Not only is she one of the foremost quantum physicists and string theorists ever, she has written two amazing books and the libretto for an opera about physics. She has a PhD from Harvard and has been a professor at MIT, Princeton, and Harvard. Not to mention she’s the most cited theoretical physicist of the last five years.
She’s a #WomanInScience but dislikes talking about it, as she would prefer to be seen on her merits, rather than on her merits “which are great (cause she’s a girl)”. Regardless of her gender, she’s a stunning scientist, and a massive inspiration.
So what did she do?
Aside from change my life? She works on string theory, which seems difficult to understand until you read her book Warped Passages, or in fact hear her talk at anything.
In conjunction with Raman Sundrum, she created the Randall-Sundrum model, which posits that the world has an extra dimension hidden by warped geometry. We experience the world on a brane, a set of dimensions – in our case 3+1 – lower than the surrounding region. In the manner that condensing drops get stuck to a shower curtain, we are stuck on a brane, only to experience our 3 + 1 dimensions. Different branes can have different rules of physics, to a certain extent.
However, this is not necessarily the fate of all particles, which gets us on to the model. The idea is that the universe has 5 dimensions, one of which is extremely warped. This warped dimension contains two branes: one where gravity is strong, and the other where we live, with all the particles you have and haven’t heard about.
But wait, I hear you say, gravity is very strong.
No, it’s not. Jump. The simple fact that you, with your little leg muscles (little compared to the size of the Earth) can overcome the Earth’s gravity for even a short amount of time say NO NO NO gravity is NOT STRONG.
This is explained in the Randall-Sundrum theory as having the graviton (the thing that makes gravity happen, as a photon makes light happen) with a very high probability function on the other brane. Basically, gravity comes from there, dissipates a bunch, and then we have the inverse square rule. The intense weakness of gravity also requires a warped fifth dimension.
So the existence of a fifth dimension (and another brane) that we cannot experience explains, in some part, why gravity is not strong.
Jeepers, that turned into a physics lesson. Sorry about that. (I’m not sorry, physics is great)
On top of all that crazy awesome physics knowledge, she’s a great science communicator. The reason I can tell you all about this quite easily, as a person who stopped physics after high school, is her amazing wonderful book Warped Passages, which I wholeheartedly recommend to anyone and everyone.
1. Warped Passages, Lisa Randall
3. Randall L, Sundrum R (1999) Large Mass Hierarchy from a Small Extra Dimension. Phys. Rev. Lett. 83, 3370-3373. Link.