How Can Space Travel Faster Than The Speed Of Light?

Light speed is often spoken of as a cosmic speed limit … but not everything plays by these rules. In fact, space itself can expand faster than a photon could ever hope to travel. » 2/22/15 10:35am 2/22/15 10:35am

Asa Butterfield Will Star As a Martian Teen In Out of This World

Ender's Game star Asa Butterfield will also play the lead in the intriguing film Out of This World, where he'll play a kid who was raised in secret on Mars. » 2/02/15 10:00pm 2/02/15 10:00pm

Yes, Time Travel Is Possible; Here's How

Time travel's been one of man's wildest fantasies for centuries. It's long been a popular trend in movies and fiction, inspiring everything from Charles Dickens' A Christmas Carol to H.G. Wells' The Time Machine to the Charlton Heston shrine that is The Planet of the Apes. And with the opening of Interstellar » 11/05/14 1:25pm 11/05/14 1:25pm

A Brief History of Scientists Hunting for Time Travelers

Time travel is possible—or at least a lot of serious physicists say so. It's probably not possible to pull it off in a souped-up Delorean, but there are wormholes, Tipler cylinders, and other Einstein-inspired theories for how it could work. Which raises the question: Why haven't we met any visitors from another time? » 10/09/14 3:03pm 10/09/14 3:03pm

What the Hell Are Tachyons?

Tachyons cause a lot of problems in movies with starships, but they also cause problems for people in real life. Specifically, they cause problems for students of relativity and string theorists. Learn about the ins and outs of tachyons, and why they need extra dimensions. » 5/30/14 11:00am 5/30/14 11:00am

How To Test Einstein's "Twin Paradox" Without Using A Spaceship

Einstein said that clocks that are moving through space at dramatically divergent speeds will measure time differently, and he used his famous "twin paradox" to illustrate the point. But there are easier ways to show that time dilation is real. » 4/16/14 3:20pm 4/16/14 3:20pm

In Cosmos, The Only Thing More Important Than Evidence Is Imagination

The universe, they say, isn't just stranger than we imagine. It's stranger than we can imagine. After three episodes focused on matters solar and mundane, from the evolution of life to the orbital dynamics of comets in our little flat circle of spacetime, episode four tackles the limits of cosmic reality far beyond… » 3/31/14 9:20am 3/31/14 9:20am

Special relativity creates its own optical illusion

Special relativity is best known for letting us know that, as a person's velocity increases, their perception of time slows down. It also creates an interesting little optical illusion that can make objects moving in a straight line appear to twist and turn. » 3/11/14 10:22am 3/11/14 10:22am

How much stuff is in a light-year?

Imagine taking the distance that light travels in an entire year. Now turn that distance into a cube, each side one light-year across. How much "stuff" would be in there? And how empty would it be? It all depends on where you put your massive cube. » 1/31/14 6:40am 1/31/14 6:40am

How fast are we really moving through space?

It might seem like a simple question, but as this TED-Ed video beautifully illustrates, the task of measuring an object's speed as it's traveling through space is far more complicated than it looks — even if you're aboard the starship Enterprise. » 1/28/14 7:20am 1/28/14 7:20am

Stephen Hawking says there are no black holes

At least, not as we've defined them. In a new paper, Hawking says that one of the defining features of black holes — the complete inability of even light to escape — may not hold true. » 1/24/14 12:42pm 1/24/14 12:42pm

Are we about to reconcile gravity with quantum mechanics?

Physics is full of paradoxes, but one of the most famous is the contradiction between quantum mechanics and Einstein's theory of general relativity. At last, a new set of incredible experiments may reconcile the two systems. » 11/07/13 9:20am 11/07/13 9:20am

The 200-year-old mystery of Mercury's orbit — solved!

It wasn't too long after Newton published his laws of motion that people noticed something was off about them. To be specific, they were off by the orbit of an entire planet. And they remained off until Einstein, and general relativity, explained why Mercury moves the way it does. » 11/05/13 12:00pm 11/05/13 12:00pm

Geons have gravity, but no mass. Could they really exist?

John Archibald Wheeler is a physicist who coined a lot of terms. You may have heard of a few of them. Wormhole. Black hole. Quantum foam. And geon. Wait, geon? » 11/01/13 11:20am 11/01/13 11:20am

Doctor Who's mode of spacetime travel described in new physics paper

The title of the paper? "Traversable Achronal Retrograde Domains In Spacetime." Yes, it is real science, and yes, the paper's figures are excellent. » 11/01/13 8:39am 11/01/13 8:39am

Time travel is possible – but where will it take us?

We know that time travel is possible, at least in the forward direction. In this recently released TEDEd video, educator Colin Stuart imagines where and when it might take us, while exploring the science behind time travel and time dilation. » 10/25/13 3:19pm 10/25/13 3:19pm

Is time real?

It's more than some half-baked question from your college days. Time and its "real"-ness are, in fact, major considerations in fields like physics and philosophy. But then, what does that question – Is time real? – even mean? Theoretical physicist Sean Carroll gets down to brass tacks on time, reality, and how we… » 10/17/13 1:08pm 10/17/13 1:08pm

Magnets: HOW DO THEY WORK? Well... like this.

It's a match made in YouTube Science Heaven: In the latest episode of Minute Physics, Henry Reich teams up with the folks at Veritasium to address one of the Internet's favorite scientific conundrums: MAGNETS. » 9/24/13 1:40pm 9/24/13 1:40pm

Discover the Ladder Paradox, relativity's greatest thought experiment

The Ladder Paradox is a famous thought experiment that shows you why you can fit objects into spaces that are too small for them. And also why you can't, depending on your perspective. » 8/30/13 1:30pm 8/30/13 1:30pm

How Einstein's theory of relativity makes you smaller

Relativity is best known for giving us a new view of time. The faster you go, the slower time moves. There are other effects as well. For example, the faster you go, the more squished you get. » 8/29/13 1:30pm 8/29/13 1:30pm