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These are the facts you could find on this page:
"Triphibian" Aircraft, Ancient Olympics, Ant Weed-killers, Autonomous Spacecraft, Backward Journey, Black Tires, Canine Color Vision, Cave Paintings, Cell Machinery, Changing Hemoglobin, Climbing Robot, Deep Volcanoes, Disappearing Species, Dizzy Asteroid, Drinking A Toast, Einstein Money, First Microscopes, First Paved Road, First Radio Telescope, First Shorthand, Gift Giving Flies, Glowing Mushrooms, Goose Bumps, Growing A New Leg, Highest Archaeological Site, Highest Skydive, Heaviest Snake, Hot Cities, Largest Bacterium, Largest Explosion, Largest Lava EventLargest Living Reptiles, Lizard Language, Lone Stars, Loud Whales, Microscopic Rockets, Mirror People, Most Common Mineral, Most Mates Mammal, Most Produced Chemical, Mysterious Explosion, Non-Coral Reef, Ocean "Termites", Oldest Fossils, Oldest Island, Plant Cleanup Crews, Radio Astronomy Crisis, Saving The Everglades, Slow Light, Slowest Drip, Smallest Tweezers, Snake-immune Animal, Solar Cycles, Solar System Objects, Star Sapphire, Synesthesia, Thermometers On Airplanes, Triggered Lightning, X Means A Kiss, Youngest Islands

"Triphibian" Aircraft
The "triphibian" Genesis aircraft will be able to take off or land on a variety of surfaces without changing the landing gear. Its unique design includes a cantilever landing gear assembly and retractable skis.
For normal hard-surface landings, the gear swings down and wheels are lowered. For snow or ice, the skis emerge. For water landings, the gear swings up, out of the way, and the plane's fuselage floats directly on the water. Optional telescopic wings can be made longer, providing extra lift that allows short take-offs and landings.
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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.
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Ant Weed-killers
Many kinds of ants are fungus farmers, growing mold on leaves or other foods and eating the mold themselves. But the ants only want one kind of mold to grow, a variety called Attamycetes, and must constantly remove another kind, a "weed" species called Escovopsis.
According to a recent study, at least 22 kinds of fungus-farming ants use Streptomyces bacteria as a living weed-killer. These ants have special patches of the bacteria on the undersides of their bodies. When the unwanted Escovopsis mold grows in their fungus farms, the ants apply the Streptomyces bacteria from their bodies, and the bacteria secrete an antibiotic that kills the Escovopsis.
This close relationship between the ants, the bacteria, and two different kinds of fungi has been going on for millions of years. The human "invention" of using antibiotics to control pests was in use by the ants long before we discovered it.
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Autonomous Spacecraft
One of NASA's goals is to design exploratory spacecraft that do not need constant monitoring and control from Earth. In the past, every single action by the spacecraft was dictated by commands sent from the ground.
A new software system called Remote Agent literally runs the whole spacecraft, making situational decisions and carrying them out without consulting with Earth, even fixing problems all by itself. This saves money and time, and makes it possible to run more missions.
The first in-space tests of Remote Agent are now taking place aboard the Deep Space 1 craft as it flies past asteroids and comets. The spacecraft makes its own decisions about the course to take, basing them on camera views of the target and the rest of the Solar System.
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Backward Journey
When Chinook salmon fry are first hatched, they cling to the pebbles and rocks of the high mountain streams where their parents laid their eggs. For a whole year and sometimes two, the fingerling salmon live in the cold waters of the high rocky mountains.
When they are about five inches long (12 cm) the young fish allow themselves to be carried downstream, but their current-fighting instinct keeps them facing upstream. They complete the entire journey to the Pacific Ocean backwards, swimming upstream but moving downstream.
The 800-mile (1300 km) backward journey is only the first challenge the salmon must face. They must stay alive in the ocean, growing strong and fat. They then must retrace their path, swimming upstream to the same cold mountain creek where they were born, to mate and begin the cycle again.
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Black Tires
In the early days of automobiles, tires were seldom black. The rubber from which they were made was naturally colored off-white or tan. Today's black tires owe their color to an accidental discovery.
In 1885, the rubber tire company B.F. Goodrich decided to try black tires, thinking that they might not show the dirt as much. They added carbon black pigment to the rubber mixture. To their surprise, they discovered that the carbon-colored rubber tires were five times more durable than the uncolored ones.
Today's tires are far tougher than those first black tires, and much more elaborate. They contain dozens of layers, with steel belts and computer-designed treads. But the basic black rubber is still an important part of the design.
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Canine Color Vision
It is not true that dogs are completely colorblind. While dogs do not have the same color vision as humans, they are able to tell yellow from blue. Like a human with red-green colorblindness, they can't tell the difference between red and green.
The reason for this limited range, in both the colorblind human and the dog, is that there are only two kinds of color receptors in the retinas of their eyes. While most humans have three kinds of color cells, with three different receptor molecules sensitive to blue, greenish-yellow, and red, dogs only have receptors for yellow and greenish-blue.
