Dark Matter

[Lost_BMW]

Interesting report on a scientist's claim to have found the dark matter component in a filament in a supercluster about 2.7 billion light years from us, called Abell 222/223.


http://www.newscientist.com/article/mg21528725.200...

[Derek Smith]

article said:

The rest must be dark matter...

I think what I meant to say was they had no idea what the rest was.

[MikeyC]

Bedazzled said:

Isn't that inference rather than detection? It could be our understanding of gravity is wrong.

Interesting bit on R4 Today progam this morning ~7:30
http://www.bbc.co.uk/programmes/b088dbxj

since several DM detectors have found absolutely zilch, some scientists are now considering our understanding of gravity might not be complete

personally, never bought into the DM theory as it seemed too much of a band-aid fix

[Einion Yrth]

Mike McCulloch's theory MiHsC is an interesting counterpoint to the whole Dark Matter shenanigans.

[MarshPhantom]

How much money have we wasted trying to figure this out?

[Atomic12C]

The theory of Dark Matter does go a long way to describe observations, BUT, as has been mentioned already there are other ways to explain observations.

Gravitation is likely not fully understood.
Given that gravitation is the main barrier from drawing together a "Theory of everything", which will merge the minuscule with the mindbogglingly massive.


I am hoping that now we can detect gravitational waves via Ligo in the USA that this will lead to a much clearer definition and most importantly a definitive relationship with this 'force' to the other fundamentals.


I also hope that Pilot Wave Theory comes to the forefront. This to me seems a more logical explanation of the minuscule that may tie in to a "Theory of everything" better than current quantum theory.

[RobM77]

Bedazzled said:

article said:

The rest must be dark matter...

Isn't that inference rather than detection? It could be our understanding of gravity is wrong.

That's the whole point of 'dark' matter Yes though, gravity being different is something some people have proposed (e.g. MOND). The goal for those hypotheses is to come up with a test so they can be verified.

Currently, Einstein's GR not only feels simple, beautiful and right in concept (even if not simple mathematically!), but it works on a multitude of different tests. GR has proved itself both very locally in our solar system at a mild level of gravity, for example the astounding perihelion of Mercury prediction; and also much further afield at very extreme levels, for example the two colliding black holes that LIGO recently detected a GW signature of behaved exactly as GR predicted. That's not to say that any new theory couldn't resolve down to match GR given appropriate parameters, but like Newtonian gravity we would expect some parameters to show up holes or weaknesses which can be described by a new theory. DM may be one of those weaknesses, but we currently lack the evidence to say that definitively. These new theories have a mountain to climb before they become accepted.

I really hope we find the answer in my lifetime

Edited by RobM77 on Thursday 5th January 10:22

[Derek Smith]

There's an article on it in New Scientist this week. The suggestion is that Einstein is 'wrong' in the sense that there's more to it than he thought.

An exciting turn.

[RobM77]

Derek Smith said:

There's an article on it in New Scientist this week. The suggestion is that Einstein is 'wrong' in the sense that there's more to it than he thought.

An exciting turn.

Thanks, I'll check that out.

[Gandahar]

Dark matter seems to be a catch all for getting results not expected. It's a bit like putting the horse before the cart.

We don't know what dark matter is or therefore it's properties, however scientists can use it to add the detail in on an event where normal explanations fall short. I guess that is what is called extrapolation. In this case " X-rays from the hot gas of normal matter in the vicinity showed that this matter lined up with the filament but made up only about 10 per cent of its mass. The rest must be dark matter"

The rest must be dark matter. Really?

If they claimed "something else" then I'd agree, but that is not as sexy as dark matter, which is mysterious but also something that sounds like you have pinned it down......

Edited by Gandahar on Saturday 7th January 21:03

[cymtriks]

Gandahar said:

Dark matter seems to be a catch all for getting results not expected. It's a bit like putting the horse before the cart.

We don't know what dark matter is or therefore it's properties, however scientists can use it to add the detail in on an event where normal explanations fall short. I guess that is what is called extrapolation. In this case " X-rays from the hot gas of normal matter in the vicinity showed that this matter lined up with the filament but made up only about 10 per cent of its mass. The rest must be dark matter"

The rest must be dark matter. Really?

If they claimed "something else" then I'd agree, but that is not as sexy as dark matter, which is mysterious but also something that sounds like you have pinned it down......

Nail. Head. Hit.

Nothing more than a very variable magic number that has to be added to whatever answer you get because otherwise (perish the thought) the theory that came up with your original numbers is wrong.

It will be relegated to the same filing cabinet as Phlogiston. But not before much wailing and gnashing of teeth and increasingly desperate attempts to prove that the emperors new clothes, sorry I meant Dark Matter, exist.