If the accelerating enlargement of the universe is driving galaxies away from one another, how is it that the Andromeda and Milky Way galaxies are on a collision course?
Steve Amundson
Littleton, Colorado
As you level out, the universe is increasing, carrying the galaxies inside it away from one another like raisins inside rising bread dough. Which means that one day, far sooner or later, inhabitants of our galaxy is not going to see another galaxies within the evening sky.
That doesn’t imply that galaxies which are close to to 1 one other don’t work together, nonetheless.
Simply as Earth’s gravity would possibly pull on a close-by asteroid, sending it on a collision course with our planet, the Andromeda and Milky Way galaxies work together with one another gravitationally. This has resulted within the two galaxies falling towards one another at a price of about 37 miles per second (60 km per second). As a result of Andromeda is 2.5 million light-years away — with 1 light-year equal to five.9 trillion miles (9.5 trillion km) — this galactic crash gained’t happen for 4.5 billion years. And fortunately, the space between stars is so nice that it’s unlikely something will really collide. However the merger will change the paths of stars inside every galaxy.
Because it seems, a majority of the Milky Way halo was “shaped by the merging of quite a few progenitor galaxies,” in line with a paper printed in The Astrophysical Journal earlier this 12 months. Although the precise variety of occasions our galaxy has merged with one other is unclear, what is obvious is that the Andromeda collision gained’t be the primary time the Milky Way has merged with one other galaxy. Nor will or not it’s the final.
Our galaxy is a part of a galaxy cluster referred to as the Native Group. One day, this assortment of practically 100 galaxies might have all merged. And there’s even proof that the Native Group would possibly itself merge with the closest massive galaxy cluster, the Virgo Cluster!
Caitlyn Buongiorno
Affiliate Editor
