Seager, 47, is an astrophysicist. Her specialty is exoplanets , namely all the planets in the universe except the ones you already know about revolving around our sun. On a blackboard, she has sketched an equation she thought up to estimate the chances of detecting life on such a planet. Beneath another blackboard filled with more equations is a clutter of memorabilia, including a vial containing some glossy black shards. Seager speaks in brisk, uninflected phrases, and she has penetrating hazel eyes that hold on to whomever she is talking to.
She explains that there are planets known as hot super-Earths whizzing about so close to their stars that a year lasts less than a day. Hence, the melted rock. The very first exoplanet found—51 Pegasi b, discovered in —was itself a surprise: A giant planet crammed up against its star, winging around it in just four days.
Today we have confirmed about 4, exoplanets. The majority were discovered by the Kepler space telescope , launched in But its ultimate purpose was to resolve a much more freighted question: Are places where life might evolve common in the universe or vanishingly rare, leaving us effectively without hope of ever knowing whether another living world exists?
With a minimum of billion stars in the Milky Way , that means there are at least 25 billion places where life could conceivably take hold in our galaxy alone—and our galaxy is one among trillions. The question is no longer, is there life beyond Earth? The question now is, how do we find it? The revelation that the galaxy is teeming with planets has reenergized the search for life. A surge in private funding has created a much more nimble, risk-friendly research agenda.
NASA too is intensifying its efforts in astrobiology. Most of the research is focused on finding signs of any sort of life on other worlds. But the prospect of new targets, new money, and ever increasing computational power has also galvanized the decades-long search for intelligent aliens.
Like Kepler, TESS looks for a slight dimming in the luminosity of a star when a planet passes—transits—in front of it. Every chemical compound absorbs a unique set of wavelengths of light. We see leaves as green, for instance, because chlorophyll is a light-hungry molecule that absorbs red and blue, so the only light reflected is green.
Covering most of the wall over her vision table is a panel of micro-thin black plastic shaped like the petal of a giant flower. Guyon grew up in France, in the countryside of Champagne. When he was 11, his parents bought him a small telescope, which he says they later regretted.
He spent many nights peering into it, only to fall asleep the next day in class. When he outgrew that telescope, he built a bigger one. But while he could magnify his view of heavenly objects, Guyon could do nothing to enlarge the number of hours in the night. Something had to give, so one day when he was a teenager, he decided to do away with sleep almost entirely.
At first he felt great, but after a week or so, he became seriously ill. Recalling it now, he still shudders. At 43 years old, Guyon today has a very big telescope to work with. Operated by the National Astronomical Observatory of Japan, the telescope has no affiliation with the car company—Subaru is the Japanese name for the Pleiades star cluster.
The proximity allows him to make frequent trips to test and improve the instrument he built and attached to the telescope, often working through the night. He carries around a thermos of espresso, and for a while he took to spiking it with shots of liquid caffeine, until a friend pointed out that his daily intake was more than half the lethal dose. Then you start forgetting to call your family.
Like Seager, Guyon is a MacArthur winner. Are there continents? Oceans and clouds? All these questions can be answered, if you can extract the light of a planet from the light of its star. In other words, if you can see the planet. Then, on 15 August, , another SETI program recorded a brief radio signal coming from the direction of Sagittarius.
But listening for ET to phone home is a bit like standing by the payphone, waiting for the phone to ring. Maybe we have to make the first move. Drake tried this too, sending a radio message towards globular star cluster M Known as the Arecibo message, it showed potential aliens our DNA structure, solar system and some of the biochemicals of earthly life.
We also tried sending aliens a greeting onboard space probes Pioneer 10 and 11, which included images of humans and directions to our planet. Then, in , we sent a more ambitious message, full of audio and images, on board the Voyager probes. We even included a mixtape of some of our favourite tunes, including Bach, Beethoven, Louis Armstrong and Chuck Berry , to impress any friendly lifeforms — or at least the ones with ears.
By now aliens might know quite a lot about us — including what we need to survive and how to reach us. Worse still, these bears might have planet-destroying interstellar missiles.
Putting aside the question of whether we should try to contact aliens, are we even doing it right? Since we have not been able to detect alien life or leave the solar system much, for that matter , how far are we from being caught up in some event that would bar us from ever finding aliens? In other words, the more life there is in the cosmos, the greater the likeliness that we are about to reach a cataclysmic, life-ending event or reach the cosmic limits of technological advancement.
The researchers argue that the laws of thermodynamics directly limit computation, as computing technologies need to be cooled in order to function. This makes it exceedingly difficult to create advanced technologies, as keeping them cool at scale quickly becomes prohibitively difficult. So the aliens are falling into a dormant until, to be blunt, the universe cools. But distilling the development of a civilization to the kinds of conditions that our current, and somewhat imperfect, models can predict could be reductive.
What if intelligent extraterrestrial life has found a way around the thermodynamic conditions that limit its ability to compute? In this case, perhaps one of the other ideas here holds true. Astrobiologists at the Australian National University penned their explanation to the Fermi Paradox in A Catch emerges: no life without habitability, no habitability without life.
Most life falls off. In this case, Earth is the exception to the rule. It offered humanity its first look at its icy surface and raised questions about the possibility of subsurface oceans of water, and lots of methane and nitrogen. Those oceans figure prominently into another theory of where life might be lurking, one that Alan Stern, the principal investigator for New Horizons, touches on.
Webb thinks that may not matter. To calculate how many intelligent, communicative civilizations may be in our galaxy, scientists usually use the so-called Drake equation. Computational neuroscientist Anders Sandberg and his colleagues at the institute wanted to include all of that doubt in their own Drake calculations, to shed some light on the dark, quiet universe.
Instead of assigning actual numbers to each term in the equation, they used the full range of numbers, for each term, that reasonable research suggests. The probability distributions that resulted surprised even them: Humans, they found, are likely to be alone in the observable universe, a possibility between 39 and 85 percent. Or maybe they never existed in the first place. Sandberg spins this possibility positively. Webb maintains a similar mindset.
Astronomers identify a new class of habitable planet. Galileo Project to search for alien artifacts hiding in the solar system. Pentagon UFO report: No confirmed aliens, but the government wants to learn more.
When did we first consider life might exist elsewhere in the universe? Red dwarf starlight used to grow photosynthesizing bacteria. Prospects for life on Venus take hit in phosphine reanalysis. Sun-like star identified as the potential source of the Wow! The Great Filter: a possible solution to the Fermi Paradox. Why haven't we found alien life yet?
Blame our closed minds. Cosmos: Origin and Fate of the Universe. Astronomy's Moon Globe. Galaxies by David Eicher. Astronomy Puzzles. Jon Lomberg Milky Way Posters. Astronomy for Kids. Sign up. Table of Contents Subscribe Digital Editons. A chronicle of the first steps on the Moon , and what it took to get there.
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