just wondering what your thoughts on dark matter are. i been watching the universe programs time and time again and i think i finally agree that dark matter does indeed hold the universal matter in situ. gravity is the other universal law that holds the planets and suns and solar systems and galaxies and galaxy clusters and super clusters together, but the scientists/astronomers just cannot find enough gravity to fully support the theory, therefore they suggest dark matter is the real stuff that moves the universe. i think some of the proof that dark matter exists is in the fact that some of the light that reaches thier telescopes is well, bent or refracted. when there is no visible substance to actually bend the light. so if it exists, is it a lifeforce.
http://en.wikipedia.org/wiki/The_Universe_(TV_series) if your watching these i have wached all 64 episodes and many more other tv series about the universe there was one episode from discovery channel how the universe works thay run a simulation on how galaxies were formed thay ran a test without dark matter and the test showed that the galaxie flew apart an could not form but thay added dark matter to a new simulation and the galaxie formed as it should and normally would be a disk shape so i do believe in dark matter it is the stuff that will kill the whole universe one day...
I think dark matter probably does exist, because as you say the universe wouldn't work without it if our curent theories are correct. However the concept is quite hard to believe (especially as they named it dark matter, which sounds like something straight out of a sci-fi movie). Sooner or later though we will have either very strong proof, or we will have found some other way to explain it, and the same goes for dark energy.
Oh... if only it was that simple. DM is that wonderful substance we have yet to detect properly. But when we do, I do hope we end up working out if we can use it as a goddamn energy resource and not just worship it like the power it is.
Multiverse... oh dear. I can't see the video as I'm stuck at the orraffice all day. However Multiverse is the greatest fun to explain to people in the world.
Dark Matter is an artifact created to explain why the current theories don't match the observed facts. I think it bad science to start from the point that our theory is correct, and to invent more and more complex reasons to make it work. For example planetary motion became more and more complex as science tried to explain the observed retrograde motion of the Mars and Jupiter in a geocentric universe but as soon as someone said "What if the planets go around the sun" it all became absurdly simple again. I'm not saying dark matter doesn't exist but to treat it as fact because it makes the theory work is to blinker scientific discovery.
This is absolutely true. Agnosticism is healthy in science. Most scientific blunders have arisen from scientists of the given day being too convinced of their established theories, and some of the greatest breakthroughs have resulted from a willingness to think laterally and not take things for granted. Michael Brooks has a good chapter on this called The Missing Universe in his pop-sci book 13 Things That Don't Make Sense. In a nutshell: We need dark matter to exist to explain the motion of galaxies. One potential candidate is the neutralino, which is non-interacting enough and massive enough to be dark matter - but we don't know whether neutralinos actually exist. Particle physicists have been looking for them for a decade and have found nothing. Furthermore, even given dark matter, 70% of the universe is still unaccounted for. By studying supernovae, scientists inferred the deceleration of the expansion of the universe and derived from it an Omega value (a value for the average density of mass/energy in the universe) that was more than twice as big as expected based on known matter and dark matter. To explain the missing 70%, dark energy was invoked. The most likely candidate for this missing entity is vacuum energy, a theoretical type implied by quantum field theory mathematics. But when the amount of vacuum energy that's meant to be there is calculated from quantum field theory, you get a value that is magnitudes too big - 10^120 times too big - suggesting an amount of energy that would've blown the universe apart at the instant of the big bang. TL;DR:, known matter is not enough by itself to explain the behaviour of the universe, known matter and the assumed (but undetected) dark matter are still not enough to explain the expansion deceleration rate of the universe, and the only forthcoming candidate for the missing mass/energy is from quantum theory, which gives a value for the mass in the universe that is unacceptably large. To resolve this, some have suggested revisiting and modifying Netwonian physics very slightly: perhaps our observations are correct, there is no dark matter or dark energy, and our understanding of how matter behaves is incorrect. But physicists tend to get angry when you start dicking around with Newton. Another possible solution is to modify our understanding of gravity, Modified Gravity theory: perhaps gravity doesn't behave uniformly, as we imagined, but behaves differently at different distances - so that our present laws for gravity make sense of things on the planetary scale, but are inapplicable to galactic scale. This has Popperian problems of being unfalsifiable and impossible to investigate - and it still doesn't account for the Omega value problem, the missing 70% of the universe's mass/energy. A further possibility - more in the realm of sci-fi, but not technically implausible - is that the universe is non-isotropic, and has local variations. So one area of the universe obeys Newtonian physics, another has different values and obeys different physical laws - a sort of patchwork of 'pocket' universes, visible to each other but governed by different laws. This is also murderously unfalsifiable and defeating. - Condensed from chapter 1. Personally, I like SMBC's take on it:
lol like the cartoon, good read elephant.. that's pretty much how I've seen dark matter too- guys who try to explain it always end up with pasty lips
Many don't believe the dark matter theory but I imagine it will continue for sometime yet, especially considering CERN has just found possible evidence for support of String Theory which you could place dark matter in alternate dimensions, and hence undetectable in ours. True scientists don't assume theories are correct, they posit that they may be and that is why they are 'theories'. It's media and the public that generally make those assumptions. Those and inept scientists.
A truly great TV series. I recommend that anyone with an interest in science, and physics particularly, watch it.
Hmmmmmmm there are a lot of cases where the initial theory is worked towards and finally proven over time. Theory of relativity is one. Theory of evolution is increasingly proven correct as time goes by. Dark matter essentially describes something that cannot be seen or quantified from earth or satelites from earth. That means it joins an enormous list of other things in the vast universe that perplex. Like black holes for instance, which in theory will decay into radiation rather than suck things in and grow indefinetly. The universe is expanding at an ever increasing rate. This cannot work as a mathematical model assuming space between planets, planetry bodies, stars, dead stars, failed stars, gas clouds, rocks, ice, comets etc is empty. There has to be another factor in play or the model is wrong. It looks more likely that the model is correct rather than incorrect. That protons and neutrons are themselves composed of even smaller particles was also theorised. Many have since been found and there are apparently more to find. Edit: Didn't read other posts. Derp
I like this thread because I'm proud of my contribution, so I don't mind it being bumped endlessly at all :>
I've just been sitting thorough a few talks on cosmology from my peers in the department. as far as I could work out from them the use the cosmological constant and this "fudge" factor seems to give values for dark energy and matter. Personally I don't take things too seriously allowing me to move from one theory to the next. The main problem in theorising such things is the experiments are so far away it seems like a waste of time . Saying that it took relativity and quantum mechanics 50 years to be believed and studied, in the mean time no-body really worked on them.
