Dark news

Dark matter could meet its nemesis on Earth - New Scientist

That's interesting. They may be able to test Modified Newtonian dynamics (MOND) via an experiment on earth.

Actually, that puts in mind of the claims in the 1990's of some Russian scientist's experiments with a spinning superconducting disc that seemed to produce a slight anti-gravity effect. Here's a Slate article about it from 2002.

Haven't heard any more about that for a long time. I guess the secret, alien-run Earth Quarantine Force that kills off potential technology that could get us to the stars saw to that. (Hey, it's a working hypothesis, OK?)

And I am also reminded of an interesting recent article on dark energy on arXiv. As you may recall, Einstein added a deliberate fudge (the cosmological constant) to general relativity to make sure the universe wasn't expanding. (Expansion was not an idea in vogue at the time Einstein was doodling in the Patent Office.) Now that observation shows it's currently not only expanding, but accelerating, the talk is all of the mystery of dark energy.

Well, a couple of European physicists argue that there is no need to call it dark energy at all: it's just what happens with relativity. They argue that people are misunderstanding the cosmological constant totally, and (I think) people just have to get used to the idea that general relativity implies expansion.

I don't fully understand the argument: I'll have to re-read it again. But it does seem to me to be an argument that the answer to dark energy is fundamentally staring us in the face.

It's not that other scientists haven't thought of this; it's just that most seem to say "that's too easy, it can't be right." They write:

There is probably nothing very original in this note. The points we make here can be heard in discussions among physicists. However, for some reason they do not have much space in the dark-energy literature.

And towards the end of the article, they summarise it like this:

..to claim that dark energy represents a profound mystery, is, in our opinion, nonsense. \Dark energy" is just a catch name for the observed acceleration of the universe, which is a phenomenon well described by currently accepted theories, and predicted by these theories, whose intensity is determined by a fundamental constant, now being measured. The measure of the acceleration only determines the value of a constant that was not previously measured. We have only discovered that a constant that so far (strangely) appeared to be vanishing, in fact is not vanishing.

Our universe is full of mystery, but there is no mystery here. To claim that the greatest mystery of humanity today is the prospect that 75% of the universe is made up of a substance known as `dark energy' about which we have almost no knowledge at all" is indefensible.

Why then all the hype about the mystery of the dark energy? Maybe because great mysteries help getting attention and funding. But o ering a sober and scienti cally sound account of what we understand and what we do not understand is preferable for science, on the long run.

Pretty interesting, hey?