Blood-Free Tissue
The only living tissue in the human body that contains no blood vessels is the transparent cornea of the eye. It's the firm, smooth outer shell that arcs across
in front of the iris and pupil. The cornea contains no blood vessels because it must be perfectly clear. Even one tiny capillary would cast the shadow of
hundreds of streaming blood cells into the light coming through the pupil. Without blood to provide oxygen and nutrients, the cornea must get them from somewhere else.
Nutrients come from the tears and from the liquid (aqueous humor) that fills the chamber behind the cornea. Oxygen is no problem, since the cornea is in direct contact with the air.
Closest Orbiting Moon
Of all the moons in the solar system, the one with the closest orbit is Phobos, the larger of the two satellites of Mars. The orbit of Phobos is less than 6000 kilometers above the surface of the planet (3700 miles).
Phobos is an irregularly shaped chunk of rock and ice about 27 kilometers long (17 miles). Because its orbit is so low, it can only be seen from a limited strip of the planet near its orbital path. Seen from that strip, it crosses the sky quickly from west to east, twice a day.
Phobos' orbit is so low that tidal forces are pulling it closer and closer to Mars. Scientists expect that in about 50 million years it will either crash into the planet or break up into a thin ring of orbiting debris.
Fastest Humans
Relative to the planet Earth, the fastest speed humans have achieved was 24,791 miles per hour (39,914 km/hr), by the Apollo 10 astronauts, on their return trip from the moon in 1969.
But the universe is much bigger than the Earth-Moon system, and everything moves. If the Sun is taken as a fixed point, then all the humans on Earth are moving at about 66,660 miles per hour (107,320 km/hr) as the Earth follows its orbit.
If the center of the Milky Way galaxy is a fixed point, then the solar system is moving at about 500,000 miles per hour (800,000 km/hr) in its orbit around the galaxy.
From an even broader reference frame, our entire local group of galaxies is moving at about one million miles per hour toward another galaxy group called Virgo Cluster.
The Keyboard
Almost every alphabetic keyboard in the world has the letters in an arrangement called "qwerty," after the first six letters in the top row. There are several popular myths about the origin of today's standard keyboard arrangement. Some say it was deliberately designed to slow down typists. What is the truth?
When inventor C. L. Sholes built his first typewriters in 1868, he arranged the keys in alphabetical order. But the clumsy mechanical linkages inside the machine could tangle if certain pairs of keys were struck quickly.
The "qwerty" arrangement fixed the tangling problem by separating the internal links for frequently paired letters, making the machines more reliable. After a historic typing contest (see today's Person Of The Day, linked below), "qwerty" became the standard way to arrange the keys.
Croissants
The delicate, flaky croissant or crescent roll is a baked pastry that is curved with pointed tips. Although its popular name in English speaking countries is French, the roll itself is of Austrian origin, commemorating a Turkish shape.
According to the most popular story, in 1683 the Ottoman Turks invaded Vienna by trying to tunnel under the city's walls. The Turks were successfully repelled, thanks to the vigilance of the only people who were awake during the night-time raid: the bakers. In celebration of the victory the bakers created the croissant, shaping it like the crescent found on the Turkish flag.
Since there are several different stories of this event, the true details may be different. But all sources agree that the croissant's shape is the Turkish crescent, and that it was created in celebration of an Austrian victory over the Turks.
False Maps
In the old Soviet Union, maps were often made with deliberate errors. Towns, rivers, and roads were placed incorrectly, and entire towns would be missing in some versions. Moscow street maps were especially inaccurate.
The false maps were part of a plan to prevent foreigners and even the Soviet citizens from knowing the details of the geography of the Soviet Union. It was thought that this would increase security, but actually it made the whole country less efficient.
The false maps were part of a much broader concept called Maskirovka, a word that has meanings relating to misdirection, camouflage, misinformation, and diversion. According to some experts, the Maskirovka philosophy is still very much a part of Russian strategy, and influences many parts of the society.
Seven Day Week
No one knows exactly where and when the seven day week got started, but it is known to be extremely ancient. The most common theory about its origin relates the seven days to the ancient astrological idea that there were seven celestial bodies revolving around the stationary Earth.
For thousands of years, the astrological seven day week was used in Mesopotamia. It was adopted by the Egyptians, who then passed it on to the Greeks. In 321 AD, Constantine The Great added the seven day week to the Roman calendar, making the first day a day of rest and worship.
What were the days of the Roman week? They were Dies Solis (Sun's Day), Dies Lunae (Moon's Day), Dies Martis (Mars's Day), Dies Mercurii (Mercury's Day), Dies Iovis (Jupiter's Day), Dies Veneris (Venus's Day), and Dies Saturni (Saturn's Day).
Coldest Place
The coldest natural outdoor temperature ever recorded (as of January, 2000) was at Russia's Vostock Station in Antarctica. In 1997 the temperature there fell to -91 degrees Celsius (-132 degrees F). At this temperature, steel becomes so brittle it shatters easily.
