Stephan's Quintet, a compact group of galaxies discovered about 130 years ago and located about 280 million light years from Earth. The galaxy NGC 7318b is passing through the core of galaxies at almost 2 million miles per hour, and is thought to be causing the ridge of X-ray emission (in blue) by generating a shock wave that heats the gas. Image: NASA. Public domain.
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The happy thing here is that when galaxies collide, individual stars most often don’t crash into each other, repelled by mutual gravitation. Instead, they generate massive amounts of gas that spin and coalesce and eventually ignite as new stars—billions upon billions of new stars.
Hubble’s brilliant image of NGC 2207 and IC 2163, a pair of colliding galaxies about 80 million light-years from earth in the constellation Canis Major. They will continue colliding for about a billion years, after which it’s thought they’ll have become an elliptical or disk galaxy finally at peace. Both were discovered by John Herschel in 1835. Image: NASA. Public Domain.
The collision of NGC 4038 and NGC 4039 near the constellation Corvus, 60 million light-years from Earth, will take hundreds of billions of years to play out. This Hubble close-up is roughly 50,000 light-years across. Its extended structures arc outwards for hundreds of thousands of light-years. Image: NASA. Public domain.
Writes NASA: Arp 148 is the staggering aftermath of an encounter between two galaxies. … The collision between the two parent galaxies produced a shockwave effect that first drew matter into the center and then caused it to propagate outwards in a ring. The elongated companion perpendicular to the ring suggests that Arp 148 is a unique snapshot of an ongoing collision. Arp 148 is nicknamed Mayall's object and is located in the constellation of Ursa Major, the Great Bear, approximately 500 million light-years away. Image: NASA. Public domain.
Andromeda Galaxy, also called Andromeda Nebula, (catalog numbers NGC 224 and M31), great spiral galaxy in the constellation Andromeda, is our closest neighbor in space—and one of the few galaxies we can see with the naked eye. It is located about 2,480,000 light-years from Earth; its diameter is approximately 200,000 light-years. It was first mentioned in 965 CE in the Book of the Fixed Stars by the Islamic astronomer al-Ṣūfī.
Oh, but the beautiful Andromeda is not colliding with anything—right? Actually, it is. It’s colliding with us! Right now!
Eventually the trillion-star Andromeda and the 300-billion-star Milky Way will slide right into each other. It’s a process that is in its early stages now, a collision that take up to 4.5 billion years to play out. The orbits of all the stars in both galaxies will change, and our solar system will likely be flung to a place far, far away from where it is now. Billions or trillions of news stars will ignite, and eventually the stars and planets of both galaxies will orbit a new, singular center.
By then, I expect, humanity will be spread across many stars with family on planets spread across many galaxies. So, not to worry.
Putting things in perspective. We are but a grain of sand in our tiny universe.
I’ve fallen in love with the Hubble telescope💕💕