The Andromeda Collision

First of all, apologies for the lack of posts in recent weeks. I have been looking into the comments and suggestions on the website for several weeks to gain inspiration for new posts.

I’ve done plenty of posts explaining the curvature of space and time, the movement of the heavenly bodies and how the fabric of the universe works. These movements and curvature can have some cataclysmic consequences, such as galactic collisions.

We live in relative bliss in the confines of our own galaxy, the Milky Way. At 100,000 light years in diameter we are a mid size spiral galaxy with a supermassive black hole at its centre, Sagittarius A*.

Our nearest galactic neighbour is the Andromeda Galaxy. The nearest galaxies to us are pooled together in what we call the Local Group. Andromeda is 2.537 million light years from us. So when we observe it today, we see it as it was 2.537 million years ago. Likewise, if there is intelligent life observing us from Andromeda, they would see the beginning of the end of the ice age when Wooly Mammoths roamed the thawing plains.

Andromeda has around a trillion stars within its confines. Around double of our 400 billion we have in ours. Andromeda has twice the diameter of the Milky Way at around 220 million light years across. In plain English, it is twice the size of us.

As the universe is expanding and taking everything embedded in it with it, from time to time galaxies can collide. It’s quite frequent in difffering galaxy groups and mergers can be observed either in process or merged entirely. At around 68 miles per second, Andromeda is coming straight for us.

Relative to the Sun’s orbit, Andromeda is approaching more like 190 miles per second. Given the Sun’s own movement within our galaxy. The sideways velocity of Andromeda is much smaller so the actual collision with the Milky Way won’t happen for around 4 billion years.

In 4 billion years time the sun will either have ended or approaching the end of its life. The sun will become larger and brighter when it has swollen into a red giant. Most likely swallowing the Earth when it expands into Earth’s orbital path.

Given that this event will happen so far into the future, there’s no need to call Bruce Willis just yet. It is interesting to wonder what this collision would look like. Given the vast distances between our own stars, it’s mathematically possible that the galaxies will merge without a single star collision.

It is also possible that the solar system could be ejected from the Milky Way and join Andromeda! Although I can’t imagine humans surviving long enough to know the ultimate fate of the solar system whenever Andromeda draws nearer.

Maybe if teenagers aspired to wanting to become scientists and observers instead of being reality TV stars or Kardashians we may one day find out.

Jude Morrow

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