Episode for August 4th, 2023 Download

We are a species of wonder. We have always looked up at the stars and wondered if we are alone in the universe. Are there other worlds out there, with other beings who look up at the stars and wonder about us?

The search for exoplanets is our best chance of finding out. Exoplanets are planets that orbit stars other than the Sun. They are incredibly faint compared to their parent stars, but scientists have come up with some clever methods to find them.

One way is to measure the radial velocity of a star. This is the speed at which the star is moving towards or away from us. If a planet is orbiting the star, the gravitational pull of the planet will cause the star to wobble a little bit as it goes around. This wobble can be detected by looking at the movement of the spectrum of the star, measuring the star’s radial velocity.

Another way to find exoplanets is to look for transits. This is when a planet passes in front of its star, blocking out a little bit of the star’s light. As the planet passes in front a tiny dip in brightness of the star is measured by very sensitive telescopes. The amount of light blocked by the star gives us important information, such as the size of the planet, it’s distance from the star as well as the length of time to complete one orbit around the star.

Recently, it has become possible to use direct imaging to find exoplanets. This requires some of the best telescopes ever built and very sophisticated processing techniques, but optics, detectors and computer software have become so good that we can actually see the planets themselves. This is the most difficult method of finding exoplanets, but it’s the only way to see what they actually look like.

Microlensing is also used by astronomers to look for the temporary brightening of a star caused by the gravitational lensing of a passing planet. As a relatively dark planet passes in front of a star, its gravitational field causes the star to brighten as the light passes by. This brightening is very small, but it can be detected with sensitive telescopes.

There are a few other methods that scientists use to find exoplanets, but these are the most common. As technology improves, we’re likely to discover more and more exoplanets using a variety of methods.

So far, scientists have discovered over 5,000 exoplanets. And they’re finding more all the time. We’re learning that there are all sorts of exoplanets out there, from gas giants to rocky worlds that could potentially support life.

The search for exoplanets is one of the most exciting and inspiring quests in human history. And who knows what we might discover in the years to come? We might find Earth-like planets that could potentially support life. We might even find evidence of extraterrestrial intelligence.

The search for exoplanets is a search for our place in the universe. It’s a search for our destiny.