This article was originally published on The Conversation.
Last week, scientists announced the discovery of Kepler-186f, a planet 492 light years away in the Cygnus constellation. Kepler-186f is special because it marks the first planet almost exactly the same size as Earth orbiting in the “habitable zone” – the distance from a star in which we might expect liquid water, and perhaps life.
What did not make the news, however, is that this discovery also slightly increases how much credence we give to the possibility of near-term human extinction. This because of a concept known as the Great Filter.
The Great Filter is an argument that attempts to resolve the Fermi Paradox: why have we not found aliens, despite the existence of hundreds of billions of solar systems in our galactic neighborhood in which life might evolve? As the namesake physicist Enrico Fermi noted, it seems rather extraordinary that not a single extraterrestrial signal or engineering project has been detected (UFO conspiracy theorists notwithstanding).
This apparent absence of thriving extraterrestrial civilizations suggests that at least one of the steps from humble planet to interstellar civilization is exceedingly unlikely. The absence could be caused because either intelligent life is extremely rare or intelligent life has a tendency to go extinct. This bottleneck for the emergence of alien civilizations from any one of the many billions of planets is referred to as the Great Filter.
“Interdisciplinary” is a huge buzzword in academia right now. But for science, it has a long history of success. Some of the best science happens when researchers cross-pollinate, applying knowledge from other fields to inform their research.
One of the best such examples in physics was the concept of a Higgs field, which led to the 2013 Nobel Prize in physics. Few people outside the physics community know that the insight to the behavior of the proposed Higgs particle actually came from solid state physics, a branch of study that looks at the processes that take place inside condensed matter such as a superconductor.
Now cosmologists are trying to borrow some ideas of their own. The new discovery of gravitational waves — the biggest news in cosmology this century — focuses fresh attention on a field in which recent progress has otherwise been slow. Cosmologists are now attempting to explore novel ways of trying to understand what happened in the Big Bang, and what, if anything, caused the gargantuan explosion believed to have launched our universe on its way. To do so they’ve turned their attention to areas of physics far removed from outer space: hydrology and turbulence. The idea is pretty clever: to view the universe as an ocean.
In 1917, a year after Albert Einstein’s general theory of relativity was published—but still two years before he would become the international celebrity we know—Einstein chose to tackle the entire universe. For anyone else, this might seem an exceedingly ambitious task—but this was Einstein.
Einstein began by applying his field equations of gravitation to what he considered to be the entire universe. The field equations were the mathematical essence of his general theory of relativity, which extended Newton’s theory of gravity to realms where speeds approach that of light and masses are very large. But his math was better than he wanted to believe—his equations told him that the universe could not stay static: it had to either expand or contract. Einstein chose to ignore what his mathematics was telling him.
The story of Einstein’s solution to this problem—the maligned “cosmological constant” (also called lambda)—is well known in the history of science. But this story, it turns out, has a different ending than everyone thought: Einstein late in life returned to considering his disgraced lambda. And his conversion foretold lambda’s use in an unexpected new setting, with immense relevance to a key conundrum in modern physics and cosmology: dark energy.
There’s something rejuvenating about escaping civilization for the quiet isolation of unadulterated wilderness. But could you leave it all behind — forever? That’s the fate that awaits the men and women still in contention for a one-way ticket to the Red Planet.
Earlier this month, when a few high-traffic news websites reported a strange object or wedge-shaped craft on Google Moon, I was skeptical. Surprised, too, because when I opened the application, there it was, a distinct V-shape of bright lights inside a tiny crater on the moon’s far side. It did not look natural. I marked its location at 142 degrees and 34 minutes east and 22 degrees 42 minutes north, at the edge of Mare Moscoviense.
In case you were asleep yesterday and missed the big news, the European Space Agency’s (ESA) Rosetta spacecraft woke up from its 31-month hibernation. After the robotic equivalent of a drinking a black coffee — warming its navigation systems, pulling out of a spin, and pointing a radio dish toward Earth — Rosetta beamed a message to its home planet: Hello, world. NASA’s Goldstone antenna in California picked up the transmission and sent it to a roomful of scientists, who engaged in some unprecedented fist-pumping at the news that their comet-chronicling craft was alive and well. Rosetta’s Twitter account then said “hello” to the world in 23 different languages.
Rosetta is on its way to Comet 67P/Churyumov-Gerasimenko, a 1.9 by 3.1-mile (3 by 5-kilometer) chunk of dust and ice that’s headed toward the sun. When the spacecraft reaches its destination, it will begin to orbit the comet, spending two months scrutinizing the surface. This is a first: While astronomers have taken fly-by pictures, no one has ever tried to give a comet a satellite.
