The Universe Tonight
Dr. Bobby Bus
from NASA Infrared Telescope Facility
The Asteroid-Meteorite Connection
Only 30 years ago, asteroids were considered by most astronomers to be "space junk" - leftover pieces from the formation of the larger planets in our Solar System. Some astronomers even referred to asteroids as "vermin of the sky", since their moving star-like appearance would often contaminate scientific observations of more distant stars and galaxies.
Today, those who study the Solar System have found a much deeper appreciation for asteroids, recognizing them not as "junk", but as containing the earliest records of the Solar System. Most asteroids circle the Sun in orbits located between those of the planets Mars and Jupiter, in a region called the Main Belt. However, over time, different forces have been at work that have sent pieces of asteroids from the Main Belt into orbits that bring them much closer to Earth. Sky surveys are discovering these near-Earth asteroids at an ever-increasing rate, and monitoring their orbits as a way of estimating the potential impact hazard they pose to Earth.
Along with the near-Earth asteroids, a multitude of very small fragments are also in orbits that bring them near the Earth, and which occasionally collide with Earth, falling harmlessly to the ground in the form of meteorites. These meteorites are samples from the main belt asteroids that have been delivered to Earth at no cost (thanks to physics), and which can be studied in detail in our laboratories. By studying the chemistry and geologic makeup of meteorites, we can set important limits on the timing, composition and temperatures at different stages throughout the formation of the Solar System. To gain as much information as possible from meteorites, it is important to understand which meteorites came from which asteroids. This is not an easy task, and is one that requires both space missions to selected asteroids and ground-based telescopic studies of large numbers of asteroids.
One of the major roles for the NASA Infrared Telescope Facility is the physical study of asteroids. In this talk, I will describe the kind of observations we can make from the ground, and what we currently know (and, more importantly, don't know) about the Asteroid-Meteorite Connection.
Bobby Bus is an associate astronomer with the University of Hawaii's Institute for Astronomy. He received his PhD in planetary science from MIT in 1999, and began his work with IfA in 2000 as a support astronomer for the NASA Infrared Telescope Facility. As part of his duties with the IRTF, Bobby helps manage the day-to-day operations of the telescope and interacts with astronomers from around the world who observe with the IRTF instruments. His research interests focus on understanding the formation and evolution of asteroids in our Solar System. These small bodies hold many exciting clues about how the Solar System began, and how it has changed over the past 4.6 billion years.
On the first Saturday of each month, the Visitor Information Station (VIS) hosts The Universe Tonight, a special presentation on the current research and discoveries occurring on Mauna Kea. The presentation begins at 6:00 PM and is followed by the regular evening stargazing program at the VIS.
The Universe Tonight typically features an astronomer from one of the observatories on Mauna Kea giving a presentation on recent observations and discoveries from their telescope. Observatories are on a rotating schedule. If you would like to know about upcoming presentations, please call the VIS at (808) 961-2180 during operational hours.