Planetary Atmospheres
Our Work
Center for Astrophysics | Harvard & Smithsonian scientists and engineers study the atmospheres of planets in many ways:
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Observing changes in the atmosphere of the planet we know best. Earth-observation satellites like the TEMPO (Tropospheric Emissions: Monitoring of Pollution) mission study the impact of humans on the atmosphere. That in turn is important for tracking air quality around the globe.
NASA's TEMPO Air Pollution Space Sensor Completed -
Studying dust storms on Mars, which are the biggest weather events on the planet. These storms are ways to track the wind patterns and global atmospheric dynamics, which reveals how Mars changes over the years. It’s also important for possible future human missions to the red planet.
Dust Storms on Mars -
Looking for signs of atmospheres on exoplanets, using a variety of powerful telescopes. Future observatories such as the Giant Magellan Telescope and the James Webb Space Telescope will be able to detect traces of chemicals that might indicate the presence of life, including oxygen and water.
Potentially Habitable Super-Earth is a Prime Target for Atmospheric Study -
Observing interactions between stars and the planets orbiting them. Some stars produce powerful flares, which may damage exoplanet atmospheres, making those worlds uninhabitable. Astronomers can observe such hostile activity using NASA’s Chandra X-ray Observatory.
Star Blasts Planet With X-rays
This artistic rendition of the exoplanet Kepler-35b depicts it as a "water world": a possibly habitable planet covered in water. CfA researchers are collaborating on advanced technology that will analyze the atmospheres of such planets for the chemical signatures of life.
Planetary Atmospheres and Habitability
Earth’s atmosphere is what enables life as we know it to exist, but it was also shaped by life. The particular chemical balance of our air was partly created by organisms over life’s four-billion-year history. Atmospheres on any world reflect the history and evolution of that particular place. Mercury’s thin, wispy atmosphere is a product of its closeness to the Sun, while Saturn’s moon Titan has a thick cold atmosphere that is the result of its mysterious history.
Researchers studying planetary atmospheres look for commonalities as well as unique details between worlds. On Earth, the presence of water has a profound effects on every aspect of the atmosphere, while Mars’ much drier and colder atmosphere produces global dust storms. Planetary scientists have learned Mars was once wetter than it is today, and studying the Martian atmosphere is essential to understanding what changed.
Meanwhile, scientists are identifying some chemical traces in the atmospheres of exoplanets. When those planets cross in front of their host star, a tiny amount of the star’s light passes through the atmosphere. Some of that light can be absorbed by atoms or molecules in the exoplanet air, leaving a distinct spectral signature. That doesn’t tell us the entire chemical composition of the planet’s atmosphere, but it can reveal water or other important molecules. The next generation of telescopes include telescopes specifically designed to look for oxygen, water, and other potential signs of life in exoplanet atmospheres.
Additionally, observers have seen signs of stellar weather affecting exoplanets. Radiation and particles from stars can puff up exoplanet atmospheres and in extreme cases strip the air away entirely. Many known exoplanets orbit active stars, which produce powerful flares. It’s possible that the interactions between stellar weather and planetary atmospheres could prevent life-supporting conditions on worlds in such star systems, even if those exoplanets might seem otherwise habitable.