Lawrence Krauss - Are there Extra Dimensions?

laurens extra dimensions have entered the public consciousness from science fiction everywhere but in recent years it has become real science you've been a pioneer in this thinking tell us about extra dimensions okay I'm not sure that's real science when he said real it's a little strong with science but we're not sure yet whether they're real the idea of extra mentions has been around for a long time in different contexts and it's hard for people to picture extra dimensions after all because we live in three-dimensional space and it's hard to picture a four dimensional space just as a two-dimensional being like in the famous book flatland couldn't picture a three-dimensional world and and that was in the 1870s in fact that was by the way the time when the idea of extra dimensions really began to get exciting to both artists and writers and scientists and partly was due to the fact that there was the discovery that electricity and magnetism were really different manifestations of the same force ultimately caused Einstein to recognize that the only way to that that one person's electricity could be another person's magnetism depending upon how they were moving with respect to one another would be its space and time were somehow relative if somehow a little bit of my space was a little bit of your time and vice versa and that was recognized by one of iodized teachers in fact the mathematician Minkowski that that that was only possible if space and time were tied together in a four-dimensional universe where time was a little bit different than space but nevertheless they were tied together in a four-dimensional universe this is not just metaphor no this is exact space and time really are do form what's called a Matkowski space that we live in a four-dimensional universe we really do live in a universe of three dimensions of space and one dimension of time that are tied together but that dimension of time is different than space you can't you can't walk into the time direction and come back okay as far as we know and that means that we don't live in this four-dimensional space that we're where you can go in that extra dimension and have lunch and come back and by the way I should in spite of that artists and writers got fascinated by this idea of four dimensions and use wonderful short stories and wonderful science fiction about fourth-dimensional I could go if there were a fourth-dimensional I could do surgery on you without ever opening you up I could just go to the fourth dimension take out your appendix and come back come back and be wonderful it was possible but that so that fourth dimensional idea was the beginning in science of the idea that we have more and more out there than meets the eye but in fact it really began to take hold in the 1960s when new particle accelerators were coming online and there was a host of new elementary particles being discovered and it just seemed like chaos and more than that the theories that people began to develop to try to explain that were chaotic they produced nonsense they produced infinities and it was recognized that one way around it was to assume that elementary particles themselves were maybe not particles but at some small scale behave kind of like strings because if that was the case you could tame those mathematical infinities but not tame them in four dimensions it turned out the only way to contain them is if there were a few extra dimensions not one not two but twenty two extra dimensions and I find it fascinating that physicists were so terrified by these infinities that even in 1960s they began to take the idea of 22 extra dimensions seriously real extra dimensions not mathematical no well often mathematical metaphor becomes real and the question is what which is which and that's that's what makes it into physics and we want to find out but they were willing to believe they were real and ultimately might have physical effects that ended in the 1970s when we can fact came up with a different theory that happened to explain all those experiments get rid of the infinities and it was beautiful but it was revitalized in the 1980s when it was discovered that that same theory that had been thrown out actually naturally produce something that looked very much like gravity now the big problem of the 20th century in the 21st century perhaps is that gravity and quantum mechanics don't mix they don't work together general tivity and quantum mechanics just don't work but here was a quantum theory that somehow had gravity embedded in it apparently so potentially this was a quantum theory of gravity and when that was discovered in 1984 that's when everything went wild and tons of physicists began to think series about these extra dimensions and the question is where are they well if we don't see him maybe they're very very small that was the idea from much.this when he century maybe they're curled up into such a small scale that we can't measure them compactified ACTA fide is the word the question is why and the answer is we don't know and so that's that's been part of the issue but it turns out that more recently people have begun to consider the possibility that maybe there other ways to hide those extra dimensions that are make it more interesting maybe they can actually be large and part of the reason trying to understand that was that one of the big mysteries in science is that gravity is much much weaker than the normal rest of the forces nature may not feel like it to you when you wake up in the morning and try and get out of bed but gravity is by far weaker than the other forces in nature it's a famous example go up to the top of a building throw a friend off or an enemy off takes gravity all that distance 200 feet to get them down to the ground but what stops them in the end electricity and magnetism because it's the electric forces between the atoms in your hand and the floor that stop you most with empty space it just forced you don't even leave a dent to the concrete so electricity and magnetism stop you in fraction inche gravity accelerates you all the way down why is gravity so weak maybe it's weak because some of its leaking out into extra dimensions so if you and I are constrained to live in our three-dimensional space in one dimension of time but somehow gravity can probe those extra dimensions then maybe those extra dimensions could be large and you could explain the weakness of gravity the final interesting aspect of these large extra dimensions is if they're large enough maybe maybe we can do experiments at high enough energy so when we bang things together some of that energy will leak off by a gravity into those extra dimensions and we might actually experimentally probe it so this stops being metaphysics and becomes physics well do you think that's likely I wouldn't bet on it III think it smells wrong but it's certainly fun to work with

Channel: Closer To Truth

Views: 39,998

Rating: 4.8842678 out of 5

Keywords: Lawrence Krauss, Closer To Truth, Science, Physics, Universe, Reality, Multiverse, Dimensions

Id: 1j6PiMHuCnQ

Length: 6min 28sec (388 seconds)

Published: Fri Jan 29 2016