Energy

In a debate with Dr. William Lane Craig in March, 2014 theoretical physicist Sean Carroll has said the following in his opening speech:

If you have a universe that obeys the conventional rules of quantum mechanics, has a non-zero energy, and the individual laws of physics are themselves not changing with time, that universe is necessarily eternal. The time parameter in Schrödinger’s equation, telling you how the universe evolves, goes from minus infinity to infinity.1

From Einstein’s special theory of relativity we come to know that matter and energy are equivalent. Matter is concentrated energy and energy is diluted matter. Again from GTR we come to know that space, time and matter are so interlinked that there cannot be any space and time without matter. Similarly there cannot be any matter without space and time. So we see that all these four are interlinked; we cannot think of any one of these four entities singularly, isolatedly. Whenever we will think of energy, we will have to think of matter.

It can be shown in some indirect way that the net energy of the universe is zero. For this, we will have to first determine as to whether the universe has a beginning in the past, or whether it has an eternal past. I think that there is a consensus among scientists that the universe is not past-eternal, but that it originated from a big bang 13.8 billion years ago. So we can say now that the universe has a beginning. Now there are only two options that can be taken into consideration while discussing the beginning of the universe. We can ask: 1) did it originate from nothing?

When scientists say that the universe can simply come out of nothing without any divine intervention, they think of the universe in terms of its energy content only. In the book ‘The Grand Design’, page 281, scientist Stephen Hawking has written that bodies like stars or black holes cannot just appear out of nothing, but a whole universe can. The message is very clear from this: The total energy of a whole universe is zero and that is why it can come out of nothing; but stars or black holes will fail to do so, because their total energy is not zero.

The first half of the 20th century brought a revolutionary change into our concept about space and time. Earlier it was thought that space and time were having independent existence, and that they were absolute. Even if all the matter disappeared from the universe, space would remain the same and unaffected. Similar view was held about time also, that time flowed in the same way throughout the universe and that this flow did not depend on anything. But with the coming of Einstein’s theory of relativity our concept about space and time has undergone a total and drastic change.