Sep 3, 2019 - Science

A fingerprint of Earth from space

Earth seen from orbit. Photo: NASA

Scientists have developed a fingerprint of Earth from space that could one day help identify other habitable worlds light-years from our own.

Why it matters: If researchers find a planet that matched Earth's fingerprint — which shows what Earth would look like in infrared if seen by an alien civilization — out there in the universe, it could indicate they've found a habitable world.

What they did: The fingerprint — detailed in a new study published in the journal Monthly Notices of the Royal Astronomical Society — was created by using data collected by the Atmospheric Chemistry Experiment onboard the SCISAT satellite.

  • That data specifically looks at the composition of Earth's atmosphere as sunlight passes through it, revealing methane, ozone and other molecules that could indicate life.
  • The new work shows Earth's fingerprint in infrared light, which could be particularly useful when hunting for habitable exoplanets using the James Webb Space Telescope, expected to launch in 2021.
"The idea is to be able to understand what we were seeing if we were observing an Earth-like planet. Our model of Earth's spectrum as observed with the James Webb Space Telescope is a benchmark to which spectra of other planets can be compared to understand how similar their atmospheres are to ours."
— Evelyn Macdonald, a co-author of the study, to Axios
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