopes to magnify distant galaxies behind them.  Around 8 billion years into its journey, light from MACS0647-JD took multiple paths around a massive galaxy cluster. Using gravitational lensing, the CLASH research team was able to observe three magnified images of MACS0647-JD with the Hubble telescope. The cluster’s gravity boosted the light from the more distant galaxy, making the images appear brighter than they otherwise would.

MACS0647-JD is small; it might be in the first steps of forming a larger galaxy. Analysis shows the galaxy is less than 600 light-years wide. Based on observations of nearer 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. Our Milky Way is 150,000 light-years across.

Image Credt: NASA/ESA

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