Wormholes Explained – Breaking Spacetime - video Dailymotion

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Are wormholes real or are they just magic disguised as physics and maths? And if they are real how do they work and where can we find them?

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00:00If you saw a wormhole in reality, it would appear round, spherical, a bit like a black hole.

00:08Light from the other side passes through and gives you a window to a faraway place.

00:13Once crossed, the other side comes fully into view, with your old home now receding into that shimmering spherical window.

00:21But are wormholes real, or are they just magic disguised as physics and maths?

00:27If they are real, how do they work, and where can we find them?

00:32For most of human history, we thought space was pretty simple.

00:35A big, flat stage where the events of the universe unfold.

00:39Even if you take down the set of planets and stars, there's still something left.

00:44That empty stage is space, and it exists. Unchanging and eternal.

00:50Einstein's theory of relativity changed that.

00:54It says that space and time make up that stage together, and they aren't the same everywhere.

01:01The things on the stage can affect the stage itself, stretching and warping it.

01:06If the old stage was like unmoving hardwood, Einstein's stage is more like a waterbed.

01:13This kind of elastic space can be bent and maybe even torn and patched together, which could make wormholes possible.

01:21Let's see what that would look like in 2D.

01:24Our universe is like a big, flat sheet.

01:27Bent in just the right way, wormholes could connect two very, very distant spots

01:32with a short bridge that you could cross almost instantaneously,

01:36enabling you to travel the universe even faster than the speed of light.

01:40So, where can we find a wormhole?

01:43Presently, only on paper.

01:46General relativity says they might be possible, but that doesn't mean they have to exist.

01:51General relativity is a mathematical theory.

01:54It's a set of equations that have many possible answers, but not all maths describes reality.

02:00But they are theoretically possible, and there are different kinds.

02:08The first kind of wormholes to be theorized were Einstein-Rosen bridges.

02:12They describe every black hole as a sort of portal to an infinite parallel universe.

02:17Let's try to picture them in 2D again.

02:19Empty space-time is flat, but curved by objects on it.

02:23If we compress that object, space-time gets more curved around it.

02:28Eventually, space-time becomes so warped that it has no choice but to collapse into a black hole.

02:35A one-way barrier forms, the event horizon, which anything can enter, but nothing can escape.

02:41Trapped forever at the singularity at its core.

02:45But maybe there is no singularity here.

02:48One possibility is that the other side of the event horizon looks a bit like our universe again,

02:53but mirrored upside down, where time runs backwards.

02:58In our universe, things fall into the black hole.

03:01In the parallel universe, with backwards time, the mirror black hole is spewing things out, a bit like a big bang.

03:08This is called a white hole.

03:10Unfortunately, Einstein-Rosen bridges can't actually be crossed.

03:14It takes an infinite amount of time to cross over to the opposite universe, and they crimp shut in the middle.

03:20If you go into a black hole, you won't become the stuff coming out of the white hole.

03:24You'll only become dead.

03:27So, to travel the cosmos in the blink of an eye, humans need a different kind of wormhole, a traversable wormhole.

03:35There we go.

03:38If string theory, or one of its variations, is the correct description of our universe,

03:43then we could be lucky, and our universe might even have a tangled web of countless wormholes already.

03:49Shortly after the big bang, quantum fluctuations in the universe at the smallest scales, far, far smaller than an atom,

03:56may have created many, many traversable wormholes.

04:00Threaded through them are strings, called cosmic strings.

04:04In the first billionth of a trillionth of a second after the big bang,

04:08the ends of these tiny, tiny wormholes were pulled light-years apart, scattering them through the universe.

04:15If wormholes were made in the early universe, whether with cosmic strings or some other way,

04:20they could be all over, just waiting to be discovered.

04:24One might even be closer than we realize.

04:27From the outside, black holes and wormholes can look very similar,

04:31leading some physicists to suggest the supermassive black holes in the center of galaxies are actually wormholes.

04:37It will be very hard to go all the way to the center of the Milky Way to find out, though, but that's okay.

04:43There might be an equally extremely hard way to get our hands on a wormhole. We could try to make one.

04:50To be traversable and useful, there are a few properties we want a wormhole to have.

04:56First, it must obviously connect two distant parts of space-time,

05:01like your bedroom and the bathroom, or Earth and Jupiter.

05:07Second, it should not contain any event horizons, which would block two-way travel.

05:14Third, it should be sufficiently sized so that the gravitational forces don't kill human travelers.

05:20The biggest problem we have to solve is keeping our wormholes open.

05:24No matter how we make wormholes, gravity tries to close them.

05:28Gravity wants to pinch it closed and cut the bridge, leaving only black holes at the ends.

05:34Whether it's a traversable wormhole with both ends and hours, or a wormhole to another universe,

05:40it will try to close unless we have something propping it open.

05:44For very old string theory wormholes, that's the cosmic strings job.

05:48For man-made wormholes, we need a new ingredient.

05:52Exotic matter.

05:54This isn't anything like we find on Earth, or even antimatter.

05:58It's something totally new and different and exciting, with crazy properties like nothing that's ever been seen before.

06:05Exotic matter is stuff that has negative mass.

06:08Positive mass, like people and planets and everything else in the universe, is attractive because of gravity.

06:14But negative mass would be repulsive. It would push you away.

06:18This makes a kind of anti-gravity that props open our wormholes.

06:23And exotic matter must exert enormous pressure to push spacetime open,

06:27greater even than the pressure at the centers of neutron stars.

06:31With exotic matter, we could weave spacetime however we see fit.

06:37We may even have a candidate for this exotic matter, the vacuum of space itself.

06:43Quantum fluctuations in empty space are constantly creating pairs of particles and antiparticles,

06:49only for them to be annihilated an instant later.

06:52The vacuum of space is boiling with them,

06:55and we can already manipulate them to produce an effect similar to the negative mass we're looking for.

07:01We could use this to stabilize our wormholes.

07:05Once we're keeping it open, the ends would start together,

07:09so we'd have to move them around to interesting places.

07:12We could start by wiring the solar system, leaving one end of each wormhole in orbit around the Earth.

07:18We could fling others into deep space.

07:21The Earth could be a wormhole hub for a vast interstellar human civilization,

07:26spread over light years, but only a wormhole away.

07:30However, wormholes have a dark side.

07:33Even opening a single wormhole kind of breaks the universe in fundamental ways,

07:38potentially creating time travel paradoxes and violating the causal structure of the universe.

07:44Many scientists think that this not only means they should be impossible to make,

07:49but that it's impossible for them to exist at all.

07:52So, for now, we only know that wormholes exist in our hearts and on paper in the form of equations.

Wormholes Explained – Breaking Spacetime

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