Friday, October 09, 2015

Equation Works Out Kinks In Knot Math

Image credit: 
fdecomite via flikr |

Knots are everywhere, from laces of shoes to stitches that seal cuts. Sailors and others have known since antiquity that some knots are stronger than others, but such knowledge came largely from intuition and tradition, rather than a fundamental understanding of what makes knots strong.

Now, experiments with wires have helped scientists develop an equation explaining the forces involved within one of the simplest knots around, the overhand knot. Such work could one day lead to a better idea of what knots work best for given applications, such as the stitches used in surgery and the steel cables used in construction, the researchers said.

"Now we can understand the basic principles underlying overhand knots, which are the most basic type of knots used in our everyday life," said study lead author Khalid Jawed, an engineer at MIT in Cambridge. "This can serve as a starting point to investigate the mechanics of more complex type of knots."

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Thursday, October 08, 2015

"Cancer Glasses" Help Surgeons See Tiny Tumors

Some people need them to see, others just to read, but a new pair of high-tech glasses could save your life.

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Wednesday, October 07, 2015

Meteorite Markings Offer Clues to Their Past

Most iron meteorites are thought to be the remnants of planetesimals that grew large enough to differentiate very early during the formation of the solar system. Later destroyed by violent collisions, the parent body broke into pieces, some of them fragments of the nickel-iron core at the center, and others parts of the silicate crust and mantle. Some of these fragments were perturbed in their orbits enough to careen into the inner solar system, and a lucky few have ended up on Earth.

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Tuesday, October 06, 2015

Two Physicists Share Nobel Prize For Detecting Changes In Neutrino Identities

Courtesy of Kamioka Observatory, ICRR (Institute for Cosmic Ray Research),
University of Tokyo, rights:
The 2015 Nobel Prize in Physics has been awarded to a Japanese physicist and a Canadian physicist for discovering that abundant subatomic particles known as neutrinos can undergo changes in their identity, a process that requires the particles, once thought to be massless, to possess mass.
The prize goes jointly to Takaaki Kajita of the University of Tokyo in Japan and Arthur B. McDonald of Queen's University in Kingston, Canada "for the discovery of neutrino oscillations, which shows that neutrinos have mass." The two recipients were leaders of two major underground neutrino observatories on opposite sides of the world. Kajita was part of the Super-Kamiokande collaboration in Japan, and McDonald led a group at the Sudbury Neutrino Observatory, or SNO, in Canada.

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Monday, October 05, 2015

The People's Choice for a Physics Nobel: Dark Matter

The Bullet Cluster is one astronomical object that proves the existence of dark matter.
The Nobel Prize committees don't seem to worry much about popular opinion (or at least my opinion), but if they did I'm pretty sure Vera Rubin and Kent Ford would win the 2015 Nobel Prize in Physics for their measurements that were the first to strongly imply the ubiquitous existence of dark matter in the universe.

I'm basing this on things like the buzz I've been hearing from science journalists and the Sigma Xi bracket to pick this year's winner (they find dark matter and planets beyond our solar system to be the two to watch for). There's also a modestly active Facebook page that's been pulling for Vera Rubin since just after last year's Nobels, but since I made the page I don't put much stock in that as a predictor.

Vera Rubin and former APS President Michael Turner in 2013.
 Photo by Mike Lucibella.
One of the best Nobel Prize prognosticators I know, Ben Stein of Inside Science News Service,  is betting on dark matter or exoplanets as well (but considering he cited my Facebook page as part of his reasoning, I have to subtract a few credibility points from him this time around).

I've also spoken to a couple of well-connected scientists who say they don't know for certain of course, but the Nobel committee members seem shockingly up to date on the history of dark matter. Why would that make a difference? To me it means that the committee at least kicked around the idea of giving it to dark matter researchers and boned up on the history as part of their deliberations.

Kent Ford reminiscing about the detectors he built to measure the orbital motions in galaxies. Photo by Mike Lucibella.
If dark matter is on the short list and, as Stein believes, physics Nobels cycle through various areas over the years, this may be the last chance for the committee to recognize Rubin and Ford together. She's 87 years old now and would be 91 or 92 the next time they get to cosmological topics again, assuming exoplanets take the prize this year. Ford is a spry 84, but will be 88 or 89 when cosmology rolls around next on the Nobel Prize calendar (according to Stein).

