Archive for November 21st, 2008

Proton Mass Calculated

It’s confirmed: Matter is merely vacuum fluctuations

Each proton (or neutron) is made of three quarks – but the individual masses of these quarks only add up to about 1% of the proton’s mass. So what accounts for the rest of it?

Theory says it is created by the force that binds quarks together, called the strong nuclear force. In quantum terms, the strong force is carried by a field of virtual particles called gluons, randomly popping into existence and disappearing again. The energy of these vacuum fluctuations has to be included in the total mass of the proton and neutron.

Ab Initio Determination of Light Hadron Masses
Dürr, et al. Science 21 November 2008:Vol. 322. no. 5905, pp. 1224 – 1227

(h/t to Martin)

Oh, Well. That's Life.

Oh, well, That’s Life
What’s Life?
A magazine.
How much does it cost?
A quarter.
I only have a dime.
Oh, well, That’s Life
What’s Life?

(OK, “Who’s on first” is much better, but off the topic here)

LIFE photo archive hosted by Google

Gears, Glorious Gears!

Helical (angled-tooth) gears. Witchcraft, because they’re made of wood.

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More at the maker’s site

Class is in Session

The List: Five Physics Lessons for Obama

Everyone expects the U.S. president to know the difference between Sunni and Shiite, or understand the causes of the financial meltdown. But in today’s high-tech world, many critical issues have more to do with electrons than economics. Here are five short physics lessons for President-elect Obama from the author of Physics for Future Presidents.

The article does a decent job of pointing out the gaps between conventional wisdom and the actual science, especially nuggets like

It’s true that after 300 years, nuclear waste is still about 100 times more radioactive than the original uranium that was removed from the earth. But even this isn’t as scary as it sounds. If the waste is stored underground in such a way that there’s only a 10 percent chance that 10 percent of it will leak—which should be more than doable—the risk will be no worse than if we had never mined the uranium in the first place.

Regarding space —

Explain to the public that putting humans in space is not only very dangerous; it usually slows the advance of science. If the public just wants the adventure, then let them know that that is the real purpose.

I think there is value in the adventure, and the engagement of kids in getting them interested in science. The “wow” factor when the shuttle astronauts dropped by for a visit was significant. It’s a question of whether it’s worth the expense, and in the reality of finite budgets, what’s more important. Alka-Seltzer tablet reactions in zero-g are cool, but are they billion-dollar cool? No, probably not.

I think the article glosses over the connection between global warming and energy independence, though — there are certainly initiatives that can attack both at once — and the global warming section flirts with a “tu quoque” fallacy.

Yes, it is true that the United States is responsible for one fourth of past global warming. However, U.S. emissions are growing relatively slowly today.

So why are we so worried? It’s the rapidly growing greenhouse gas emissions of the developing world.

Is slowly growing emissions good enough, from the perspective of either reversing warming or setting an example? I don’t thinks so. I’m not sure how well a do-as-I-say-not-as-I-do policy plays out. Reduced dependence on foreign oil and a reduction in carbon dioxide emissions are both achievable, and needs to be done in parallel with getting developing nations to follow suit.