It’s difficult to know what your home looks like if you don’t, or can’t, leave it.
Take the Milky Way, for instance. Astronomers think it is a barred spiral galaxy, a bit like this one, which is called NGC 7773, which is about 392 million light years away. They can’t be sure, though, mainly because no human-made imaging vessel has thus far escaped the galaxy, turned around and taken a snap.
This image of NGC 7773, taken by NASA/ESA Hubble Space Telescope’s Wide Field Camera 3 (WFC3), reveals the existence of a series of luminous bars – they appear orangey-brown in this instance.
Astronomers think that the bars develop as galaxies mature, and comprise star-forming material slowly being pulled into the centre of the system.
The Milky Way is a spiral, and quite old, as galaxies go, so it is reasonable to suspect it also contains bars. It might be a very long time indeed, however, before the photographic material exists to prove the contention.
