Great Scott! Where Is That Hoverboard?

Damn, where is that kid?

Marty McFly is probably riding his hoverboard into the further future because it’s 2015, and we still don’t have them yet. There’s a reason we don’t have hoverboards, jetpacks, or flying cars just yet: physics. It’s tough to get things off the ground without a great amount of power and propulsion pushing downward. Lexus’s test hoverboard uses nitrogen-cooled superconducting magnets to hover above the ground, but it can only do so above another magnetized surface. Jetpacks are tough, too; you have to push enough energy toward the ground without blowing your feet off. And flying cars have no regulation yet, mainly because the government hasn’t had to deal with anything that’s road-legal and legal to fly as well.

TIME Physics

Physicists Prove a New Particle Exists

An illustration of the possible layout of quarks in a pentaquark CERN

The discovery may provide hints as to what happens when giant stars collapse

Physicists at the Large Hadron Collider at the CERN in Switzerland announced the discovery of a new particle, the pentaquark.

The Collider, which smashes atoms together, showed signs of the pentaquark in 2011 and 2012, but scientists wanted to make absolutely sure of its existence before announcing its discovery.

“We have made very detailed checks to verify that there can be no other explanation,” Guy Wilkinson, a spokesman for CERN, said.

The history of the pentaquark dates back to 1964, when two physicists, Murray Gell-Mann and George Zweig, independently came to the conclusion that a group of subatomic particles that acted as building blocks for another form of matter existed.

Referred to as “quarks,” these particles were thought to exist in varied states, much like matter can be found in solid, liquid or gas forms. One of these alternative states was the pentaquark, which was made up of four quarks and an antiquark, or a quark’s anti-matter.

Scientists were hesitant to announce the recent discovery of the pentaquark, because its existence had been purely theoretical and efforts to prove its existence previously had failed.

“We were very careful in putting this paper forward,” Patrick Koppenburg, a physicist at the Large Hadron Collider in Cern, told BBC. “It’s just the word ‘pentaquark’ which seems to be cursed somehow because there have been many discoveries that were then superseded by new results that showed that previous ones were actually fluctuations and not real signals.”

The discovery of the pentaquark may provide hints as to what happens when giant stars collapse.

TIME Physics

Charles Townes, Inventor of the Laser, Dies Aged 99

Townes jointly won the 1964 Nobel Prize in Physics for his invention

Charles Townes, the Nobel Prize-winning physicist credited with the invention of the laser and its predecessor — the maser — died in Oakland, Calif., on Tuesday.

Townes’ health had been rapidly deteriorating and he died on the way to the hospital, according to the University of California Berkeley, where he had taught physics since 1967.

Townes, who was 99, jointly won the 1964 Nobel Prize in Physics for his contribution to the field of lasers, sharing it with two Russian scientists.

Born in Greenville, S.C., in 1915, Townes studied at Duke University before completing his PhD at Caltech in 1939. A stint at Bell Labs was followed by a faculty position at Columbia University, where he taught before moving to MIT in 1961 and finally to Berkeley six years later.

“Charlie Townes had an enormous impact on physics and society in general,” said Steven Boggs, professor and chair of the UC Berkeley Department of Physics. “His overwhelming dedication to science and personal commitment to remaining active in research was inspirational to all of us.”

TIME Physics

Watch Droplets Bounce Off Amazing New Water-Repellent Metal

The laser-etched material is more effective than traditional hydrophobic chemical coatings.

Scientists have used lasers to create a water-repelling metal surface that acts like a trampoline for water droplets.

Researchers at the University of Rochester, who published an article in the Journal of Applied Physics this week, used lasers to etch micro- and nanoscale structures into a metal surface that make it almost completely water-repellent, or hydrophobic.

The material could have a transformative impact on everything from aviation to sanitation, Chunlei Guo, a professor of optics and co-author of the study said in a press release and accompanying explanatory video. Airplane surfaces, for example, could use the material to repel water and prevent surface freezing.

