Andromeda in Our Skies

Once I had a very interesting chat with a friend of mine in which I knew Andromeda was on a collision course with the Milky Way, our own galaxy. There are two questions I still remember:

1. Will that collision destroy our Sun or our Solar System?
2. How will the night sky look like during that event?

Well, I've done my research and found very interesting things about this topic. First, the event will take place four billion years from now and although the two galaxies will pass through each other at a velocity of 1,000,000 mi/h (yes, a million), the duration of the crash will last millions of years. This suggest that our descendants will not be amazed by their night sky as it will be always the same to them as our night sky is to us, oblivious to the changes it has gone through. Our Sun will be safe in this collision as the space between stars is so vast there's no chance of being hit by another star. So there, we're safe if we, as humans, make it that far. So there's the answer to question number one: We are safe, at least our sun and planets.

The second question is how will the night sky look like when this happens? Well, at the beginning the Andromeda galaxy will be visible to the naked eye in a very dark night approaching us until we see it crossing through the Milky Way (the starry band we see at night, that's our galaxy seen sideways). Different from the picture below, Andromeda will not be as shiny, it will have the same luminosity as the Milky Way. In the end, the merged galaxies will settle as a big elliptical galaxy in which new stars will be created due to the crash. Take a look at the pictures and be amazed at the greatness of the Universe!

In the first picture, Andromeda will appear as a smudge in the sky.

Once Andromeda is close enough, it will appear cutting through the Milky Way.As the collision compress the gases within the galaxies, massive stars will form.
Many of the new massive stars will go supernovae, like cosmic firecrackers.
Once the collision stage slows down, the resulting image on the sky will be the core of the new elliptical galaxy and no trace of the spiral galaxies will remain.

This event has occurred millions of times before, is happening as we speak and will occur millions of times in the future. Just think about this: there's an estimate of about 100 billion (100,000,000,000) galaxies in the universe, which makes me think of a previous post.

Cheers!!