To mark his 70th birthday, physicist Professor Stephen Hawking answered a selection of questions from listeners to Radio 4’s Today Programme.
Topics ranged from the origins of the universe to the prospects for extra terrestrial life and the impact on Einstein’s theory of relativity should neutrinos be confirmed to travel faster than light.
It seems clear that Professor Hawking believes we we will have to colonise space if we are to avoid catastrophe, but he is upbeat about the prospects for self-sustaining colonies on Mars and believes the human race will eventually spread out across the far reaches of the universe.
Finding intelligent life elsewhere in the universe, he says, would be the greatest scientific discovery ever, but he is not optimistic about the likely outcome.
1. Was there a “time” when there was “nothing”? – Roland, Lagos
The origin of the universe can be explained by the laws of physics, without any need for miracles or Divine intervention.
These laws predict that the universe was spontaneously created out of nothing in a rapidly expanding state.
This is called inflation because it is like the way prices in the shops go up at an ever increasing rate.
Time is defined only with the universe, so it makes no sense to talk about time before the universe began, it would be like asking for a point south of the South Pole.
2. What will be the impact on Einstein’s theory of relativity if the neutrino is confirmed to be able to travel faster than the speed of light? – David Pointon, Maidstone
Einstein’s theory of relativity predicts that nothing can travel faster than light.
Thus if the Opera experiment is correct and neutrinos do travel faster than light, then relativity theory is wrong.
However, I don’t believe the Opera results, because they disagree with the detection of neutrinos from supernova SN1987A.
3. Some people hypothesise that what we call the universe may only be one of many. Is there any conceivable way that we could ever detect and study other universes if they exist? Is it even falsifiable? – Toby North, Essex
Our best bet for a theory of everything is M-theory [an extension of string theory].
One prediction of M-theory is that there are many different universes, with different values for the physical constants.
This might explain why the physical constants we measure seem fine-tuned to the values required for life to exist.
It is no surprise that we observe the physical constants to be finely-tuned.
If they weren’t, we wouldn’t be here to observe them.
One way of testing this would be to look for features in the cosmic microwave background radiation which would indicate the collision of another universe with ours in the distant past.
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