The search for Earth-like planets around other stars is one of the great endeavors in modern science. Astronomers have discovered numerous candidates that orbit other stars in the Goldilocks zone where liquid water is likely to exist.
The next step is to study the atmosphere of these exoplanets, looking for evidence that they are Earth-like. The huge distances of these planets, their tiny sizes and the even smaller signatures from their atmospheres make this a horrendously difficult task.
Which is why astronomers are so excited about the James Webb Space Telescope. As the most powerful space observatory ever launched, it has the capability to characterize the atmospheres of exoplanets in the habitable zones of some stars. But it can only do this by spending huge amounts of time gathering the necessary light.