Canine eyes also lack another human trait: the fovea, an area especially dense with detail-sensing cells. As a result, their detail vision is not as good as ours. But they make up for this by having much better night vision and greater sensitivity to movement.
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Cave Paintings
On September 12, 1940, four teenagers were exploring a cave in the French countryside when they found a series of rock paintings made by early humans. Within days, archaeologists were examining the paintings, which made science headlines around the world.
The Lascaux cave paintings are among the world's most famous examples of early human art. In the shallow cave are detailed, highly artistic paintings of animals, people, and abstract forms, revealing much about the people who lived there 17,000 years ago.
For more than two decades, the Lascaux caves were open for public tours. But the constant stream of visitors took its toll, and the paintings began to deteriorate as the carbon dioxide from visitors' breathing corroded them. The cave was closed to tours in 1963, but a replica site nearby is now open for visits.
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Cell Machinery
The new science of proteomics describes the proteins that do the work required to run a living cell. The name is modeled after genomics, the science dealing with genetics and the genetic code. Just as the genome is a cell's total "library" of DNA information, the proteome is a cell's total complement of proteins.
A living cell is a very busy place packed with active molecules. Much of the volume of the cell's contents is taken up by enzymes, molecular carriers, and structural elements all of which are made out of protein. Proteomics describes the structure, function, and interactions of all those protein molecules with each other and with the many smaller molecules that also fill living cells.
Without high-speed computers, proteomics would be impossible to study. By creating detailed models of the molecules and simulating their interactions, scientists are discovering the detailed operations of life itself.
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Changing Hemoglobin
Before a baby is born it's faced with some special challenges, one of which is to get enough oxygen to its tissues from the mother's blood supply. In order to do this, the developing fetus uses a special trick.
The red blood cells of fetuses contain a special kind of hemoglobin (the molecule that carries oxygen). Because this "fetal hemoglobin" has a higher affinity for oxygen (it can grab it and hold on tighter), it's able to "pull" oxygen out of the mother's blood. This genetic adaptation, believed to be over 200 million years old, comes from a duplication of one of the normal hemoglobal genes.
Once a baby is born, the fetal hemoglobin gene becomes inactive and adult hemoglobin begins to fill its red blood cells.
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Climbing Robot
Engineers at the University of Madrid have developed "ROMA," a robot able to nimbly climb the complex girders of bridges, towers, and buildings under construction. While it climbs, it sends a constant stream of video and other data to operators on the ground.
The robot can replace human climbers who put themselves in danger by scaling tall structures looking for flaws, damage, or corrosion. It can carry a complete, 3-D map of whatever structure it is climbing, and can make immediate decisions to protect itself from slips or falls.
With two powerful, swiveling claws attached on opposite sides of a rectangular "brain box", the robot climbs by swinging on one claw, attaching the other, and releasing the first. It can be powered by a long cable or onboard batteries. In the future, robots like ROMA may assist human astronauts constructing large space structures.
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Deep Volcanoes
Most volcanoes are created at "subduction zones," where the Earth's crust slides down into the mantle and part of the melted crust rises back to the surface. They erupt material from just below the lower crust, seldom deeper than 150 km (90 miles). But some volcanoes have much deeper roots.
The volcanoes of Hawaii and the Galapagos Islands are examples of "mantle plume hot spots," the tops of long columns of hot rock that rise from very deep within the Earth, possibly from the boundary between Earth's core and mantle, about 2,900 kilometers down (1800 miles).
The lava at mantle plume volcanoes is different in composition from subduction lava, and the eruptions have a different character, being gentler and often lasting much longer. The mantle lava does not usually contain as much dissolved gas as that of the subduction volcanoes, so there are fewer explosive eruptions.
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Disappearing Species
According to various estimates by scientists, every day 35-150 species of life become extinct. Most of these vanishing species are (or were) inhabitants of tropical rain forests. A majority of them are insects or plants, and most remain undiscovered by humans at the time of their extinction.
The vast majority of these extinctions are the result of forest clearing and other human disturbances. Since humans began changing the planet, the number of extinctions has exceeded several of the great prehistoric die-offs caused by giant comet impacts or climate changes. If current trends continue, the human-caused die-off will be the worst one ever.
Earth's tropical rainforests are the oldest, most diverse continuously existing ecosystems on the planet. Some forests in southeast Asia have been in existence for 100 million years. Now, because of human actions, these fabulous, fragile treasures are threatened.
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Dizzy Asteroid
The fastest known spinning object in the solar system is the asteroid 1998 KY26, a 30 meter (100 foot) chunk of carbon, water ice, and organic substances that completes a rotation every 10.7 minutes. It rotates ten times as fast as the next fastest object, and sixty times faster than most asteroids.
1998 KY26 is an "Earth-crossing" asteroid, meaning that its orbit crosses Earth's orbit. During a recent pass, scientists discovered that it contains about 3.8 million liters (1 million gallons) of water, making it potentially valuable as a resource for future space explorers.
Because it spins so fast, 1998 KY26 would be a challenging place to land. Its tiny gravity is just barely enough to keep visitors from being flung out into space by its rapid spin.
