Apparently. >90% dark matter.

And we can’t even see the frikin’ stuff! Although it does apparently bind the whole universe together, stop entire galaxies pinging off to who knows where..

Which is nice.

Or… is ‘dark matter’ a simply convenient deux ex machina used by current physics to explain away the inconveniently unexplainable. Will developments in theoretical physics eventually make it disappear – like phlogiston was – before oxygen was discovered?

upto a point, you’re right:

– Spiral galaxies spin too fast, stars at the outer edges should fly off into deep space. They don’t, so galaxies are heavier than we can account for with stuff we can see. we don’t know what this ‘stuff’ is, so it’s been called dark matter. naming the problem, isn’t the same as understanding the problem. To a point, there’s a little bit of deux ex machina, or what-you-said, going on.

But, there is actual evidence for this-stuff-we’re-calling-dark-matter, beyond galaxies being seen to spin faster than Newton/Einstein can explain. There’s lots of different things we can see, that can’t be explained without a LOT of invisible mass.

Will developments in theoretical physics eventually make it disappear…?

we’re talking about dark matter because we’ve seen things that can’t be explained properly, those things won’t dissappear…

Makes you think.

This thread doesn’t matter 😡

Yeah.. but what if it’s simply ordinary gravity from ordinary matter operating across multiple dimensions in some sort of weirdly integrated way that we haven’t figured out yet?

well that would be cool.

Or… is ‘dark matter’ a simply convenient deux ex machina used by current physics to explain away the inconveniently unexplainable.

Well not quite like that.

As awhiles says – what we observe, and what our equations predict don’t match – so there must be a lot of mass that we can’t see. Hence the term ‘dark’.

It could be that our equations are wrong, so that’s why it’s just a theory.. but a lot of work was done and the best guess was extra dark mass. Doens’t seem too unreasonable to me – why would we expect to be able to see everything with mass?

It’s a bit like the term “UFO”; you can’t point at a specific UFO because then it wouldn’t be U, it would just be an FO. Until we know what it is, or what causes the effect, we just give it a name that says “we don’t know what this is”. Hopefully we’ll find out sooner or later…

You never know, maybe phlogiston might actually come back. Aether sort of managed it; I love that the experiment that pretty much put paid to the idea of aether is basically the same experiment as more recently used to demonstrate the existence of gravity waves…

Aether came back?

Given that we have not the faintest idea what dark matter actually is (or even if it is matter at all), the explanation is absolutely deus ex machina. The observations are correct and won’t go away, but the explanation is entirely speculative.

Aether came back?

Certainly:

Most of the matter in “Space” is wasted

I’m sure it doesn’t matter.

I read a news article last week that said one theory is that dark matter is comprised of primordial black holes that cluster around the edges of the galaxies. These are “primordial” as if they exist they were created early on in the life of the universe from collapsing gas clouds.

Apparently the recently observed collision between two black holes lends some credence to this theory as the masses of the black holes in question are too big for them to have been created from collapsing stars and too small to qualify as the supermassive black holes that hang about at the centre of galaxies. Their masses do however fall into the range suggested as possible for primordial black holes.

Presumably black holes could work as dark matter as unless they are interacting with something else black holes are very hard to spot. And if they’re sitting outside of galaxies there isn’t that much for them to interact with.

This brought to mind a quote from a scientist on some programme that I saw a while back, may have been Horizon:
“You find dark matter, which you can’t, by definition, see. You discover it by not seeing it”
Which sums it up, I think.

Remembering of course that the observer changes the reality and so therefore, what we observe, or predict through our human construct/s and point of perspective, is just that. Our observable aspect of the Universe may or may not be the absolute truth.

But then the truth is also relative in this instance.

Personally, I reckon this unobservable stuff is the Zero Point Field, the web of energy that connects everything and is much faster and more reliable than the Internet. 😀

CountZero – isn’t that how they find submarines? They look for the silent spots in the ocean?

Just goes to show how much we don’t know. It’s all theory at this stage, but there are some clever buggers around so it’s only a matter of time till they crack it.

So we don’t know what we don’t know – and name that dark matter?

Personally, I reckon this unobservable stuff is the Zero Point Field, the web of energy that connects everything and is much faster and more reliable than the Internet.

Aether came back?

LIGO is basically a really really really really really accurate Michelson–Morley experiment, used in 1887 to show the lack of evidence for Aether.

I wonder what direction physics would have taken if they had been able get more accuracy back then…