Large membranes may resemble universes like our own floating in eleven dimensional hyper-space. However, tiny membranes can be viewed as subatomic particles whose vibration and interaction give us the laws of Chemistry. Therefore M-Theory unifies subatomic particles and universes.

Trici Shaw: What is the "F" from F-Theory?
Dr Michio Kaku: F for F-Theory stands for Father. M for M-Theory may stand for Mother, Mystery or Membrane.

Alan Trevitt: If universes are parallel to each other, why does gravity run in only one direction i.e., downwards?
Dr Michio Kaku: Gravity is caused by the working of space time. Therefore, if we have two bubbles close to each other they will distort the space time surrounding them and feel each others gravity. Therefore, dark matter may be the presence of a neighbouring universe that we cannot see.

Alex Greybrook: How was hyper space discovered?
Dr Michio Kaku: The Greeks tried to prove 2000 years ago that hyper-space was impossible. However, Vernhard Riemann proved in the 1870s that hyper-space was possible. Then Kaluza in 1921 showed that universes may exist in hyper-space.

Richie Lunt: Although atoms are stable in our dimension would this be this case in others?
Dr Michio Kaku: Atoms in other dimensions may be unstable because the inverse square law does not hold. However, two forms of stable matter may exist in hyper universes, which are not based on atoms. But, physicists do not know any more than this.

Funky Monkey: Why are the other parallel universe's membranes different shapes. Shouldn't they be the same? Does what happens on the inside effects the universe's physical shape?
Dr Michio Kaku: Membranes can come in many sizes and many shapes. For example, a zerobrane is a particle, a onebrane is a string, a twobrane may be a membrane and a threebrane maybe a universe.

Zhou Fang: M-Theory may be shown to be mathematically possible, but would we ever be able to prove that it is actually the case?
Dr Michio Kaku: Experimentally, we hope to find super particles in the next few years with our atom-smashers. However, I believe that if we are smart enough we could solve the theory and then derive all the laws of Chemistry and Physics. That to me would be a proof that M-Theory is correct. So, those experiments are not really necessary. Theory is enough.

Ross Campbell: Where did the energy required to produce membranes in the first instance come from?
Dr Michio Kaku: The amount of energy necessary to create a bubbled universe is zero. Matter has positive energy, but gravity has negative energy. The sum of the two might be zero. This means that bubbled universes can be created all the time. So the Universe is for free.

Kevin Wan: If the fabric of the Universe is being stretched, does this also mean that the membrane is also being stretched? If so, when will the stretching cease?
Dr Michio Kaku: In one theory, our Universe is a membrane. We live on the skin of this membrane which is constantly expanding because of dark energy. We think this expansion is accelerating and may go on for ever without limit.

Pimmy: Have any major "flaws" or "gaps" been found in M-theory so far which makes it unable to explain something?
Dr Michio Kaku: So far, M-Theory has withstood every mathematical challenge. In the past, previous attempts at a theory of everything could be shown to be mathematically inconsistent. M-Theory is the only theory which seems to be mathematically consistent. However, there are many solutions to M-Theory, one of which may be our Universe. No-one has found that one solution yet.

Adrian: I've heard that in other universes time might flow backwards! Is this true?
Dr Michio Kaku: Not long ago, Stephen Hawking thought that time may go backwards. If the Universe pulsated then during the contraction he thought that time might run backward. However, he has since admitted that he was wrong. Therefore, most physicists do not believe that time will reverse itself in our Universe. If there are time machines, you might be able to reverse time in a small area, but not for the entire Universe.

Trekkie: Is there a possibility of a 12th dimension?
Dr Michio Kaku: In F-Theory the physicists at Harvard University have proposed a universe with two-times, so that you would have to have two watches on your wrist to tell you what time it is. However, most physicists today do not take F-Theory seriously although it seems compatible with M-Theory. This is still a mystery.

