As always, thanks so much for submitting your Stump the Scientist questions! We appreciate everyone playing along with us. Read on to find out the answer to this week’s question!
Question from Facebook Fan Conor Crossey:
If space is expanding where did it start? Also what was there before the big bang?
Response from Chief Scientist Jim Bray:
The first question is: “If space is expanding where did it start?”. Indeed, all our astronomical observations tell us not only that space (the universe) is expanding, but that it appears to be expanding faster all the time. This was a relatively recent surprise to scientists and led to the proposal of “dark energy” to explain the increasing expansion rate. The answer to this question is probably best said: “nowhere in particular”. The concept of “where” assumes that there is a space, objects, or coordinate system, around us to which we can reference positions. This is easy to do in our universe because we can reference everything to the earth or to other objects such as stars. Now imagine that only you exist in a black void with nothing else around. How would you tell anyone your position? You could not, because there is nothing to which you could reference yourself. This is the problem with asking where space (the universe) started; there was nothing else around to provide the reference for “where”.
The second question is: “what was there before the big bang?”. The best answer is probably “no one knows” (you have stumped all scientists). Books have been written about this, but they are all speculation or opinion at this time. Some theories have proposed that our universe arose from events within a larger universe or from the rebound of the collapse of an earlier universe. Some people question the validity of the word “before” in the question, if time began with the big bang. We should also recognize that we can answer such questions only within the bounds of science, which is to say that the answer should have some observable, verifiable, testable consequences within our present universe and reality. If we propose answers which have no consequences or verifiability within our universe, then such answers belong to the realm of philosophy or religion, not science.