Warm Dark Matter?

Say hello to Jason Lisle, the Institute for Creation Research’s new Director of Research. He’s an astronomer – a real one – who did his thesis on “Probing the Dynamics of Solar Supergranulation and its Interaction with Magnetism.”

For his first ICR article, he gives us a Daily Science Update article called No Nearby Dark Matter. As Dr Lisle seems to be at least vaguely competent, and is as such a real catch for the Institute, this article isn’t nearly as bad as the usual fare.

His article is based on a space.com article, If Not Dark Matter, Then What?, discussing recent findings that show that there is effectively no dark matter in the solar neighbourhood. He begins:

A new Chilean study has found that there is essentially no “dark matter” in the solar neighborhood. Dark matter is the name of an as-yet-unobserved material whose existence is inferred by its gravitational effects on visible objects. Three independent lines of evidence support the existence of dark matter, so why was it not detected in this study?

An interesting question. The Nature News article I filched the above video from, Survey finds no hint of dark matter near Solar System, says:

“I wouldn’t throw out nearby dark matter quite yet,” says Chris Flynn, an astronomer at the Swinburne University of Technology in Melbourne, Australia, who reviewed the paper, which has been accepted by the Astrophysical Journal.  “The measurement being made is very challenging, and there are a number of ways for it to miss the dark matter even if is there.” Despite his qualms, Flynn says that he “agreed to disagree” with the authors of the study and approved the paper for publication.

Alternatively, the study could be correct and it simply might not be there. Importantly, however:

Heidi Newberg, an astronomer at the Rensselaer Polytechnic Institute in Troy, New York, notes that the difficult measurement is dominated by the matter near the plane of the Milky Way, which, unlike the rest of the Galaxy, is expected to be made up mainly of normal matter.  That makes it more difficult to tease out whatever dark-matter component may exist in the region.

So, yeah – we need some replication here. Back to Dr Lisle:

The gravitational pull of this unseen material causes stars to orbit the galaxy faster than they would if there were no such material. Also, gravitational macro-lensing (the bending of light as it passes by a galaxy) allows scientists to compute the mass of the galaxy. Such calculations confirm that galaxies contain far more mass than simply their visible components (stars, gas, and dust). Moreover, the motions of galaxies themselves as inferred from their Doppler shifts suggest that dark matter holds together clusters of galaxies.

There’s the interesting question of how many of these things would be out the window if some of the stranger cosmological ideas of certain young Earth creationists were true, but we’re not going there. Instead, Lisle borrows from the space.com article two of their candidates for alternatives to dark matter, as these results are unfortunate in that our current models apparently predict that there should be some of the dark stuff nearby. He writes:

One possibility is that dark matter is not the correct explanation for stellar and galactic motions. Perhaps the current understanding of the laws of physics is slightly off.

One of the more popular alternatives to dark matter is a model called Modified Newtonian Dynamics (MOND). This model proposes that the force of gravity is slightly stronger than the standard Newtonian law of gravity (the inverse-square law), particularly in cases of very weak fields. MOND has had some success in accounting for the velocities of stars in spiral galaxies, and it would be consistent with the new research indicating the absence of dark matter in our solar neighborhood. But it is unclear whether MOND accounts for other observations in the cosmos.

From my reading, MOND can really be dismissed. From the space.com article:

However, MOND doesn’t fill as many gaps as dark matter does: it works perfectly only for spiral galaxies, Clowe said. For elliptical galaxies, galaxy groups, galaxy clusters, and larger-scale structures, the theory doesn’t quite fit observations, and so it requires that extra matter — i.e., dark matter — be invoked once again. “So instead of just using an undiscovered particle to explain our observations of structures in the universe, MOND requires both an undiscovered particle and a modification to the gravitational-force law,” he said.

It’s not a great alternative. But there’s another idea:

Another possibility is that dark matter is distributed differently than astronomers had previously thought. The motion of stars as they revolve around the galaxy is consistent with the presence of dark matter interior to their orbits. But the dark matter would not necessarily have to be abundant in the vicinity of the sun to account for stellar motions around the galaxy. For example, “warm dark matter” (particles with intermediate energy) might explain all the observations. But there is a catch—at least in the secular view. Warm dark matter cannot account for the formation of galaxies after the big bang. Most astronomers search for cold dark matter instead, since they believe it helps gas to collapse into galaxies.

That’s not quite true. Lisle is presumably getting this entirely from the article – I can’t find much about it elsewhere – and the quote about galaxy formation actually says:

However, the researchers said that cold dark matter particles are strongly preferred by cosmologists, because less massive dark particles would have problems forming galaxies quickly enough to match astronomers’ observations of the early universe.

