“A cosmic mystery of immense proportions, once seemingly on the verge of solution, has deepened and left astronomers and astrophysicists more baffled than ever. The crux… is that the vast majority of mass of the universe seems to be missing.” -William J. Broad
When we look out at the Universe, the other things we see -- stars, galaxies, and as we're learning, planets -- look an awful lot like the ones right here in our own backyard. Sure, there are subtle differences, but at a macro scale, the Universe appears to look very much like the Universe near and dear to us.
So what a surprise it would be if it turned out that the Universe weren't like us at all! In fact, when we ask the Universe what it's made up of, it tells us that normal matter -- protons, neutrons, electrons or anything made out of Standard Model particles -- simply won't cut it; that's not the majority of what's out there. Sounds crazy, right? Yet we have multiple, independent lines of evidence that all lead to the same conclusion: the mass of the Universe is mostly made out of dark matter!
There are implications on all of the above listed phenomena currently attributed to Dark Matter if it is confirmed that antimatter falls up. There are ongoing experiments to determine if antimatter falls up or down and preliminary research has been published. The early results are admittedly not favorable but were largely inconclusive.
"Our results far from settle the question of antimatter gravity. But they open the way towards higher-precision measurements in the future, using the same technique, but more, and colder trapped antihydrogen atoms, and a better understanding of the systematic effects in our apparatus."
Given the problems with Dark Matter such as the lack of anything showing up in detectors, the requirement for changes to the so far rock solid Standard Model, and the distribution issues with using DM to correctly model the rotation of all stars in spiral galaxies, the word "inescapable" may be a bit premature.
Good stuff there Denier, thanks for the added input.
I always appreciate your MOND input as well.
What would those implications be?
@Patrick Dennis #2
If gravity is dipolar there is no need for Dark Matter, and no need to expand the Standard Model.
The need for Dark Matter is in the inability to account for all of the gravity needed to describe the things we observe in the universe. Ethan's list of 7 pieces of evidence for Dark Matter is not so much actual evidence for Dark Matter as it is a list phenomena where extra gravity is at play.
The current consensus position is that there must be otherwise undetectable "dark" matter attracting in the same way all matter does. The antimatter-antigravity idea is that there is no additional matter acting to attract, but rather antimatter adding a gravitational push to normal matter's gravitational pull to create all the gravity we see exhibited in the above listed phenomena.
CERN Physicist Dragan Slavkov Hajdukovic has published work out on how antimatter-antigravity can be used to much more accurately model the observed spin of spiral galaxies.
I admit antimatter-antigravity is a bit of a long shot as a lot of smart people are lined up behind Dark Matter, but it is interesting. There are ongoing experiments, the most prominent of which is probably the AEgIS Experiment at CERN.
Until they actually detect Dark Matter, or mathematically describe the fundamental pieces that make it up, or explain away its shortcomings, or definitively prove antimatter falls down, I'm not ready to admit that Dark Matter is an inescapable truth. I say that if DM wants that title then it has some proving to do.
"There are implications on all of the above listed phenomena currently attributed to Dark Matter if it is confirmed that antimatter falls up."
Indeed. The operative word being "If".
However, many and varied problems arise if this were so.
ALL of which were brought up last time you promulgated this shit and completely ignored.
Mesons would not describe the same path as their mas indicated.
Antimatter would have different properties depending on where they are in a gravity well.
Cosmic rays would be separated out into different types based on their matter and antimatter constituents.
NONE OF THEM ARE SEEN.
Just because the SF Writer E E Smith got his antimatter wrong and gave it the opposite factor in reaction mass doesn't make it science fact.
If these objections were brought up before, then I missed them. If you have more information so I can look into their validity I would appreciate your posting it. So far as I know Dirac-Milne Cosmology (antimatter-antigravity) has not been disproven and fits well with observed cosmological phenomena.
No, you didn't miss them, you actively refuted them and argued they were not true.
Just like you're doing now.
PS, by the way, vastly more scientists with higher standing in their field agree AGW is real and a problem, yet somehow a smaller segment of less well known scientists in their field are enough to convince you that antigravitic antimatter is real.
Oh, remember too, that Einstein got things wrong too.
Yet somehow Dirac is immune?
