dark energy

Yesterday evening we headed out to Café Scientifique at the Branch Tavern to listen to Bob Nichol answer the question “Has anyone seen our universe?”

Now me and maths, and physics for that matter, just don’t get on. I did try but for some reason each lesson became a struggle to keep my eyes open, to concentrate as equations and theories went way over my head and travelled off into the distance. And brown: there seemed to be a lot of brown involved in both maths and physics. Brown shirts, brown trousers, brown floors. However I was greatly impressed to understand (all bar the equations of course) the premise behind dark energy.

What really got to me though were a couple of small sentences. Firstly, what if the mass within the universe has enough gravity to stop it expanding? Will it then stop and reverse the expansion? Hold on! I thought, does this mean that we’ll end up being squished out of existence? And then my brain went down the whole, “but if we’re not here, and the universe isn’t here – what would be left?” series of questions, which make my brain boggle and the rest of me feel slightly disorientated.

Secondly there was supernovas, and how if one happened near us we’d have a whole two seconds before our atmosphere evaporated. “Don’t worry about global warming or your mortgage!” we were told. But somehow I have a feeling that the bank might get a little bit shirty if I told them that I didn’t want to pay the mortgage anymore because a supernova could happen at any minute and then we’d all be dead.

Fascinatingly though, I learnt that gravity may work in a different way when dealing with space-time. In fact, whole chunks of gravity may be leaching off into another dimension. String theory and the eleven dimensions are apparently not just way beyond my mathematical abilities but everyone else’s too, and so five dimensions seems a sensible place to start. Five? I thought. And then decided to stop thinking and go home and have some dinner.