Question: Do you think we’ll ever be able to understand dark energy and how it affects the universe so that it is increasingly expanding? Any theories in your workplaces?

Jose Eliel Camargo Molina answered on 12 Mar 2019:

This is a good question!

I think we will understand it, and I’m quite hopeful that new data from gravitational waves and astrophysics will give us the clues we need to do it.

At the moment, we know the universe is expanding at an accelerated rate, and we know how to explain that by putting some number in Einstein equations. But it is just a number that we get by looking at the universe and we don’t have any explanation for why it has that precise value:

0.00000000000000000000000000000000000000000000000000011056 1/m2

Within Einstein’s equations, it plays the role of vacuum energy of space. But why is it so small? we don’t like to just put such a “strange” number and that’s it. We would like to have an explanation to where it comes from.

So there are many theories for where it could come from, but none of those have been tested with experimental evidence.

I’m currently working with some other people at Imperial on a way to generate such a small number from the energy of a “close cousin” of Higgs boson. We know nature loves to go to places with the least amount of energy (I like to think the universe is super lazy 🙂 ). The super small value of that constant in the model I’m working on is related to the “laziness” of that scalar particle, which just goes and finds the place with the least amount of energy and settles comfortably there.