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?"
Oh good lord. (Score:5, Informative)
There's always the possibility of a theory being falsified but in this case the answer is almost certainly no.
The big bang is not going to be invalidated, so say COBE, WMAP and PLANCK.
Also, it's actually less than 5% baryonic matter it seems, 4.4%
http://map.gsfc.nasa.gov/unive... [nasa.gov]
Be aware that dark matter is just matter we can't directly detect with our current technology (or just haven't /yet/), it's not something magical.
Oh good lord. (Score:5, Informative)
Well, the fact that we can still hear the universe ringing at the exact range and frequency curve predicted by George Gamow nearly twenty years before Wilson and Penzias "discovered" it (see the cosmic background radiation - look it up), I'd say no.
Also, the farther out we look, the faster galaxies are moving away from us. Run that backwards in time and we're all in the same place about 13.7 billion years ago. Again, I'd say no.
Also, the balance of H, He and Li that was predicted...
Also, the evolution and make-up of stars and proportions of heavy elements in near and far galaxies...
Etc. etc.
Electric Universe (Score:2, Informative)
I would say quite the opposite - that the existence of dark mater and dark energy suggests a possible mechanism for the initial rapid expansion (inflation) without resorting to "magic" forces we have not yet observed.
The electric universe or ionized plasma theory looks great on paper, but the cosmic scale currents and magnetic fields it describes would create easily detectable phenomena which are not actually observed.
I've personally observed a number of Christian astronomers cite "The Big Bang Never Happened", as possible testimony that the universe isn't 13.8 billion years old after all. Having actually read the book I enjoy pointing out that Eric Lerner's conclusion about the age of the universe being 150 billions of years old is completely out of wack with actual observations, and cherry picking parts of scientific ideas doesn't work the same way as cherry picking passages of other books. If your theory predicts things that don't match reality - throw it away and try again. Read up on dating quasars using spin decay rates if you really want to know.
Isn't it the other way around? (Score:2, Informative)
I thought Dark Matter was conceived to account for missing matter that the Big Bang theory predicts needs to exist.
No, it (mostly) came about when it was noticed that galaxies required a lot more mass than was visiible to keep from flying apart. The speeds of stars 'orbiting' was too high, and the things should have flown off. There were other oddities observed as well. All the behaviors observed could be explained if there was a lot more gravitational mass than what could be seen. Some of things seen were quite bizarre, too, and required the stuff to account for things acting the way they did.
Enter Dark Matter as a formal theory..
Re:Dark matter (Score:5, Informative)
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.
Repeating the ignorant doesn't make it true, that "dark matter" is simply ordinary matter we couldn't detect was a good first guess. Very strong evidence indicate it's not [wikipedia.org] because that would create other interactions as well that aren't there. There's some small fraction that is regular matter [wikipedia.org] and some is neutrinos, but without some other form of particles it just doesn't add up.
Re:Isn't it the other way around? (Score:5, Informative)
I thought Dark Matter was conceived to account for missing matter that the Big Bang theory predicts needs to exist.
No, it (mostly) came about when it was noticed that galaxies required a lot more mass than was visiible
It's both, and other observations as well. That's why dark matter is a good theory for the observations we have at this time - several phenomena all point to the same explanation.
Also dark (Score:3, Informative)
The Dark Side of the Moon
The Bullet Cluster Makes it Unlikely (Score:5, Informative)
What if this is a similar case? Like, say, (normal) matter having gravity properties that only become noticeable on a cosmic scale?
Models like this have been considered such as MOND (MOdified Newtonian Dynamics). These models were largely shot down by the aptly named Bullet Cluster [wikipedia.org]. This is a system of two galaxies colliding at a high relative speed. The gas from the smaller "bullet" cluster collides with the gas in the larger cluster causing it to slow down, heat up and emit X-rays so we can see it.
So far so go. However you can also look at the mass distribution by seeing how it distorts the light from galaxies behind the cluster (this is called gravitational lensing). This shows that most of the mass of the smaller cluster has not slowed down and is now separated from where all the gas in the cluster is located. Effectively the collision has separated the matter from the dark matter because, unlike normal matter, dark matter has a tiny cross-section for interacting with itself or other matter. This is exceedingly hard to explain by modifying the behaviour of normal matter since you are observing a gravitational field where there is no normal matter.
complete and utter rubbish (Score:5, Informative)
I'm probably a bit biased here, but also an expert, since I am a physicist who studies dark matter for a living.
The title's question doesn't even make sense! Big bang theory, and in particular studying the exact power spectrum of the cosmic microwave background, is by far the strongest evidence we have for the existence of dark matter and dark energy. All those pie charts you've seen showing the divisions of baryonic matter, dark matter, and dark energy? If they're properly cited, I guarantee every single one of them comes from data from WMAP or PLANCK: CMB experiments! You can't say that dark matter gives you room to invalidate the big bang, because without that we don't have really any strong evidence for non-baryonic dark matter in the first place...
Re:Oh good lord. (Score:4, Informative)
A. What part of Gamow's ABC paper was "make theories to fit your observations"??
He published a paper on April 1st, 1948 with Ralph Alpher and Hans Bethe (Alphar - Bethe - Gamow... get it?) on Big Bang nucleosynthesis that explicitly stated that if there had been a Big Bang, that you still would be able to detect a black body radiation light curve from the first moments that the cosmos expanded (cooled) enough to allow photons to survive. Alpher soon calculated that the peek would be below 5 degrees by now.
Radioastronomers couldn't be bothered to check this out - it wasn't until 1964 that W&P (not radio astronomers) were trying to fix a "noisy" antenna that this was discovered. They got a Noble prize for this, which should have also gone to Alpher and Gamow.
B. That you say "And no, if you run that backwards it doesn't work out that its all in the same place." shows that you're thinking of the Big Bang as an explosion - as if you were observing it from outside. This isn't correct at all - everything you are, and the stars and galaxies are part of the cosmos. Two weeks ago - most galaxies were millions of miles closer - i.e. the cosmos was more dense. A few months ago - a few billion miles closer - more dense still. 13.7 billion years ago all the matter/energy OF the cosmos was so close - so dense and hot that there was a hot particle soup - that locally some galaxies are coming together due to gravity rather than spreading apart is irrelevant.
It's like saying - all the cars on the road couldn't be from a factory - they're all going different directions!