Do Dark Matter and Dark Energy Cast Doubt On the Big Bang? 225
StartsWithABang (3485481) writes "Back in the 1960s, after the discovery of the Cosmic Microwave Background, the Big Bang reigned supreme as the only game in town. But back then, we also assumed that what we consider as "normal matter" — i.e., protons, neutrons and electrons — was, along with photons and neutrinos, the only stuff that made up the Universe. But the last 50 years have shown us that dark matter and dark energy actually make up 95% of the energy composition of our cosmos. Given that, is there any wiggle room to possibly invalidate the Big Bang?"
Re:Oh good lord. (Score:5, Interesting)
And maybe dark matter isn't at all, but just a matter (bad pun, I know) of our misunderstanding of something.
Take the planet Vulcan [wikipedia.org]. No, not THAT Vulcan. But also a fictional one. Astronomers noticed Mercury isn't circling the Sun as it should, so something had to account for this. In their understanding back then, there had to be another planet that causes that. But then uncle Albert came along and explained it with relativity and now we know that gravity is the culprit, not some planet we can't see.
What if this is a similar case? Like, say, (normal) matter having gravity properties that only become noticeable on a cosmic scale? Like, say, relativistic effects that take a DAMN LOT of gravity to become noticeable?
I'm not saying it is so, I just wonder if we're dead set on Dark Matter or whether we're actually still looking in other directions? Or rather, whether serious scientists actually look into different options aside of Dark Matter to explain the discrepancies, not just crackpots and snakeoil peddlers.
Dark matter (Score:1, Interesting)
As stated below by others, just because it's "dark" doesn't mean it's not just ordinary matter.
It's just that we can't actually see it.
Given the twists and turns of galaxy-sized gravitational pulls, it's hardly surprising that there's stuff out there that we can't directly or indirectly observe (but that we believe has to be out there for other things to look like they do).
The only reason that something is "dark" is because we think it should be there but can't actually find it. Having 95% dark matter/energy just means that we know LESS about the universe than we did before - which is not at all unusual when you've just passed a cusp of understanding.
When we "knew" everything was atoms, we thought we had 100% knowledge. When we split the atom, we then realised that we knew only 1% of what was happening. Then we caught up again to something approaching 100% "understanding". And hit a wall. When we scale that wall, our "understanding" will drop dramatically.
That's what's happened with dark energy/dark matter. Think of it as our ignorance quotient increasing because of the discovery of new evidence. Not as some vast debunking of existing science - that's like saying "atoms don't exist" and abandoning all the working atomic science we already have just because we find out that the atom isn't the complete story, or abandoning all Newtonian physics because of the discovery of quantum physics.
It just doesn't work like that. The best bit of dark matter science is ahead of us. We're in ignorance, looking for the light. Or, in this case, the dark.
Isn't it the other way around? (Score:3, Interesting)
I thought Dark Matter was conceived to account for missing matter that the Big Bang theory predicts needs to exist.
Oh good lord. (Score:4, Interesting)
We're finding it quite easy to directly detect its affects with our current technology - it's called a telescope. We just have no clue as to what it is or how it works.
I'd like to point out that gravity is in the same category. Also time.
We do know a lot more about light and electricity. Please check out "QED" by Richard Feynman. Well we actually don't know how that works ether, but we've figured out the math to make very precise predictions that usually match reality so we must be on the right track.
Dark matter and dark energy (Score:4, Interesting)
These theories have their own problems. As noted on Slashdot previously, neither exist around dwarf globular clusters or in the local region of the Milky Way. It is not altogether impossible that our models of gravity are flawed at supermassive scales at relativistic velocities, that there's corrections needed that would produce the same effect as currently theorized for this new kind of matter and energy.
Remembering that one should never multiply entities unnecessarily, one correction factor seems preferable to two exotic phenomena that cannot be directly observed by definition.
But only if such a correction factor is theoretically justified AND explains all related observations AND is actually simpler.
There is just as much evidence these criteria are true as there is for dark stuff - currently none.
Re:Oh good lord. (Score:2, Interesting)
Please check out "QED" by Richard Feynman. Well we actually don't know how that works ether, but we've figured out the math to make very precise predictions that usually match reality so we must be on the right track.
Indeed, QED is the most successful theory that man has ever formulated, and Feynman was IMHO far greater than Einstein or Hawking.
When the first shuttle blew up, NASA picked up the phone and called Feynman, someone that never did anything for NASA before and was not involved in any way with the shuttles, rockets, or even anything astronomy. Feynman figured out what happened quite quickly, went before congress and both explained and demonstrated the problem.
Einstein has a brilliant idea. Hawking had a brilliant idea. Feynman was simply raw brilliance.
Re:Oh good lord. (Score:5, Interesting)
We just have no clue as to what it is or how it works.
