AstronomyCast 84: Getting Around the Solar System

Astronomers have been cataloging star positions for thousands of years, from the first calculations made by Hipparchus, to the more recent star catalogs made by the spacecraft named after him. This is astrometry; another way to find our place in the Universe.

AstronomyCast 177: Mysteries of the Milky Way, pt. 2

Everything in the Universe is spinning. In fact, without this rotation, life on Earth wouldn't exist. We need the conservation of angular momentum to flatten out galaxies and solar systems, to make planets possible. Let's find out about the physics involved with everything that spins, and finally figure out the difference between centripetal and centrifugal force.

AstronomyCast 176: Mysteries of the Milky Way, pt. 1

Why are some objects in the Solar System bright while others are dim? Much of an object's brightness is caused by its albedo, or how well it reflects radiation from the Sun. If you want to know how big a distant moon, comet, or asteroid is, you've got to know its albedo.

AstronomyCast 175: Mysteries of the Universe, pt. 2

Today we tackle more thrilling mysteries of the Universe. And by tackle, we mean, acknowledge their puzzling existence. Some mysteries will be solved shortly, others will likely trouble astronomers for centuries to come. Join us for part 2.

AstronomyCast 174: Mysteries of the Universe, pt. 1

All finished with the Milky Way, it's time to move on to the biggest mysteries of all. The mysteries of the Universe. Let's wonder about dark matter and dark energy, and the very nature of reality itself.