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Drinking A Toast
In medieval times, a common way to kill an enemy was to offer him a poisoned drink. To prove to the guest that a drink was safe, the host would receive a small amount of the guest's drink in his own glass, and both would drink at the same time.
If the guest trusted the host, rather than pouring some of his drink into the host's glass he would simply clink his glass against it. Although offering a poisoned drink is no longer a popular way to kill someone, the custom of clinking glasses still remains.
There is another reason why the custom has held so long: in medieval times, the sound of bells was thought to scare off the Devil. The Devil was thought to frequent festive occasions, so the bell-like sound of glasses clinking was often heard at such events.
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Einstein Money
Einstein was born in Germany and was a citizen of Switzerland and then of The United States, but his picture was featured on Israel's five-pound note. His Jewish heritage qualified him to appear on Israel's currency. (Note: Israel's unit of currency was changed from the Israeli pound to the sheqel in 1980, and from the sheqel to the new sheqel in 1985. The sheqel was defined as ten pounds, and the new sheqel as 1,000 sheqels.)
Other famous scientists and inventors who have been featured on currencies include Marie and Pierre Curie (discoverers of radioactivity, French 500 franc note), Nikola Tesla (invented alternating current, Yugoslavian 5 million dinar note), Benjamin Franklin (showed that lightning is electricity, USA 100 dollar note), and Niels Bohr (quantum mechanical model of atom, Danish 500 kroner note).
Although Albert Einstein has not been featured on US currency, he has not been completely ignored: he's been honored on a 15-cent postage stamp.
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First Microscopes
The first microscope was probably invented in 1595 by Zacharias Janssen and his father in Middleburg, Holland. Their compound microscope used two lenses, one convex and one concave. The Janssen microscope marked the beginning of a period of rapid development of microscopes throughout Europe.
In 1610, the Italian Galileo Galilei made a microscope by adapting one of his telescopes, reversing the lenses. After that discovery, he made more of these "occhialini," sending some of them to other experimenters.
In 1660, another Dutchman named Anton van Leeuwenhoek developed a single-lens microscope that magnified up to 270 times. He was probably the first human to directly observe bacteria.
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First Paved Road
To build their monuments and temples, the ancient Egyptians needed huge blocks of black basalt, which they floated to Giza (just outside Cairo) using wooden barges on the Nile River. But how did they get the blocks of stone from the quarry to the water, which was about seven miles away (11 km)?
They solved the problem by building what may have been the world's first paved road. The six-foot wide (1.8 meter) road was paved mostly with flat slabs of sandstone and limestone. Because there are no grooves on the ancient stones, it is thought that the blocks of basalt were moved on rollers.
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First Radio Telescope
A radio telescope is a highly directional radio antenna that is able to create a map of the sky by recording signals coming from different directions. Although radio engineer Karl Jansky was the first to identify deep space radio signals in 1931, his antenna was not good at pinpointing individual sources.
The first steerable radio telescope was built in 1937 by Grote Reber, who had applied to work with Jansky but was turned down because of the poor economic times. So he decided to build his own radio telescope, a 31.4-foot metal dish (9.6 meters) mounted on a directional cradle in Wheaton, Illinois.
With his radio telescope, Reber was able to detect radio emissions from the Sun, the center of the Milky Way Galaxy, and several other "radio-bright" sources. By 1941, he had completed the first crude radio survey of the northern sky. Today his radio telescope is an historical monument in Green Bank, West Virginia.
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First Shorthand
Shorthand writing uses condensed symbols for words and phrases, making it possible to take notes or dictation very quickly. The first such system was "Tironian annotation," invented in 63 BC by Tiro, a freed Roman slave who used it to write down the speeches of Cicero.
One of Tiro's symbols is still in use today: the ampersand (&), which means "and." He also was one of the first writers to use initial letters to create acronyms, like "AD" for "Anno Domini."
Various other shorthand systems have since been used. In 1588, the first phonetic system was devised by Timothe Bright. Another system by Thomas Gurney was published in 1750. Modern written shorthand uses two systems. One was invented in 1837 by Isaac Pitman, and the other was invented in 1888 by John Robert Gregg.
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Gift Giving Flies
Dance flies (family Empididae) do their courting on the wing. The males of some species will catch an insect and wrap it in white silk. The finished product resembles a shiny balloon, and can be almost as large as the insect that made it.
The male then flies to a place where other males have gathered and they form a swarm, dancing up and down in the air. Females soon show up, attracted by the shiny gifts. Each male presents his balloon gift to a female fly, who eats it. While she is eating, the male mates with her.
In some species of dance flies, the male doesn't bother to catch an insect. Instead, he creates a gift made of hundreds of empty silk balloons. Although the gift is empty, females are still attracted. Other dance flies steal food from spiders' webs.
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Glowing Mushrooms
If you have walked in damp woods on a dark night and you have good night vision, you may have noticed a glowing mushroom growing from a decaying log. Although glowing mushrooms are common, their glow is not usually bright enough to attract human attention.
