The Europa Clipper mission represents NASA’s first mission dedicated to exploring an ocean world within our Solar System. Covered in exterior ice and with a strongly suspected worldwide ocean beneath it, Europa is one of the best candidate worlds for life of extraterrestrial origin. (Credit: NASA/Jet Propulsion Laboratory-Caltech)
Could life be widespread throughout the cosmos, in the subsurface oceans of ice-covered worlds? NASA’s Europa Clipper mission investigates.
With such large numbers of planets, moons, stars, and galaxies present within the observable Universe — so many of which have been confirmed to have similar raw ingredients to those found in our own Solar System — it seems inevitable that alien life must be out there somewhere. How are we going to find it? In general, there are two main methods that astronomers are leveraging today.
SETI, and SETI-like efforts, that look directly for signals, largely in the radio portion of the electromagnetic spectrum, that could potentially indicate the presence of intelligent extraterrestrials. Any signal of a non-astrophysical origin, or that shows characteristics of it willfully being sent Earthwards, would be revolutionary.
Similarly, astronomers using methods like direct exoplanet imaging or transit spectroscopy could reveal potential biosignatures, or at least what we might more responsibly call “bio-hints,” that would leave their mark on an inhabited planet’s atmosphere.
However, there’s a third method that’s generally underappreciated: looking up close…