However, one new theory says that dark matter may be ordinary matter in a parallel universe. If a galaxy is hovering above in another dimension, we would not be able to see it. It would be invisible, yet we would feel its gravity. Hence, it might explain dark matter.

One in 200 stars has habitable Earth-like planets surrounding it - in the galaxy, half a billion stars have Earth-like planets going around them - that's huge, half a billion. So when we look at the night sky, it makes sense that someone is looking back at us.

I used to watch the old 'Flash Gordon' series on TV, and it was thrilling to rocket to the planet Mongo every week. But after a while, I figured out that although Flash got the girl and all the accolades, it was really Dr. Zarkov who made the series work. Without Dr. Zarkov, there could be no Flash Gordon.

The best theory comes from string theory, which states that dark matter is nothing but a higher vibration of the string. We are, in some sense, the lowest octave of a vibrating string.

String theory is based on the simple idea that all the four forces of the universe: gravity, the electromagnetic force and the two nuclear forces, can be viewed, as music.

For most of human history, we could only watch, like bystanders, the beautiful dance of Nature. But today, we are on the cusp of an epoch-making transition, from being passive observers of Nature to being active choreographers of Nature. The Age of Discovery in science is coming to a close, opening up an Age of Mastery.

One theory is that the universe came from nothing. i.e. perhaps bubble-universes collided, as in a bubble bath, and gave birth to the universe. Or perhaps the big bang was created by a bubble-universe which split into two universes. The universe does seem to be compatible with nothing.