Perturbations in the Milky Way. Image. ESA
Milky Way was shaken by near-collision 500 million years ago and is still vibrating - space short science news

The Milky Way has been shaken by the Sagittarius dwarf galaxy that came passing buy some 500 million years ago. Research carried out with the European Gaia satellite revealed that this near-collision has caused groups of stars to move. These starts are still moving after all these years in a circular “snail-house pattern”. It was already known that Sagittarius came along the Milky Way, but because the mass of that system was so much smaller than that of the Milky Way, it was always assumed that it had little effect on the Milky Way. The new observations give reason to reconsider some assumptions about the Milky Way, including those about black matter, researchers say.

Read the full story: Universitat de Barcelona
Scientific publication: Nature