Our Exoplanets Projects

Helping scientists search for 100 Earth-like planets around other stars

At a Glance

  • Exoplanets are planets orbiting other stars. To find Earth-like exoplanets, we need new, revolutionary technologies.
  • 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.
  • Thanks to our members and supporters, Fischer's team is replacing a piece of telescope equipment needed to help search for 100 Earth-like exoplanets.

The Challenge

Somewhere in the cosmos—possibly even in our stellar neighborhood—there could be a planet that supports life as we know it. Finding this hypothetical Earth 2.0 would change the course of human history, regardless of whether it hosted bacteria or sentient beings.

Finding Earth-like planets is difficult. Our own Sun is so huge, more than 1 million Earths could fit inside it. Consider that the next time you stare up at a starry sky: Scientists searching for exoplanets are searching for worlds a million times smaller than those tiny pinpricks of light.

Your Guide to Exoplanets

We know of more than 4,000 planets orbiting other stars. Does one of them host life as we know it?

So far, we've found about 4,000 exoplanets, but the majority of those are big worlds like Neptune and Jupiter. We only know of about 160 planets that are Earth-sized or smaller, which we think is a prerequisite for finding an Earth-like planet. Of those, just 20 or so may have the potential to support life as we know it. 

Fortunately, exoplanet research technologies are improving. Multi-billion-dollar observatories like the James Webb Space Telescope and the Giant Magellan Telescope will greatly advance our understanding of other solar systems. But to find more Earth-like exoplanets, we need more advanced technologies—some of which need seed funding to grow.

How are we helping?

Since 2009, The Planetary Society has spent more than $100,000 helping Yale University astronomer Debra Fischer and other scientists improve exoplanet-hunting technologies. One of Fischer's specialties is a technique called radial velocity measurements. Here's how it works: even though a planet is minuscule in comparison to a star, a planet’s gravity gently pulls a star in its direction as it orbits, making the star wobble. By measuring these star wobbles, scientists can infer that a planet is present.

The smaller the wobble speeds we can detect, the smaller the planets we can detect. The wobble speeds caused by Earth-size planets are just a few tens of centimeters per second—we’re talking turtle-like speeds! At those scales, you need ultra-precise telescope instruments that can be calibrated to filter out false readings.

In 2009 we supported a device called FINDS that was able to filter out radial velocity data errors by 30 percent, and search for planets around nearby Alpha Centauri. Then in 2014 we funded Exoplanets Laser, a calibration system used to fine-tune exoplanet-hunting instruments even further. These projects led to Fischer's team getting a National Science Foundation grant to build EXPRES, a precision exoplanet-hunting instrument installed on the Lowell Discovery Telescope in northern Arizona. 

Your Impact

The Planetary Society's members provided more than $150,000 in contributions to directly support exoplanet discovery and research:

Fischer's teams are now on a quest to find 100 Earth-like exoplanets. They're getting so good at recording star wobbles that they have to account for the natural fluctuations in stars' surfaces. Although stars appear round from a distance, their surfaces consist of turbulent, boiling gas that moves enough to interfere with radial velocity measurements. Fischer and her colleagues are using a solar telescope to study both our Sun and other stars to learn how to account for these fluctuations.

What can you do to advance our exoplanets research?

Thanks to our members and supporters, Fischer's team is replacing a piece of telescope equipment needed to help search for 100 Earth-like exoplanets. We raised $42,000 to buy a new Photonic Crystal Fiber, or PCF. 

It may sound like science fiction, but a PCF isn’t what powers lightsabers in Star Wars. A PCF is an ultra-sensitive cable used to transport light. Fischer’s teams are using it to send light from the Lowell Discovery Telescope and a solar telescope into the exoplanets laser calibration device that grew out of research Planetary Society members helped fund in 2014. The cable degrades with every use, and we raised the funds to help replace it. Thank you, members and supporters!

You can also help us support exoplanets research by learning more about how and why we search for exoplanets, and becoming an informed, engaged space advocate.

Your Guide to Exoplanets

We know of more than 4,000 planets orbiting other stars. Does one of them host life as we know it?

Three ways you can be a space advocate

  • Sign up for The Downlink, our weekly toolkit that contains news, announcements, and actions you can take to support space science and exploration.
  • Take our Space Advocacy 101 course to learn the inner works of NASA, how Congress develops space legislation, and how to engage with your elected officials.
  • Share this page with a friend, spread the word on social media, and tell others about the importance of knowing the cosmos and our place within it.