Episode for July 24th, 2023 Download

Did you know that the discovery of other planets in orbit around other stars is a very recent one?  Only 25 years ago, we had no idea there were any planets in our galaxy besides those in our solar system.  Now, not only have we discovered them, but astronomers estimate there are trillions of them.  There are so many exoplanets out there that every star in our galaxy could have at least one.

Of course, not every star has a planet in orbit around it.  Some stars have no planets, others can have 3, 4, 9, 10 or more.

So far, astronomers have confirmed over 5,000 exoplanets and there are many different kinds:  there are hot Jupiters - large, massive planets that dwarf even our own Jupiter, Neptune-like planets that are similar to Uranus or Neptune, Super-Earths - large, rocky planets more massive than the Earth with gravity that would squash the strongest human, and Terrestrial planets, small, rocky worlds about the size of Earth or smaller.

Of all these types of exoplanets, the most common found so far are the Super-Earths.  These are rocky planets that are between two and up to ten times the mass of our planet.  We find most exoplanets by measuring dips in brightness from the star when the planet blocks light as it passes between the star and the telescope.  Because of this technique, we may be preferentially seeing more of this type of planet than others.  We need to keep looking.

One thing is certain however: ever since we’ve been looking for these distant planets around other stars, we’ve discovered that they are everywhere.