Astronomers Discover Rare Spiral Galaxy in Early Universe
The early universe isn't known for order or symmetry, which is why the discovery of a spiral galaxy observed as it existed only three billion years after the Big Bang has astronomers excited.
Using the Hubble Space Telescope to study 300 very distant galaxies, researchers happened upon a diamond in the cosmic rough.
"As you go back in time to the early universe, galaxies look really strange, clumpy and irregular, not symmetric," said Alice Shapley, a UCLA associate professor of physics and astronomy, and co-author of the findings published in Nature. "The vast majority of old galaxies look like train wrecks. Our first thought was, why is this one so different, and so beautiful?"
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Spiral galaxies, like our very own Milky Way, are rotating disks of stars and gas and they are common in today's universe. But long ago, galaxy collisions were much more common and black holes grew faster than they do now, resulting in the irregular galaxy structures found in the early universe.
"The fact that this galaxy exists is astounding," said lead author David Law of the University of Toronto's Dunlap Institute for Astronomy & Astrophysics. "Current wisdom holds that such 'grand-design' spiral galaxies simply didn't exist at such an early time in the history of the universe."
So-called 'grand design' galaxies have prominent, well-formed spiral arms.
"We first thought this could just be an illusion, and that perhaps we were being led astray by the picture," Shapley told NBC News. Using a spectrograph at the Keck Observatory in Hawaii, the team confirmed that the galaxy - dubbed BX442 - was indeed a rotating spiral and not two overlapping galaxies playing a trick of perspective.
"What we found when we took this spectral image of this galaxy is that the spiral arms do belong to this galaxy; it wasn't an illusion. It's rotating and has spiral arms. Not only does it look like a rotating disk galaxy - it really is. We were blown away."
Its very existence is strange, but the reason BX442 forms a spiral may be due to the companion dwarf galaxy that appears to be merging with it, according to The Los Angeles Times.
Shapley said that BX442 represents a link between early galaxies that are much more turbulent and the rotating spiral galaxies that we see around us. "Indeed, this galaxy may highlight the importance of merger interactions at any cosmic epoch in creating grand design spiral structure," she said.
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