Rob Wood: How does M-theory explain quantum entanglement - is it via the collapsed dimensions?
Dr Michio Kaku: Quantum entanglement is a problem for all quantum theories including M-Theory. Quantum entanglement says that the Universe is non-local and that information may travel faster than light,. However, no useful information can be sent faster than light by means of quantum entanglement so there are no paradoxes in time.

Bernard Hunt: Is time just the human awareness; a thing that isn't really a dimension?
Dr Michio Kaku: Space time is an arena on which matter can exist. Therefore, time is a co-ordinate that measures the passing or evolution of an object. Some people have said that time does not exist, which confuses the perception of time with time as a co-ordinate on this arena.

Max Guglia: Apart from empirical speculation, what could be the benefits for humanity of proving the M-Theory?
Dr Michio Kaku: In the short term, nothing. But when Newton worked out the Force of Gravity, he helped to set into motion the industrial revolution. When Faraday worked out electricity and magnetism he set into motion the electric age. When Einstein wrote down E=MC² he unleashed the nuclear age. Now, we are on the verge of a theory of all forces which may, one day, determine the fate of the human species. Centuries from now, M-Theory, I feel, may eventually determine the destiny of all intelligent life in the Universe.

Horizon Host: Here's our special guest with a final word:
Dr Michio Kaku: I am proud to be part of this BBC documentary, on the cutting edge of my field - M-Theory. It is absolutely essential that scientists speak to the public about the exciting and revolutionary developments rocking the foundations of modern Physics. Hopefully, one of you viewers will be inspired by this programme to become a physicist, who will eventually complete the M-Theory and answer questions like: 'Is time travel possible?' 'Can we journey to another dimension?' and 'What happened before The Big Bang?'

er and black holes be explained using the M-Theory?
Dr Michio Kaku: Partially yes. In M-Theory, black hole solutions exist not only as a remnant of a dying star; they also exist as subatomic particles. So there is an unity between black holes and elementary particles. Also, the next vibration of the string includes a photino or particle which may make up most of the dark matter in the Universe. So dark matter maybe a higher musical note on the string.

Pieter Verhoeven: What is meant by "Bubbles of Nothing"?
Dr Michio Kaku: Boiling water is a purely quantum mechanical event. If water molecules were like billiard balls, water would never boil. Water boils and a tiny fluctuation occurs in water. Similarly, universes maybe created all the time, even as we speak, due to fluctuation in Nothing. In other words, universes maybe for free and Big Bangs, happen all the time like in boiling water.

Peter Wentworth: What are the possibilities for a second Big Bang collision? Is it theoretically possible?
Dr Michio Kaku: There is some speculation that gamma-ray bursters release the greatest amount s of energy since the Big Bang. There is some speculation that they maybe powerful enough to open a hole in our bubble Universe, so that our Universe buds into two universes, creating a baby universe which leaves the mother universe. However, until M-Theory becomes better understood we cannot prove that baby universes can be created from our Universe.

John Reyes: Dr Kaku, how can one travel in time when time does not exist? And if it did, would you know which way to point your ship?
Dr Michio Kaku: Time is like a river. It bends and flows around the Universe. Time may also have whirlpools and also may fork into two rivers. In this way, time travel might be possible. However, you have to have the Plank energy to create a time machine or the energy of a Black Hole. That is far beyond our technology.

Firstly Wagner is concerned that careless atom boffins might slip up and create a miniature black hole. This would then suck in surrounding mass, gaining unstoppably in size and power in a runaway process until it had engulfed the entire Earth and packed it down inside its swelling, unescapable event horizon.

Some physicists have theorised that black holes might act as spacewarp wormhole portals into alternate universes, or something. Summarising, it appears that the boffins at the LHC - should one of them clumsily spill his tea on the controls, for instance - could easily catapult the entire world through a rift in the very fabric of space-time, into another universe which could be entirely hostile to life as we know it. (Eg, essential processes such as fermentation of alcohol, TV, pizza delivery, gravity etc might simply not work; or there could be a parallel Earth ruled by an evil victorious Nazi empire with space battlecruisers and so forth.)