BX442 is a handsome, tight spiral galaxy tucked away in a distant part of the universe. But it’s so far away and so old that it never should have been allowed to form in the early chaos of existence.
This latest mystery was discovered by the Hubble Space Telescope. BX442 is about 10.7 billion years old, making it the oldest and farthest spiral on record.
The galaxy confused astronomers when Hubble first picked it up and the Keck Observatory in Hawaii refined the images.
Technically, if prevailing theories about the Big Bang are correct, the developing universe would have been too hot and chaotic for a spiral galaxy to form the way it did.
A team in Nature, The International Weekly Journal of Science thinks they know what happened. According to lead researcher David Law of the University of Toronto’s Dunlap Institute for Astronomy and Astrophysics, a nearby dwarf galaxy might have provided the gravitational support BX442 needed.
“You can get a little extra help if you’ve got a satellite galaxy orbiting around,” said Law. “It gives that extra little gravitational kick to help accentuate the strength of the arm and make it into one of those eye-popping examples like the Whirlpool galaxy that you see all the pictures of.
“What we’ve learned when we look at galaxies at that epoch is that they’re very dynamically hot. Even though we see some discs existing at that time, they’re very thick and puffy, whereas the Milky Way has an… amount of random motion only about a tenth or so the amount of ordered rotation, giving rise to a very thin disc.”
If Law’s findings are correct, there might be other far off spiral galaxies lying in wait.