Freesteel Blog » Galaxy road south

Galaxy road south

Sunday, February 18th, 2007 at 2:18 am Written by:


I’ve suddenly wound up in Cambridge for two weeks to keep house for my grandfather as he gets radiotherapy treatment at the large hospital on the other side of town. They send a taxi over every day. If I’m lucky there might be room for me to go in it.

I’ve got limited internet connection here, which is a good thing because I’ll be able to get through to the end of all this drop cutter coding without too much distraction.

I spent all of Thursday ranting about UN documents to an unlucky visitor to Liverpool who probably didn’t know what hit him. Then I went to Manchester to experience the misery of cycling down Oxford Street in the rain, leapfrogging the double-decker busses until I gave up and went on the pavement, before dropping off Becka’s passport at the Chinese consul and getting a blood test on the way back.

Then I had two hours programming the ball-nosed cutter case before going to a public lecture by some nutty particle physicist called Martinus Veltman who believes that the general theory of relativity and our understanding is gravity is all wrong.

He made a reasonable case, beginning with the fact that astrophysicists are full of crap, what with their going on about reading the handwriting of god. Nothing that they’re doing goes anywhere close to the real mystery of life, which is: How do our brains think? Also, they don’t do any experiments, so they can say whatever they like about the existance of a black hole at a certain place in space, and no one can prove them right or wrong.

Particle physicists, on the other hand, do experiments. For many decades they have been having to invent numerous new nuclear forces to explain what they are seeing. These new forces all start out as fudge factors, from which they make predictions that they then test on a particle accelerator. The latest and greatest fudge factor is the Higgs field, against which they’ve bet three billion Swiss francs on building the Large Hadron Collider. Either they’ll see direct evidence of it this year, or they won’t. Nobody really knows. That’s what really makes it interesting.

Meanwhile the cosmologists, who are able to make pretty photographs through their telescopes, have their own fudge factor known as Dark Matter on account of the fact that nobody has ever seen it. It’s only there, according to them, because they believe that even at the super large scales of a galaxy, that familiar law known as gravity must explain everything.

Why should it?

The subatomic physicists have had to invent the strong force, the weak force, the Higgs force, spin, quark, strangeness, and charm; so should we be surprised if the same nonsense of new laws unobservable on a human scale need to be postulated at large scales beyond the level of the solar system?

Of course not. There’s the Pioneer anomaly and the flyby anomaly where man-made objects in space don’t quite go where they ought to. I don’t know what’s special about them, except they have transmitters and we know how heavy they are because we put them there, so we’re not deducing an equally anomalous mass from an anomalous motion in such a way that we don’t notice it.

But worse is the galaxy winding problem where, if gravity was all that’s involved, there would never be any spiral arms because they would rapidly be smoothed into an disk, like the trail of cream on the surface of a stirred cup of coffee. The stars near the centre should go round faster and leave the far tips of the arms many revolutions behind. But because the cosmologists observe that the whole galaxy seems spins as one, they need to invent a huge halo of invisible “dark” matter around the outside to make it so.

This is real science: a model which produces predictions that don’t match observations without faking it, and suggests that there is something big we don’t know. We need to deal with the data and invent new and interesting theories to explain it which, if we’re lucky, we can test with an experiment.

On the other hand, the science of climate change doesn’t have any mysteries left in it; at least not of the sort that makes it worth running this particular excess atmospheric CO2 experiment we are currently conducting on ourselves, because we already know the answer and are not going to like it. Nevertheless, we still pay our politicians to lie about the facts, and put our minds at rest with the proposal that we had managed to weather a similar scare story in the past about global cooling that so convinced the scientific establishment it amounted to two whole articles in Newsweek in 1978.

I’m lucky to have been allotted a life span that fits into the most perfect time slot that a human being could ask for. Presently, medical science is good enough to avoid needless suffering, and we have the internet, and I will be able to watch the world through the most amazing period of transition with a mind is just mature enough to really appreciate it, without being too old and bitter. If I live to be as old as my grandfather, that’ll take me to around 2060, which is not many years short of when our life supporting environment is scheduled to really go tits up.

Of course, I could die young if I don’t stop staying up so late after my bed time. Night night.