The metal surface is more effective than traditional chemical-based surfaces like Teflon and, because it’s a structural alteration, doesn’t wear off.

“The material is so strongly water-repellent, the water actually gets bounced off,” Guo said in a statement. “Then it lands on the surface again, gets bounced off again, and then it will just roll off from the surface.”


TIME celebrities

Stephen Hawking Is Celebrating His Birthday and a Golden Globe Nod

"The Theory Of Everything" - UK Premiere - Red Carpet Arrivals
Karwai Tang — Getty Images Felicity Jones, Professor Stephen Hawking and Eddie Redmayne attend the UK Premiere of "The Theory Of Everything" at Odeon Leicester Square on Dec. 9, 2014 in London, England.

The famed theoretical physicist turned 73 on Thursday

Legendary cosmologist and theoretical physicist Stephen Hawking has much to celebrate this week.

On Thursday, Hawking turned 73 years old, defying the doctors who, 50 years ago, told him he had two years to live after he contracted motor neurone disease.

Meanwhile, the biopic The Theory of Everything, which chronicles the scientist’s relationship with his first wife and his rise in the world of physics, is up for best motion picture in the drama category at the Golden Globes on Sunday.

Eddie Redmayne who portrays Hawking in the film is also nominated for best actor. Hawking had high praise for the film and described it as an “intense emotional experience” after attending the premiere in London last month.

“It is perhaps the closest I will come to time travel,” wrote Hawkings on his Facebook page in December.

TIME space

Ka-Boom! Two Black Holes Get Ready to Collide

Don't get too close: A black hole in the galaxy Centaurus A emitting gas jets as it sucks in matter.
NASA NASA; Getty Images/Photo Researchers RM Don't get too close: A black hole in the galaxy Centaurus A emitting gas jets as it sucks in matter.

A dance of death that's never been seen before is slowly unfolding now

For cosmic drama, nothing should beat a supermassive black hole. It weighs millions, or even billions of times as much as the Sun; it eats stars whole with no apparent difficulty (although it does sometimes burp); it heats up surrounding gases to such insane temperatures that you can see the glow halfway across the universe; and perhaps best of all, it gives Stephen Hawking something to theorize and argue about.

For all that, it turns out that something does beat a giant black hole: two giant black holes, especially ones circling each other like wary Sumo wrestlers getting ready to grapple. Such things are by no means unheard of: just about every galaxy has a supermassive black hole lurking at its core, and when two galaxies merge, as they often do, their central black holes orbit each other in an ever-tightening dance, and in many cases they eventually coalesce into one. When that happens, says General Relativity, they should trigger ripples in the fabric of spacetime itself, in the form of so-called gravitational waves that Einstein predicted, but that no one has yet detected directly.

Such a merger hasn’t ever been seen, but astronomers have just announced the discovery of the next best thing: a pair of supermassive black holes orbiting each other more closely than any ever before observed. Other twin black holes won’t merge for another few billion years, but these, says Caltech’s George Djorgovski, co-author of a paper in Nature describing the new discovery, “could merge in a mere million years.”

That still sounds like a long time, but it means the two black holes are virtually on top of each other—on a cosmic scale at least. If one were sitting in the Sun’s position, the other might be as close as the Oort Cloud of comets that sits at the edge of the Solar System. That’s crucial: astrophysicists don’t really know what happens in the last stages of the spiraling-in process—it’s known as the “final parsec problem,” a parsec being a bit over three light-years. And these two are very much in the thick of it.

Djorgovski and his colleagues hasten to say they haven’t seen the black holes as individual objects: instead, they’re looking at the bright spot of light that marks the “accretion disk” of superheated gas that often surrounds black holes. Accretion disks flicker sometimes, as new gas is pulled in, but in the case of this object, known as PG 1302-102, the flicker is periodic, waxing and waning over a period of about five years. That’s the telltale sign that two objects are involved: one of the black holes’ accretion disks may be warped somehow by the gravity of the other, causing a hot spot that flashes us as it rotates into view.