Mushrooms that glow are attracting insects and small animals that want to eat them. Some of the spores the mushroom produces end up getting attached to the outside of the eaters, and are later deposited far away, spreading the fungus around.
Fungi have other ways of attracting potential spore-spreaders. Some, like the foul-smelling stinkhorns, emit an odor that attracts flies and beetles. Some flowering plants also use foul odors to attract the flies or other insects that pollinate them.
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Goose Bumps
When you are cold, frightened, or angry, you might notice a peculiar prickly sensation on your arms and legs, and maybe on the back of your neck. You've got goose bumps, also known as piloerection.
Piloerection is the tightening of tiny muscles at the bases of hairs. When it happens, the skin puckers into thousands of tiny peaks, one for each hair. Each hair stands straight out from the skin, and the skin itself becomes tighter.
When you get goose bumps, your body is trying to stay warm by "fluffing out" your fur. This is a trait that we carry from our ancient ancestors who, millions of years ago, had a lot more hair than we do. Since we no longer have fur, it is not thought to serve any useful function today.
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Growing A New Leg
The only vertebrates (animals with a spinal cord) that are known to be able to re-grow an entire lost limb as an adult are the newts and salamanders (Class Caudata).
If a newt's leg is removed, cells near the injury convert to an almost embryonic state, losing whatever special qualities they had as skin, muscle, or nerve tissue. These new "baby" cells then begin dividing, and as they divide they re-specialize into new bone, muscle, cartilage, nerves, and so on.
No one knows exactly how the regeneration works, but it seems to have something to do with changes in the blood. When blood begins to clot at an injury, substances are released that cause cells to start dividing to heal the injury. In a newt, the cells return to an embryonic state at the same time.
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Highest Archaeological Site
The highest archaeological site in the world is on the summit of Cerro Llullaillaco [SER-oh yu-yai-YAH-ko] in the Andes Mountains on the border between Chile and northwestern Argentina. At 22,110 feet (6743 meters), Llullaillaco is also the second highest volcano in the world.
Llullaillaco is a desolate, forbidding peak. Capped with windblown snow, it is surrounded by a stark, ash-gray desert. At its peak a stone and gravel platform was recently discovered with a chamber dug into the rock underneath. In the chamber were the mummified remains of three children sacrificed in a long-forgotten Inca ritual, together with statues and jewelry.
Another valuable find might have been at 20,112 feet atop nearby Nevado Quehuar, but tomb-raiders looted that site before archaeologists could get there, leaving little of scientific value.
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Highest Skydive
On August 16, 1960, a US Air Force balloonist named Joseph Kittinger ascended in an open-gondola balloon to a record-setting altitude of 102,800 feet (31,300 meters). Wearing a pressure suit and a parachute, he stepped out of the balloon into very thin air.
Kittinger free-fell for four minutes and 37 seconds. With almost no air resistance at that altitude, his vertical speed reached almost 1000 kilometers per hour (600 mph) -- about the same speed as a jet airliner, only going straight down.
Eight minutes after his chute opened, he landed at White Sands Missile Range in New Mexico, having set records for highest open-gondola balloon flight, longest free-fall, fastest free-fall, and longest parachute descent.
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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.
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Hot Cities
A large city can create its own local weather patterns, including a bubble of warm air called an "urban heat island." The heat island is created by rooftops, streets, and parking lots, which absorb the sun's energy during the day, and radiate it at night.
In moderately moist climates, these warm city "bubbles" can cause clouds and even thunderstorms to form. The warm air rises up from the city, creating an area of low pressure that pulls in moist air from the surrounding countryside. The rising air cools, and clouds can condense.
If there's enough water in the air, thunderstorms can occur. As a result, cities like Atlanta, St. Louis, and Paris experience more thunderstorms than the rural areas that surround them.
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Largest Bacterium
Sometimes a Cool Fact is made obsolete by a new discovery. Such a discovery is the giant bacterium Thiomargarita namibiensis, which is now the largest known bacterium. This new find eclipses the previous record holder, which we reported in a Cool Fact (linked below).
T. namibiensis is a spherical, one-celled organism that lives in sediments off the coast of Africa. It is up to 750 microns (0.030 inch) wide, about the size of a fly's head, and easily visible without a microscope.
The organisms name means "Sulfur Pearl of Namibia", because the cells of T. namibiensis are filled with a pearly, sulfur-containing substance. The pearly-white material is a collection of substances that the cell uses to generate energy.
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Largest Explosion
The largest man-made explosion was the explosion of a hydrogen bomb at Bikini Atoll in the Pacific Ocean on March 1, 1954. The resulting fireball was expected to be the equivalent of 3-6 million tons of TNT (3-6 megatons), but it turned out to yield a whopping 15 megatons.
The titanic explosion, which blasted out a crater 2,000 meters (6560 feet) across, was 1,200 times as powerful as the bomb that leveled Hiroshima. It completely vaporized three islands and cast radioactive debris over an area of 50,000 square miles (129,400 square km).
