131–140 of 315 posts
Meta-source: https://en.m.wikipedia.org/wiki/Dark_galaxy
I like how we have an article explaining the rationale behind dark matter and the scientific principles that lead to the conclusion that it exists, but most of the threads here are simple declarations that no, they must all simply be wrong or not considering some simple alternative. Can people maybe, just maybe not assume that scientists are idiots or, as once dead commenter puts it, charlatans? If you disagree with…
Almost all of our current scientific knowledge has come from challenging the consensus of the times. Scientific skepticism is always healthy and should be welcomed. Even if the original theory is correct, that doubt will simply help science better explain and prove the current understanding. I'd actually be more worried if everyone agreed about something. Even gravity we thought was fully solved until Einstein doubte…
I like how we have an article explaining the rationale behind dark matter and the scientific principles that lead to the conclusion that it exists, but most of the threads here are simple declarations that no, they must all simply be wrong or not considering some simple alternative. Can people maybe, just maybe not assume that scientists are idiots or, as once dead commenter puts it, charlatans? If you disagree with…
One problem with dark matter is that there have been an increasingly large number of quite clever experiments to try to detect various concepts of it, WIMPs in particular. And each and every one has been a negative. This should, in and of itself, begin to cast down on the hypothesis even lacking a better alternative.
Despite recent some initial evidence to the contrary,[1] I'm still a fan of the idea that dark mater is actually concentrations of matter/energy outside of our universe. If string theory is true, gravity does leak into the multiverse, and we survive the Great Filter, then someday we may be able to use gravity to communicate universes outside of our own. https://www.sciencenews.org/article/gravity-doesnt-leak-larg...
Can someone that knows a bit more about this explain why we believe that this dark matter substance must exist and not simply that we have an incorrect model of gravitation?
I think their may be a small number of languishing models that aren't totally disproven but don't look very promising. But I'm not sure.
« On 25 August 2016, astronomers reported that Dragonfly 44, an ultra diffuse galaxy (UDG) with the mass of the Milky Way galaxy, but with nearly no discernable stars or galactic structure, may be made almost entirely of dark matter.[6][7][8] » Meta-source: https://en.m.wikipedia.org/wiki/Dark_galaxy
Earlier quoted context omitted.
Our understanding of gravity might be completely wrong. If 85% of the gravity is unexplainable that seems like a pretty safe bet. Maybe it just behaves very differently at galactic scale. Much like the aether, it seemed most likely that light traveled through a medium until it turned out that it probably doesn't.
The aether stuff confuses me. We replaced light traveling through some medium, the aether, with light traveling through a photon field which permeates all of space, among many other fields. That sounds like an aether by another name. Yet now we say aether theories of the turn of the 20th century types are debunked and everyone then was wrong. Yes the medium of a field is very different in nature than any classical on…
The aether was a good idea, it was wrong, but it was a good idea anyway. Perhaps they exaggerated trying to model it like a solid/liquid and deduce the properties, so they got weird results, but it was common those days. For example, the first model of Maxwell used some weird mechanical elements. The mechanical part was useful to deduce the equations. A few years later he dropped the mechanical part and keep only the equations. https://en.wikipedia.org/wiki/History_of_Maxwell%27s_equatio...
The main difference between aether and a modern field theory is that with aether you have a preferred reference frame. Some things are not moving and other things are moving. Like in a lake with still water, the buoys are not moving, a moving boat is moving, and you can make some experiments to measure your speed of the boat relative to the water.
In the field that is used currently for photons (and other elementary particles) is different. You don't have a preferred reference frame. Any object that is not accelerating can be selected as a not moving object. But any other object that is moving at a constant speed can be also selected as a not moving object too. Any of them can be selected as not moving! But to compare the measurements in one of the object with the measurements in another object you must make some corrections. And the most important property is that there is no experiment that you can do to measure your speed relative to the field. This is related to the fact that light goes at the same speed for every "boat" here, even when they are moving at a constant relative speed.
So the field is like a magical fluid, even more magical than the aether. The important part is that there are accurate equations to describe all this handwaving and all the magical properties of both. The equations for the aether doesn't agree with the measurements in experiments, the equations of the field agree.
Earlier quoted context omitted.
Agreed 100%. Indeed, this is one of the best articles I've come across which covers several of the reasons we believe dark matter exists, as opposed to us just needing to modify the theory of gravity. For whatever reason, dark matter seems to repeatedly rub people the wrong way today, more so than any other scientific concept I can think of. I actually wonder if it's something psychological -- if the universe is only…
>For whatever reason, dark matter seems to repeatedly rub people the wrong way today, more so than any other scientific concept I can think of. I think that it is because it is so hard to understand. You can't see it or touch it but it is supposed to make up the majority of mater in the universe. So what is it then? For a lot of people that's a hard thing to get and it would be easier if the answer was something we u…
This strikes me a lot like “flatland”, ie. there’s something there but we’re not equipped to perceive it. Our experiments are mostly like extreme extensions of our own senses - seeing and touching things. But could something exist entirely within a dimensional space that we can’t touch or see? And if so how would we ever figure out how to detect it ... and even more meta, what if it was impossible for us to perceive…
Scientists have explored alternative models of gravity or spacetime with additional spatial dimensions and things like that. As far as I know, none of them are very promising. There was an interesting PBS space time video about one example recently: https://youtu.be/3HYw6vPR9qU
Of course, it is definitely interesting to think about :)
I like how we have an article explaining the rationale behind dark matter and the scientific principles that lead to the conclusion that it exists, but most of the threads here are simple declarations that no, they must all simply be wrong or not considering some simple alternative. Can people maybe, just maybe not assume that scientists are idiots or, as once dead commenter puts it, charlatans? If you disagree with…