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.

We have learned more about the brain in the last fifteen years than in all prior human history, and the mind, once considered out of reach, is finally assuming center stage.

A hydrogen bomb, for me, was puny compared to the Big Bang - the creation of the universe. That's what I really wanted to work on - the nature of the universe itself, and that's what I do for a living.

There are so many wonders awaiting us. If we can upload memories, then we might be able to combat Alzheimers, as well as create a brain-net of memories and emotions to replace the internet, which would revolutionize entertainment, the economy, and our way of life. Maybe even to help us live forever, and send consciousness into outer space.

The reactors in Japan are stable in the same way that a ticking time bomb is also stable. It wouldn't take much to light the fuse - a 6.6 earthquake, like what happened today in Japan, a pipe break, an over-pressurized containment vessel - anything could set it off, in which case we would have another Chernobyl, three times the magnitude of a Chernobyl accident.

The job market of the future will consist of those jobs that robots cannot perform. Our blue-collar work is pattern recognition, making sense of what you see. Gardeners will still have jobs because every garden is different. The same goes for construction workers. The losers are white-collar workers, low-level accountants, brokers, and agents.

It's humbling to realise that the developmental gulf between a miniscule ant colony and our modern human civilisation is only a tiny fraction of the distance between a Type 0 and a Type III civilisation - a factor of 100 billion billion, in fact. Yet we have such a highly regarded view of ourselves, we believe a Type III civilisation would find us irresistible and would rush to make contact with us. The truth is, however, they may be as interested in communicating with humans as we are keen to communicate with ants.