Galaxies, worm holes and spoilsports

It was reported last week that a new study showed that the MOND theory (the modified gravity theory that some astrophysicists are still pursing despite it not being widely accepted) works well with yet another class of galaxy.  This got some mainstream media attention, which really annoyed physicist Sean Carroll at Cosmic Variance.    Carroll complains about the reports said this theory challenges the existence of dark matter.  Not so, said Carroll, pointing out that MOND works well at galaxy level, but everyone knows it doesn’t work at the scale of galactic clusters.   What’s more (he says) it’s not an elegant theory at all – it’s ugly, and we all know how physicists hate “ugly”.  (Except when it comes to string theory, in a large number of cases.)

So the short story is:  even with MOND, you still need dark matter to make the universe work right.

I find that’s a pity.  Big science is stuck in a bit of a rut at the moment, and it would be good to see something major which is currently widely accepted turn out to be wrong.

Of more science fiction-y interest is a new paper that talks about the possibility of wormholes existing on the insides of stars - forming connections with stars on the other side of the universe:

The scientists began investigating the idea of wormholes between stars when they were researching what kinds of astrophysical objects could serve as entrances to wormholes. According to previous models, some of these objects could look similar to stars.

This idea led the scientists to wonder if wormholes might exist in otherwise ordinary stars and neutron stars. From a distance, these stars would look very much like normal stars (and normal neutron stars), but they might have a few differences that could be detectable.

To investigate these differences, the researchers developed a model of an ordinary star with a tunnel at the star’s center, through which matter could move. Two stars that share a wormhole would have a unique connection, since they are associated with the two mouths of the wormhole. Because exotic matter in the wormhole could flow like a fluid between the stars, both stars would likely pulse in an unusual way. This pulsing could lead to the release of various kinds of energy, such as ultrahigh-energy cosmic rays.

I hope Sean Carroll stays away from this one: it's too intriguing an idea to be shot down too quickly.