Have cosmologists lost their minds in the multiverse?

Sorry, I've been traveling. I'll be posting soon, but please check out a recent article of mine over at the Conversation called Have Cosmologists Lost their Minds in the Multiverse?


Location: Sydney NSW, Australia

Comments

Post a Comment

Popular posts from this blog

Falling into a black hole: Just what do you see?

Image
Everyone loves black holes. Immense gravity, a one-way space-time membrane, the possibility of links to other universes. All lovely stuff. A little trawl of the internets reveals an awful lot of web pages discussing black holes, and discussions about spaghettification, firewalls, lost information, and many other things. Actually, a lot of the stuff out there on the web is nonsense, hand-waving, partly informed guesswork. And one of the questions that gets asked is "What would you see looking out into the universe?" Some (incorrectly) say that you would never cross the event horizon, a significant mis-understanding of the coordinates of relativity. Other (incorrectly) conclude from this that you actually see the entire future history of the universe play out in front of your eyes. What we have to remember, of course, is that relativity is a mathematical theory, and instead of hand waving, we can use mathematics to work out what we will see. And that's what I did. ...
Read more

The Event Horizon

Image
Event Horizon was a somewhat dodgy sci-fi-horror movie that came out in the late 1990s. As the title suggests, associated with an Event Horizon is "Infinite Space, Infinite Terror". Luckily, the Event Horizon in the film as a black hole Event Horizon, and I'll leave discussing those to another time. Today, we'll try and understand the Cosmological Event Horizons. To explain these, I am shamelessly going to use the (still) excellent cosmological figures produced by Tamara Davis . OK, let's start with this one. To understand what this picture is telling us, we need to remember a few things. Our universe has three spatial dimensions, and any spatial point can be labelled with three numbers. In a Cartesian coordinate system , these are (x,y,z). As we are dealing with relativity, we are dealing with not only space, but space-time, and every point in the universe is labelled by 4 numbers, the three spatial coordinates and the time, t. So, every point is labelled...
Read more

Moving Charges and Magnetic Fields

Image
Still struggling with grant writing season, so another post which has resulted in my random musings about the Universe (which actually happens quite a lot). In second semester, I am teaching  electricity and magnetism to our First Year Advanced Class . I really enjoy teaching this class as the kids are on the ball and can ask some deep and meaningful questions. But the course is not ideal. Why? Because we teach from a textbook and the problem is that virtually all modern text books are almost the same. Science is trotted out in an almost historical progression. But it does not have to be taught that way. In fact, it would be great if we could start with  Hamiltonian and Lagrangian  approaches, and derive physics from a top down approach. We're told that it's mathematically too challenging, but it really isn't. In fact, I would start with a book like  The Theoretical Minimum , not some multicoloured compendium of physics. We have to work with what we have! ...
Read more