Learn about the tools and techniques that scientists use in their search for signs of life on distant planets, in this video from NOVA Wonders: Are We Alone? Astronomers like MIT’s Sara Seager think that the presence of certain gases in a planet’s atmosphere—including carbon dioxide, water vapor, and methane—would provide the first such sign. Scientists can detect gases from afar by studying the starlight shining through a planet’s atmosphere using a device called a spectrometer. Because different gases interact with light in different ways, each gas produces a unique light signature. NASA’s James Webb Space Telescope is designed to provide astronomers with the most powerful tool yet to detect “biosignatures,” or gases that provide evidence of past or present life. This resource is part of the NOVA Wonders Collection.
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