Milky Way’s bulge may have been formed by the galaxy buckling | New Scientist
https://www.newscientist.com/...097181-milky-ways-bulge-may-have-been-formed-by-the-galaxy-buckling/
Many disc galaxies, including our own Milky Way, have a central bulge that resembles either a box or an unshelled peanut.
This bulge may form when the circular orbits of stars become elongated, creating a “bar” of stars that runs through the centre
and tilts out of the disc’s plane. The combined effect makes the once-flat galaxy look like it has buckled under enormous pressure.
There’s just one problem – we’ve never seen this buckling occur. The whole process is thought to take a few hundred million years,
so it’s not surprising that we haven’t caught it in action. But it does make the theory difficult to confirm.
“It would be a bit tedious to wait for the whole thing,” says Peter Erwin of the Max Planck Institute for Extraterrestrial Physics
in Garching, Germany.
Now, Erwin and Victor Debattista of the University of Central Lancashire in Preston, UK, think they have spotted a couple of galaxies
in mid-buckle. “It’s probably what the Milky Way looked like billions of years ago,” Erwin says.
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