What the astronomers are hoping for now is to find more examples like this. They have some 20 candidates already, and the more twin black holes they can find that are in tight orbits, the better they can understand what’s really going on. We may not be around to see PG 1302-102’s final collision—if it ever takes place—but somewhere out there, two black holes may be even closer to tangling.

Read next: The 20 Most Eye-Catching Booths at CES 2015

TIME movies

What Interstellar Got Right and Wrong About Science

Warner Brothers—Melinda Sue Gordon Matthew McConaughey in 'Interstellar'

Even a movie largely based on real science is bound to bend the rules a bit

If you’re one of the estimated 3 gajillion people who have seen or will see Chris Nolan’s blockbuster movie Interstellar, one thing is already clear to you: this is not a documentary. That means it’s fiction, specifically science fiction, which is how you get the sci and the fi in the sci-fi pairing. So if you go into the movie looking for a lot of scientific ‘gotcha’ moments, let’s stipulate up front that you’re going to find some.

That said, part of Interstellar’s considerable appeal is that it does go heavy on the science part of things. Nolan enlisted Caltech cosmologist Kip Thorne as the film’s technical adviser, and Thorne kept a whip hand on the production, ensuring that the storyline hewed as closely as possible to the head-crackingly complex physics that govern the universe.

So where did Interstellar play it absolutely straight and where did it take the occasional narrative liberty? Here are a few of the key plot points and the verdict from the scientists (warning, there may be spoilers ahead):

1. A worm hole could open in space, providing a short cut from one side of the universe to the other. Verdict: Mostly true

Worm holes are a pretty well-accepted part of modern cosmology and it’s Thorne’s theorems that have helped make them that way. The idea is that if you think of space-time less as a void than as a sort of fabric—which it is—it could, under the right circumstances fold over on itself. Punching the necessary holes in that fabric so that you could make your universe-transiting trip would be a bit more difficult. That would require what’s known as negative energy—an energetic state less than zero—to create the portal and keep it open, says Princeton cosmologist J. Richard Gott. There have been attempts to create such conditions in the lab, which is a long way from a real wormhole but at least helps prove the theory.

One bit of license the Interstellar story did take concerns how the wormhole came to be. It takes a massive object to generate a gravity field sufficient to fold space-time in half, and the one in the movie would have to be the equivalent of 100 million of our suns, says Gott. Depending on where in the universe you placed an object with that kind of mass, it could make a real mess of the surrounding worlds—but it doesn’t in the movie.

2. Getting too close to the gravity well of a massive object like a black hole causes time to move more slowly for you than it would for people on Earth. Verdict: True

For this one, stay with space-time as a fabric—a stretched one, like a trampoline. Now place a 500-lb. cannon ball on it. That’s your black hole with its massive gravity field. The vertical threads in the weave of the fabric are space, the horizontal ones are time, and the cannon ball can’t distort one without distorting the other, too. That means that everything—including how soon your next birthday comes—will be stretched out. Really, it’s as simple as that—unless you want to spend some time with the equations that prove the point, which, trust us, you don’t.

3. It would be possible to communicate to Earth from within a black hole. Verdict: Maybe

The accepted truth about a black hole is that its gravitational grip is so powerful that not even light can escape—which is how it got its name. But even physics may have loopholes, and one of them is something known as Hawking radiation, discovered by, well, guess who. When a particle falls into a black hole, the fact that it’s falling creates another form of negative energy. But nature hates when its books are unbalanced—a negative without a corresponding positive is like a debit without a credit. So the black hole emits a particle to keep everything revenue- neutral. Zillions of those particles create a form of outflowing energy—and energy can be encoded to carry information, which is how all forms of wireless communication work. That’s hardly the same as being able to radio down to Houston from within a black hole’s maw, but it takes you a big step closer.

