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Spit spares tongues, gastrotriches gulp microbes, cold nuclear fusion languishes

Q: Why doesn't saliva break down the tongue like it does food? (Tracy Jane, Los Angeles, California)

A healthy tongue [US Fish & Wildlife Service]

A: The muscular tongue is made of the wrong stuff — protein — for saliva to work on. Saliva has special enzymes (catalysts, called salivary amylase) that target and breakdown starches and sugars but not proteins. That’s why tongues escape unscathed.

So, when we hold bits of crackers, popcorn, bread, or chocolate in our mouths, they "melt" because the saliva breaks them down. Bits of meat, however, just sit there until we chew enough to swallow them into the stomach where other enzymes dissolve them.

Further Reading:

Dummies.com: Running through the human digestive system

Gastrotriches gulp microbes

Q: What is a gastrotrich? Is it a fish, a mammal, reptile or amphibian? (Humera, Karachi, Pakistan)

A gastrotrich, which is about as wide (50 micrometers) as the groove in a long-playing record. Note the straight-through gut. [Linda Amaral Zettler, David Patterson, Marine Biological Laboratory, NASA]  Please click here for a video of a swimming gastrotrich.

A: None of the above. It’s a tiny worm — a microscopic aquatic wormlike invertebrate — whose 400 species live in salt and fresh water and also on sandy seashores.

A gastrotrich (meaning "hairy stomach") uses myriad hairs over its head and belly to glide, wriggle, and squirm, looking for food. If it detects, say, a bacteria in its path, it sucks the creature into its straight-through gut and, satisfied for the moment, continues its simple hunting life.

Further Reading:

Florida State University: Molecular Expressions by Michael W. Davidson — A video of a gastrotrich swimming in a tangle of pond scum. ©1995–2004. Used with permission.

NASA Astrobiology: microscope images of microbes

Cold nuclear fusion languishes

Q: Is cold nuclear fusion possible? (Bert, Vaals, The Netherlands)

A cold fusion reactor. Naudin’s tests produce power at an output to input ratio ranging from 1.62 to 2.23. [Images courtesy of Jean-Louis Naudin (http://www.jlnlabs.org). Copyright 2004, Jean-Louis Naudin. All rights reserved. These images may not be used without the express written permission of Jean-Louis Naudin.]

A: It’s difficult to see how. We should know soon, however, since, in April 2004, the US Department of Energy decided to review the research. So, cold nuclear fusion gets another day in court.

Remember, back in March 1989, when two chemists — mind you, chemists of all things — shook up the physics world? Stanley Pons and Martin Fleischmann of the University of Utah announced they had created a controlled nuclear fusion — in a lab beaker! They fused deuterium (heavy hydrogen) inside metal electrodes at room temperature and produced heat. A scientific breakthrough!

Scientists leapt to their labs. The possibilities bubbled: a cheap energy source! A home could make its own electricity with little more than heavy water. No more oil! Some researchers managed to duplicate Pons and Fleischmann’s feat but, unfortunately, most didn’t.

In November 1989, the US Department of Energy stepped into the brawl. After investigating the various experiments, they concluded: botched measurements.

Some experimenters, though, continued to work. Now, 15 years and 15,000 experiments later, results pile up. Twenty researchers from seven countries claim to have successfully replicated the Fleischmann–Pons experiment: Naval Research Laboratory, SRI International, MIT. . .

The barrier to successful cold fusion, though, is enormous.

The tiny hydrogen nucleus has a radius of just 1 fermi (10^-15 m).  The radius of the entire hydrogen atom is roughly 50,000 times bigger than its nucleus (a proton).

Hydrogen nuclei repulse each other so strongly that the molecules normally never get closer that about 50,000 fermi — the distance of the atom radius. Molecular attractive forces are only strong enough to bring them that close together — an atom’s width.

In order to fuse two hydrogen nuclei together, though, we must force another proton into the hydrogen atom within a distance of 1 fermi from the atom’s proton. That takes a force 2.5 billion times the repulsive force (50,000 squared).

Doing this at room temperature with only electrodes providing the energy... "Fat chance!" Says Rod Nave, physics professor at George State University and most physicists.

Maybe the extra unexplained energy in the chemical process is real, says Nave, but the repulsive nuclear electric force "never sleeps." He doubts cold-fusion experimenters have overcome that barrier.

Further Reading:

JLN Labs: The quest for over-unity

Wired Magazine: What if cold fusion were real?

Pure Energy Systems: Data versus dogma – the continuing battle over cold fusion

(Answered June 18, 2004)