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Noah Zark.
6th Apr 2018, 16:19
A chap on this morning's news prog (BBC) was enthusiastically expounding about Dark Matter in space. To the average guy, the concept is boggling to say the least.
A physicist I once conversed with told me -" The beauty of my job is, I can tell you any old guff I want, and you can't disprove it, and I get paid a fair old lump to do it!"
Listening to the guy on the telly this morning, case proven!

ORAC
6th Apr 2018, 16:35
Well it certainly pulls its weight....

le Pingouin
6th Apr 2018, 16:41
Does General Relativity matter?

wiggy
6th Apr 2018, 16:45
Well it certainly pulls its weight....

Thatís the problem though isnít it? If something isnít pulling itís weight, or it is not pulling it as calculated then most of the currently accepted models of life the universe and everything are stuffed.....now whether that is of concern to the man on the omnibus is another matter :ok:

ORAC
6th Apr 2018, 16:50
Does General Relativity matter?

It depends on your frame of reference....

Argonautical
6th Apr 2018, 17:46
I don't think we appreciate the gravity of the question.

ImageGear
6th Apr 2018, 17:51
I could use a bit of enlightenment...

MG23
6th Apr 2018, 19:04
Dark Matter appears to be the modern equivalent of Phlogiston. That is, a load of twaddle that may eventually lead to something useful, just as phlogiston theory eventually led to the discovery of oxygen and oxidation.

ORAC
6th Apr 2018, 19:53
Well it’s aether one or the other.....

Loose rivets
7th Apr 2018, 00:51
Diphthong! :p


śther, or the vacuum of space is a subject I study hours a night. In fact, last summer it was often light before I set off for bed.

Do I know how it all works? Nope.

Does anyone know how it all works? Nope.

I think my proposal about the lack of a Dark Matter requirement is as good as anyone's. But then I would, wouldn't I?

One of the few people in the world working along the lines of my gravitational inflow hypothesis, a Dr R T Carhill in a down under university, seems to be travelling the same route. If I understand him correctly, he also realised that if such an inflow was the basis of a gravitational mechanism, then the huge increase in such an inflow into galaxies might alter the way in which they bind at the periphery and rotate. (my wording, not his)

Remember, galaxies do not orbit the central black holes - such as our Sagittarius A*. That is not even remotely able to hold the entire galaxy in it's clutches.

I've become obsessed with finding out what's going on before I pop off. But then, so did Dr's Einstein, and Hawking, and they were gifted with brains.

ricardian
7th Apr 2018, 01:41
Does General Relativity matter?

Yes, to the soldiers under his command

Loose rivets
7th Apr 2018, 01:48
The big objection to any kind of River hypotheses, and indeed R T Carhill's paper to an American professor, was the question of where all this spacetime is going. I have suggested three models, but suffice it to suggest for now that such a flow is taking place.

It's been a rather lonely 50 year crusade until recently when I found I was not entirely alone. Indeed, even Newton considered it for a while. But back to Dark Matter, or the possibility that there is no need for it. Something I posted on Quora last year based on my prodding away with the proposal that spacetime is flowing into matter.

Something is causing a vast observable change in the way galaxies behave and it’s thought the same something can account for ~27% of the Universe’s mass. It is demonstrating its presence, yet refuses to reveal its material fabric.

. . . substantiating the existence of a complex and energetic vacuum of space.

If this fabric of fields or what have you does exist, then is it not reasonable to believe that it might be concentrated around huge masses like galaxies and give the impression of concentrated mass?


. . . if spacetime were to be flowing into matter then it should not be too difficult to model how such a spacetime might behave when ‘supplying’ the vast mass of a galaxy: the way it would interact with the billions of peripheral masses and its own thick fluidity between the point-masses in particular. If anything would alter the relative movement of the component parts of a granular disc, I imagine that would.”
I’m sure this is just one back-of-the-envelope idea out many, many unqualified notions but it does show that there are other ways of looking at a mystery that seemingly demands massive particles that will not reveal themselves. While I accept history shows a record of wondrously accurate predictive modelling I’m still instinctively uneasy about a mist of particles that don’t coalesce in billions of years.