4. It would be possible to survive the leap into the black hole from which you hope to do your communicating in the first place. Verdict: False—except…

Cosmologists vie for the best term to describe what would happen to you if you crossed over a black hole’s so-called event horizon, or its light-gobbling threshold. The winner, in a linguistic landslide: spaghettification—which does not sound good. But that nasty end may not happen immediately. “Most people would agree that a person who jumps into a black hole is doomed,” says Columbia University cosmologist and best-selling author Brian Greene, “but if the black hole is big enough, you wouldn’t get spaghettified right away.” That’s small comfort, but for a good screenwriter, it’s all the wiggle room you need.

5. And finally: Anne Hathaway could move through time and space and help save all of humanity and her hair would still look fabulous. Verdict: Who cares? We wouldn’t have it any other way.

Read next: Watch an Exclusive Interstellar Clip With Matthew McConaughey

TIME movies

How Stephen Hawking Went Hollywood

A theory of love: Eddie Redmayne, as a young Hawking, meets the future Mrs. Hawking
A theory of love: Eddie Redmayne, as a young Hawking, meets the future Mrs. Hawking

James Marsh, director of the poignant Hawking biopic The Theory of Everything, talks about making a movie with—and about—a living legend

It’s a very good thing director James Marsh isn’t a defeatist. If he were, he would curse the Hollywood calendar that has his compelling biopic of Stephen Hawking, The Theory of Everything, opening in the same week as Christopher Nolan’s blockbuster Interstellar. Ordinarily, an arena-scale spectacle like Interstellar and a bit of cinematic chamber music like Theory wouldn’t have a lot to fear from each other, since their audiences would be decidedly different. But that’s not so this time.

Both movies, in their own ways, wrestle with the same head-spinning questions: the mysteries of the universe and the physics of, well, pretty much everything there is. And both, in their own ways, succeed splendidly. Nolan had the far heavier lift when it came to the sheer scale of the production he was undertaking. But Marsh had the tougher go when it came to making sure his audiences sat still for the tale he wanted to tell, since he didn’t have eye-popping special effects and a thumping score to make the science go down easier. But he plays to that minimalism as a strength, keeping things small, intimate and sometimes brilliantly metaphorical.

On occasion, the facts of Hawking’s own life supplied those metaphors. Even as the great physicist was descending into the black hole of an illness that would render him both immobile and mute, he discovered the phenomenon now known as Hawking radiation, a form of energy that allows information to escape from the gravitational grip of a black hole—a grip so great that it swallows even light. Hawking has spent most of his life finding his own way to get information and ideas out to the world.

And when did the young Hawking have the flash of insight that the eponymous radiation exists? While struggling to free himself from a tangled pajama top that his weakened muscles could no longer negotiate. When life throws a good director a fat, over-the-plate pitch like that, the good director hits it out of the park—and Marsh excels in that moment, as he does with the film as a whole.

Taking a break from both promoting Theory and directing a new project for HBO, Marsh spoke to TIME about getting to know Hawking, working to understand his physics, and turning what could have been a mawkish tale of sickness and survival into a movie that is equal parts drama, wit, love story and ingenious science lesson.

How difficult was it to weave hard cosmological science into a personal story about a man, his marriage and his illness?

I think of myself as a member of the general audience who comes to the movie not overly familiar with cosmology. I pitched the science at a level that I think I would understand, so audiences will too. The movie is really a story of the heart, about two people [Hawking and his wife Jane], and we give them equal screen time. There was a very interesting tension between Hawking’s scientific career on the one hand and his marriage and health on the other. They move in opposite directions, with one soaring as the other is declining. A drama wouldn’t ordinarily be the best way of exploring complex ideas like Hawking radiation, but that balance, that tension made it possible.