I must have argued it in my sleep and subsequently deleted it from the internet because I don't remember it and can't find it. So far as I knew the single biggest argument against antimatter-antigravity was disagreement with the observations on Baryonic Acoustic Oscillations.
Well you usually make the same sense as some somnolent.
But I gave you the cliff notes version.
You will note NOWHERE are these observations accorded for in these theories you pursue. Nowhere.
Moreover, the theory had to be changed with different magic numbers (this "theory" is based on a magic number, remember) to fit the data when some other astronomer pointed out it didn't fit the data after all.
For someone who whines incessantly about how "line fitting post-hoc rationalisation rubbish" Dark Matter is, why you leap to another even worse case of "line fitting post-hoc rationalisation rubbish" remains explicable only by your denial of AGW wanting you to "prove" that the mainstream science is wrong.
But like I said earlier, you have been given the cliff notes version, and nowhere in your links have these problems been even looked at.
Hell, you can get more than just baryonic oscillation as a problem if you just look in wikipedia for Drac-Milne.
Denier offered a proposed Fact Number 11 to supplement Sabine's recent post on DM, but I'm gonna have to respectfully disagree: Fact Number 11 about Dark Matter is actually that any mention of it in a public forum instantly elicits shrieks of, "No, NO, this CANNOT be so, because, well because.... " and, "But what about the Woo?" (among so many others having in common their abject refusal to address the logic ( = observations + equations) underlying the hypotheses being presented.)
@1: I'm highly skeptical. But IMO developing techniques for measuring the gravitational force on subatomic charged particles is a worthwhile thing to do, regardless of whether their hypothesis turns out wrong or not.
" vastly more scientists with higher standing in their field agree AGW is real and a problem,"
Like the whole field of junk science Psychiatry which the highest one in standing Freud (Oedipus complex) has now become a Fraud and it trickles down the chain to all the other frauds in the man created field to delude himself?
When SPS was rebuilt to proton-antiproton colider, they needed to correct the beam trajectory even for Earth gravity (to keep the beams on stable trajectory for long time). And both protons and antiprotons fall down to the Earth. So antimater antigravity is falsified for more then 30 years.
So far as I knew the electromagnetic force so overwhelmed the gravitational force that gravitational measurements for charged particles such as protons and anti-protons was impossible. The very first link in this thread actually mentions it.
If it has been falsified then you should probably get that information over to CERN. They still seem think this is an active area of research.
@Patrick Dennis #12
As Professor Spider-Man says: Extraordinary claims that run contrary to consensus school of thought require extraordinary proof. I am fine with that. In making such claims, as I am prone to do, I generally try to provide support for my arguments in the form of peer review papers published in reliable scientific journals.
The other thread where the "Fact 11" post was made was admittedly missing such support but it was only because the Theoretical Physicist who's blog you are reading has mentioned in the past. If you would like to take a moment to research for yourself, "Fact 11" is better known as the Core-Cusp Problem.
There is also a "Fact 12" better known as the Satellite Galaxy Problem. Essentially the observed quantity and distribution of satellite galaxies around spiral galaxies disagree with the predictions made by Dark Matter theory.
I never mind providing support for things I say, but in the future if you want to call me out on something I ask that you stick to the thread where the comment was originally made.
"Like the whole field of junk science Psychiatry"
Nope. Climate science isn't junk. You just hate it.
Different thing, dearie.
"So far as I knew the electromagnetic force so overwhelmed the gravitational force"
Nope, the protons are much heavier. YOU'RE "thinking" of the difference between electrons and the electric force vs gravitational one.
Add in that at high energies, they have "earth relative" mass much much higher.
You DO remember that, don't you, denier?
"The other thread where the “Fact 11″ post was made was admittedly missing such support"
And wasn't a fact.
Don't forget that, diddums.
As someone who has studied dark matter (and helped discovery dark energy) for over 30 years, this is a rather biased selection forgetting some of the pioneering work. For instance, in the early 80s, the work of Rubin and Ford was beginning to be accepted, but without other lines of evidence, we could not rule out "maximal disks." Two lines of evidence were discovered, that were key. The first was the velocity dispersions in dwarf spheroidal galaxies were much larger than expected for the number of stars, by about a factor of 50. This work was pioneered by Marc Aaronson, and was very compelling. It is His work was motivated by the size of the tidal radii of these galaxies which (more weakly) implied dark matter content of Draco, Sculptor, and UMi dwarfs. This was as compelling at the Bullet Cluster some 30 years later, but has been forgotten in all the popular histories.
