Please don't take this too seriously.

[Buster Crabbe's Uncle]

Dark energy is real.

No, the effects they explain w/ dark whatever are real. Dark whatever is a weak fudge factor to make the equations balance. I'd rather believe there are shortcomings in our understanding of how gravity works at galactic scale/in a very young universe/over 13 billion years than believe in magic goop/energy doing it. It's "The Ether" and "The Bodily Humors", "Phlogiston" and "The Spheres". I don't doubt the sincerity of anyone's belief about "Dark Matter" - but it does smell to me of serious error - Great Embarrassing Boners of Science History serious. Occam's Razor and all that.

[Buster Crabbe's Uncle]

Does Antimatter Fall Up or Down? New Device May Tell
LiveScience.com
By Charles Q. Choi, Live Science Contributor 6 hours ago



Antimatter refers to sub-atomic particles that have properties opposite normal sub-atomic particles.



The mystery of whether antimatter falls up or down could be solved with a new experiment to weigh matter's odd cousin, researchers say.

Antimatter is identical to normal matter in some respects but the exact opposite in others. For instance, although the antiproton has the same mass as its counterpart the proton, it is negatively charged instead of positively charged.

When a particle meets its antiparticle, they annihilate each other, giving off a burst of energy — a proof of Einstein's famous equation, E=mc2, which revealed mass can be converted to energy and vice versa. A gram of antimatter annihilating a gram of matter would release about twice the energy as the nuclear bomb dropped on Hiroshima. (Have no fear of antimatter bombs popping up anytime soon — researchers are very far from creating anywhere near a gram of antimatter.)

Scientists have long wondered if antimatter falls down, responding the same way to gravity as ordinary matter. Physicists have generally assumed it does, but many have kept an open mind regarding antimatter's behavior since much about it remains a mystery.

"We don't really understand antimatter," study author Holger Müller, a physicist at the University of California at Berkeley, told Live Science. "For instance, the fundamental laws of physics suggest there should be equal amounts of matter and antimatter in the universe, but our observations tell us there is vastly more matter than antimatter in the universe, and there is no agreed-upon explanation for that."

In addition, there is much about gravity that remains uncertain. For instance, astronomers looking at how galaxies rotate discovered there is far more gravity holding them together than there should be, "which is usually ascribed to gravity from dark matter, but nobody knows what that is," Müller said.

Direct evidence of whether or not antimatter falls downward remains difficult to experimentally gather. Antimatter is rare, and annihilates when it comes into contact with regular matter.

"The combination of antimatter and gravity has never been directly experimentally tested before," Müller said. "There are indirect observations others have obtained, but the very simple experiment of letting a chunk of antimatter drop and seeing what happens has never been done."

Now researchers have proposed a device they suggest could help solve the mystery of whether antimatter falls up or down.

"We don't understand 100 percent about antimatter, and the same is true for how gravity works, so looking at them in combination seems a good spot to look for a new discovery in physics," Müller said.

The instrument, a light-pulse atom interferometer, could measure the behavior of any particle — atoms, electrons and protons, as well as their antimatter counterparts. It works by studying cold particles — ones cooled to a degree above the coldest possible temperature, absolute zero.

At such cold temperatures, scientists can see particles behaving much like waves, rippling up and down within a chamber. By analyzing how these "matter waves" interfere with each other, the researchers can distinguish the force of gravity each particle is experiencing.

Müller and his colleaguesare working to construct their device and integrate into the ALPHA experiment at the CERN physics lab in Geneva, Switzerland, which makes, captures and studies atoms of anti-hydrogen, the antimatter counterpart of the simplest atom, hydrogen.

"Currently the production rate of anti-hydrogen at CERN is four atoms per hour, or an atom every 15 minutes," Müller said. "This production rate currently cannot be sustained 24-7, so 300 anti-hydrogen atoms a month or so is all we can hope for right now."

Since the researchers have very few anti-hydrogen atoms for experiments, their system essentially "recycles" each atom. Magnetic fields trap the atoms so the device can potentially measure the way each atom behaves multiple times.

"We need to get a signal out of each and every single atom — we can't afford to lose a single one," Müller said.

The scientists expect their system will reach an initial accuracy of better than 1 percent for measuring how anti-hydrogen falls, and they noted they could eventually improve this accuracy 10,000-fold.

The scientists detailed their findings online March 25 in the journal Physical Review Letters.

http://news.yahoo.com/does-antimatte...144324040.html

[Lorizael]

No, the effects they explain w/ dark whatever are real. Dark whatever is a weak fudge factor to make the equations balance. I'd rather believe there are shortcomings in our understanding of how gravity works at galactic scale/in a very young universe/over 13 billion years than believe in magic goop/energy doing it. It's "The Ether" and "The Bodily Humors", "Phlogiston" and "The Spheres". I don't doubt the sincerity of anyone's belief about "Dark Matter" - but it does smell to me of serious error - Great Embarrassing Boners of Science History serious. Occam's Razor and all that.

