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The Proton Is Lighter Than We Thought (sciencemag.org)
sciencehabit writes from a report via Science Magazine: You can't weigh the universe's smallest particles on a bathroom scale. But in a clever new experiment, physicists have found one such particle -- the proton -- is lighter than previously thought. The researchers found the mass to be 1.007276466583 atomic mass units. That's roughly 30 billionths of a percent lower than the average value from past experiments -- a seemingly tiny difference that is actually significant by three standard deviations. The result both creates and clears up mysteries, and could help explain the universe as we know it. The findings have been published in the journal Physical Review Letters.
Don't take it lightly!
Sig?
As we used to say: "Constants aren't, variables won't".
That's just astonishing. Get the Nobel committee on the phone. It'll be interesting to see what tweaks to the Standard Model come about as a result of this -- one of its 72 unexplained empirical "constants" has suddenly been (drastically) updated.
"You can't weigh the universe's smallest particles on a bathroom scale"
Of course you can, duh. You get a bucket full of them (say, 10 trillion), weigh it on the bathroom scale then subtract the weight of the bucket and divide what's left by 10 trillion. Voila, the weight of 1 proton. Silly scientists, do I have to think of everything?
OTOH, weighing a labrador who doesn't want to stand still on the bathroom scale - now, that's the REAL Nobel-worthy challenge.
In physics, we're limited by our environment. I've seen ridiculous things like the sprinklers coming on disrupt gravity constant measurements. Air conditioning, doors opening and closing, trains running a block away... there are so many things that can screw up these kinds of measurements.
A precise measurement is not the same thing as an accurate measurement. These guys went to great lengths to be as accurate as possible, but in situations like this, it's not reasonable to try to use a single apparatus to definitively contradict what people have measured for the last 5-10 years.
So... the mass of the proton isn't changing (by this honestly insignificant amount) until a couple of other groups independently verify this measurement.
Standard model doesn't cover gravity so a change in mass means fuck all. Last I remember it couldn't even explain why neutrinos have mass.
But then what is mass, what actually happens when mass turns to photons? What is energy in photons different from kinetic energy in particles? Why does light travel at C in a vacuum. What's special about C? Even before we get onto the train wreck that is QM.
The actual value is -
Just take a value that clears up the most mysteries.
(cheaper than building another damn super-collider)
I haven't seen a single important implication published about this other than our understanding of the proton is now more complete and it makes some nuclear physics calculations more accurate. I think the significance is more that something we thought wouldn't change finally changed.
Googling CODATA values:
proton mass = 1.672 621 898 (21) x 10^-27 kg
Atomic mass unit = 1.660 539 040 (20) x 10^-27 kg
Releative standard deviations: 1.25 x 10^-8
Ratio of codata values: 1.007 276 467 285 (i.e., codata proton mass in terms of atomic units)
New measurement: 1.007 276 466 583
Difference: 7.0198469259707963 x 10^-10
Relative difference: 6.9691362341583399 x 10^-10
How is this three standard deviations?
There is no substitute for common sense. Especially, no body of rules will do.
If you think of speed as distance per unit of time, then you could view that as the photon not having any speed at all, since it does not experience time. `c` is not special at all, it just happens to be the speed at which certain massless effects propagate in the universe. It's a limiting condition, sort of inherent to the idea that space and time can be traversed. You might also think of it as the "clock rate" of the universe.
Those who advocate genocide deserve every protection afforded by law, and none afforded by common human decency.
But don't worry, they've got the estimate of mass in the universe 100% flawlessly calculated based on observations and dark matter is totally real and not a math mistake.
I understand that there's a good chance that I'm able to access this source for free though one of my state's local libraries, and that's wonderful. I tried and failed to access it through one library card. I still feel as though more this entity would generate more net revenue and have the side effect of more people able to speak intelligently on the subject if the cost of a single paper was $2-$5 each.
In writing out this frustration, I think I'm beginning to understand, and I'm wondering if I might have a possible solution. I believe the average paper out of a scolarly journal produces effectively zero interest from the general public. They are too niche or too complicated or the findings are too unsurprising. For these papers, it doesn't matter if it costs $25 dollars or if it costs $1, you're still selling about the same number of copies. So it makes sense to charge the higher price. Every month or so, a decent journal such as this manages to publish an article that some science-news entity thinks is interesting enough to post a writeup. Every few months, they publish something that interests a number of science-writers, and manages to hit the slashdot level of interest. Once or twice a year, they publish something that gets mainstream attention and shows up on the level of something like SciShow (one of the few entities that makes science friendly and digestible, but also fact-checks and doesn't constantly get details plain wrong like so many other pop-sci media sources). The lower pricing would only make sense on those higher tiers, where greater demand for the original paper is generated. So now I'm wondering, why don't journals re-actively price accordingly? When a paper gets wider attention, slash the price. I suppose the response to this is that this isn't done for fear of it generating bias in publication selection. And I get that; greed is the enemy of integrity; it's why MTV stopped playing music videos long before the days where we could just stream them, it's why History channel and Discovery Networks bailed on quality educational programming. You don't want your academic journals vying to go viral; so you isolate yourself from that business. But in rea