“Settled Science”
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As a modern example, “dark matter” was proposed as an explanation for the observation that galaxies weren’t spinning the way models predict they should be. But after decades of searching for dark matter, no candidate particles (for example, “wimps”) have been found.
So, maybe the initial hypothesis is wrong. Maybe it’s not dark matter. Maybe the answer is “mond” (modified Newtonian)
Isn’t that cool? When science gets something wrong, we correct. We move forward.
…but, for some reason, which makes no sense at all but trust me on this… if you refuse to bend the knee and accept global warming and dismantle your entire economy to “fix” it …. For some reason that stops astronomers from considering other explanations for dark matter.
QED
I recall learning about dark matter; possibly on NOVA or another program. It was s sort of magical presence that made a lot of other theories and calculations work. I also remember the narrator made it sound like "settled science" because they were so sure they were on the way to proving it at the time.
Also, it looks like String Theory hasn't made much progress since I read books about it almost a decade ago.
Dark matter is a pretty reasonable guess to explain a very clear observation.
You’ve seen animations of the solar system, right? The inner planets are wizzing around really fast, but the outer planets are going quite slow. A galaxy should work the same way. But when you measure the speed of stars at various distances (using red shift and blue shift) the speed is a lot more uniform.
So, something is missing. Maybe red shift/blue shift doesn’t work the way we think it does. Maybe gravity doesn’t work the way we think it does. Or maybe there’s a lot of extra mass we can’t see.
For a long time (and mostly still today) people thought the most likely explanation was missing mass. We know there are particles we haven’t discovered. The discovery of the neutrino happened just like this: an experiment got a strange result, and someone proposed a new particle to explain it.
But with the neutrino, they came up with a clever way to test the hypothesis, and when they did, they found neutrinos.
Actually, I suppose a similar thing has been done with dark matter. Given the hypothesis called dark matter, they make a prediction: light should bend around galaxies a lot more than it would otherwise. They set out to find examples and it took the resolution of the HST to finally find any. “Gravitational lenses” they’re called.
But unlike with the neutrino, this doesn’t give us any insight into what dark matter actually is. So, people are still open to other possibilities. MOND is one.
Brane theory is the latest one I've heard.
I thought "Dark Matter" was just mass in distant galaxies that didn't reflect light? At least not light that travels a bazillion light-years anyhow. That makes sense to me.
"Distant Galaxies" = lolz! Like there's any other kind?
Yes but for it to cause the effect we see with galaxy rotation, there would have to be an absolute shit-ton of it; way more than any theory predicted.
Every type of matter that is floating around out there gets incorporated into stars. The reason for this is that there’s nothing special about the process that makes stars. It’s just a gravitational collapse. It can’t select for one type of matter and exclude another. So for example, if carbon atoms are floating around, they end up in stars. Make sense?
We can use spectrographs to get the proportion of different types of matter in stars, and (with some adjustments for the age of stars) the proportion that should be in the rest of the galaxy.
But then, based on the anomalous spin, there must be a lot more - a lot more.
Or, theories of gravity are wrong, or maybe the speed of light isn’t constant. There are several possibilities, but “missing matter we can’t see” is definitely the simplest. It’s just that, after all these years we haven’t found it.