Remember when we didn't know how the dinosaurs died? Or when the solar system only had nine planets? How about the time everyone thought that Earth was the only planet in the universe? My how far we've come in the past couple of decades. And based the recent pace of new discoveries in the sky, we're about to go much further, much faster.
This week, a team of astronomers announced the discovery of three habitable planets circling a red dwarf in the Gliese 667 star system. They're all larger than Earth, but at roughly twice Earth's size, the smallest of the bunch is "the lowest mass planet in the habitable zone detected to date," said lead astronomer Philip Gregory. This is especially relevant since planets with a larger mass have a stronger gravitational pull, thus a greater risk of humans actually being able to move on the surface.
But you know what the best part is? Gliese 667 and its habitable planets are only 22 light years away, which means there's at least a tiny bit of a chance that we might actually go there one day. That's far, but it's not impossibly far in a universe where most things are measured by hundreds of millions of light years. This is the second time in the last three months that planets have been found close to Earth, too. In October, astronomers discovered an Earth-sized planet circling a star in Alpha Centauri, the closest start system to Earth. Although that planet is not habitable, its discovery combined with the three planets found in the Gliese 667 star system is encouraging astronomers to double down on their effort both to develop better ways to spot planets and, further down the road, to create an interstellar ship.
Neither of these are easy tasks. Most of the discoveries come from using High Accuracy Radial Velocity Planet Searcher in Chile and the orbiting Kepler Space Telescope. Until newer, bigger telescopes are built, astronomers simply calculate the data received in different ways to try to spot a characteristic wobble of a planet. Gregory is a pioneer in this field and actually invented a new technique to locate the planets in Gliese 667. Gregory says that he's not the only one making an effort. "The excitement generated by … many … exoplanetary discoveries has spurred a significant eﬀort to improve the statistical tools for analyzing data in this ﬁeld," he said. So that's a good sign.
Building a spaceship that can make it to another star system is an entirely different story. With our existing rockets, it would take about 100,000 years to get to Alpha Centauri, which would make the trip to Gliese 667 over half a million years long. DARPA is funding an initiative known as the 100 Year Starship in order to develop new technology that could cut the trip down enough that astronauts could reach the star within their lifetime. With funding from the 100 Year Starship project, NASA is developing a warp drive that could take them there. So far, they're still pretty speculative about whether or not warp drives are actually scientifically possible.
So don't get too excited about going alien hunting just yet. However, imagine the possibilities of an entire generation of humans that know our planet is not alone in the universe. And maybe we aren't either.
Image via ESO