I'd like to point out that gravity is in the same category. Also time.
This.
When Newton was first discussing his theories of universal gravitation, the scientific community was rather skeptical, because it invoked spooky "unseen forces" acting at a distance (i.e., gravity). The previous Aristotelean model of physics asserted that "normal" terrestrial matter came to a nature place of rest (earth sinks down to equilibrium, air rises to equilibrium, etc.), since Newton's first law hadn't been realized yet. Instead, real-world friction, etc. tends to bring things to a state of rest, which accords with everyday experience. All motion had to be explained by a "cause," something that propelled it into motion, and ultimately the matter would stop moving once it came to its natural state of rest.
The motion of the planets could not be explained using this physics, so the celestial bodies were assumed to be of a different type of aetherial matter (or something) which was set in motion at the beginning of time or something.
That was the proper scientific theory of the day, and it accorded with empirical observation and common sense -- terrestrial bodies stopped, celestial ones seemed to go in continuous motion forever.
But Newton came along and equated the two -- and he developed a mathematics that described the motion. Unfortunately it depended on a "spooky" occult idea of forces acting at a distance. (Newton, of course, was really into the occult, alchemy, etc.)
So, scientists of the day were skeptical. Newton eventually even published an appendix with future editions of the Principia explaining that his model didn't depend on "real" unseen forces acting -- instead, he basically came up with the modern scientific ideal that says: if the math works and predicts the phenomena, that's enough for science. A scientific model need not be concerned with philosophical questions or ultimate causes of phenomena as long as it can actually make good predictions.
THAT, probably more than anything else, was the foundation of modern "science" laid down by Newton during the Scientific Revolution. People had been doing experiments and empirical investigations for millennia, but they always had to worry about ultimate "causes," which inevitably depended on somebody's pet theory of reality. After Newton, though, what matters is that the math works. Maybe the dark matter/dark energy model is hinting at some deeper aspect of reality and a more elegant theory that we will come up with many years from now... or not. But regardless, these ideas are exactly like Newton's "gravity" -- something which we observe, something we can have an accurate mathematical model of, but also something "spooky" that we don't understand completely yet.
That's what the modern scientific process is all about.
Re:Oh good lord. (Score:4, Interesting)
Dark matter was there in todays proportions in the hot early universe, so no. All the MACHO theories went by the wayside with the CMBR data, it's WIMPs now for sure.
Re:Don't ask me (Score:5, Interesting)
This morning, I was reading about quantum phenomena and how some string theories posit that the length of a string is approximately the Planck length. Strings being the basic quantum unit, nothing can be measured to be smaller than 1 Planck length or measured with more precision than 1 Planck length. What you end up with then, is a universe where the spatial dimensions are a grid, that cannot be traversed continuously, but only in Planck-length increments. In other words - it is essentially digital. Like pixels on a display, where the pixels are much smaller than an atom. My understanding of string and quantum theory (admittedly far from complete) is that all aspects of the universe could be quantized, and thus simulated digitally in a computer.
If anyone can clarify/elaborate/refute, please do.
Re:Certainly yes (Score:3, Interesting)
Not only can we not find the dark matter or dark energy...
Look. We just recently mapped the Earth's radiation belts. Oops, they did not match prediction. At all. Not even the right number of belts.
Voyager is out exploring the Solar System's heliopause. Ooops, not as predicted.
That is the recent actual experimental work that has come out of cosmology lately. The rest of it is a lot of hand-waving using edge data points, at scales where nothing can be verified.
Compare that to the work that actual physicists do at the subatomic level, where experiments usually match predictions to insane numbers of decimal points. That is what real science looks like.
This stuff about, "oh we got our own neighborhood totally wrong, we don't understand how the solar system formed well enough to predict the heliopause, we don't understand our own planet well enough to predict the radiation belts, but when it comes to the really large measurements using edge data, we're really right-on, and sure of it." It is just total crap, at the flat-Earth level. Background radiation is the ultimate edge data; if Big Bang is true, it would be like God; an un-provabable hypothesis that science should ignore in preference of logical positivism. If it is true, we can't prove it, because we'll never have a sensor where we can test it on both sides of the value we want to measure. We can never calibrate a sensor, so we just can't know.
Maybe old photons just turn redder and redder and then die, and the cosmic background radiation is a giant field of dead photons that all average the same age because they then fade away after another n years. Maybe there is more than one cause of redshift; the cause we can verify at very tiny scales, and another one at cosmic scales that we haven't even tested for yet, or had the chance to test for yet. Nobody in academia wants to ask about that, because if they start the experiment now, they won't be the ones to write the papers in a few million years when the answer comes in.
Edge data tells us nothing. That the "early Universe" is presumed to have simpler laws of physics reminds of me something. The way that trees on the horizon at the edge of my vision appear simpler and simpler; and yet retain all their symmetries.