It's so strange to have spent a working career making machines claw their way just off the surface of the planet, and watch thousands of tonnes of rocket fuel lift a few kilos of matter into orbit, yet realise that no one knows what is giving the impression of some kind of force.

Mr Optimistic
7th Apr 2018, 10:13
Suppose it's better than having a proper job where you might need to stand up and go outside into the cold.

Loose rivets
7th Apr 2018, 12:17
Well, 18months away from 80 so no real requirement, but I'll challenge you to the Naze cliffs, on which there's scarce a day I'm not galumphing up.

"move in a clumsy, ponderous, or noisy manner." Yes, that about sums it up, but a 72' accent while barging 60-year-olds out of the way. :}

meadowrun
7th Apr 2018, 12:26
Funny how the universe is comprised of mostly hydrogen and helium (98+%), spread thinner than a schmeer of Marmite on a slice of toast, leaving precious little of the other neat elements life needs to survive. So little, it beggars belief that we evolved at all.


So far, no one has demonstrated any effect "dark matter" might have in that process.

G-CPTN
7th Apr 2018, 12:35
Perhaps SH will return and explain it all . . .

cattletruck
7th Apr 2018, 12:39
So what's the matter? There is no matter, not even light matter, that's why it must be so dark. Could it just be a void of I.O.U gravity where light travelling for millions of years towards this void gets ever so slightly pulled away towards something with more gravitational attraction, much like the reverse of a black hole. And if there are lots of these voids as there are stars then could the mass of the universe have been over calculated?

Hokulea
7th Apr 2018, 12:47
Funny how the universe is comprised of mostly hydrogen and helium (98+%), spread thinner that a schmeer of Marmite on a slice of toast, leaving precious little of the other neat elements life needs to survive. So little, it beggars belief that we evolved at all.

So far, no one has demonstrated any effect "dark matter" might have in that process.The latest is that dark matter had a big influence on the universe becoming "clumpy" which led to the first stars and galaxies being formed. When those stars died, a long time ago, they provided the heavier elements that created us. Without dark matter, the universe would have just kept on expanding with no stars, galaxies or planets - or people here to question dark matter...

https://arxiv.org/pdf/0909.2021.pdf

Loose rivets
7th Apr 2018, 14:25
.2021.pdf

Does that obviate the need for an inflationary period? Or part thereof?

I assume the Lambda in the Lambda Cold Dark Matter is the Cosmological constant.

Hokulea
7th Apr 2018, 15:26
The Lambda is indeed a cosmological constant, although not the same as Einstein's. And no, the cold dark matter theory still includes a period of inflation (i.e., the universe expanding faster than the speed of light in its very early stages).

meadowrun
7th Apr 2018, 15:43
Just wondered who would be stepping into (up to?) the position of:


Director of Research at the Centre for Theoretical Cosmology within the University of Cambridge, now?

Loose rivets
7th Apr 2018, 19:47
Well, the Lucasian chair was relinquished some time ago to . . . erm, two Michaels. I'm not sure who'd want to take over Stephen's rooms, they'll be steeped in his aura for many years to come.


And no, the cold dark matter theory still includes a period of inflation

I could never quite visualise how that brief flash could cause the clustering. Indeed nor could I extrapolate that to the spider's web of neural pathway-like concentrations of galaxies. 'tis a mystery.

Gertrude the Wombat
7th Apr 2018, 20:38
I could never quite visualise how that brief flash could cause the clustering. Indeed nor could I extrapolate that to the spider's web of neural pathway-like concentrations of galaxies. 'tis a mystery.
Anthropic principle. You can explain anything that way :D:=:):D

Buster15
7th Apr 2018, 20:49
It only 'matters' if we want to understand how/why our Universe developed the way it did. There are potentially an infinite number of ways that it could have developed in the first fractions of a second after the Big Bang and fortunately for us one of those possibilities was the outcome, so in answer YES IT DOES MATTER.

Mr Optimistic
8th Apr 2018, 18:12
I will be more impressed when they can explain gastric fluctuations.

Lonewolf_50
9th Apr 2018, 15:31
Dark Matter, and mass, influence gravity. For any travel beyond our solar system, being able to account for these factors are like knowing/understanding the wind, weather, tide and current for a sea voyage.