From 1946 through 1958 the Bikini Atoll was the location of 23 atmospheric atomic bomb tests. Today, the radioactivity has diminished and it is possible to tour the underwater ruins of ships that were anchored in the lagoon during the tests.
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Largest Lava Event
The largest known outpouring of lava on Earth happened when the giant supercontinent of Pangaea split apart. The split formed what is today the Atlantic Ocean, and separated Africa and Europe from North and South America. This happened at the end of the Triassic Period, at the same time as one of Earth's largest (and least understood) mass extinction events.
This extraordinary flood of lava covered an area of seven million square kilometers (2,700,000 square miles) and may have released enough carbon dioxide to dramatically alter the planet's climate. We don't know yet whether the eruptions caused the mass extinction, but it is considered likely.
Today, remnants of that ancient lava flood can be found at New York's Palisades basalt cliffs, as well as many locations in North and South America and Africa.
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Largest Living Reptiles
The largest living reptiles are Australian saltwater crocodiles (Crocodylus porosus), which can reach lengths of 6 or 7 meters (20 to 23 feet). These huge predators live in rivers and estuaries in southern Asia and northern Australia, and sometimes enter the open ocean.
Of all crocodiles, this one is the most deserving of the title "man-eater." Saltwater crocodiles are able to take down even large prey, such as wild boar and deer. When it catches its prey, the crocodile twists over and over sideways, drowning the animal.
Because individual crocodiles cannot get enough leverage to rip apart large prey, they use teamwork, taking turns twisting and pulling. While one crocodile holds the prey, another twists off pieces. They then change places, so each crocodile gets to eat.
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Lizard Language
Lizards in the suborder Iguania communicate by doing push-ups and other athletic displays. They convey territoriality, courtship displays, and other messages with various combinations of push-ups, body postures, head movements, and displays of colorful belly patches or throat dewlaps.
The Iguania includes the common sagebrush lizards of the American west, as well as iguanas and tropical anoles. Different species have different languages, and within each species there may be regional "dialects."
A recent study showed that, like the languages of humans and some kinds of birds, lizard body language is an open grammatical system. This means that they can express many different messages using a fixed set of symbols combined in various orders.
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Lone Stars
Although almost all the stars in the universe are part of one galaxy or another, there are still many billions of stars that float in the almost completely empty space between galaxies.
These stars formed inside galaxies but were cast out in gravitational encounters between galaxies. These encounters can pull long arcs of gas, dust, and stars into the intergalactic void. The gas and dust dissipate and are lost in the vastness, leaving the stars (and their planets, if any) to drift for billions of years, far away from any others.
Recent work with the orbiting Hubble Telescope has finally revealed 600 of these isolated stars in the space between galaxies of the Virgo Cluster, 60 million light years away from our Milky Way Galaxy.
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Loud Whales
People who live near the shores of quiet bays where whales visit can sometimes hear their beautiful songs even above water. At times, the whale songs can be loud enough to be heard indoors.
The songs of humpback whales have been measured at 170 decibels underwater, which is equivalent to 144 decibels in the air (every 10 decibels represents a 10-fold increase in sound intensity.) This is louder than a jet engine, which blasts 140 decibels at full throttle.
But the loud-song champions are the blue whales, whose earsplitting melodies can reach 188 decibels underwater (162 db in air), more than 100 times louder than a roaring jet engine. These ocean leviathans are the world's champion loud noise making animals.
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Microscopic Rockets
As spacecraft become smaller and lighter, it is important to design tiny thrusters to power them. Recently, there has been a new breakthrough: scientists are building pinhead-size rocket engines out of silicon and glass.
An array of tiny rockets are used together, as each one fires only once. Each rocket has a tiny chamber that contains fuel. To fire it, an electrical lead is suddenly energized. The fuel ignites, blasting through a cap that protects the fuel chamber, providing propulsion.
Because each rocket is so small, it produces only a very tiny thrust. This is good for tiny spacecraft, which require very delicate guidance. With thousands or even millions of rockets in each array, the micro-thrusters might be perfect for long missions by tiny robot explorers.
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Mirror People
About one person in 8,500 has a condition called situs inversus in which all the internal organs are located in mirror-image to the usual arrangement. People with situs inversus have their heart on the right and their liver on the left. The condition does not usually result in any medical problems.
No one knows why some people are internally flip-flopped, but recently scientists have discovered some clues.
In the earliest days of embryo development there is a critical period during which cilia (tiny beating hairs) cause a current to flow across the embryo. This current carries certain substances to one side more than the other, creating a left-right difference that becomes amplified into the left-right positions of the organs. People with situs inversus may have a genetic quirk that reverses or removes that current.
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Most Common Mineral
About 60% of the Earth's outer crust is composed of feldspar. There are nine common varieties, all of which are aluminum silicate with one or more other elements mixed in. Some varieties, such as labradorite, can form beautiful crystals with multicolored irridescence.
The feldspar minerals form a "solid solution" series, meaning they can contain varying proportions of calcium, sodium, and potassium atoms mixed into the aluminum silicate crystal structure. The shape and color of the crystals are used to distinguish the varieties, and depend on the proportion of elements in them.
