« on: 28/01/2024 16:17:25 »
Andromeda is moving away from us as it is red shifted. And yet we are going to collide with it. So how can we collide with an object that is red shifted?Andromeda is blue shifted. It is part of our local group of galaxies which are gravitationally bound to each other. The Universe is composed as a hierarchy of structures. Star systems group together to form galaxies, individual galaxies form groups, groups form clusters... It isn't until you get beyond the cluster stage that you begin to see the effects of the expansion. So when it's said that the galaxies are receding from each other, it really means that structures that are formed from galaxies and are beyond a certain size are receding from each other.
It should be blue shifted if it is heading our way regardless of the universe expansion.
If the local gravity is overcoming the expansion and that is the explanation for our collision then how can it be red shifted when we observe it?
(local dynamics, such as the gravitational interaction between the Milky Way and Andromeda, cannot explain why Andromeda's light appears redshifted if it is indeed moving towards us).
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