How Do We Learn About An Alien Planet’s Size And Atmosphere?

The fun and challenge of exoplanet science is the planets are so far away and so tiny. Figuring out what they look like isn’t as simple as just pointing a telescope and observing. This new video from NASA explains how astronomers use the parent star to figure out the planet’s size, mass, atmosphere and more.

Alien planets are generally detected through blocking the light of their parent star (from the vantage point of Earth) or through their gravitational effects that cause the star to slightly “wobble” during each orbit. These methods can reveal the mass and size of the planet. As for the atmosphere, that takes a bit more work.

“As the planet crosses its star, its atmosphere absorbs certain wavelengths of light or colors, while allowing other wavelengths of light to pass through,” the video stated.

“Because each molecule absorbs distinct wavelengths, astronomers spread the light into its spectrum of colors to see which wavelengths have been absorbed. The dark absorption bands act as molecular fingerprints, revealing the atmosphere’s chemical makeup.”

And this science can reveal amazing things, such as the recent Hubble find of a “clear signal” of water in five exoplanet atmospheres. The video has more detail on how individual elements are identified, so be sure to check it out.

Elizabeth Howell

Elizabeth Howell is the senior writer at Universe Today. She also works for Space.com, Space Exploration Network, the NASA Lunar Science Institute, NASA Astrobiology Magazine and LiveScience, among others. Career highlights include watching three shuttle launches, and going on a two-week simulated Mars expedition in rural Utah. You can follow her on Twitter @howellspace or contact her at her website.

Recent Posts

Curiosity Rover is Climbing Through Dramatic Striped Terrain on Mars

Just about every day we here on Earth get a breathtaking picture of Mars's terrain…

6 hours ago

A Giant Gamma-Ray Bubble is a Source of Extreme Cosmic Rays

Gamma-ray bursts (GRBs) are one of the most powerful phenomena in the Universe and something…

7 hours ago

New Study Addresses how Lunar Missions will Kick up Moondust.

Before the end of this decade, NASA plans to return astronauts to the Moon for…

2 days ago

How Warm Are the Oceans on the Icy Moons? The Ice Thickness Provides a Clue.

Scientists are discovering that more and more Solar System objects have warm oceans under icy…

2 days ago

NASA Tests the New Starship Docking System

The Apollo Program delivered 12 American astronauts to the surface of the Moon. But that…

2 days ago

China Has Built a Huge Space Simulation Chamber

Well it certainly caught my attention when I saw the headlines  “China’s first Space Environment…

3 days ago