By Keely Savoie
Mount Holyoke’s Thomas Burbine, visiting lecturer of astronomy and director of the Williston Observatory, spends much of the year in the lab. There he analyzes the mineral composition of asteroids by comparing their light-reflecting properties to that of their earthbound cousins, meteorites.
But in early August, under the dark of night, Burbine leaves the lab and heads for open land to take in the Perseid meteor shower.
The shower happens each year when the Earth’s orbit takes it through a stretch of space dust left behind by Comet Swift-Tuttle, and bits and pieces of the comet debris penetrate the atmosphere and rain down through the night sky in a dazzling display. The particles themselves are typically very small — most range in size from a grain of dust to a small pebble — but when they burn through the atmosphere at speeds of up to 45 miles per second, they create one of the biggest and all-time favorite falling-star showers in the world.
“It’s pretty spectacular,” said Burbine of the celestial show. “Every one that I have seen has been amazing.”
Lucky observers may see fireballs — the larger, brighter streaks from bigger pieces of debris — or bolides, which explode brilliantly in the sky.
This year, the shower is predicted to peak on August 12, at about one meteor per minute. The new moon will set before midnight to make for good viewing conditions. While the early evening viewers may catch a glimpse of earthgrazers — large, slow-moving meteors that move horizontally across the sky — the best time to skywatch is after Mars and Venus have set, about 11:00 p.m. Keep in mind that it takes 20 – 30 minutes for eyes to adjust to the dark.
“If you wait long enough, you will definitely see some meteors,” said Burbine.
While the Perseid meteor shower offers astronomers an opportunity to learn more about comets and meteors, Burbine, who focuses on asteroids, sees the shower as something to enjoy for its own sake.
“These meteors show the relationship between the Earth and space. Stuff enters the Earth’s atmosphere all the time. Luckily, this material is usually very small and rarely strikes the ground,” said Burbine, who is the author of the recently published book, “Asteroids: Astronomical and Geological Bodies.”
In the lab, Burbine is working in concert with Darby Dyar, Mount Holyoke’s award-winning astronomy chair and Kennedy-Schelkunoff Professor of Astronomy, to develop a new taxonomy for asteroids. To help analyze the vast quantities of spectroscopic data that can be used to determine the mineral composition of the asteroids, they will use a process called machine-learning, which tasks computers with the analysis. Ultimately, a better taxonomy of asteroids will improve the process linking these bodies to particular meteorite types.
Burbine also teaches an introductory-level class for newbie skygazers, The Sky, each fall and spring. On clear nights, the class leaves the observatory classroom and uses telescopes to observe the night sky. On overcast evenings, they stay inside and discuss basic principles of astronomy and how celestial bodies move through space and interact with each other.
Burbine has invited interested Perseid meteor shower viewers to join him — weather permitting — in the parking lot of the Williston observatory, starting at 8:30 p.m. August 12, to enjoy the show. No specialized equipment is necessary, just a dark, open space.
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