On the Universe We Live In

Sometimes, I really wish I could live to see the world three billion years hence.

Okay, I take that back. It’s not just sometimes. I wish that all the time.

In three billion years, give or take a few hundred million years, astronomers believe that the Milky Way, our home galaxy, and M-31, better known as the Andromeda Galaxy, will collide.

Oh, to be alive then! To see a barred spiral galaxy dominate the night sky for millions of years, and then to stand somewhere outside the galaxy and watch as the arms of the two galaxies comingle.

Why can’t it happen now? Why must things happen on a cosmic scale where we humans are merely dust motes that matter not at all, where the span of our existence registers as nothing in the grand scale of time?

Alas, I can bemoan the cosmic unfairness of it, content myself with watching simulations of what might happen, read Wikipedia articles until I’m bored out of my skull.

Such is my life.

Then I read this today — our own galaxy is larger than scientists had previously thought.

For a number of years, the Andromeda Galaxy was believed to dwarf the Milky Way. But as radio astronomy has improved as we’ve had better tools to chart the heavens, many of the assumptions about a galaxy have been altered. For many years our galaxy was believed to be a true spiral, but now we know that it is a barred spiral. Now we know that the galaxy rotates faster than had been previously believed; a faster rotation means a greater mass.

The researchers estimate that the Milky Way contains about 50% more mass than earlier predictions – putting it on a par with the Andromeda galaxy, previously thought to be our much bigger neighbour and the largest in our Local Group of galaxies.

“No longer will we think of the Milky Way as the little sister of the Andromeda Galaxy,” Dr Reid said.

That higher mass makes for a higher gravitational pull, suggesting that collisions with Andromeda and other nearby galaxies may happen much sooner than thought – but still billions of years in the future.

So that far distant collision between the Milky Way and Andromeda? It might only be 2 and a half billion years away, not that impossibly far distant 3 billion years. I won’t have to live quite as long. πŸ˜‰

The Earth will still exist then. Our solar system will still be here. Sol has another five billion years of life left to it. I wonder what strange creatures will inhabit the Earth billions of years from now. Will they be descended from us? Or will evolution have taken a different path, so it is descendents of blowfish, for example, that have inherited the Earth?

Too bad I won’t see it.

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