Saturday, January 23, 2010

Humans Could Run 40 MPH - in Theory

Humans could perhaps run as fast 40 mph, a new study suggests. Such a feat would leave in the dust the world's fastest runner, Usain Bolt, who has clocked nearly 28 mph in the 100-meter sprint.

The new findings come after researchers took a new look at the factors that limit human speed. Their conclusions? The top speed humans could reach may come down to how quickly muscles in the body can move.

Previous studies have suggested the main hindrance to speed is that our limbs can only take a certain amount of force when they strike the ground. This may not be the whole story, however.

"If one considers that elite sprinters can apply peak forces of 800 to 1,000 pounds with a single limb during each sprinting step, it's easy to believe that runners are probably operating at or near the force limits of their muscles and limbs," said Peter Weyand of Southern Methodist University, one of the study's authors.

But Weyand and colleagues found in treadmill tests that our limbs can handle a lot more force than what is applied during top-speed running.

What really holds us back

Their results showed the critical biological limit is imposed by time - specifically, the very brief periods of time available to apply force to the ground while sprinting. In elite sprinters, foot-ground contact times are less than one-tenth of a second, and peak ground forces occur within less than one-twentieth of that second for the first instant of foot-ground contact.

To figure out what limits how fast we can run, the researchers used a high-speed treadmill equipped to precisely measure the forces applied to its surface with each footfall. Study participants then ran on the treadmill using different gaits, including hopping, and running forward and backwards as fast as they possibly could.

The ground forces applied while hopping on one leg at top speed exceeded those applied during top-speed forward running by 30 percent or more. That suggests our limbs can handle greater forces than those found for two-legged running at top speeds.

And although top backward speed was substantially slower than top forward speed, as expected, the minimum periods of foot-ground contact at top backward and forward speeds were essentially identical. The fact that these two drastically different running styles had such similar intervals for foot-ground contact suggest that there is a physical limit to how fast your muscle fibers can work to get your feet off the ground, the researchers say.

New speed limit

The new work shows that running speed limits are set by the contractile speed limits of the muscle fibers themselves, with fiber contractile speeds setting the limit on how quickly the runner's limb can apply force to the running surface.

"Our simple projections indicate that muscle contractile speeds that would allow for maximal or near-maximal forces would permit running speeds of 35 to 40 miles per hour and conceivably faster," Bundle said.

While 40 mph may not impress the cheetah, the world's fastest land animal reaching speeds of 70 mph (112 kph), it's enough to escape a grizzly bear and much quicker than T. rex, which may have reached 18 mph (29 kph) during a good jog.

The results were published in the Jan. issue of the Journal of Applied Physiology.

Close Encounters of the Martian Kind

If you head outside around 8 p.m. this week and face due east, you'll see a brilliant, fiery-colored, non-twinkling "star" that immediately will attract your attention. It's not a star, however, but the planet Mars.

Mars, the most Earthlike planet of all the planets, has been absent from our evening sky for well over a year. Now it's coming back. Here's why:

Earth and Mars are in an eternal dance with the two parties sometimes close, sometimes very far apart. Both worlds orbit the sun, with Earth doing so more quickly on the inner path. Every 2.1 years, Earth laps Mars, like a race car on the inside track. At that moment, the sun, Earth and Mars are all lined up. Astronomers call it opposition. During much of January we've been speeding toward Mars in our orbit by an average of 3 miles per second; so Mars has been gradually getting brighter and larger in apparent size.

Mars will pass closest to the Earth at 2:01 p.m. EST during the American afternoon of Jan. 27, just two days before its Jan. 29 opposition, (when it will appear to rise at sunset and set at sunrise and will be visible all night). As a bonus, on opposition night, the Moon, just hours before officially turning full, will sit well off to the right of Mars as they climb the early evening eastern sky.

An "off year" by Mars standards

This year's apparition of Mars is actually one of the poorer and more distant ones in the planet's 15-year cycle of oppositions near and far. This is due chiefly to the fact that just over two months after opposition, Mars will arrive at aphelion (its farthest point from the sun) in its eccentric orbit. So we will come no closer than 61,720,695 miles to it on this occasion. Shining with a yellow-orange hue, it will attain a peak brightness of -1.3; just a trifle fainter than Sirius, the brightest star in the sky. (On this scale, smaller number represent brighter objects, and the brightest get negative rankings.)

Mars will also be almost twice as far away from Earth compared to its historic approach to Earth back on Aug. 27, 2003. On that date the red planet made the closest approach to ours in nearly 60,000-years. As compared to 2003, the 2010 approach of Mars will provide telescopic viewers with a very small disk even at high magnification. This will actually be its second farthest opposition; the next one, on Mar. 3, 2012 will be the farthest.

So this month's peak brilliance and very modest disk size will be the best that Mars achieves until Apr. 2014. On opposition night, the season is early spring in Mars' northern hemisphere. The Martian north polar cap, tipped 12-degrees toward us, will therefore shrink noticeably in the weeks that follow.

Mars is never easy to study, and this season its small diameter presents special challenges. The best telescope for studying the red planet is a large, high quality refractor or a large aperture Dobsonian reflector. But usually the limiting factor is the atmospheric seeing, which can change literally from minute to minute. Studying the planets always means spending a lot of time watching and waiting for elusive moments of steady seeing. Just as important, the more you look the better trained your eye will become. So plan to spend lots of time behind your eyepiece.

