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Our future, our universe, and other weighty topics


Monday, August 29, 2016

Galaxy Expert Confesses We Don't Understand How Galaxies Form

Last Friday scientists made a surprising announcement. They announced findings about a mysterious galaxy 300 million light-years away, a galaxy named Dragonfly 44. This galaxy seems to have about roughly the mass of our galaxy, but only emits 1 percent of the light our galaxy emits. Astronomers stated that this Dragonfly 44 galaxy is 99.99% dark matter. Dark matter is believed to be a mysterious form of matter that makes up about 27% of the universe. Ordinary matter is believed to make up only about 5% of the universe, with dark energy making up about 68% of the universe.

But such an announcement presents a great paradox. If ordinary matter makes up 5% of the universe, and dark matter and ordinary matter are mixed together throughout the universe, how could it possibly be that a particular galaxy would be 99.99% dark matter? This would seem to be as unlikely as that there might be some weird local change in the composition of the air, which is normally 78% nitrogen and 21% oxygen. Imagine if somehow the nitrogen in the air became so dominant that the air above a town became 99% nitrogen, causing all the people in the town to die of oxygen starvation. Such an event seems as improbable as that some galaxy would consist of 99.99% dark matter, when dark matter and ordinary matter are mixed throughout the universe.

After a result this surprising, we must take a step back and realize that there is really no firm basis for making statements such as the claim that this Dragonfly 44 galaxy is 99.99% dark matter. Dark matter has never been directly observed, and a multi-year attempt to directly observe it has failed. What we see in this Dragonfly 44 galaxy can most simply be described like this: a galaxy is behaving in a way that is inexplicable under our current understanding of gravity, inexplicable by a factor of 1000 times. Imagine if I see a bus floating up into the air. It would be rather presumptuous to make a statement such as: “The bus must consist of 99% antigravity material.” I should instead simply say that the bus is behaving in a way I don't understand. Similarly, rather than using some exact dark matter figure that makes it sound as if they understand what is going on, our scientists should be candidly confessing their lack of understanding of what is going on.

But that is not the way of the modern theoretical scientist. The modern theoretical scientist seems to be very prone to exaggerate his understanding, to make it look as if his understanding of some great mystery of nature is good, even when it is very poor. Here are some of the techniques that are typically employed as part of such a thing.

Ignore the unanswered questions. Asked to explain what we know about a particular topic, a modern scientist will probably go into a discussion that focuses entirely on what has been discovered, as well as what has been theorized, without mentioning what we are ignorant about. For example, a scientist asked to talk about the Big Bang will go into a discussion of why we think there was a Big Bang, and may also go into speculations about some details of the first second of the Big Bang. He will avoid mentioning that we don't understand the cause of this event.

Weave a blend of fact and speculation. Asked to explain a mystery such as the origin of life, the modern scientist is often like someone who needs to have a coat, but who merely has some assorted threads of fact. The scientists will then augment his threads of fact with some threads of speculation. By artfully weaving these together, and focusing only on bits and pieces here and there, the scientist may leave you with the impression that he has something like a coat, even though he may have perhaps merely a few scattered pieces, like a collar that is half fact and half speculation, and a coat elbow that is more speculation than fact.

Clutter the answer with jargon and minutiae. Asked what we know about some mystery that is not understood, the modern scientist will very often give an answer filled with jargon and a discussion of intricate fine details – the details often being details of a speculation rather than details of fact. To the average person, this may seem very impressive, and may leave him with an impression the scientist has a deep understanding of the mystery, even when the scientist has no such thing. For example, if asked to explain how humans can remember childhood memories for 50 years, a neurologist may launch into a jargon-filled discussion of some “clustering dynamics” theory attempting to explain the persistence of human memory. It may seem impressive in all its details, until you find out that it is mere speculation.

Don't mention the problems with your explanation. Very many or most theoretical explanations have some problems associated with them, reasons for doubting such explanations. When asked about some great mystery of nature, a scientist will very often confidently discuss some theoretical explanation, but fail to make any mention of problems associated with such an explanation. For example, when asked about how memory is stored, a neuroscientist may tell you that this is caused by LTP (long term potentiation) in synapses – but completely fail to mention that LTP is actually something that quickly decays, and generally doesn't last longer than a few weeks. Similarly, when asked about the origin of species, the modern biologist will confidently offer the Neo-Darwinism explanation that the cause was natural selection and random mutations. Our biologist will not mention that such an explanation does absolutely nothing to explain why any particular biological implementation would have made the large leap from a starting point to a “reward threshold” level of complexity and coordination (often very high) necessary for the implementation to first start yielding any survival value reward. Our biologist also will not mention that helpful random mutations are many times less common than harmful mutations. 
 
I have seen these techniques used hundreds of times by scientists trying to depict themselves as “lords of knowledge” about matters which mankind is really very ignorant about. So I was utterly flabbergasted to read a statement by galaxy expert Pieter van Dokkum, a statement of great candor. Talking about the mysterious Dragonfly 44 galaxy just discussed, van Dokkum says, "It means we don’t understand, kind of fundamentally, how galaxy formation works."

No doubt van Dokkum's colleagues would respond by saying, “It's just gravitation,” but I would remind them that gravitation cannot explain the persistence of spiral galaxies such as the Milky Way, nor can it even explain the appearance of galaxies with such a shape.  See here for more on why the persistence of spiral galaxies is so hard to explain.

A spiral galaxy (Credit: NASA)

I think van Dokkum deserves great applause for this rather rare case of explanatory candor by a scientist. This is what I want from a scientist – a candid statement of ignorance where knowledge is lacking, rather than some pretentious pedantic affectation in which the speaker pretends to understand some deep mystery he does not really understand. Let's hope we can start seeing more of this candor from our biologists and neuroscientists.