Extreme-velocity stars, which travel through the Milky Way with speeds of hundreds of kilometres per second, may come from dwarf galaxies that our own galaxy gobbled up

Illustration of the Milky Way
Mark Garlick/Science Photo Library/Getty Images
The speediest stars in the galaxy, moving at hundreds or even thousands of kilometres per second, are also some of the least well-studied. A study of 15 of these fast-moving objects has found that most of them probably came from dwarf galaxies devoured by the Milky Way in the distant past.
“Some stars that are travelling fast have been [proposed to have] an extragalactic origin, but this is the first time that a relatively large sample has been analysed and evidence has been shown that they …
Article amended on 8 April 2022
We corrected the speeds of the stars.