Vostok Station is located in the middle of a vast expanse of uninterrupted ice, on a high plateau about 780 miles (1260 km) from the South Pole. The ice at Vostok is about 3700 meters thick (12,100 feet) and the surface elevation is 3488 meters (11,444 feet).
Vostok Station is not only the coldest place on Earth, it is also one of the driest. Because the air is so cold, it can hold very little moisture. The air's absolute humidity at Vostok is lower than that of the Sahara Desert.
Cricket Thermometer
If you hear a cricket chirping and you have a watch, you can estimate the temperature where the cricket is. If you can hear more than one, you can tell whether they are experiencing different temperatures.
To calculate the "cricket temperature," count the number of chirps in a 14-second period. Add forty to the result, and you have a rough estimate of the Fahrenheit temperature of the cricket.
This method works best with the snowy tree cricket, whose song sounds like gently ringing sleigh bells. Depending on the species of cricket, you might have to adjust the counting time by one or two seconds, up or down.
Why does it work? Because crickets are cold-blooded creatures, the rate of their metabolism is strictly determined by temperature. The warmer it is, the faster they move and the faster they chirp. The same method would work equally well with other insects if they had the regular chirping habits of crickets.
Diamond Formation
Natural diamonds are formed at least 150 kilometers deep in the Earth (93 miles) where the heat and pressure are great enough to squeeze carbon atoms together into the diamonds' tight crystal structure.
How do they get to the surface? Almost all diamonds mined today are collected from "diamond pipes," deep channels of a kind of volcanic rock called kimberlite or blueground. These structures started as nearly vertical columns of magma that pushed their way up carrying diamonds formed much deeper, and solidified in place. The best known kimberlite pipes are in South Africa.
Most mined diamonds are of low quality, suitable for use in industrial abrasives. These are called "boart." The gem quality stones are only 15 to 20 percent of those mined.
First Television
The first television was created by John Logie Baird, a Scottish engineer. In 1924 he built a working, mechanically-scanned television out of cardboard, scrap wood, needles and string, among other materials.
Baird was a driven inventor and researcher. For years he battled ill health, poor funding, and inadequate technology. Among his greatest challenges were amplification of the tiny electrical signals from the camera's photocells and the problem of synchronizing the signals so that a recognizable image could be produced.
His first working prototype was called the "Televisor." It was a rickety assembly glued together with sealing wax, but it worked. With it, he was able to transmit the profile of a Maltese cross several yards away, to a receiver where the image was displayed.
Ancient Olympics
The first organized Olympic Games were held in Greece in 776 BC. It is thought that competitive athletic games had been held in Greece since about 800 BC, but not as an organized festival. The Games were then held every four years until 393 AD, when they were abolished by Christian occupiers of Greece.
The only event at the first Games was the stadion footrace, a 600 foot (183 meter) sprint. In later Games, many other competitions were added including javelin throws, horse racing, and wrestling.
For more than a thousand years the Olympic Games were a time when conflicts were forgotten and a spirit of honest competition ruled. If the modern Olympic Games last as long as the ancient Games, they will still be held in 3066 AD.
Heaviest Snake
Female anacondas can weigh more than 200 pounds (91 kilograms), making them the heaviest snakes. Although the longest anaconda was measured at 28 feet (8.5 meters), it was not weighed, but scientific estimates place it at about 500 pounds (227 kilograms).
A female anaconda mates with as many as a dozen of the much smaller males. They form a "breeding ball" that can remain together for several weeks. The female later gives birth to as many as 70 young snakes, most of which will be eaten by various predators.
Anacondas are as comfortable in water as they are on land. They ambush their prey, slowly creeping up on it, then strangling it with their muscular bodies. They are found throughout tropical South America, but their range is decreasing as humans destroy their swampy habitat.
Bubble Gum
The first bubble gum ever marketed was called "Blibber-Blubber." Offered by the Frank Fleer Corporation in 1906, it never caught on because it was sticky and brittle and the bubbles often burst into sticky fragments all over the chewer's face.
In 1928 Fleer introduced a much-improved product called "Dubble Bubble" using a formula developed by an accountant in his company. Unlike Blibber-Blubber, the bright pink Dubble Bubble had a high surface tension and elasticity, so the bubbles were firm. When they did pop, Dubble Bubble bubbles snapped back quickly instead of splattering.
Marketed specifically for children, Dubble Bubble became a quick success. During World War II, US Soldiers in foreign lands offered it as gifts. According to one story, once when headhunters in Borneo captured a diplomat they demanded tons of Dubble Bubble as a ransom.
Megamouth Shark
In 1976, the marine biology world was amazed by the capture of a very peculiar, previously unknown shark off the Hawaiian island of Oahu. The new species was called "megamouth" for its bathtub-size mouth.
The megamouth shark (Megachasma pelagios) is the rarest of all sharks. As of 1999, only 13 have been sighted or captured. The largest specimen is 5.1 meters long (17 feet).
Like its cousin the whale shark, the megamouth is a harmless filter feeder. Because the inside of its mouth is lined with a silvery reflective layer, some scientists think the megamouth might emit light to attract tiny animals into its mouth. If so, that makes it the largest known luminescent life form.
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