Science has done it again everybody! Brace yourselves for this groundbreaking news, freshly determined by physicists: Time travel, if it exists, may have some weird consequences. Gosh, who’d have thunk it?
But no, seriously, a recent article suggests that a certain kind of theoretically possible time machine would wreak minor havoc with a firm principle of quantum mechanics, the often-weird science of the smallest bits of the universe. You know what this means: We get to explore the science of time travel!
Let’s get this out of the way first: Obviously time travel exists, because it’s already the third week of 2014. We’re all time travelers (chrononauts), technically, moving 1 second per second through time. Certain weird side effects of relativity theory also mean time can travel more quickly under certain conditions, so it’s even possible for you to travel into the future (someone else’s future, at least) faster than the usual rate.
The “useful” kind of time travel, though, for sci-fi authors and dreamers alike, is into the past, Back to the Future style. And, happily, relativity theoretically can make that possible, too, by warping the fabric of reality, space-time, so much that it loops back on itself. A so-called wormhole (again, officially deemed possible by science) could be the bridge that connects two different times.
In 2007, astronomer Duncan Lorimer was searching for pulsars in nine-year-old data when he found something he didn’t expect and couldn’t explain: a burst of radio waves appearing to come from outside our galaxy, lasting just 5 milliseconds but possessing as much energy as the sun releases in 30 days.
Pulsars, Lorimer’s original objects of affection, are strange enough. They’re as big as cities and as dense as an atom’s nucleus, and each time they spin around (which can be hundreds of times per second), they send a lighthouse-like beam of radio waves in our direction. But the single burst that Lorimer found was even weirder, and for years astronomers couldn’t even decide whether they thought it was real.
The burst belongs to a class of phenomena known as “fast radio transients” – objects and events that emit radio waves on ultra-short timescales. They could include stars’ flares, collisions between black holes, lightning on other planets, and RRATs – Rotating RAdio Transients, pulsars that only fire up when they feel like it. More speculatively, some scientists believe extraterrestrial civilizations could be flashing fast radio beacons into space.
Astronomers’ interest in fast radio transients is just beginning, as computers chop data into ever tinier pockets of time. Scientists call this kind of analysis “time domain astronomy.” Rather than focusing just on what wavelengths of light an object emits or how bright it is, time domain astronomy investigates how those properties change as the seconds, or milliseconds, tick by.
We’ve all had the experience—over and over all the time. You go down to the street to wait for the bus (the train, the subway, the boat); you know that buses come roughly every 10 minutes, so you expect to wait about 5 minutes (arriving, on average, in the middle of the between-buses interval). But in fact, we all know that almost always you have to wait longer than that! Is this an illusion we’ve developed over the centuries because we believe in the “persistence of bad luck,” or is it, perhaps, something real?
It is, in fact, a real phenomenon, and this result can even be proved mathematically. Because you arrived after the last bus has left, your overall waiting time is, on average, longer than half the average
interval of 10 minutes.
An intuitive way of seeing this is to draw the timeline, with short and long intervals—their average is indeed 10 minutes long, but by randomness some of them will be longer and some will be shorter than the stated average.
Your appearance at the bus stop is also a random event, and this event is more likely to take place during a long interval
between two buses than during a short one!
By Rebecca Boyle
When NASA announced in May that its celebrated planet-finding telescope Kepler was broken, astronomers and journalists started collectively mourning. The Kepler space telescope had found 2,740 possible exoplanets since its launch in March 2009, and it was so successful that NASA approved funding for it through 2016, with hopes that many years of discoveries would follow.
And Kepler managers finally announced last week that they are giving up trying to reactivate the telescope’s busted gyroscopic wheels, which stabilize it for staring at possible planet-harboring stars.
But that doesn’t mean the telescope’s days of discovery are over. NASA is soliciting ideas for using Kepler in its hobbled form — something for which there’s plenty of precedent.
Kepler was designed to stare at bright stars to look for blips in their brightness that could indicate planets passing in front of them, a technique called photometry. It was built with four gyroscopic reaction wheels — one for each axis of movement, and one spare — that spin to correct for the solar wind and keep Kepler precisely pointed at those bright stars. One wheel stopped working more than a year ago, and astronomers started wondering what Kepler could do should another wheel fail.
When that happened, in May, scientists initially worried Kepler would move around too jerkily for any precision photometry. But, while it won’t be able to find Earth-sized planets around sun-like stars, tests this summer showed it may still be up for other tasks, including looking for bigger planets.
“Everybody is excited; they’re thinking, ‘Hey, we have a telescope in space, what can we do with it?’” said Steve Howell, Kepler project scientist at NASA’s Ames Research Center. “And you can do a lot with it.”