You're conflating dark matter and dark energy. They both describe cosmological effects, but they are otherwise completely different. Additionally, while you can point to examples of hypothesized stuff that has since been discarded, I can easily point to hypothesized stuff that has since been confirmed (antimatter, the Higgs boson, neutrinos, etc.). Also, while it's possible that gravity works differently on large scales, general relativity has so far passed every single test it's been given with astonishing accuracy.

And if we're going the Occam's razor route, it's important to realize that there is no single change to how gravity works that would explain every effect of either dark matter or dark energy. Multiple changes are needed. On the other hand, all you need to do is add x amount of some weakly-interacting particle (dark matter) and you can describe the evolution and structure of the universe, or y amount of some cosmological constant (dark energy) to explain the universe's recent history. Given that the Standard Model contains 61-ish fundamental particles that have been confirmed to exist, what does the razor cut: adding one more particle, or adding a number of ad-hoc additions to gravity?

[DaShi]

Don't look back, look forward.

Terrible advice. Try instead to recreate the past. It worked for Jay Gatsby.

[DaShi]

You're conflating dark matter and dark energy. They both describe cosmological effects, but they are otherwise completely different. Additionally, while you can point to examples of hypothesized stuff that has since been discarded, I can easily point to hypothesized stuff that has since been confirmed (antimatter, the Higgs boson, neutrinos, etc.). Also, while it's possible that gravity works differently on large scales, general relativity has so far passed every single test it's been given with astonishing accuracy.

And if we're going the Occam's razor route, it's important to realize that there is no single change to how gravity works that would explain every effect of either dark matter or dark energy. Multiple changes are needed. On the other hand, all you need to do is add x amount of some weakly-interacting particle (dark matter) and you can describe the evolution and structure of the universe, or y amount of some cosmological constant (dark energy) to explain the universe's recent history. Given that the Standard Model contains 61-ish fundamental particles that have been confirmed to exist, what does the razor cut: adding one more particle, or adding a number of ad-hoc additions to gravity?

I'm concerned about how much dark energy our universe. It may have chosen the quick and easy path.

[Buster Crabbe's Uncle]

Bullcrap is dark, Lori. I don't have the answers, but I'm not convinced the science group mind is grazing in the right place.

[Lorizael]

Sure, that's possible. But I don't really think dark energy is an instance of groupthink. Sixteen years ago, cosmologists discovered a property of the universe that was precisely the opposite of what they expected to observe. Rather than try to explain away this new discovery, they hypothesized a mechanism to account for it. It turns out that a specific amount of this mechanism also explains what they observe in the CMB and in the universe's larger structure. Sounds like a good theory to me.

It could be wrong, of course. Again, dark energy has only been a thing since the 90s. But I am in no way qualified to evaluate the claims of either those supporting the dark energy model or those supporting alternative theories. So in the mean time I'll accept the consensus, especially since doing so entails no risk that I can imagine.

[Buster Crabbe's Uncle]

The risk of being wrong on the internet, perhaps?

This missing mass is a problem almost as old as I am, I think. One day in the late 90s, I woke up and found all shows touching on cosmology on the assorted documentary channels asserting Dark Matter as fact. This isn't like figuring out what quasars are, which made sense and is supported with evidence...

I do know the difference with dark energy, but note that the two rather opposite things are the same thing in being fudge factors to explain puzzling observations w/o much supporting evidence beyond filling in the blanks those observations create. I further suggest that the observations in question are unlikely to be complete enough.

[Lorizael]

The thing it appears you're missing is that dark matter explains so much more than just the missing mass problem.

[Buster Crabbe's Uncle]

I can't claim to wrap my head around the miniscule variations in the CMB or why they find the particular spiderweb arrangement of galaxies so interesting. I've never seen an adequate explanation for assuming the standard candle for supernovae, for that matter. [shrugs] I love this cosmology ****, but I can't say I study it all that seriously.

[Lorizael]

Well, do you know who does...?

[Buster Crabbe's Uncle]

I envy you the talent at maths.




But from what I can follow of the history of the investigation, I cannot agree that the consensus on the dark fudge hypothesis(es) is warranted. More evidence, please.

[ZEE]

cKan we Please get BacK to the main toPicK of this thrade. Thanks.

[Lorizael]

Heh, no, not what I was going for. I am essentially an amateur when it comes to this stuff, which is why I defer to the experts. Yeah, I know some calculus and some physics, but nothing close to the level of general relativity.

[Buster Crabbe's Uncle]

cKan we Please get BacK to the main toPicK of this thrade. Thanks.

I get along with schizos surprisingly well, but I don't have anything useful to say on the subject...