~The Kepler Space Observatory has had a very busy and exciting last couple of years. By detecting the infinitesimal dimming of distant stars as objects cross in front of them from our perspective, it’s been able to locate thousands of potential planets orbiting other stars.
Most of these planets are “Hot Jupiters” -- massive gas giants orbiting very close to their primary stars – presumably because with their rapid revolutions and large sizes, they’re the easiest to detect. However, a number of these planetary candidates have been found in the fabled “goldilocks zone”: an area of the stellar system where liquid water can exist. Even more exciting is that some of those planets are “Earth-like”.
Don’t get too excited: in this case “Earth-like” means that the planet is small and rocky, as opposed to large and gaseous. Still, the prospect of liquid water on a planet in the habitable zone is both thrilling and tantalizing. Here’s a handy chart of planetary candidates found by Kepler so far, sorted by sizes and distances (that is, distances from the star they orbit):
For a more complete breakdown of the potentially-habitable planets, check out the website of the Planetary Habitability Laboratory at the University of Puerto Rico at Arecibo (yes, that Arecibo). Although you can find an explanation for what the data in each column means by looking at the bottom of this page, the key measurement is the last one: the ESI, or Earth Similarity Index, which combines and weighs all the numbers to estimate how similar the planet is to Earth.
Look how many there are over 0.90 (90%)…how exciting! Hopefully the James Webb Space Telescope and other future space observatories will be able to discover more about them.
