Uncategorized
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19042
The brief article on the discovery of sheets of melted sand in Australia mentioned several possible sources of the heat that produced this material, but it failed to mention the most probable source–the impact of a comet on the upper atmosphere. The nature of comets is that when they encounter an atmosphere of significant density […]
- Earth
Desert glass: Is it baked Australia?
A profusion of fused, glassy material found on the desert plain of southern Australia might be the result of the intense heat from an extraterrestrial impact.
- Earth
Wind Chill Update
The National Weather Service has revised its formula for calculating wind chill. These Web pages feature an explanation of the changes, a new wind chill chart relating temperature and wind speed, and a handy wind chill calculator. Go to: http://205.156.54.206/om/windchill/.
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From the November 21, 1931, issue
TURKEYS The beautiful bronze turkeys that furnish the biggest specimens for the family festivities were domesticated before white men came to America. Cortez found them in the markets of Mexico, and showed that he was a gourmet as well as freebooter; for turkeys soon found their way to Spain and thence all over Europe, finally […]
- Health & Medicine
Heart pump extends patients’ survival
Patients who have an implanted device to help the heart pump blood have a higher survival rate than patients getting only heart medication.
- Astronomy
SOHO craft gets the lowdown on sunspots
Using sound waves to obtain the first clear picture of the structure beneath the surface of a sunspot, scientists say they now have an explanation for why these dark blemishes-sites of intense magnetic activity-can persist for days.
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18978
The article notes that Joo Zilho has hypothesized that the rapid spread of agriculture in Europe occurred as a result of peoples need to escape conflicts in heavily populated communities marked by class and social division. I believe a more likely cause is the catastrophic flooding of the Black Sea, which occurred 7,500 years ago. […]
- Archaeology
Farmers took fast track in settling Europe
A review of radiocarbon evidence indicates that farming groups colonized southern Europe over no more than 100 to 200 years, beginning around 7,400 years ago.
- Paleontology
New fossils threaten an extinction theory
Recent discoveries of long-dead marine invertebrates call into question the occurrence of a catastrophic global extinction during the Late Devonian period, between 385 and 375 million years ago.
- Animals
She-male garter snakes: Some like it hot
Male garter snakes that emerge from hibernation and attract a mob of deluded male suitors may just be looking for safety in numbers and body heat.
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19041
I think this article ignored the major reason that large particles rise to the surface. The laws of inertia and momentum indicate that larger particles don’t react as quickly as smaller particles do at the end of each back-and-forth shake of the container. This means there is a force for relative motion between different-sized particles. […]
- Physics
The Brazil nut effect gets more jumbled
New and puzzling evidence for why big particles bob to the top when mixtures of granular materials are shaken-the so-called Brazil nut effect-emerges from an experiment showing that even the air between grains plays a role.
