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.”
On April 17 of this year, a relatively unknown Chinese-born mathematician in his fifties—who since coming to the U.S. had to work odd jobs, including at a sandwich shop, before joining the faculty of the University of New Hampshire—announced a discovery that shocked the world of mathematics. Yitang (“Tom”) Zhang just solved one of the most persistent mysteries in the theory of numbers—of the kind that the famous British mathematician G. H. Hardy had described as being “at present beyond the resources of mathematics.”*
Ever since the Greek mathematician Euclid of Alexandria proved 2,300 years ago that there are infinitely many prime numbers, mathematicians have been intrigued by the existence of twin primes, a pair of prime numbers that differ by two—such as 11 and 13; 17 and 19; 29 and 31; and 41 and 43. Other than the first pair of prime numbers, 2 and 3, which are adjacent to each other, all further pairs of primes must be separated by at least one number because even numbers greater than two cannot be primes (since they are divisible by 2).
Mathematicians have wanted to learn about the behavior of pairs of primes, in particular pairs separated by one number, such as the twin primes in the examples above. Their hunt even has a name, the “twin prime conjecture,” which asks: are there an infinity of twin primes?
The thing about crossing into uncharted territory is that you may not know when, exactly, you have crossed into it. No one needs to tell that to the Voyager 1 spacecraft, which is currently at the center of a controversy about where the solar system ends and interstellar space begins.
Today, a press release from the American Geophysical Union initially stated Voyager had left our solar system. Two hours later, though, they issued a correction calling Voyager’s current location a “new region of space,” which is considerably less flashy (but equally scientifically valuable). The NASA Jet Propulsion Laboratory, which oversees the spacecraft, weighed in with a press release saying that no, in fact Voyager was still in the solar system.
So why the controversy? What is the debate about the boundary of the solar system? And what is this “new region” of which the scientists speak?