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At a glance

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.

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

Your recent contributions to our exoplanets research have directly advanced space science and exploration:

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?

In 2020, our members and supporters helped us buy Debra Fischer’s team a new $25,000 photonic crystal fiber (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. Unfortunately, the cable degrades with every use, and had to be replaced. We couldn't have done this without you—thanks!

You can learn more about why and how we search for exoplanets, and help us advocate for WFIRST, NASA’s next exoplanet mission. Visit our exoplanets page to learn more:

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