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from the mini-halos-are-for-really-small-angels dept.
Missing Galaxies? Now There's Too Many:
Gaze skyward from the Southern Hemisphere and it's hard to miss the Large Magellanic Cloud. The fact that it looks like one of the Milky Way's spiral arms, albeit smaller, reveals that it's a small galaxy roughly 30,000 light-years across with a few billion stars. Indeed, any small telescope will show that it's scattered with glowing nebulae that are punctured by dark dollops of dust.
And it isn't the only satellite galaxy that slowly swirls around the Milky Way. By 1999, astronomers had detected a dozen companions, many of them invisible to the unaided eye. But at that time, computer simulations of the evolution of the universe had predicted that the Milky Way's neighborhood should be bustling with activity — hosting not a dozen, but thousands, of tiny companions. So where were the missing satellites?
That astronomical riddle went on to bedevil astronomers for nearly two decades. Researchers came up with a number of potential explanations. Some involved speculative new ideas about how galaxies evolve. Others proposed the existence of exotic forms of dark matter — the mysterious substance that makes up 84 percent of the matter in the universe.
But within the past few years something strange happened. New surveys allowed astronomers to find more satellite galaxies that had previously been hidden. At the same time, updated computer simulations predicted the existence of far fewer galaxies than their predecessors did.
In fact, the estimates of galaxy numbers from observational studies and from theoretical simulations converged so quickly that they ended up overshooting each other. Whereas in the early 2000s astronomers worried that there were too few satellites, by 2018 there appeared to be too many. The missing satellites problem had been turned inside out.
The story dives into ultra faint dwarf galaxies, dark matter halos, mini-halos, tiny little ghost galaxies, as well as computer simulations of the Milky Way galaxy having different results depending on whether they were based on dark matter or on our everyday baryonic matter.
But [University of California, Irvine astronomer James] Bullock and his colleagues didn't merely outline the problem, they also proposed a solution. Simulations have long suggested that lots of dark-matter mini-halos formed around the Milky Way. But astronomers argued that these halos didn't form galaxies. There's a threshold, the argument went, below which these halos simply didn't have enough gravity to hold on to the gas necessary to form stars. They were thus star-free and invisible.
For nearly 20 years, astronomers thought that threshold for the mass of a dark-matter halo that could form a galaxy rested around 500 million times the mass of the sun. But Bullock's team suspects that it's much lower, around 30 million times the mass of the sun.
If such small globs of dark matter can grab onto enough ordinary matter to create stars (and thus galaxies), then simulations start to match observations. Indeed, Bullock's team was able to model galaxies that are eerily real. Not only do the numbers of simulated mini-halos match the numbers that are predicted by observations, but the shapes of the galaxies' orbits even look like the ones we have already detected.
(Score: 2) by Gaaark on Wednesday January 30 2019, @03:59PM (5 children)
You are correct, sir!
Read
http://physicsfromtheedge.blogspot.com/ [blogspot.com]
for REAL science and scientific method at work.
--- Please remind me if I haven't been civil to you: I'm channeling MDC. ---Gaaark 2.0 ---
(Score: 3, Interesting) by AthanasiusKircher on Wednesday January 30 2019, @07:44PM (2 children)
Okay, I looked over it for about a half hour. I also spent another 15 minutes reading other commentary on this theory.
I've heard of QI and this guy several years back, but I never looked into it in great detail. Now the guy's got a DARPA grant to test his theory practically. Good for him! Seriously. If it pans out, he will be heralded as the next Einstein, the wonder who could see past everything that thousands of other scientists could not. Actually, it would be bigger than Einstein, since there were a number of other physicists and mathematicians playing around with stuff like special and general relativity ideas before Einstein came along -- Einstein brought it all together. But this guy -- he's apparently been actively shunned by the scientific establishment. What a coup if he turns out to be right!!
And I'll give him that with all seriousness. Let him test his theory. And I will be the first to congratulate him if it turns out.
But, I'll be honest, from what I've seen so far, it doesn't bode well. This guy shows the patterns of a crank. If I had to give odds, I'd say there's ~2% possibility that his DARPA grant will show him to be an unparalleled genius, 98% that he's just a crank.
