Try to make sense of what you see and wonder about what makes the universe exist. Be curious, and however difficult life may seem, there is always something you can do, and succeed at. It matters that you don’t just give up.
Professor Stephen Hawking, author of The Theory Of Everything
asks some Big Questions about our universe:
Where did we come from? How did the universe come into being? Are we alone in the universe? Is there alien life out there? What is the future of the human race?
Up until the 1920s, everyone thought the universe was essentially static and unchanging in time. Then it was discovered that the universe was expanding. Distant galaxies were moving away from us.This meant they must have been closer together in the past. If we extrapolate back, we find we must have all been on top of each otherabout 15 billion years ago. This was the Big Bang, the beginning of the universe.
But was there anything before the Big Bang? If not, what created the universe? Why did the universe emerge from the Big Bang the way it did?
We used to think that the theory of the universe could be divided into two parts. First, there were the laws like Maxwell’s equations and general relativity that determined the evolution of the universe, given its state over all of space at one time. And second, there was no question of the initial state of the universe.
Moreover, we can calculate a probability that the universe was created in different states. These predictions are in excellent agreement with observations by the WMAP satellite of the cosmic microwave background, which is an imprint of the very early universe. We think we have solved the mystery of creation. Maybe we should patent the universe and charge everyone royalties for their existence.
Are we alone, or is there other life in the universe?
We don’t know how life first appeared. We have two pieces of observational evidence on the probability of life appearing.
The first is that we have fossils of algae from 3.5 billion years ago. The Earth was formed 4.6 billion years ago and was probably too hot for about the first half billion years. So life appeared on Earth within half a billion years of it being possible, which is short compared to the 10-billion-year lifetime of a planet of Earth type. This suggests that the probability of life appearing is reasonably high.
On the other hand, we don’t seem to have been visited by aliens.
What’s the future of the human race?
If we are the only intelligent beings in the galaxy, we should make sure we survive and continue.But we are entering an increasingly dangerous period of our history. Our population and our use of the finite resources of planet Earth are growing exponentially, along with our technical ability to change the environment for good or ill. But our genetic code still carries the selfish and aggressive instincts that were of survival advantage in the past. It will be difficult enough to avoid disaster in the next hundred years, let alone the next thousand or million.
Our only chance of long-term survival is not to remain inward-looking on planet Earth,but to spread out into space
Complement The Theory Of Everything with Why does time go forward?