Expansion of the Universe

[j d worthington]

I have a problem with both dark energy and dark matter. Do they really exist?

For the time being, they are the only things that fit the evidence we have; and there is a fair amount of evidence to support them, all right. Should a new model that explains our ever-increasing knowledge be developed, that does without them (which would also mean something that accurately fits the evidence in support of their existence), then it will eventually replace the current one. But, from what I've seen over the last several years, the supporting evidence has definitely been increasing. Query: Do you know of some evidence that would seem to indicate the contrary?

 

[The Pelagic Argosy]

Of course dark matter theories do explain a lot more about the universe and what's hidden from our current explanations of it.. Dark matter theories say basically "if we want such and such a result, we have to have an 'x' factor, which is the difference between what we want, and what we can actually detect. Now we describe what characteristics this 'x' factor must have, postulate its existance, and specify that it will be detected in the future." This is called "circular reasoning" even when it's well concealed, and is practiced in many disciplines, and should be violently repressed.

Which doesn't mean dark matter doesn't exist; it's not a bad theory, but it's like the "steady state/continuous creation of matter" Hoyle theory (now in quiet retirement), a way of explaining away inconsistancies in present theories, rather than scrapping them and starting over.

Yes! I think they should just called it "ether" already.

j.d. Worthington: You asked if there is evidence against dark matter. How about the fact that they are, as of yet, undefined.

 

[GrownUp]

There were 2 propositions of dark matter from different areas of science of a type of particle that has to behave in a certain way.


Dark matter was proposed first in the Astrophysics field of galaxy formation - because of the kinetics of, well... forming galaxies.


The dark matter proposed in Cosmology came later, all to do with a sort of energy conservation....the amount of each type of matter there has to be for the successful creation of stars and elements that we can see exist, the cake itsn't crumbly therefore we infer the presence of eggs in the mixture.



The elements we know exist out in the Universe- like carbon and hydrogen- are observed through the light of stars. If it doesn't glow, we can't see it. If something doesn't glow, but causes other effects, like bending the paths of light at matter around it (gravitational interactions - being heavy) or holding galaxies together, then we infer that it may be present.


It's only called dark matter because it doesn't actually glow like stars do.


In fact, there are many types of particle that we know exist on earth that may be up in the sky behaving like dark matter. But, short of going up there and capturing some of it in a cup, there is no way to see.


....Double in fact....people are trying that. The motion of the earth takes us through regions of our local galaxy, and if there is dark matter about we should be passing through it. Particle detectors deep underground are monitoring background particle interactions - as the seasons change.


...to see what's in the cup....

 

[tegeus-Cromis]

Not sure about that - don't recall that idea.

I like the version where the universe continues expanding out - the Hyperbolic Universe, I believe it is. Which means that space is "saddle-shaped" rather than flat or spherical.

If you'd like to see some different "saddle-shaped" shapes then really do check out this site here:

http://www.indiana.edu/~minimal/gallery/index/catalog.html

and

Image 1

Just think - when you look at those graphics, you could be viewing something of the fundamental reality of the universe.

Ha ha! I know IRL the guy whose website you linked to!