Earth seen from orbit at night. Photo: NASA
The Hubble Space Telescope observed Earth as future tools could one day see a distant, alien planet.
Why it matters: These kinds of analogous experiments using Earth in place of an exoplanet (a world orbiting another star) give scientists a chance to see what a habitable planet may look like through telescopes if one is eventually found.
What they did: Researchers used the Hubble Space Telescope to observe the Earth during a total lunar eclipse, allowing the storied telescope to detect ozone, a gas thought to be key to the evolution of life, in our planet's atmosphere.
- The scientists behind the observations — detailed in a study due to be published in the Astronomical Journal — used the Hubble to look at light that had been filtered through Earth's atmosphere reflected from the Moon.
- That allowed the researchers to parse out the makeup of our planet's atmosphere in much the same way as future missions could when observing a planet passing across the face of its star.
- "We want to make sure we know what the Earth, the only habitable and inhabited planet we know of, looks like using the same methods astronomers use for exoplanets," Allison Youngblood, one of the authors of the new study, told me via email.
What's next: Scientists don't yet have the tools in orbit to confirm the discovery of a habitable planet orbiting a distant star, but future missions could one day confirm another Earth-like planet out there in the galaxy.