The galaxy that shouldn't be there
It may sound like a robot from Star Wars, but BX422 is in fact a distant galaxy, formed around 3 billion years after the Big Bang. The strange thing is, the galaxy's spiral shape is closer to that of older galaxies such as our own Milky Way and nothing at all like the sort of structure you would expect from something much, much younger.
BX422 isn't alone either - it's being orbited by a smaller dwarf galaxy and as Nature are reporting, it is postulated that this smaller galaxy is the cause of the unexpected galactic structure. Effectively, the gravity from the smaller galaxy is pulling the stars in it's big brother into the shape we can now see.
BX422 was included in a survey of around 300 early galaxies studied by the Hubble space telescope, and the only one to have that distinctive whirlpool appearance...
Image credit: Dunlap Institute for Astronomy and Astrophysics / Joe Bergeron
Last updated: 18/04/2018 08:09:03