If andromeda galaxy and milky way galaxy collided would any new substance be formed?

Question

every action has an equal and opposite reaction

Answer 1

You are probably thinking of the way a particle collider works. The speeds in a collider on Earth are far faster than the two galaxies are in collision.

The chances of any stars striking each other during a collision of two galaxies is slim, the stars are too spread out (Space is vast). The gasses, however, do collide and in some galactic merging images from the Hubble Space Telescope, the gasses show up glowing from the heat.

Sorry, there is not enough energy in the colliding gas atoms to create a new substance.

.

Answer 2

No.. some of the stars will change its position.. some of them will ejected right out the newly form galaxy.. some them will get sucked right into super massive black hole..