In addition, the work by Faber, Davis, Gallagher, and collaborators showed that the internal stellar dynamics of elliptical galaxies also required a large unseen mass component. This was complicated by the unknown nature of the axial ratios in three dimensions of ellipticals, but that was ironed out.
To ignore these discoveries for mostly more modern ones, reduces the true historical impact of these earlier pioneers. It is a lot more courageous to make a claim of something extraordinary like dark matter when few believe it, rather than later when it is generally accepted. It saddens me to know that the work of Aaronson is no longer acknowledged, even as he lost list life in a freak accident during an observing run where he was studying dark matter.
Its amazing that a blog dedicated to evidenced based science can allow some of the things it allows in this comment section.
Like I said before not all opinions are made equal.
I need a chronological record of this blogs comment section devolving into full-Guptaness
Also, re Deniers' "Fact12", it's not a fact either.
It's a single paper making a claim.
I claim "Fact 12 false" because there's a paper that says dark matter explains the velocities of the dwarf galaxies.
Just as valid.
I also claim fact12 false because the paper doesn't make the claim denier is professing on its behalf. Probably doesn't care because it doesn't matter to HIM whether his claims are true, all he needs is to BELIEVE they are.
"I am fine with that. In making such claims, as I am prone to do, I generally try to provide support for my arguments in the form of peer review papers published in reliable scientific journals."
Yet when that's done for climate science and collected for you by the IPCC, it's all a conspiracy and consensus isn't science, and peer review is "pal review" and corruption is there because scientists just want grant money.
But not here...
I don't know anyone on this board, but through the way everyone writes I build up images in my mind of the various contributors. Often there are theme songs I attach to each of the personality types I have imagined you to be. It may be light years off base but the theme song I have attached to @Wow is this one.
Denier, when you want to get off your drug addiction, there's plenty of help.
Nobody here will judge you worse for being a druggie.
Oddly enough, when you decided to ascribe songs to posters (what on earth are you doing?), I immediately thought of this one for you, dearie:
Problem is, it fits Raggie to a T too.
For Ragtag I have an image that is more Western.
@Ethan is an oddball mix and has a theme song to match. Little bit of the universe. Little bit of Portland, Oregon.
Actually, especially with this avatar's costume, Elton John's "Rocket Man"...
That would be good too.
As for Sabine who wrote the '10 Facts' article, she gets KT Tunstall. I know she wants Meredith Brooks but sorry Sabine, you don't get to chose your own theme song. Because you do identify with track of audio estrogen that is 'Bitch', 'Suddenly I See' seems a good fit.
@Sinisa Lazarek gets Immigraniada by Gogol Bordello.
@eric, in his direct no-nonsense style of discussing topics reminds me of Mark Knopfler's 'Working On It'.
@TK for the disdain shown towards those who don't conform to the ideal of how comments should be made gets Tegan and Sara as produced by the genius frontman of Devo.
Thought we were discussing dark matter, rather than 'dark humor' .....
@PJ for the silly spot in the GMT that you choose to be awake is Vampires and Wolves. The crack about astrophysics is delivered with a wink.
There are some more pieces of evidence too. Ever since the Millennium (IIRC, that or the next one) cosmological simulation, spiral galaxy analogs appear as in the real universe, but only if you have dark matter in the simulation.
And today galaxy models not only predict the non-cusp dark matter profile observed (cusp removed by supernova outflows) but Cold Dark Matter is - not unexpectedly seeing how the other evidence stack up - _the best model_:
"By adopting an astrophysical mass-dependent DM halo density profile and looking at galaxies velocity function and the Tully-Fisher relation, the authors highlighted how we can distinguish if DM cores form via astrophysical process or is a consequence of alternative dark matter models. Comparisons of their model with the NFW profile and alternative dark matters seem to suggest their model has the upper hand."
Unless I am mistaken, dark matter is now the reigning theory everywhere (despite some remaining tension with observation, I'm sure).