5 Min Read
Hubble came into astronomy in the 1920's at a very propitious time. It was at just the time that astronomers were gaining access to these large dome telescopes that were able to resolve very tiny pinpoints of light in the night sky. Prior to Hubble and the scientists who were looking into the night sky in the 1920's, there was debate among astronomers as to whether or not the Milky Way galaxy, in which our solar system resides, was the only galaxy, or whether there might be others beyond it. Hubble resolved that issue as he also resolved these points of light, because as he looked through this great dome telescope at the Palomar Observatory, he was able to determine that little points of light that had been viewed through ordinary telescopes before, and just looked like little points, actually revealed galaxies—whole galaxies with hundreds and millions of stars.
The picture behind us is a Spindle Nebula, and he saw Spiral Nebula, many different galaxies in every quadrant of the sky. Such that today, astronomers have something they call the "Hubble Deep Field," and it's a picture of the night sky. On the picture behind you'll see a little square box, a little quadrant. Now the next slide is going to be that quadrant magnified further and you see that even in the tiniest little square in the night sky there are galaxies galore.
And so, the first thing that Hubble determined was that we live in an immense universe. It was grand in scope beyond our wildest imaginations; galaxies in every direction. Now that was just awe-inspiring, but there was also a very theoretically and philosophically significant discovery that he made that was closely associated with this, and that is the discovery that these galaxies are moving away from us. In every direction of the night sky the galaxies are receding. And the evidence for that came from something called "Red Shift." It's that the light coming from those distant galaxies was redder in its hue, in its electromagnetic spectrum, in its color, than it would otherwise be if the galaxies were stationary in relationship to us.
How many have heard of the Doppler Effect? Do you know of that? If you have a train moving away from us, the sound of the train whistle will drop in pitch. Well the drop in pitch corresponds to a shift in wavelength. Up in Seattle, we have these…I don't know if you can talk about beer commercials in a church, but why not…we have these beer commercials for Rainier Beer. And they had these guys dressed up as beer cans that rode around on motor bikes. And at the end of the commercial they would ride off into the sunset saying, "Raaainieeerrrrr Beeeeer," and you had the Doppler shift happening. I'm probably the only person that watched that and thought Doppler shift rather than let's go get a brewsky, you know?
The same thing happens with light. Now what do you infer from that? I have a visual aide, and it's not a beer can, it's a balloon. Hubble got to thinking about this and he realized that if the galaxies—and I've drawn these little spirals on the balloon, so think going in the forward direction of time what's happening—If all the galaxies are moving away from us, that means the universe must be expanding outward in a kind of spherically symmetric expansion. So as you go forward in time, you get the universe getting bigger, and bigger, and bigger. Now what happens if you wind the clock backwards like the Saturday morning cartoons where they make the characters go backwards? What if you, the technical term is back extrapolate in time, if you go back 1,000 years? Is the universe bigger or smaller? Ok, and as you go back, and go back, and back, and back, and back, the further you go back in time the universe gets smaller, and smaller, and smaller until eventually you reach the beginning point of the expansion, where everything was congealed together. And Hubble realized that an expanding universe implied a finite universe—a universe that actually has a beginning; a beginning in time.
Now this was a really significant discovery because at the very same time on the other side of the country there was this physicist with bad hair named, Albert Einstein. And Einstein had come to the same conclusion that the universe must have a beginning, but then he said, "No, no, no, no, that cannot be right." And Einstein came to it on the basis of his theory of general relativity which was a theory of gravitation. And the equations of his theory suggested that the universe must be expanding outward and decelerating in order for all the math to work out. But when he realized that if it was expanding outward it must have had a beginning, he said no that can't be right. So then he posited an arbitrary force that was meant to counter act the force of expansion in just the right measure so that the universe would be static, and therefore could have existed eternally, without expanding or contracting.
When I was a physics student we use to call this "dry-labbing." Where you know, the professor gives you an experiment to do and you know what the answer is supposed to be, but you do the thing with the hockey pucks on the air table, and it's not coming out right. And it's getting near the end of the period and you want to go to dinner, and so what do you do? Now I'm not saying I ever did this, but I know some people who did. And you take the pen and you adjust the values so that they match the theory. Ok—that's called dry-labbing. That's essentially what Einstein, one of the greatest physicists in the history of the world, that's essentially what he did. He fudged. He fudged, because he had a preconceived idea that the universe must be eternal. And that was such a strong philosophical predilection that he adjusted the science to try to meet with that.
Then Hubble comes along and discovers that the universe actually is expanding; there must have been a beginning. And so he invites Einstein out to California to view the evidence that he'd been viewing through this grand telescope. And there's some famous newsreel footage where Einstein comes out and he looks through the telescope with Hubble in the background smoking his pipe, and he comes out and meets the media and says, "I now see the necessity of a beginning."
In any case, Einstein gets it, and later says that his cosmological constant, his little fudge factor, was the greatest mistake of his scientific career. In essence, the heavens talked back. And the testimony of the sky was that there was a beginning to the universe.