4 Comments

  • 1. Julian replies at 19th February 2007, 10:07 am :

    I ranted at a friend about all this, and got the following response:

    [Two of my friends] have heard of arguments that
    there is no dark matter, but instead gravity behaves
    differently at large scales. However, they are fairly
    sure that dark matter is true. [One] pointed me to
    this interesting article on the subject.

    http://cosmicvariance.com/2006/08/21/dark-matter-exists/

  • 2. Julian replies at 19th February 2007, 10:27 am :

    Whatever it says here, I’m extremely annoyed with the fact that I have been mislead by the hypothesis: “dark matter exists”, rather than the more correct:

    “Either we don’t have the full story on gravitation beyond the limit of the solar system, or 90% of the universe is infused with an utterly transparent substance in exactly the right distribution to preserve constant rotation of spiral galaxies including our own, meaning it’s here in this solar system, yet we know of no particle it could be composed of.”

    Here’s the give-away paragraph in that article:

    Theorists now know what to think about (particle-physics models of dark matter) and experimentalists know what to look for (direct and indirect detection of dark matter particles, production of dark matter candidates at accelerators). The dark matter isn’t just ordinary matter that’s not shining… This new result doesn’t tell us which particle the new dark matter is, but it confirms that there is such a particle. We’re definitely making progress on the crucial project of understanding the inventory of the universe.

    Meanwhile, the particle physicists are telling us they’ve pretty much accounted for everything that they can see in their accelerators, and this quest is on the level of irritation as being told to go look for a new chemical element between Hydrogen and Helium that has the shape of a tiny mushroom.

    This looks exactly like the epicycles problem that Kepler was stuck with, where the sun was supposed going round the earth. They’ve calculated a the equivalent of the diameter of an epicycle — that blue probability map diagram — and said that it proves it because they’ve drawn a picture of it and there’s nothing else in that hole of empty space it could possibly be.

    Why? Well earlier in the article it said that any alternative theory should have the property:

    [T]hat the gravitational force should point in the direction of its source, not off at some bizarrely skewed angle. So if we imagine doing away with dark matter, we can safely predict that gravity always be pointing in the direction of the ordinary matter.

    In other words, it’s not allowed to be as “bizarre” as the motion of a charged particle in a magnetic field.

    To me there’s a credibility problem, which can be tracked down to the way reporters are able to buy this horseshit. This myth has caught on, and everyone’s running with it. The situation is much worse in Psychology where, struggling for something to say to a reporter, some researchers have blurted out that you could use their fMRI machine to probe the mind and detect criminal behavior. The actual experiment was about the 60% probability of being able to determin if the subject was seeing a blue square or a red square by examining their brain scan (chance is 50%). All it says is that these scientists ought to apply a little more thought into how to explain what they’re doing to the public because it appears that they think we’re all Daily Mail readers.

  • 3. Alistair Turnbull replies at 19th February 2007, 7:17 pm :

    I think you’re being unfair on the cosmologists. The particle physicists are only up to four forces so far, including gravity and electromagnetism (the others are the weak force and the strong force). Nobody is yet suggesting that more are needed. Strange and charm are new kinds of quarks: new matter, not new forces. Spin is a property of existing particles.

    There’s no evidence what so ever for the Higgs boson yet, and perhaps there never will be. Similarly, supersymmetry and string theory are studied only in the hope that some conceptual simplification might come of them. None has yet.

    On the other hand, there’s beginning to be quite a lot of evidence both for black holes and for dark matter. This ten-year movie of stars in the vicinity of the centre of our galaxy is especially good evidence for a gigantic (but invisible) black hole there:

    http://www.astro.ucla.edu/~ghezgroup/gc/pictures/orbitsMovie.shtml

    I reckon the Cosmic Variance article quoted in an earlier comment presents quite good evidence for the existence of some sort of dark matter. While you are right that it is possible to imagine a new force which has the same effect, why bother? The simpler model called dark matter seems to be adequate, and Occam’s Razor therefore applies.

    Of course, the real weight of evidence is not individual experiments/observations such as these, but the consistency of many independent experiments and observations. Individual studies can be flawed, and their conclusions can be misleading, but when a whole raft of complementary studies point in the same direction then your beliefs should follow.

    Dark matter and black holes are both looking pretty healthy, despite having been tested repeatedly over the last decade. In contrast there’s no MOND theory that has been specified and worked out in such detail, and is so consistent with observations.

  • 4. Iain Coleman replies at 26th July 2007, 8:43 pm :

    You really are talking pish. The existence of dark matter in the galactic halo can be detected by gravitational microlensing observations of the Magellanic Clouds. And at cosmological scales, the distribution of intergalactic dark matter can be mapped by observing the gravitational lensing of background galaxies. Either dark matter is out there, or there is some new physics as yet unconjectured by man that exactly mimics the gravitational lensing effects that we would expect to see from dark matter.

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