Cosmology is that rare science that almost no one understands but almost everyone finds fascinating. Why do you think that’s so?

These are the biggest questions imaginable. Stephen’s work is dealing with the nature of time and the boundaries of the universe. He approaches them through the lens of physics, but what he’s engaging with are the deepest mysteries we can contemplate.

How involved was Hawking in the production?

[Screenwriter] Anthony McCarten spent many years working on a screenplay and talking to Jane Hawking, whose memoir is the source of the movie. We then went to Stephen and he read the script. He wasn’t wildly enthusiastic with the idea but he agreed to cooperate. He offered us some items from his personal collection, including the medal that [his character is seen] wearing at the end of the movie. At each step of the production we involved him, consulted with him. We had a physicist—a former student of his—on the set at all times to make sure all of the equations looked right.

Did Hawking himself ever visit?

During the May Ball shoot [a scene at an outdoor dance], he came to the set with his handlers and other assistants. He was very impressed by the scale of everything, but it raised the stakes a lot when he was there, especially because it was on the same night Jane showed up. Earlier, Jane took us to the house where they lived when they were first married. She showed us the spot where Stephen was saying “I have an idea” when he was struggling with his pajamas and came up with Hawking radiation. Scientists are like filmmakers: they have the oddest ideas at the oddest times.

Did you give Hawking any kind of final approval of the film before it was released?

When it was cut but not finalized, we took the film and showed it to him as a mark of respect. Had he not liked it we would have failed, so that was very nerve-wracking. It seemed to us that he had an emotional reaction while he was watching the movie. His response afterwards was very generous. He said the movie felt ‘broadly true,’ and then he sent the company an e-mail saying that when he watched Eddie [Redmayne, who plays Hawking] perform, it was like watching himself. He also offered us the use of the real electronic voice he uses to communicate to replace the one we were using. It has a weird emotional spectrum and it made the movie better. It felt like an endorsement.

TIME Physics

Why LED Lights Won the Nobel Prize

Chances are you're using an LED right now

You might have heard that researchers, two Japanese and one American, recently won the Nobel Prize for Physics for inventing blue light-emitting diodes (LEDs), but you might not know what LEDs are and why they’re important. With energy-saving light bulbs becoming more commonplace and smartphone use as widespread as ever, there might be more LEDs in your life than you realize.

TIME Physics

This Discovery Brings Us One Step Closer to Harry Potter’s Invisibility Cloak

Handout photo of cloaking device using four lenses developed by University of Rochester physics professor Howell and graduate student Choi is demonstrated in Rochester
Reuters A cloaking device using four lenses developed by University of Rochester physics professor John Howell and graduate student Joseph Choi is demonstrated in Rochester, New York on Sept. 11, 2014.

It's like a very small invisibility cloak made of glass

Researchers at the University of Rochester seem to be taking the words of science fiction writer Arthur C. Clarke’s to heart: “any sufficiently advanced technology is indistinguishable from magic.”

Inspired in part by the famous Invisibility Cloak from Harry Potter, scientists at Rochester have discovered new ways to use complex lenses to hide objects from view. While previous cloaking devices distort the background and make it apparent that an object is being cloaked, the four lenses used at Rochester keep an object hidden as the viewer moves up to several degrees away.

“This is the first device that we know of that can do three-dimensional, continuously multidirectional cloaking, which works for transmitting rays in the visible spectrum,” said Joseph Choi, a PhD student at Rochester’s Institute of Optics who is working with physics professor John Howell at the university.

While the lenses do truly disguise the image of an object, scientists aren’t claiming a suit-sized version of the lens will work, much less help its wearers sneak past Death Eaters or into a Room of Requirement.

But there are practical uses for the technology: Howell says that the lenses could help a surgeon “look through his hands to what he is actually operating on,” and the lenses could be applied to a truck to allow drivers to see through blind spots on their vehicles.

Here’s a video that shows in more detail how the lenses work:


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