Whether these problems can be reconciled is an open question, as far as I can tell. Does warm dark matter have other disadvantages? Could there be a mixture? It was once thought that dark matter could be made up of brown dwarves and other interstellar detritus – while we now know that there isn’t nearly enough of the stuff around to do the job, it does exist. Could ‘cold’ dark matter also exist, in great enough quantities to cause speedy galaxy formation but not so much that it would have to be in this part of the galaxy? Who knows.

Dr Lisle, however, has found a bias in the scientific investigation, and goes in for the kill…or something:

Here, a solution that seems to best fit the data has been largely rejected, not for scientific reasons, but rather on the basis that it does not fit the secularists’ belief about origins. It’s not that this is wrong. Everyone interprets data in light of his or her worldview. But it shows that secularists are not “neutral” or objective in their approach to science. In the biblical model, there is no reason to believe that galaxies have or can form spontaneously. Therefore, warm dark matter might be a nice explanation for the data.

If you’re wondering, what makes this better than a Brian Thomas article is that he would probably just dismiss the whole thing out of hand – there is no shortage of articles on the ICR’s website making snide remarks about the concept, including from Mr Thomas.

The trouble with this paragraph is that it’s a bit of a double standard. He was perfectly ok with being a little cautious with the MOND idea due to it not lining up with what we know about the universe so well, but now that the conflicting observable reality is one that he doesn’t agree with it’s all “secularists are not “neutral” or objective in their approach to science.” We have lots of evidence at this point that the Big Bang took place, that galaxies “form[ed] spontaneously,” and if this conflicts with that it’s naturally going to look a little doubtful.

Dr Lisle concludes:

Also, this research illustrates that many secularists are willing to believe in something that cannot be seen, heard, touched, or detected in any way—they believe in dark matter (perhaps rightly) by faith because it can make sense of that which is visible. And yet many of those same secularists would reject a belief in God on the basis that He cannot be directly observed, despite the fact that the biblical God alone makes sense of the universe and our ability to understand the universe through science. Romans 1:18-20 explains that God has clearly made Himself known to all mankind, and those who reject Him are “without excuse.”

But dark matter can be detected, just not directly. Lisle, after all, gave a good list of reasons for its existence above. But the evidence for a God (the ‘directly’ in “He cannot be directly observed” is not needed – if you needed a telescope to see God, but could indeed see Him through it, that would be ‘indirect’ but still good enough for most people), and especially the God these YECs believe in, is in a completely different league. The Romans verse doesn’t give any, for example, and just ascribes phenomenon that I would put under “shit happens” to Him.

I complained about the search box, with instructions on how it might be fixed. No response.

3 thoughts on “Warm Dark Matter?

  1. I am unclear on what grounds Lisle states that from the available alternatives, ‘warm dark matter’ is: “a solution that seems to best fit the data”.

    HOWEVER I suspect he may be attracted to his opinion because “less massive dark particles would have problems forming galaxies quickly enough to match astronomers’ observations of the early universe”. YECs presumably say that astronomers’ did not really see what they thought they observed (at great distances and thus in the past) because the whole universe was created by God – much as it is now, ex nihilo and within the last 10,000 years.

  2. Oh the, “secular scientists are biased line.” It’s probably the most annoying sentence on the internet.

    I have a question for you.

    “There’s the interesting question of how many of these things would be out the window if some of the stranger cosmological ideas of certain young Earth creationists were true”

    I am writing an article on a related theme. Inspired by this paragraph I found doing the rounds online:

    “If the universe is less than 10,000 years old, then: all of geology and biology are wrong; the speed of light has been wrongly calculated, so Einsteinian physics is wrong; the distance and speed of other galaxies has been wrongly calculated, meaning that all of astronomy and therefore Newtonian physics are also wrong.”

    A scientist friend of mine looked at that and thought it was only partly correct, but I would be interested in information like that if you could point me in the right direction.

  3. All of geology – yes, geology requires deep time.

    All of biology – yes, biology requires evolution, which requires deep time.

    All of astronomy – well, yes, all of the explanation bits. The pretty pictures are still valid.

    Einsteinian and Newtonian physics – however. These are both provable in the lab (for a large enough lab). Therefore if the measurements are wrong, then there must be a confounding factor. Whether this is a malicious creator or some other effect, it is impossible to speculate.

    As an example – Newtonian physics based around orbits predicts that stars further out in spiral galaxies should orbit more slowly than they do. Hence there needs to be more mass, hence we postulate the various forms of dark matter. However, at further distances, supernova measurements suggest that the retardation of velocity due to the gravitation of the universe is not just slower than we expected but has actually reversed. Hence we postulate dark energy. Both of these are “confounding factors” to the previous scientific model.


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