Goodyear's Moon Tires Simply Do Not Deflate, Ever [Tires]

Goodyear's Moon Tires Simply Do Not Deflate, Ever [Tires]: "

When NASA and Goodyear set out to develop a tire, they could not do so with the Earth in mind. This tire is Moon-bound and beyond, you see, where failure is not an option. More »

Molecular biologist on the dangers of pornoscanners

Molecular biologist on the dangers of pornoscanners: "Jason Bell, 'a molecular biologist and biophysicist... a Ph.D. candidate in Steve Kowalczykowski's lab at UC Davis,' has posted a detailed critique of the research on the safety of airport backscatter radiation scanners. His specialty is the 'molecular mechanism of how mutations in the breast cancer susceptibility gene, BRCA2, result in cancer,' and he's posted a detailed, lay-friendly explanation of the scientific concerns expressed by the UCSF team that believes that they are unsafe for use.

Which brings me to how the scanner works. Essentially, it appears that an X-ray beam is rastered across the body, which highlights the importance of one of the specific concerns raised by the UCSF scientists... what happens if the machine fails, or gets stuck, during a raster. How much radiation would a person's eye, hand, testicle, stomach, etc be exposed to during such a failure. What is the failure rate of these machines? What is the failure rate in an operational environment? Who services the machine? What is the decay rate of the filter? What is the decay rate of the shielding material? What is the variability in the power of the X-ray source during the manufacturing process? This last question may seem trivial; however, the Johns Hopkins Applied Physics Laboratory noted significant differences in their test models, which were supposed to be precisely up to spec. Its also interesting to note that the Johns Hopkins Applied Physics Laboratory criticized other reports from NIST (the National Institute of Standards and Technology) and a group called Medical and Health Physics Consulting for testing the machine while one of the two X-ray sources was disabled (citations at the bottom of the page).

These questions have not been answered to any satisfaction and the UCSF scientists, all esteemed in their fields and members of the National Academy of Sciences have been dismissed based on a couple of reports seemingly hastily put together by mid-level government lab technicians. The documents that I have reviewed thus far either have NO AUTHOR CREDITS or are NOT authored by anyone with either a Ph.D. or a M.D., raising serious concerns of the extent of the expertise of the individuals and organizations evaluating these machines. Yet, the FDA and TSA continue to dismiss some of the most talented scientists in the country...

Furthermore, when making this comparison, the TSA and FDA are calculating that the dose is absorbed throughout the body. According the simulations performed by NIST, the relative absorption of the radiation is ~20-35-fold higher in the skin, breast, testes and thymus than the brain, or 7-12-fold higher than bone marrow. So a total body dose is misleading, because there is differential absorption in some tissues. Of particular concern is radiation exposure to the testes, which could result in infertility or birth defects, and breasts for women who might carry a BRCA1 or BRCA2 mutation. Even more alarming is that because the radiation energy is the same for all adults, children or infants, the relative absorbed dose is twice as high for small children and infants because they have a smaller body mass (both total and tissue specific) to distribute the dose. Alarmingly, the radiation dose to an infant's testes and skeleton is 60-fold higher than the absorbed dose to an adult brain!

Review of the TSA X-ray backscatter body scanner safety report: hide your kids, hide your wife

• Pornoscanner advisory flier - Boing Boing


• NJ, ID legislators ready to ban airport pornoscanners - your help ...

(Thanks, Marilyn!)




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The 100 Greatest Movie Spaceships Of All Time [Spaceship Mania]

The 100 Greatest Movie Spaceships Of All Time [Spaceship Mania]: "

Maybe you want to argue over which ship could kick another ship's ass, or maybe you just want to ogle lots and lots of pretty spaceship pictures. Either way, you need to check out Jordan Hoffman's 100 greatest spaceships list. More »

Accurately weighing a pulsating giant

Accurately weighing a pulsating giant: "

Cepheid variables are a
class of stars with a luminosity that changes as a function of time. Cepheids are well-studied
astronomical bodies—they were first discovered in 1784—and
subsequent work has been able to identify a precise relationship
linking their luminosity and pulsation period. Because of this
well-defined relationship, they have been employed as standard candles
and used to accurately measure intergalactic distances. In fact, it was
calculations based on Cepheids that led Hubble and Humason to formulate
Hubble's law and conclude that the Universe was expanding.

Despite all that we know, however, there is a problem when it comes to Cepheids. Calculations of their mass based on two
different stellar theories leads to two very different numbers. In fact, using
the theory of pulsating stars will result in a mass prediction 20
percent less than that arrived at using the theory of stellar evolution. This problem has troubled astrophysicists since the 1960s.

To resolve this discrepancy,
astronomers need an independent measurement of the mass of a Cepheid to
see which theory—if either—is correct. Prior attempts at mass
measurements have given estimates
to within only 15 to 30 percent accuracy, not enough to resolve the
discrepancy between the two theories. An independent measurement, to get the right precision, requires a Cepheid to be one half of a pair of binary
eclipsing stars that orbit each other in a plane that would be seen
edge-on from Earth. Since neither Cepheids or binary eclipsing stars in
such orbital arrangements are common, a combination of both is
exceedingly rare.

This week's
edition of Nature contains a letter reporting on just such a rare find.
OGLE-LMC-CEP0227 is a stellar pair in the Large Magellanic
Cloud that orbits us in the right orientation and contains a Cepheid
star. According to the paper, the Cepheid variable star pulsated every
3.8 days and the two orbited each other every 310 days.

By measuring the orbits of both
stars, as well as the contraction-and-expansion of the Cepheid over the
entire orbit, astronomers were able to determine the Cepheid's mass to within 1 percent error. The
observed mass matched exactly with that predicted by the theory of
stellar pulsation; the larger mass predicted by the theory of stellar
evolution was shown to be largely in error.

Future work by the group
will involve looking for more such binary systems. With more data on
hand, they believe they can much more accurately pin down the distance
between Earth and the Large Magellanic Cloud, a
result that will greatly increase the accuracy of our cosmic-scale distance estimates.

Nature, 2010. DOI: 10.1038/nature09598
(About
DOIs).

Russia Spending $2 Billion to Play Garbage Man in Outer Space [Space]

Russia Spending $2 Billion to Play Garbage Man in Outer Space [Space]: "

All those defunct satellites up in space? They don't just float away into the ether. Instead, they make space travel dangerous. That's why Russia is spending $2 billion on a craft to clean up around 600 pieces of space junk. More »

Saturn's moon Rhea may have a breathable atmosphere [Future Space Colony]

Saturn's moon Rhea may have a breathable atmosphere [Future Space Colony]: "

Saturn's icy moon Rhea has an oxygen and carbon dioxide atmosphere that is very similar to Earth's. Even better, the carbon dioxide suggests there's life - and that possibly humans could breathe the air. More »

What does stoning a person to death entail?

What does stoning a person to death entail?: "

Canada's National Post created a two-page spread to explain the procedure for stoning condemned adulterer to death.

Since 1980, at least 150 men and women have been stoned to death in Iran, said Farshad Hoseini, head of the International Committee against Execution, who has compiled a report on the practice from media reports and human rights organizations.

However, he cautions in the report, 'It should be pointed out that obtaining a true and complete list of the victims is extremely difficult, if not totally impossible, due to the regime's systematic censorship of such news.'

He added, 'Stoning in Iran is a political tool in the hands of an Islamic regime to oppress the society as a whole in one of the most savage ways. The overwhelming majority of the victims of stoning are women. Stoning in Iran is therefore a tool, among many such religious, oppressive tools, for keeping women in their place.'

Iran's stone-age justice system

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