This week Mars become just large enough to show touches of dark surface detail and perhaps occasional white clouds or limb hazes in medium-sized amateur telescopes at the best moments on those steady nights when it's high up.

Bones of English Princess Discovered in Germany?

LONDON - She was a beautiful English princess who married one of Europe's most powerful monarchs and dazzled subjects with her charity and charm.

Now an international team of scientists say they think they've found the body of Princess Eadgyth (pronounced Edith) -- a 10th-century noblewoman who has been compared to Princess Diana.

"She was a very, very popular person," said Mark Horton, an archaeology professor at Bristol University in western England. "She was sort of the Diana of her day if you like -- pretty and full of good works."

Horton is one of a team of experts working to verify the identity of some bones found bundled in silk at Magdeburg Cathedral in Germany. Should the skeleton be positively identified as belonging to Eadgyth, it would be oldest remains of any English royal discovered so far. Experts say her closest competitors -- the bones of various Saxon royals in Winchester Cathedral in southern England -- are so hopelessly jumbled together that no single person can be identified.

"If (Eadgyth's) skeleton is intact then, yes, as far as I'm aware, it would be the earliest identifiable remains from Anglo-Saxon England," said Simon Keynes, a professor of Anglo-Saxon history at the University of Cambridge.

The skeleton was uncovered as part of a wider research project into Magdeburg Cathedral, about 90 miles west of Berlin. The elaborate 16th-century monument in which the body was found was long thought to be empty. When archaeologists opened the monument in 2008, they found a lead coffin bearing her name and carrying a nearly complete set of bones wrapped in silk.

Horton said the skeleton belonged to a woman between 30 years and 40 years of age. But there is some doubt as to whether it is the late royal: Historians believe Eadgyth's body was moved several times -- a common practice as far as the bodies of saints and royalty were concerned.

"The inscription (on the coffin) says she's been moved twice previously," Horton said, adding there's archaeological evidence of at least two more moves. It was possible that the bones were lost and swapped with someone else's during any one of the moves, he said.

"Quite often they scooped up any old bones and put them in," he noted.

Tests will now be performed to figure out the age of the bones and where they come from, including strontium isotope analysis -- a technique that measures the ratio of strontium isotopes in a person's tooth enamel to determine where they grew up. Because different isotope ratios correspond to different kinds of geographic locations, the technique can help pinpoint where a person lived. "Strontium is the smoking gun if you like," Horton said.

Gareth Williams, a curator at the British Museum, said the technique was "fairly highly regarded" among archeologists and should be able to show whether the skeleton's owner grew up in Germany or England, for example.

Keynes said if the skeleton could be shown to come from western or southern England there would be little doubt it was Eadgyth. Eadgyth grew up at the dawn of the 10th century, a period during which her half brother King Athelstan extended his rule over all of England and drew on his sisters to cement his influence among foreign rulers.

"He's well known for having a superfluity of half sisters, and he married them off to the ruling houses of the rest of the known world," Keynes said.

Eadgyth was destined for Duke Otto of Saxony, a warlord's son who would eventually rise to become the first ruler of the Holy Roman Empire. Tradition holds that she and her younger sister Adiva were both presented to Otto, who was invited to pick which one he liked best. Eadgyth's looks and charm won out over her sister's youth.

Keynes groaned when asked whether Eadgyth could be compared to Diana, whose marriage to Prince Charles in 1981 captured the world's imagination. But then he read from the chronicle of Hroswitha of Gandersheim, a contemporary of the princess, who said Eadgyth was "resplendent with a wondrous charm of queenly bearing."

Then followed a particularly florid passage in which German nun writes: "Public opinion by unanimous decision rated her the best of all women who existed at that time."

Keynes came around. Eadgyth bore Otto at least two children, but like Diana, died young, both at age 36.

Test results are on the bones are expected back within six months or so.

Ancient Greek Temple Dedicated to Cat Goddess Unearthed in Egypt

Egyptian archaeologists unearthed the remains of an ancient Greek temple dedicated to Egyptian cat goddess Bastet in the Mediterranean city of Alexandria, the antiquities department said Tuesday. The mission, led by Mohamed Abdel Maqsoud, head of Antiquities of Lower Egypt, discovered the remains of a temple of Queen Berenike, the wife of King Ptolemy III who ruled Egypt between 246 and 222 B.C., in the Kom al Dikka area in Alexandria.

"The discovered remains are 196 feet tall and 49 feet in width," antiquities chief Zahi Hawass said in a statement. He said the temple was "subjected to destruction during later eras when it was used as a quarry, which led to the disappearance of many of its stone blocks."

A group of 600 Ptolemaic statues were also unearthed during the routine excavations, including a large collection of icons depicting Bastet, goddess of protection and motherhood. The discovery in Kom al Dikka is the first Ptolemaic temple discovered in Alexandria to be dedicated to the goddess Bastet, Abdel Maqsoud was quoted as saying in the statement.

"It indicates that the worship of the goddess Bastet continued in Egypt after the decline of the ancient Egyptian era," he said.

The Ptolemaic period marks the Greek rule of Egypt from 305 B.C. until the Roman conquest in 30 B.C.

Alexandria became the capital city of Ptolemaic Egypt and thrived as the center of Greek culture and trade.

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