Why is the oldest galaxy ever discovered puzzling scientists?
Researchers found the most distant galaxy yet, and they're not quite sure why it shines the way it does.
Researchers at Caltech have just discovered the oldest galaxy ever found, and they're scratching their heads about it.
The team, led by Adi Zitrin, an Israeli post-doctoral fellow on a NASA fellowship, and Richard Ellis, a British professor at the University College in London, studied the galaxy's redshift and published their findings in the latest issue of Astrophysical Journal Letters a couple of weeks ago. Here's what's odd:
The universe is 13.8 billion years old, and this newly discovered galaxy, dubbed EGS8p7, is 13.2 billion years old. That means that looking into this galaxy is like looking into a window from the very distant past. And the researchers weren't expecting the past to look like this.
It's too bright.
For about a billion years, the universe was filled with neutral hydrogen atoms that absorbed starlight. Early universe galaxies would have been relatively dark ... Well, that's what scientists used to think, anyway. EGS8p7 emits so much light, scientists can even spot stars forming there.
"We expect that most of the radiation from this galaxy would be absorbed by the hydrogen in the intervening space. Yet still we see Lyman-alpha from this galaxy," said Zitrin.
The researchers are hypothesizing that some galaxies became brighter earlier. Or maybe EGS8p7 has a core of very hot stars.
Caltech graduate student Sirio Belli added that EGS8p7 "may have special properties that enabled it to create a large bubble of ionised hydrogen much earlier than is possible for more typical galaxies at these times."
Whatever the reason, EGS8p7 is making us question our assumptions. While high school classes often make science look fixed and stagnant, findings like this one show that science is actually fluid; scientists change their ideas about the universe all the time. Who would have expected such an old galaxy to shine so bright?
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