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Astronomycast Episode 187 from Monday, April 26, 2010. History of Astronomy Part 5, the 20th century.

Welcome to Astronomycast, our weekly facts based journey through the cosmos to help you understand not only what we know, but how we know what we know.

My name is Fraser Cain, I'm the publisher of University Day, and with me is Dr. Pamela Gaia Professor at Southern Illinois University, Abertsville.

I Pamela, how are you doing?

I'm doing well, how are you doing?

Good, I get uninterrupted Pamela time for like the better part of a month before you're traveling.

So we've got a lot of shows that are going to be coming out hopefully very quickly.

So I hope this will show our commitment to you, the listener, as you get buried in audio.

So I think this is going to be the last part of the history of astronomy.

So let's go into it.

So many of the modern ideas in astronomy happened right in the 20th century, dark matter, the big bang, inflation, quasars, black holes, neutron stars, pulsars, and even dark energy.

So with so many discoveries in one important century, let's get started.

All right, episode four, we wrapped up right with Hubble's discovery that those blurry spots that they thought might be nebulae were actually whole other galaxies, which means the universe is much bigger, and that the Milky Way is just another galaxy in a gigantic universe.

And you mentioned that you've met astronomers who remember that, which is quite amazing to think.

I mean, you look at all the books and you think about all of our modern concepts of astronomy and the sort of size and scale of the universe, that really plays a big role in that.

And yet all of the stuff just came in the last 70, 80 years.

So let's proceed from Hubble's discovery of our place in the universe. And what would you say is the next big discovery that was made?

Well, I think it was figuring out our place in our own galaxy in 1927 with Orts. Up until that point, we still didn't know where in the Milky Way we were.

There were people who put us in the center. There were people who, if we just didn't know, the problem is you look out in the disc and because of dust, because of the density of stars, you can see within the disc the same direction, the same distance in all directions.

Right, I remember that it was like, Hershel first took a shot at that, right? Try to do a try to figure out our place and try and map out the size and shape of the of the Milky Way, but it was hopeless because didn't realize that the gas and dust was going to be obscuring our view towards the core of the galaxy.

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