by Throughout the Milky Way galaxy, planets orbit hundreds of millions of stars other than the Sun. And in galaxies beyond our own, stars orbit enormous black holes millions or even billions of times the mass of the Sun. Telescopes on high mountains and deserts and in space help scientists gather data about these planets, stars, and black holes. And Scott Tremaine, a theoretical astrophysicist at the Institute for Advanced Study (where Albert Einstein worked from 1933 until 1955) uses that data to help us “see” even more.
As a child in Toronto, Tremaine didn’t like having to memorize facts in history class. He preferred math and science, which didn’t require much memorization once he understood each topic. He went on to study physics in college and to get his doctorate in that subject at Princeton University. While at California Institute of Technology in the 1970s, Tremaine studied the rings around Saturn and Uranus. The collisions between ice chunks orbiting the planets in these rings should cause the rings to spread out. Scott used math to suggest reasons why the rings are as narrow as they are. Imagine how exciting it must have been when NASA’s Voyager spacecraft confirmed some of his hypotheses.
These days, Tremaine examines the planets orbiting other stars in galaxies. “Examines” might not be the right word, because it’s very difficult to see those planets, as they’re buried in the glare from the star. Using powerful tools like the Hubble and Kepler telescopes in space, scientists sometimes notice stars wobbling just a bit, or dimming periodically. This wobble happens as a planet orbits the star, and the dimming happens if the planet passes in front of it. The scientists making the observations publish their findings and theorists like Tremaine analyze those findings, using algebra, calculus, and physics as well as numerical analysis and differential equations to draw conclusions about planetary systems.
Astronomy may have few practical applications but according to Tremaine, that may be an advantage. He points out that the “benefits” science offers can be complicated, suggesting that advances such as genetically-modified crops and nuclear power bring us both gains and losses. As “one of the purest sciences,” astronomy tends to be done mainly to satisfy human curiosity. And studying the laws of nature in space can teach us a good deal about what happens here on Earth. As laboratory experiments become very expensive, it can be useful to use astronomical phenomena to explore Earth-bound physics.