Feldspar generally forms when hot magma solidifies deep underground, but can sometimes form in other kinds of rock that are subjected to great heat. Its crystals are usually mixed with other minerals like quartz or mica. It is one of the main components of igneous rock like granite.
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Most Mates Mammal
A mature male northern fur seal (Callorhinus ursinus) establishes a territory and gathers a group of females that he actively defends and herds. There may be as many as 100 females in a single male's territory, making male northern fur seals the mammals with the most mates in any one season.
Male northern fur seals are much larger than the females even at birth. An adult male might weigh as much as 450-600 pounds (200-275 kg), while an adult female could weigh 90-110 pounds (40-50 kg). The males begin to guard their territories in May and June, and at about the same time pregnant females from the previous year's matings come ashore to give birth.
Northern fur seals are found in the northern reaches of the Pacific Ocean. They spend much of the year in open water where they eat schooling fish and squid. Their numbers have declined recently and they are now a protected species.
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Most Produced Chemical
Of all the products of the chemical industry, the one made in the largest quantity is sulfuric acid or hydrogen sulfate (H2SO4). In the US, about 40 million tons are produced every year.
In its pure form, sulfuric acid is an oily liquid, also known as oil of vitriol. Pure sulfuric acid is very dangerous because it reacts quickly with water, releasing a large amount of heat. Sulfuric acid is usually sold in a dilute solution, which is much easier to work with.
Sulfuric acid is used in a wide variety of processes in almost every major industry. About 65% of it is used to make phosphate fertilizers. It is also important in the manufacture of explosives, dyes, paper, glue, and lead-acid batteries.
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Mysterious Explosion
On June 30, 1908, there was an enormous explosion in the air above a remote region of Siberia called Tunguska. The gigantic blast, about as powerful as 10-40 million tons of TNT, created an orange glow in the sky that was seen as far away as Europe.
Nineteen years later, scientists visited the spot. They found that sixty million trees had been felled, pointing in a radial pattern away from the center of the blast, but to their amazement they found no crater.
There were many theories about the cause of blast. There was no trace of radiation, so it was unlikely to have been a nuclear explosion. Today, scientists think it might have been a comet or asteroid about as big as a small mountain that exploded as it fell through the air.
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Non-Coral Reef
Not all ocean reefs are made from coral. Although they are now rare, reefs built by Serpula tube-worms can be found in several places. The most well developed Serpula reefs are found near the shores of Loch Creran, a sea in Scotland.
Serpula worms secrete calcium carbonate which they form into long tubes to make their homes. When thousands of worms build their tubes on top of each other, a reef forms. A Serpula reef is a unique ecosystem, with its own fish, plants, and other organisms.
Millions of years ago, such reefs were much more common, along with other kinds of reefs built by clams and other molluscs. Like coral reefs, Serpula reefs are endangered by human changes to their environment.
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Ocean "Termites"
For centuries, ocean-going vessels were subject to sinking when the wood they were made of collapsed due to the honeycombed tunnels of the teredo, or ship worm. The teredo is a bivalve (two-shelled) mollusc that eats waterlogged wood.
Each teredo larva enters the wood through a tiny hole. It uses its two small shells to bore out a tunnel, and consumes the wood. As it goes, it secretes a layer of shelly material to coat the inside of the tunnel. As an adult, it can grow to one meter long (three feet).
Teredoes have been boring into driftwood for millions of years, almost the age of the forests that provide the wood they eat. Today, wooden ships are protected from teredoes by special coatings.
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Oldest Fossils
The oldest fossils found so far are life forms called cyanobacteria that lived more than 3.5 billion years ago. Many species still survive today. These simple, light-loving cells are sometimes known as blue-green algae, although they are actually photosynthetic bacteria.
Cyanobacteria were the first photosynthetic organisms on the planet and they were the source of the Earth's oxygen atmosphere. By absorbing carbon dioxide and releasing oxygen, ancient cyanobacteria set the stage for the emergence of all the other forms that require oxygen to survive.
Today, cyanobacteria survive in aquatic environments everywhere and also in a very special place: inside the cells of every green plant. Each chloroplast is actually a cyanobacterium living in partnership with its plant host. Some cyanobacteria also live as one half of the partnerships known as lichens.
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Oldest Island
According to geologists, the oldest island on Earth is Madagascar, a large, mountainous island off the southeast coast of Africa. Unlike most islands, which are less than a million years old, Madagascar has been surrounded by ocean since it separated from Africa at least 85 million years ago.
Because of its long isolation, Madagascar developed one of the most unusual and interesting ecosystems on the planet. In its original form (prior to human transformation) its mountains were covered with dense rainforest on the east side, and deciduous forest and savanna on the west.
Madagascar's forests, now much reduced, are still home to many curious species, almost all of which are found nowhere else. Because of human activity, many of the remaining species are threatened with extinction.
