Olympic biathlon: Watch the Snow Queen’s Pee-Wow Party #PyeongChangin2018 pic.twitter.com/2OvJZjcEyc — ⒜The Olympians⒜ (@Olympians) February 12, 2018
“Search for Life on Other Planets” could be an even better headline for this column. We’ve been saying it for years, and so far not one other article has ever bothered to say it, but it’s probably the first sentence we’ll write every time a new planet is announced.
Over the years, there have been more and more developments in the search for exoplanets, worlds outside our solar system that have some form of atmosphere or conditions conducive to liquid water. Several thousand planets have been found so far. They are less dense than Earth and possible for liquid water to exist, so planets with life on them would be no less likely to have evidence of life elsewhere in the universe.
When we first thought about the search for life beyond Earth, however, we knew that planets much smaller and harder to analyze than Earth would be considered prime candidates. That’s an important distinction to understand.
The most famous example is the planet HD 189733b, a star far less massive than our sun, only 30 percent as bright, and not even in the star’s habitable zone. But this same star also produces five other planets in a system with a similar mass to our own: the Kepler-61b, Kepler-62e, Kepler-62f, Kepler-62j and Kepler-62k. No Earths on them, but all of them are believed to be rocky, maybe even have lakes of water.
These planets are exactly the type of distance between us and the sun we need to look for life, a one- or two-light-year trip. They’re just about not planets we know of, but the ones we’d find most likely to support life if there were life out there.
These weeks’ news is even more intriguing, but not the kinds of planets we’d expect to be the easiest to find. They’re hundreds or thousands of light-years away in distant stars. The closest to home is the second planet from the bright star KIC 8462852.
Scientists came upon it in December, finding thousands of small craters on the surface. In the center of each crater was a massive meteorite that hit the planet, filling in the hundreds of craters in its skies. This likely happened at least 2 million years ago, putting it back long before any planet was discovered by any other telescope.
We’ve had telescopes launched to study stars and galaxies, and they have been finding planets around them as well. Among the best are the Spitzer and Hubble Space Telescopes. They’ve been watching closely and producing portraits of stars and galaxies billions of years old.
They’ve been confirming planets around our own solar system, discovering our own white dwarf and studying the evolution of our own sun. As Spitzer pointed out in 2015, the gravitational pull of our sun could cause bits of our sun to fly off into space, potentially making our solar system a multi-planet system for future generations.
That may be happening already. The planet HD 212932 b, discovered only a few months ago, may be hanging around our solar system as a part of its twin, HD 212932 d. Meanwhile, a team of American and French scientists has discovered how strong the pull of the sun is on a planet we thought we already knew. The dwarf star Fomalhaut is perfectly different from our sun, giving it lots of moons to give it a Neptune-like gravity. Why is it so different? Because of the pull of the sun. Its giant atmosphere is strong enough to dislodge the moons within its orbit, creating planets that look much like those we already know: Jupiter and Saturn. If they exist at all, our Jupiter and Saturn are just a single planet.
So yes, there’s clearly more to say about these exoplanets. And yes, it’s definitely time to write about it more.