How do we figure out if a planet in the habitable zone is, in fact, habitable? Or inhabited? Imagine what our Sun and Earth would look like from a few hundred light-years away. Using our present-day technologies, you might be able to determine that Earth is a small, rocky planet that sits in the Sun's habitable zone.

Next, you could look for signs of water in the Earth's atmosphere, to rule out it wasn't a dry, desert planet like Mars. Our current technologies are just barely capable of doing this, while upcoming ground and space-based observatories will be able to do it even better.

By then, you might be able to conclude Earth was habitable. But to tell if there was actually life on the surface, you'd need to find gases in the planet's atmosphere like ozone that are possible byproducts of life. Our current and near-future telescopes won't be able to do this, but several proposed space telescopes might.

Even then, you probably wouldn't be able to say for certain that you'd found life. Ultimately, it could take something like a telescope that uses our Sun's gravity as a giant lens to capture a sharp picture of an exoplanet and see signs of life on the surface. This may sound impossibly futuristic, but the technology is not beyond our reach.

What can you do to advance exoplanet research?

Since 2009, Planetary Society members have supported work by Debra Fischer, one of the world's top exoplanet researchers. These projects have greatly improved our ability to search for Earth-like exoplanets.

We've been working with Fischer on exoplanet projects since 2009. People like you helped us fund FINDS, a new instrument to detect tiny star wobbles caused by orbiting Earth-sized exoplanets, and Exoplanets Laser, a cutting-edge telescope calibration system. We also supported a search for exoplanets around Alpha Centauri, the closest star system to Earth.