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Plant Cleanup Crews
Toxic chemicals contaminate many places around the world. Traditional cleanup methods are expensive and difficult, and may require digging up soil for reprocessing, which destroys the natural biology of the soil. There is a simpler way to clean up toxic sites that takes advantage of nature's tools.
A natural ecosystem like a wetlands or a forest purifies the environment by removing toxic substances from the soil, water, and air. In a process called phytoremediation, this natural purification is harnessed by growing carefully selected plants at the toxic waste site.
The plants remove heavy metals, pesticides, or organic solvents from the ground. Some poisons are transformed into harmless substances, and others are concentrated in plant tissues where they can be controlled.
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Radio Astronomy Crisis
Radio astronomers "look" at the universe as it appears in radio frequencies, the lowest energy form of electromagnetic waves. The long, low-frequency waves of radio energy from space are so weak that all the natural radio waves collected by all the radio telescopes in the world do not contain enough energy to light a single light bulb.
Because they are collecting such weak signals, radio astronomers throughout the world are facing a growing crisis: much stronger signals generated by humans are drowning out the natural radio waves. Radio signals from the ground are bad enough, but as more and more satellites are placed in orbit radio telescopes must weed out their noise to find the natural signals coming from much farther out.
In the short term, there is no easy solution. Eventually it may be necessary to put radio telescopes on the far side of the moon, where the din of human communications do not overlay the subtle radio waves from distant galaxies.
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Saving The Everglades
The largest ecological restoration project in history is just beginning. In an attempt to reverse more than 50 years of ecological damage, the US Army Corps of Engineers will try to restore as much as possible of the Everglades wetlands.
The sprawling Everglades ecosystem was originally a vast, shallow basin fed by pure water from Lake Okeechobee to the north. It was a wide, slow-moving "river of grass," with a rich, diverse ecology including many animal and plant species that are now endangered or extinct.
Today, that ecology has been drastically changed by human attempts to tame the periodic flooding of the Everglades basin. To restore the natural flow, the Corps will remove artificial dams and fill artificial canals. If the project succeeds, the Everglades might one day return to their former beauty.
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Slow Light
Usually, light zooms through space at 300 million meters (186,000 miles) per second. But in a recent experiment, a pulse of light was slowed down to only 17 meters (55.7 feet) per second. Sound travels at 340 meters (1115 feet) per second in air.
The trick was to pass the light pulse through a cloud of extremely cold sodium atoms. The sodium atoms, which were cooled to a frigid 50 billionths of a degree above absolute zero, entered a special state called a "Bose-Einstein condensate." In this state, millions of atoms act as if they are one single atom.
The light pulse slowed down because it constantly exchanged energy with the atoms in the cloud. Upon leaving the cloud, it returned to its normal zippy pace. Scientists are excited by the experiment's implications for physics. It might also lead to new components for optical computers or other devices.
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Slowest Drip
The experiment started in 1927 when a physics professor at Australia's Queensland University poured some molten tar into a stoppered glass funnel. Three years later, he removed the stopper, placed the funnel on a stand, and put the whole setup inside a glass bell jar. Slowly, the almost-solid tar began oozing down the funnel.
Every nine or ten years the accumulating drop of tar drips down into a beaker below. The seventh drip happened in 1988. The eighth drip was expected to happen over Christmas in 1998, but the tar oozed more slowly than expected because the room had been air-conditioned, cooling it slightly and hardening the tar.
According to the current physics professor at the University, the tar should keep dripping for another century at ever-increasing intervals.
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Smallest Tweezers
Scientists at Harvard University have created the world's smallest pair of general-purpose, controllable tweezers. Using a pair of carbon nanotubes (long tube-shaped molecules of carbon) attached to gold electrodes they have successfully grasped and moved tiny wires only 20 nanometers wide (0.02 microns, or less than one millionth of an inch).
The tweezers work when the electrodes are given opposite electrical charges, causing the tips to be attracted together. By varying the electric charge, the amount of force exerted by the tips can be delicately controlled. The prototype tweezers used nanotube tips that were 50 nanometers wide, but work is under way to reduce the tips to smaller dimensions, perhaps small enough to grasp and manipulate individual molecules.
The tiny tweezers could become part of the toolbox for nanotechnology, the new science of building machines out of individual atoms and molecules. They could also be used in biological research for manipulating parts of living cells.
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Snake-immune Animal
Most animals go out of their way to avoid rattlesnakes, since their venom is strong enough to kill even large creatures. But the California ground squirrel (Otospermophilus beecheyi) has quite a different strategy for dealing with the venomous predator.
If a rattlesnake is seen anywhere near a ground squirrel nest, the squirrels immediately mount an offensive campaign. They rush in and out, kicking sand at the snake, even biting it if they can. A snake might be buried in dirt and pebbles, or even killed by the feisty squirrels.
The adult squirrels are partly immune to rattlesnake venom. A squirrel that is bitten by the snake during the fight usually suffers no long-term damage. Young squirrels are not quite so immune, so they tend to stay out of the fray.
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Solar Cycles
Like most stars, the Sun is not completely steady. It has a cycle of activity that lasts eleven years from one peak to the next. At this moment (October 2000) the Sun is near one of its peaks of activity.
