Over the past two decades, astronomers have discovered a veritable glut of planets orbiting stars other than our Sun. Thanks to the way we have detected these exoplanets, many of them are so-called hot Jupiters – being significantly larger than the Earth and orbiting close to their parent stars. But exoplanet discoveries are now coming thick and fast, and we are starting to discover planets that are increasingly more Earth-like and orbiting their stars closer to the “Goldilocks zone” where it is possible for liquid water to be maintained.
In this short explainer video, the astronomer Sara Seager of the Massachusetts Institute of Technology (MIT) explains how we can look for some of the telltale signs of life on these planets. She explains that by examining the starlight coming from their planetary systems, we can infer some of the constituents of the exoplanet atmospheres by looking for signatures within the spectra. The study of planetary atmospheres in this way will be greatly enhanced by the instruments aboard the James Webb Space Telescope (JWST), which is set for launch in 2018.
Seager spoke in more depth about the search for life beyond the Earth in the July edition of the Physics World podcast series. Our next podcast – available later this month – is an interview with the astrobiologist Lewis Dartnell, who talks about what life beyond the Earth might actually be like.
