Astronomer Dean C. Hines of the Space Telescope ScIence Institute is using the Hubble Space Telescope to study Comet ISON in polarized light. This technique offers new insight into ISON’s structure and composition – factors that will play a key role in the comet’s eventual fate. We sat down with Dean to discuss his recent results.
ISONblog: Can you briefly explain polarization?
Dean Hines: Sure. Polarization is a property of light that happens most frequently when light scatters off particles like dust or reflects off a surface. We use polarization to tell us about the scattering material or the reflective surface. Different materials will scatter or reflect light differently, and will impart different polarization signatures. If you’re looking at snow with polarized sunglasses, for example, that’s a lot different than looking at the surface of water. You can put on polarized sunglasses, which filter out polarized light, and see the fish in the pond without the glare from the reflected sunlight. But putting on polarized sunglasses when you’re snow skiing reduces the brightness, but doesn’t do much else because the snow doesn’t polarize the scattered sunlight.
When you look at a comet with polarization data, what can you see?