Nasa has been forced to rethink how galaxies are formed after the team behind the Hubble Space Telescope revealed stunning new data about the evolution of the universe.
It had previously been thought that disk galaxies like our own were formed roughly eight billion years ago, and had stayed in their current form since that point.
But according to Nasa, new data shows exactly the opposite.
The team behind Hubble and the Keck telescopes in Hawaii said that galaxies like our own have in fact been steadily changing over the last eight billion years, or more than half the age of our universe.
"Astronomers thought disk galaxies in the nearby universe had settled into their present form by about 8 billion years ago, with little additional development since," said Susan Kassin, an astronomer at the Goddard Space Flight Center.
"The trend we've observed instead shows the opposite, that galaxies were steadily changing over this time period."
Star forming galaxies like the Milky Way or Andromeda are relatively orderly disk-shapes, where rotation dominates over other "internal motions", Nasa said.
But the most distant galaxies appear to be much more disorganised and rotate in many directions. Gradually over time these galaxies settle into more organised disks themselves.
Previous studies made the mistake of only studying settled galaxies.
The new data suggests our sun and the Earth were formed while the Milky Way was still developing ,about 4.6 billion years ago.
The data was taken in a study of 544 galaxies, called the Deep Extragalactic Evolutionary Probe 2 Redshift Survey.