Vesta is one of the larger asteroids in the asteroid belt. It is the third largest (about 500 kilometers wide), but the second most massive (after Ceres). It is also the only large asteroid for which we have high resolution data, when the Dawn spacecraft orbited it for a while in 2012. You can see a view of Vesta in …
Cosmic Corn Syrup
Previously I showed how you can use polarizing filters and corn syrup to demonstrate the rotation of polarized light. So what does corn syrup have to do with astrophysics? It turns out that visible light isn’t the only thing that can be polarized. Radio waves can have polarization as well. It also happens that the radio pulses generated by pulsars …
Rock On
You might think that meteorites are all very similar, simply being rocks from space, but actually meteorites are quite varied. Their physical and chemical makeups tell a distinct story about their origin and history, and we can even identify some as originating from Mars or the Moon. Meteorites are divided into four broad categories: chondrites, achondrites, pallasites and iron meteorites.
Color and Light
I’ve already discussed polarization of light and how it can be used to determine the position of the Sun, even on a cloudy day. This works because sunlight is polarized when it scatters in the air. There are lots of materials that can affect the orientation of light. One of the more interesting effects can be seen with corn syrup …
Variable Variables
Yesterday I talked about how Henrietta Leavitt discovered the period-luminosity relation for Cepheid variable stars, and how that allows us to determine the distances of galaxies. You can see this relation in the image below, which plots the brightness of several Cepheid variables versus their period. As you can see, there is a simple relation between them. Since Leavitt’s discovery …
Astronomy Rocks
Recently the popular science press has heralded the discovery of a legendary Viking Sunstone. The sunstone is mentioned a few times in Medieval Icelandic literature, where it was claimed that it could be used to determine the position of the sun on cloudy days, and even at twilight after the sun has set. Not being an archeologist, I can’t comment …
After the Ecstasy, the Laundry
Often in science we talk about the latest sexy findings. The discovery of the Higgs boson, the minute by minute coverage of comet ISON, the most Earth-like planet around another star. Given all that attention, you might imagine that as an astrophysicist I spend my days playing with multi-million dollar space telescopes. What I actually do is analyze data and …
Astronomy at Home
Einstein@Home is a distributed computing program you can download to your personal computer. It was originally intended to search through LIGO data for gravitational waves, but in 2009 it also began searching through radio data from Arecibo radio telescope to look for radio pulsars. While the LIGO data hasn’t yielded any gravitational waves, the radio data has detected more than …
Scales of Magellan
One of the big challenges in astronomy is determining cosmic distances. There are lots of ways we can do this, including things like Type Ia supernovae, brightness changing stars called Cepheid variables, parallax, etc. Each method has advantages and disadvantages, and each has certain inherent uncertainties. To minimize these uncertainties, we try to find objects we can measure in multiple …