When the cycle is at its peak the Sun's surface is pocked with dozens of dark sunspots, magnetic "storms" that restrict energy flow andhave a cooler temperature than the rest of the Sun. During the peak, there are more solar flares and coronal mass ejections. These powerful events can hurl billions of tons of plasma outward, possibly towards Earth where they may cause electrical disruptions and create colorful auroral displays.
When the Sun is quiet about five years later there are very few sunspots and flares, and the Sun's overall energy output is slightly lower. No one knows exactly why the Sun goes through these cycles, but it is probably related to the way magnetic fields move inside the Sun.
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Solar System Objects
The most abundant, substantial objects in the Solar System are the comets of the Oort Cloud, a roughly spherical shell that begins at three times the distance of Pluto's orbit and extends about halfway to the nearest stars. According to current estimates, there are about six trillion comets in the Oort Cloud.
From the distance of the Oort cloud, the sun is a bright star, about as bright as Venus looks from Earth. The temperature there is only four degrees Kelvin, which is about as cold as gets in the natural universe.
Once in a while, an Oort comet falls into the inner solar system. These rare visitors are interesting to science because they represent a sample of conditions as they were in the earliest stages of formation of the solar system.
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Star Sapphire
A star sapphire is a gem that shows a six-pointed (or rarely, twelve-pointed) star-shaped image when viewed under a point light source. There are also other star-reflecting minerals, all of which show stars for the same reason: there are thousands of tiny needle-shaped crystals within the gem.
Star sapphires contain microscopically thin needles of the mineral rutile. The crystals are oriented along the molecular axes of the sapphire crystal, which has six-way symmetry. Light is reflected by the shiny rutile crystals into the six-pointed star.
Sapphires are crystals of aluminum oxide, also known as corundum. Corundum is the second hardest mineral, after diamond. Rubies are also corundum crystals.
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Do numbers, letters, or days of the week have colors or smells? They might if you experience the unusual phenomenon called synesthesia. To a synesthete, one or more sensory channels cause a kind of "cross-talk" that triggers experience in another channel.
A synesthete may experience colors with numbers or letters (very common) colors with sounds or musical notes (also common), taste or touch with various sounds (much less common), or even colors with changes in temperature (very rare).
No one really knows what causes synesthesia, but neuroscientists are fascinated by it and are conducting research to try to better their understanding. Some believe that we all started out as synesthetes, but lost the ability in early childhood.
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Thermometers On Airplanes
Commercial airlines prohibit the carry-on of mercury thermometers because of the way mercury reacts with aluminum. If such a thermometer were to break and spill on a plane, even a tiny amount of mercury could badly damage the plane's aluminum frame.
Aluminum is used in the frames of airplanes because it is light and strong. Unfortunately, it is also highly reactive. It reacts strongly with the oxygen in air, but quickly forms a thin, protective coating of aluminum oxide.
Aluminum's reaction with mercury is not so benign. Mercury breaks through the protective layer of oxide, releasing lots of heat in the process, and eats away the aluminum metal.
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Triggered Lightning
Science has come a long way from the dangerous experiments of Ben Franklin and his kite, in which he demonstrated that thunderstorms carry electrical charges. Now, full-strength lightning strokes are routinely triggered and measured without endangering a human being.
To trigger a stroke, a small rocket attached to a long, grounded wire, is fired into the storm. If there's a strong electrical field in the air, lightning will strike the rocket. Sensors at the bottom of the wire record data about the stroke, including its current, voltage, and timing.
Free-flying rockets are also used to investigate the conditions within storm clouds. They can fly into turbulent, dangerous places no plane could ever go, sending back continuous streams of data.
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X Means A Kiss
In medieval times, most people were unable to read or write. When it came time to sign a document, people who could not write usually made an "X" mark. Of course, an "X" is not much of a signature. To add a sense of commitment, it became customary to kiss the "X" after writing it.
Kissing the "X" was "performance law," a ritual act that bound the parties the way legal documents bind us today. This act, witnessed by the person who wrote the text, represented a solemn guarantee of the truthfulness of what was written, and an oath to carry out whatever obligations were stated in the document.
Over the years, the "X" and the kiss became interchangeable. Today, people who can read and write might still add one or more "X" marks to their letters, maybe with a couple of "O"s thrown in for hugs.
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Youngest Islands
All around the world there are underwater volcanoes that may produce new islands at any time. As of July, 1999, the youngest island in the world is a 21 acre (8.4 hectare) island near Metis Shoal in the Tonga Archipelago. It erupted from the sea on June 6, 1995.
Like many new volcanic islands, Metis Shoal is still subject to rapid erosion by waves and weather. Although the unstable volcanic cinder cones formed in 1995 may not last, the volcano continues to erupt. Eventually, it will probably be covered by a hard lava flow that will endure the waves.
The second youngest island is Fukoto Kuokanaba, a 50 acre (20 hectare) volcanic cone in the Pacific Ocean near Iwo Jima. It was created in January, 1986.
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