Tuesday, March 28, 2017

Galileo and Dark Matter

I was drafted recently to give a talk about Galileo, a subject on which I am no expert. So I relied heavily on Rocky Kolb's book, Blind Watchers of the Sky (I wrote my very first physics paper with Rocky back in 1981, back when we were both, uh, about 12 years old), and on Michael Flynn's brilliant, if somewhat irreverent (coming from me, the latter is higher praise than the former), The Great Ptolemaic Smackdown.

When doing scientific research, you quickly come to realize that progress in science consists of thousands of blind alleys (for you), punctuated by the occasional breakthrough (for someone else). In the textbooks, all of the blind alleys get airbrushed away (who has time to study incorrect theories?), leading to the erroneous impression that science has been been one long march to the Truth. But it never happens that way.

For example, one of Galileo's main arguments for the Copernican model was his theory of the tides. He noticed that as the Earth moves around the Sun, the surface is moving faster at midnight than at noon, since in the former case the motion around the sun is in the same direction as the rotation of the Earth, and vice-versa at midnight.




So Galileo claimed that the water would bunch up at noon and spread out at midnight, leading to a low tide at midnight and high tide at noon (or maybe the other way around?)  A couple of problems here:  there are two high tides and two low tides a day, not one, and they occur at different times of the day, not just noon and midnight.  Galileo's theory was completely wrong, which is why you've never heard of it (except for you, Michael...)  But (and this is the weird part), I drew a diagram exactly like this one for my cosmology class a few weeks ago. Why?

Tuesday, March 14, 2017

Science Fiction Set In Your Home Town

If you grew up in New York or Los Angeles, you'll find no dearth of science fiction set in your home town, with familiar locales and landmarks. The same thing applies if you were born in Trantor, Diaspar, or Coruscant. But if, like me, you come from the Midwest, you won't see a lot of local color in the science fiction you read.

I grew up in St. Louis, so I was delighted to encounter The Jericho Iteration, by Allen Steele. Steele's novel is a science fiction conspiracy thriller set in a St. Louis devastated by an earthquake on the New Madrid fault. I enjoyed recognizing the numerous local landmarks in the novel, although I didn't actually like the story itself. But that's beside the point -- the important thing is that St. Louis has a science fiction novel to call its own.

I should also mention that the near-future dystopian film Escape from New York was filmed in St. Louis, despite being set in New York. Apparently New York was insufficiently run down to serve the filmmakers, so they came to St. Louis instead. Now that's something for a native St. Louisan like me to be proud of.

What about my adopted home of Nashville?

Wednesday, March 8, 2017

Texas Talk on Science and Science Fiction

I'm giving the physics colloquium at Texas A&M tomorrow (Thursday, Mar. 9) on science and science fiction. Details are here.

Friday, March 3, 2017

What if Robert E. Lee had Tactical Nuclear Weapons at Gettsyburg?

The Confederacy would have won the battle, but the battlefield park probably wouldn't be such a nice place to visit these days.

The genre of "alternate history" explores fictional paths that history might have taken. Is it a branch of science fiction? I have no idea. Certainly time-travel alterations to the historical timeline and parallel universes fall squarely under the science fiction heading, but straight alternate history is often placed in a category all its own.

I enjoy alternate history, although it tends to follow just a few well-worn themes:  What if the South had won the Civil War? What if Hitler had won World War II? What if the South had won the Civil War? What if Hitler had won World War II?...  So I was eager to read Harry Turtledove's new novel, Bombs Away, which examines the consequences of Harry Truman deciding to use nuclear weapons to wrap up the Korean War. This historical era (the early Cold War) is one that I find particularly fascinating, and I've enjoyed Turtledove's work in the past -- he's built an impressive career in the field of alternate history.