Why do I say that? I'll admit I haven't had time to investigate the theory in detail, though I get the gist of it. What worries me is the pattern of other stuff surrounding it. He promotes his ideas on a personal blog and gave a TED talk. His ideas promise "energy from nothing" that would revolutionize space travel. I read a post there where he claims he hasn't had a paper accepted at a conference since 2012, and other physicists won't even return his emails. Other prominent physicists have derided his ideas, no because of what they seem to model well, but because they not only do away with dark matter, but also break a lot of standard physics theories (like relativity) that have huge empirical support. When challenged in the press on how his theories break Relativity, he himself admits on his blog that there would be a lot of work required to bridge the gaps between his theory and GR (again, which has lot of well-tested empirical support) -- but he says it isn't a high priority for him to deal with such inconsistencies... and then blames the lack of attention to this to the fact that other physicists ignore his emails, or else he could perhaps collaborate with them and get them to solve the problem of connecting his theory to the rest of standard physics. (He doesn't quite put it so starkly, but that's the implication.)
I've personally known people like this over the years -- people with outrageous ideas that claim to completely overturn a field of study. One guy I am thinking of made a big splash in his field starting about 15 years ago, when he started standing up at conferences and giving talks declaring that all the standard ideas were wrong, and/or that his theory was an overarching theory that united everyone else's ideas. He was a jerk who got incredibly defensive when questioned. He thus alienated other scholars. He started complaining that nobody would publish his research, because he started redefining common terms to fit his own weird theory, and editors (rightly) challenged him and said it was at best confusing to do this and at worst made his theory a hodge-podge of gobbledygook.
Eventually, he made it big by going outside his field and publishing in a more prominent journal outside his main field, where the editors obviously didn't realize that most of the grandiose claims he was making were exaggerated. It's not that he was wrong exactly about his ideas (though he was wrong about groundbreaking they supposedly were, a statement he kept repeating) -- it's that he created a kind of diffuse mega-apparatus for understanding several other theories using complex math, but his conceptualization didn't add anything. It was confusing, overly abstract, and really not worth the time. But his grandiose claims were enough to get him a little media attention in the mainstream media, since he now had this article published in a more prominent journal. A couple years later, instead of writing journal articles and debating with other figures, he wrote a big book claiming everyone else in his field was wrong. Eventually, some in the field accepted the more useful aspects of his research (which mostly weren't connected to the grandiose mega-theory), and he calmed down a bit after he got tenure and had kids.
That's someone who wasn't quite a crank, but he did push the boundaries of "conspiracy theory" in the way he thought the field was persecuting him and refusing to listen to him, when in reality he didn't care about how his theory might intersect with others in his field, and he took to becoming defensive, acting like a jerk, and refusing to acknowledge criticisms, even when they were quite reasonable.
I was involved another time in publishing a rebuttal (along with a colleague) against a true crank. Once again, someone who went away from his original field of study. He managed to get an article published in a prominent journal on a topic that was again a bit out the journal's mainstream, and likely the editors didn't send it out to the right people for review. So, it got published, and suddenly it was the talk of various media outlets for two days. Except it was complete BS, founded on complete misunderstandings of fundamental concepts in the field, along with some incredibly statistical errors in his methodology that ensured he'd find patterns wherever he looked for them.
Although my colleague and I submitted a rebuttal to the journal within two weeks after the story got media attention, the journal dragged its feet in reviewing it, probably because they didn't want the embarrassment of the fact that they had published something so questionable. Eventually, our rebuttal was published, but the crank went on as if nothing had happened. He gave talks, and he convinced a smaller publisher to accept a book on his topic. I was asked to review it, but I declined: our rebuttal was so utterly clear to anyone who knew anything about the topic that it should have stood alone to ruin the ideas. But he kept going on as if nothing had happened. The mainstream media of course never published anything about a debunking of this story they had plastered everywhere, so this guy could still convince people (particularly those outside his subfield) that his work was legit. I don't really know what happened to him -- the ideas he had had no practical significance, so I don't really care anymore. (I do still get a few emails every year from scholars who have discovered my rebuttal and are mostly just floored that this guy still maintains any credibility as a scholar in any field.)
