Farthest Known Galaxy Captured on Camera
The farthest known galaxy has recently been captured on camera, giving scientists a glimpse back in time to when the Universe was only five percent of its present age, according to new research.
Using the powerful MOSFIRE instrument on the W.M. Keck Observatory in Hawaii, and NASA's Hubble and Spitzer space telescopes, an international team of astronomers discovered an exceptionally luminous galaxy more than 13 billion years in the past.
The galaxy, EGS-zs8-1, is one of the brightest and most massive objects in the early Universe.
So how exactly did astronomers, led by Yale University and the University of California-Santa Cruz, determine the galaxy's age from their observations?
Age and distance are vitally connected in any discussion of the Universe. The light we see from our Sun, for example, takes just eight minutes to reach us, whereas the light from distant galaxies we see via today's advanced telescopes travels for billions of years before it reaches us - so we're actually seeing what those galaxies looked like billions of years ago.
"It has already built more than 15% of the mass of our own Milky Way today," Pascal Oesch, a Yale astronomer and the study's lead author, said in a statement. "But it had only 670 million years to do so. The universe was still very young then."
Amazingly, the new findings also showed that EGS-zs8-1 is still forming stars rapidly, about 80 times faster than our galaxy.
This discovery is not only remarkable because it is the farthest known galaxy captured on camera, but also because only a handful of galaxies currently have accurate distances measured in this very early Universe.
"Every confirmation adds another piece to the puzzle of how the first generations of galaxies formed in the early universe," said Pieter van Dokkum, one of the researchers. "Only the largest telescopes are powerful enough to reach to these large distances."
Taken together, the new Keck Observatory, Hubble, and Spitzer observations help to shed light on the early Universe. They confirm that massive galaxies already existed early in the history of the Universe, and that those galaxies had very different physical properties from what is seen today.
For example, the unique colors of these galaxies may come from the rapid formation of massive, young stars, which interacted with the primordial gas in these galaxies, such as hydrogen.
Scientists hope to study EGS-zs8-1 in even more detail with NASA's James Webb Space Telescope, which is scheduled to launch in 2018, as well as better understand the formation of other galaxies in the early Universe.
The study's findings were published in The Astrophysical Journal.
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