Josh Wynn

This is the beginning of the next big phase of exoplanet discovery. A few years from now, we're going to be in a position to use this technique to find potentially thousands of new exoplanets, and they're going to be different from the ones that we already know about.

Sure. We have two main methods that have led to most of the discoveries. As of today, there are about 5,800 known exoplanets.

Sure. We have two main methods that have led to most of the discoveries. As of today, there are about 5,800 known exoplanets.

Sure. We have two main methods that have led to most of the discoveries. As of today, there are about 5,800 known exoplanets.

And about 4,000 of them come from a very clever trick, which is based on eclipses. If a planet's orbit happens to carry it directly in front of the star that it orbits, then it will block a little bit of that star's light. And we can tell because the star appears to get slightly fainter for a few hours. That's called the transit method. We say the planet is transiting across the star.

And about 4,000 of them come from a very clever trick, which is based on eclipses. If a planet's orbit happens to carry it directly in front of the star that it orbits, then it will block a little bit of that star's light. And we can tell because the star appears to get slightly fainter for a few hours. That's called the transit method. We say the planet is transiting across the star.

And about 4,000 of them come from a very clever trick, which is based on eclipses. If a planet's orbit happens to carry it directly in front of the star that it orbits, then it will block a little bit of that star's light. And we can tell because the star appears to get slightly fainter for a few hours. That's called the transit method. We say the planet is transiting across the star.

But the transit method, while it's a wonderful technique, it has the serious problem, which is that it requires a very special coincidence for the orbit to be oriented just right so that from our vantage point, we see these eclipses.

But the transit method, while it's a wonderful technique, it has the serious problem, which is that it requires a very special coincidence for the orbit to be oriented just right so that from our vantage point, we see these eclipses.

But the transit method, while it's a wonderful technique, it has the serious problem, which is that it requires a very special coincidence for the orbit to be oriented just right so that from our vantage point, we see these eclipses.

And so it misses most of the planets that are out there.

And so it misses most of the planets that are out there.

And so it misses most of the planets that are out there.

That's right. So if there are aliens viewing our solar system from every possible direction, only one out of 200 of them would ever see the Earth go directly in front of the sun.

That's right. So if there are aliens viewing our solar system from every possible direction, only one out of 200 of them would ever see the Earth go directly in front of the sun.

That's right. So if there are aliens viewing our solar system from every possible direction, only one out of 200 of them would ever see the Earth go directly in front of the sun.

Now, the second best method, and really the first one that worked in the mid-1990s, is based on sensing the motion of the star. And we can detect the motion of the star using a trick called the Doppler effect.

Now, the second best method, and really the first one that worked in the mid-1990s, is based on sensing the motion of the star. And we can detect the motion of the star using a trick called the Doppler effect.

Now, the second best method, and really the first one that worked in the mid-1990s, is based on sensing the motion of the star. And we can detect the motion of the star using a trick called the Doppler effect.

Now, the term Doppler probably rings a bell because of a Doppler radar that's used to measure the speed of a car or the speed of raindrops falling from the sky. It's the effect that you get whenever you have a source of waves that's moving relative to the observer, and light is a wave.