I'm not sure how old the exoplanet researchers are, but I think they have a few more years to spare.

What is Dark Matter?

Nobody knows. There are lots of good guesses, but really dark matter is whatever is causing stars and other cosmic stuff to move around as though there's lots more matter in the universe than we can see. Fritz Zwicky was the first person on record noting the problem, and the first person to coin the phrase "dark matter" to account for it. (If he were alive today, I would put him on the list with Rubin and Ford to share the prize. Unfortunately, the Nobels are not given posthumously.) Although Zwicky was the pioneer, Rubin and Ford proved that Zwicky's observations were not some cosmic anomaly but instead the norm across the universe as far as we can tell.

We haven't been able to capture a bit of dark matter yet, or make a piece of it in labs like the LHC. That's not terribly surprising. The reason dark matter is dark is that it doesn't seem to interact except through gravity. But gravity is weak, and finding a tiny bit of something that you can't see, touch, smell or hear is really hard. Even if dark matter particles (assuming they are particles) are really heavy by particle standards, the gravitational forces any one particle exerts would probably be undetectable, particularly because you can't hold one in one place - or even be certain it's there at all. As I see it, if dark matter only interacts through gravity, then it's possible we will never detect it except by looking at the motion of stars and galaxies.

A Nobel Prize for Something We Haven't Found?!?!? Come on . . .

So why would the Nobel prize go for dark matter if we haven't found any yet, and may never find any at all? A lot of people seem to think that's a problem.

Actually, Ruben and Ford wouldn't get the prize for discovering dark matter -- they would get it for observing orbits of astronomical objects that are moving too fast, as though there is more matter there than we can see. So even if they win, don't expect dark matter to be in the Nobel Prize citation.

Still, like dark energy, the cosmic motions that might be explained by dark matter are among the greatest outstanding mysteries of modern science. That is a Nobel-worthy discovery.

More recently other things, like mass distribution in the Bullet Cluster and gravitational lensing due to dark matter, have essentially proven that the orbital motions Rubin and Ford measured are almost certainly the result of dark matter. So expect Ford and Rubin to share the prize with an astronomer who made those the Bullet Cluster or lensing measurements (I don't know who they would be because I don't follow astronomy much).

Will the People's Choice Take It?

I believe this is the year the Nobel Committee will recognize Vera Rubin and Kent Ford for their measurements of galactic rotation curves. And if they don't, whatever else they choose is just plain wrong, all things considered.

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Friday, October 02, 2015

Moonshine and Lunacy

I got an email from a reader yesterday asking for help in understanding a video that she’d seen, in which a citizen-scientist performs an experiment with a very surprising result: moonlight makes things colder! How could this be? To find out, I took a dive into the well-intentioned but deeply problematic world of Youtube science.

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Thursday, October 01, 2015

A Rough Neighborhood

Once every century or so, a supernova occurs somewhere in the Milky Way, blasting out as much energy in one event as a sun-like star emits over billions of years. According to a paper recently accepted for publication in Physical Review Letters, the level of antimatter in the vacuum of our solar system makes it look like one of these supernovas happened pretty close to home, and not too long ago.

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Friday, September 25, 2015

The Math Of Brewing Coffee Can Model Anesthesia

Mathematics that can describe coffeepots, forest fires and flu outbreaks may also underpin the brain’s response to anesthesia, a new study suggests.

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Wednesday, September 23, 2015

Ask a Physicist: Cold Light and Negative Work

It's been a while since we got around to opening up the "Ask a Physicist" inbox, but we've had some great questions recently, and you can look forward to Ask a Physicist being a more regular feature on the Buzz Blog. Let's get to it!

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Friday, September 18, 2015

Papers in the Pipeline: Simulating New Materials

Designing things like LEDs and transistors has, for a long time, been an arduous process of trial and error, but that could be changing soon, thanks in part to a technique developed by physicists at SUNY-Buffalo.

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