So, I've seen cranks. I've known them personally. There's a pattern of reaching a bit outside one's field (this QI guy wasn't trained as a cosmologist or theoretical physicist), followed by denial when papers or conference presentations are rejected, then treating anyone who disagrees with disrespect or presenting their views as strawmen (as you do here, and he does regarding dark matter on his blog -- there are flaws in dark matter theory, but he seems to oversimplify and misrepresent them), followed by a persecution complex that no one will take him seriously, often followed by writing a book or having a blog to promote ideas outside the mainstream research path of peer-reviewed journals. Your QI guy shows a lot of these features. His book was apparently published in 2014, but it has only 7 reviews on Amazon, none of which seems to have been written by an actual physicist (though a couple identify as "physics groupies"). I tried poking around in searches for professional reviews in journals or something, but I see nothing. Which is frankly weird, if his theory is so amazing. (Even if mainstream physicists didn't like it, you'd at least expect a critical review SOMEWHERE debunking it, if anyone thought of it as a serious theory.)
After his DARPA grant award, you don't see a lot of physicists coming to his side either. I know that scholars tend to be attached to their theories, but it's very hard to believe that something this groundbreaking (and potentially amazing for reasons outside of cosmology, such in practical applications of space travel) would be ignored by basically ALL mainstream scholars for no good reason.
I'll withhold judgment until after he has time with his grant to prove or falsify his own theory. But I'm not holding my breath for confirmation.
As for "REAL science" and the "scientific method at work," well, he now has a chance to test his theories. When they bear out (or are falsified), THEN we can say the scientific method is at work. For now, this is just another hypothetical model that needs clear empirical support.
(Score: 2) by Gaaark on Wednesday January 30 2019, @08:37PM
Einstein was a crank once, also. He had many detractors.
I'm not married to him, lol. If something better comes along, I'd like to know about it.
BUT, It seems far more scientific than dark matter AND his formula fits better than dark matter and MOND: I'll go with that.
But...show me something better. And no, dark matter is not better.
I too hope he pushes science forward (whether through success or failure) instead of backwards like DM is doing.
--- Please remind me if I haven't been civil to you: I'm channeling MDC. ---Gaaark 2.0 ---
(Score: 0) by Anonymous Coward on Thursday January 31 2019, @12:04AM
So instead of look at the actual work you took all that time to write up your judgement of the person? A heuristic is supposed to be quick... I think you are elevating one to an importance it does not deserve.
(Score: 2) by AthanasiusKircher on Wednesday January 30 2019, @07:57PM (1 child)
One last thing I'll add after an overlong post: there are lots of theories in science that have long histories of not being directly observed for long periods. As I mentioned in another post, the underlying mechanism for gravity wasn't known for centuries after Newton's theory advanced physics (and some would argue we're still sorting it out), but no one is claiming gravity -- an invisible force acting at a distance -- doesn't exist. The atomic model was essential in advancing modern chemistry out of alchemy, as theories about molecules and chemical equations started to be written when no one had directly observed the existence of molecules or atoms. Electrons were postulated to explain electricity long before the structure of the (still invisible) atom was understood in any detail. Huge theories of electromagnetism were built on it. And when unusual results came along that seemed to conflict with theories (e.g., Rutherford's experiments), they didn't conclude that the unseen atoms and electrons didn't exist -- merely that the properties must be more specific and perhaps different than theorized. I could go on, but hopefully I've made my point.
Just because you can't observe something directly doesn't mean it's not there, or that you can't create a detailed mathematical model of it that could lead to advancements in science. You're right that the dark matter theory has some problems, though you tend to overstate or misrepresent them -- it's nowhere near as arbitrary a theory as you imply. Perhaps it will turn out to be like phlogiston or the lumeniferous ether, or perhaps it will turn out to be like so many other scientific theories over the years that modeled unseen things and unseen forces and turned out to be broadly correct.
(Score: 2) by Gaaark on Wednesday January 30 2019, @08:24PM
Yet, MAYBE gravity DOESN'T exist, at least not as a folding of space thing: maybe gravity is a PUSH, as in QI, the Unruh waves PUSH objects. A planet blocks the Unruh waves from a certain direction, the waves from the other direction push objects TOWARDS the planet.
To me, a PUSH makes more sense than a Folding of space... A 'PULL'.
And where is dark matter not arbitrary? Your other examples had more science behind them than dark matter.
--- Please remind me if I haven't been civil to you: I'm channeling MDC. ---Gaaark 2.0 ---