A new "super-Earth" was just discovered in the constellation Cetus some 40 light-years away. This newfound planet could be Earth’s big brother. It’s roughly 40 percent larger than our world.
OK, you say, so what? Thousands of exoplanets have been found in the past decade. True, but this one has been called "the best candidate in the search for signs of life." And that sounds pretty special.
But before you start high-fiving strangers or wagering with your significant other that we’re about to hear from the little gray guys, consider the bigger picture. When should we get excited about progress in the search for alien life — and when should we merely note the story and return to those cat videos?
Let’s ask why this new planet, designated LHS 1140, is touted as the top candidate so far in the hunt for alien life. Does it have big oceans? A thick atmosphere? Or more real estate for the Klingons to grow their veggies? We don’t know. All we know is that LHS 1140 is well situated for follow-up studies that would give us a chance to find out.
This is a bit like finding a nearby island in the Pacific Ocean where pirate treasure could be buried. Because the island’s conveniently located, it’s easier to mount a search there. But convenience doesn’t make it the most likely place to be sheltering a steamer trunk stuffed with swag.
While the discovery of LHS 1140 is remarkable, this bulked-up Earth simply hasn’t yet yielded its secrets. And as you may know, the rate of exoplanet discovery is increasing. Planets similar in size to Earth are beginning to dominate the statistics, just the way Honda Civics dominate parking lots. So let’s resist the temptation to get into a Twitter fight about whether this new super-Earth is the best candidate or not. Your satisfaction will be temporary, as new contenders are coming down the pike faster than greased weasels.
Also, keep in mind that finding a cousin of Earth doesn’t guarantee that it harbors sentient beings. Anyone could have monitored our planet for 99.999998 percent of its 4.5-billion-year existence without picking up any signs of intelligent life — because humans didn’t start sending out radio waves until a century or so ago.
Finding extraterrestrials is a process, like traveling along the yellow brick road. LHS 1140 is another brick in that road and, of course, represents progress. But what’s really exciting is to occasionally find a shortcut, a detour that might get us to Oz faster.
Planets similar in size to Earth are beginning to dominate the statistics, just the way Honda Civics dominate parking lots.
Take Tabby’s star, for example. It’s an oddball object that occasionally dims by more than 20 percent, and it’s been in the news for more than a year now. So far there is no good explanation for this remarkable darkening, although by far the most intriguing possibility is that this sun is encircled by an alien megastructure (a so-called Dyson sphere) that occasionally blocks some of its light.
Unlike the discovery of a new exoplanet, this is something out of left field — a possible shortcut to Oz.
The same is true of fast radio bursts — brief pings of radio waves and light that seem to come from deep space. Could FRBs, which astronomers have been observing for a decade and more, be some sort of signaling by intelligence in faraway galaxies, with energy resources beyond our ken? And what about the X-ray burster CDF-S XT1, recently found by NASA’s Chandra X-Ray Observatory? Is someone out there trying to get in touch by flashing the cosmos with extremely short-wavelength radiation?
While it takes industrial-strength imagination to reason that these strange objects are indicators of intelligence and not just natural phenomena, we’ll never make a big discovery by focusing only on the tried-and-true. As Isaac Asimov wrote, the most exciting thing to hear in science is "that’s funny."
Having tried to sell you on the idea of paying attention to phenomena that are not just one more duck in a row, but entirely new quackers, I’ll now offer what is, to my mind, the most enticing of the new discoveries, at least from the standpoint of finding intelligence beyond Earth: the TRAPPIST-1 system.
There are seven known planets in this relatively nearby stellar system, and all are roughly the size of Earth. At least three of them are at a distance from their sun that would allow Earth-like oceans and temperatures. But these worlds are all very close together. With a good rocket, you could go from one to the next in less time than it would take to drive from Chicago to Miami.
So consider: TRAPPIST-1 offers not one, but at least three opportunities for life to arise. And if any of them has sprouted biology, the planets are so close to one another that the neighbors are probably "infected" too. Even microbes could migrate from one world to the next inside rocks kicked up by meteor strikes. Any intelligent life would be able to easily colonize all seven of these planets.
But, you may say, this is just another exoplanet system — so why the excitement? Ah, but this is the first case where we might hope to find not just one world covered in biology, but an entire multi-world ecosystem, maybe even a small "federation of planets."
Now that’s a really different quacker.