An artist’s illustration of the TRAPPIST-1 planetary system
One thing from this unit I found interesting was learning about extrasolar planets. The Hubble Space Telescope was the first to detect an exoplanet’s atmospheric conditions and collect data about its makeup. In 2000, Hubble was used to study the exoplanet 209458 b which was the first extrasolar planet that was known to make transits across its host star.
One notable discovery by Hubble is the TRAPPIST-1 planetary system which contains seven Earth-sized planets. All seven of the planets orbit closer to the host star than Mercury orbits our Sun! The planets are also orbiting very close to each other. This means that if you are standing on any given planet, it is possible that you could see clouds or geological features on the neighboring planets!
The TRAPPIST-1 system compared to our solar system
Since the TRAPPIST-1 star is an ultra-cool dwarf, it is possible that liquid water could survive on some of the planets. Planets e, f, and g are in the habitable zone, which is where temperatures are optimal for liquid water to exist on the worlds’ surfaces.
Angela Harris 
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