Probing the Earth from Astronomical Distances

Dr. Darren Williams is a Professor of Astronomy and Astrophysics, and Planetary Science at Penn State Behrend in Erie Pennsylvania. As a teen, he started his future career endeavors as an astronomy hobbyist right here at the Martz Kohl Observatory. In addition to teaching, Dr. Williams studies the climates, orbits, observable characteristics, and dynamical evolution of planets and satellites. He is perhaps best known for his innovative work on the formation and habitability of exoplanetary moons, as well as the climates of Earth-like planets with unusual spins and orbital shapes. His present work is on the final stages of planetary accretion, and designs for a new miniature space telescope (The Pale-Blue-Dot Telescope) to remotely observe terrestrial planets at sub-pixel resolution.

This presentation asks the question, “What would Earth look like to someone light years away? Would it be a featureless blue dot, or could we possibly see oceans, snow and ice, forests, or even cities through the clouds?” The answer to this seemingly benign, academic question is what astronomers are considering in their efforts to collect and interpret the light from distant exoplanets. Today, hundreds of Earth-sized exoplanets are known but are too far and too faint to “see” even with current advanced telescopes. But futuristic telescopes will literally photograph their targets and be used to determine their sizes, spin properties, and atmospheric compositions. In addition, astronomers should be able to distinguish between worlds with water, like Earth, from planets without, like Mercury or Mars, from a single pixel of an unresolved planet.

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