Map of life expectancy at birth from Global Education Project.

Friday, January 04, 2019

Hold onto your hats . . .

In about 2 billion years the Large Magellanic Cloud will collide with our galaxy. It's not actually a cloud, of course. It was named before people had powerful telescopes and could figure out that many of the so-called nebulae were actually galaxies. The LMC is a satellite of our galaxy, which we call the Milky Way. We have many such satellites but the LMC is the biggest.

The collision will result in an influx of material into Sagittarius A*, the black hole at the center of the galaxy, "waking up" the Milky Way to become an active galaxy, with powerful jets of high energy radiation emitted from the poles of A*. This won't affect the earth particularly, although there is a small chance the sun's orbit could be disrupted and the solar system expelled from the galaxy. I know you probably figure you won't be around that long . . .

This interests me because it's a reminder of how radically our understanding of the universe and our place in it has changed in a short time. In fact, it was less than 100 years ago that Edwin Hubble discovered the universe. Literally. Galileo figured out that the earth was not at the center of the universe, but it was not until just a couple of years before Hubble's discovery that Harlow Shapley was able to describe the Milky Way galaxy and expand our vision of the universe by what we now know was a minute increment. We now estimate that Hubble's universe contains about 200 billion galaxies, and that our own quite typical galaxy contains more than 200 billion stars.

This knowledge has not affected the philosophy of most people, who still put humanity at the focus of concern of an imagined creator God. If in fact God created this universe of 200 billion galaxies 14 1/2 billion years ago for the essential purpose of bringing to consciousness some bags of organic carbon soup in a thin layer of slime on an infinitesimal speck of dust, he is mighty damn inefficient.

In reality, it doesn't matter what happens to us. We are nothing. The earth, the solar system, the galaxy, the universe, will go on without us until they do no longer, billions of years after we are gone. We only matter because we matter to ourselves. This profoundest of all revelations, once again, is less than 100 years old. Think about that.


3 comments:

Don Quixote said...

https://www.youtube.com/watch?v=yq4uCWtQE24

Mark P said...

One of the most amazing images taken by the Hubble is the deep field image showing thousands of galaxies in a piece of the sky approximately the angular size of a tennis ball at 100 yards. It reminded me of the phrase associated with 2001: A Space Odyssey, "My god -- it's full of stars!" (It seems it actually comes from the novelization of the movie.) Only in this case, it's my god, it's full of galaxies. There are now some estimates of 2 trillion galaxies in the universe. Numbers like that are inconceivable for most people. I calculated that if you visited every star in the Milky Way for a day and could travel instantaneously from star to star, it would take about 274 million years. The idea that humans have some special place in the universe is absurd. I think it was Arthur C. Clarke who said, "Two possibilities exist: Either we are alone in the Universe or we are not. Both are equally terrifying."

Cervantes said...

I used to have the Hubble Deep Field as the wallpaper on my office computer. Yeah, that's a lot of galaxies but we still don't now what 95% of the universe even consists of -- it's something that is only detectable by gravity. We still don't understand jack shit.