One hundred years ago this month, astronomers discovered the universe.
Before that, they thought the universe was nothing more than the Milky Way galaxy. All those other fuzzy things they saw in space they considered to be just nebulas.
But 100 years ago, Edwin Hubble and Henrietta Swan Leavitt collaboratively figured out that what was known as the Andromeda Nebula was way super far away, well beyond the confines of the Milky Way Galaxy. Like 2+ million light years away.
They came to the realization that this was no mere nebula, but a second galaxy like the Milky Way, which at the time they decided to call an “island universe,” I guess because they were used to thinking of the one galaxy they knew about as “the universe.”
Crazy to think that it was only 100 years ago that humans figured out how the universe is really designed.
One other fascinating thing about Andromeda Galaxy is that it’s one of the rare galaxies whose light is blue shifted. Most of them are red shifted, meaning they’re shooting away from us thanks to the expansion of the universe. As they shoot away, the wavelengths of the light from them gets spread out, which shifts the color of the light toward the red end of the spectrum.
So Andromeda’s blue-shifted light means it’s heading right for us, and in fact will collide with the Milky Way galaxy in about, oh, a bazillion years. So don’t buy any galaxy collision insurance just yet.
The truth is, galaxies colliding is a very low crisis event. The distance between individual stars is so vast, there’s as much chance of two stars colliding as there is of two flies flying around in the Grand Canyon colliding. But the collision will disrupt the spiral shapes of both galaxies and cause them to form into one single mega-galaxy.
Damn, I wish I could find the Fountain of Youth so I could live long enough to witness that event. Of course, by then someone will have had to invent interstellar travel so I can migrate to a much newer solar system, since long before this happens the sun will swell up to a red giant and swallow the Earth, and anyone hanging around when that happens will be a toasted marshmallow.