These are the facts you could find on this page:
3-D Fax Machine, Ancient Marbles, Ancient Weapon, Body Snatchers, Bone-shaped Asteroid, Catnip, Cholera Outbreak, Closest Flyby, Coldest Biome, Coldest Place, Crack-Protected Hooves, Cricket Thermometer, Cross Your Fingers, Deepest Dive, Domesticated Insect, Durian, Elephant Birds, Expanding Universe, Femtosecond Laser, First Domestic Animal, First Newspaper, First Stop Signs, Flame Zones, Flying Car, Flying In A "V", Forest Fires, Global Positioning System, Hay fever, Highest Islands, Hot Larvae, Hot Sloths, Hungry Caterpillar, Ice-Melting Robot, Io's Auroras, Largest Dolphin, Largest Herb, Largest Pipe Organ, Largest Telescope, Lasers, Making Protein, Most Tornadoes, Moths and Bats, Mushroom Clouds, Oldest Board Game, Oldest Viable Seeds, Owls and Snakes, Pendulum Clock, Play-Doh, Popsicles, Pure Ocean Sound, Quadruplets Animal, Seawater Composition, Self-splicing Proteins, Slowest Pulsar, Snowballs, Spitting Spider, Starfish Eyes, The Tongass, Thin Crust, Useless Bone

3-D Fax Machine
A normal fax machine receives a coded message over the phone and translates it into a pattern of black and white dots on a page of paper. But there's a kind of fax machine that builds a three- dimensional object instead of a picture on paper.
Charles Hull invented the process, called stereolithography or solid imaging, in 1984. More than just a 3-D fax machine, it's a whole new way of making things. Descriptions of objects are stored as computer data files, which can be given physical form in a solid imaging machine.
A solid imaging machine creates an object by scanning a light beam across the surface of a liquid. The liquid solidifies wherever the light touches it. The newly created solid is lowered slightly, and another scan adds another layer of solid material. An object of almost any shape can be created.
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Ancient Marbles
Marbles have been used for games since the times of the Egyptian Pharaohs, when they were made out of fired clay. Clay marbles were also made by Native Americans, who also used round stones and nuts for their games.
The first glass marbles were made in Venice, Italy around 900 AD. Italian marbles were also made out of polished marble and other kinds of stone around the same time. These stone and glass marbles were used throughout Europe for hundreds of years.
Modern glass marbles did not appear until about 1860, when they were made in Germany. Around 1905, machine-made marbles were first sold in the United States, and their higher quality seriously impacted the European handmade marble marketplace. Today, though, the very best marbles are still made by hand, using secret methods.
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Ancient Weapon
Before the bow and arrow were invented about 15,000 years ago, a simpler weapon was used to throw long darts with great power and accuracy. The atlatl [at-LAT-ul] was invented at least 25,000 years ago, and is still used by Australian aborigines.
The atlatl is a stick about 60 centimeters long (24 inches), with a notched hook at one end. Into the notch is placed the end of a flexible, feathered "dart" that is at least 150 centimeters long (59 inches) and possibly longer. By flicking the atlatl quickly forward, the user is able to fling the dart toward the target with tremendous speed.
Recently, there has been a surge of interest in the atlatl. Its physics are surprisingly sophisticated, involving temporary storage of energy in the flexing of the dart as it is thrown. Enthusiasts are now designing ever-better atlatls using high-tech materials, and there are world-wide competitions.
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Body Snatchers
Throughout the animal kingdom there are examples of parasites that take over the behavior of their hosts in order to improve their own chances of survival. These "body snatcher" parasites cause their hosts to act in ways that are very different from their normal behavior.
When a thorny-headed worm reaches maturity inside a pillbug, it causes the pillbug to move out into the light, against its normal urge. Exposed, the pillbug is more likely to be eaten by a bird. If it is eaten, the thorny-headed worm then enters the next stage of its life cycle inside the bird, its new host.
There are dozens of examples of this kind of control. In most cases, the parasite controls its host's behavior by adjusting levels of hormones in the host's body. In at least one case, the parasite actually manipulates the host's DNA directly, turning certain genes on or off.
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Bone-shaped Asteroid
An asteroid called 216 Kleopatra that orbits between Mars and Jupiter has been imaged by radar, creating a detailed model of its shape. It is shaped like a giant dog bone as big as New Jersey.
Because of its optical color and because it reflects radar waves very well, astronomers believe that 216 Kleopatra is made mostly out of metals like nickel or iron. Large parts of it are composed of loose, metal-rich rubble, although there may be larger solid chunks in the center.
How did 216 Kleopatra get to be so strangely shaped? It may have been sculpted by one or more tremendous collisions billions of years ago. With two lobes connected by a thin neck, 216 Kleopatra is the most unusually shaped object found in the Solar System so far.
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Catnip
Something about catnip (Nepeta cataria) is very appealing for cats. Crush a few leaves of this herb in the mint family, and many cats will rub their faces on it, roll around on it, and dig their claws into it. Why do they do this?
Like many predatory mammals, cats are very sensitive to smells. Humans, who do not generally share this kind of deep olfactory experience, may not fully understand what it is like for a kitty to smell catnip.
For years, catnip's effects were mysterious. Then the active ingredient was discovered, a complex molecule called nepetalactone. Researchers suspect that nepetalactone resembles some of the molecules cats respond to during the hunt. Maybe it smells like "super prey," triggering an extreme response. However it smells, catnip is harmless fun for your pet.
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Cholera Outbreak
In London in the 1830s through the 1850s cholera was a major disease, often reaching epidemic proportions. Preventing these epidemics was almost impossible without our modern understanding of how diseases are transmitted.
It was not until 1854 that a real breakthrough came. A doctor named John Snow carefully mapped the location of each case. He discovered that one particular outbreak was clearly centered around a single water pump in a certain section of town.
He advised local officials to remove the handle of that one water pump, and before long the outbreak ended. He had proved his theory that the cholera was being transmitted, at least in part, through the public water supply.
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Closest Flyby
On July 28, 1999 the spacecraft Deep Space 1 (DS1) passed within ten kilometers (six miles) of a tiny Asteroid called 9969 Braille, in the closest non-impact fly-by to date of a spacecraft past any celestial object.
Moving at a relative speed of 15.5 kilometers per second (nearly 35,000 miles/hour), DS1 zoomed past Braille more than 50 times faster than the speed of a commercial jet, and twice as fast as the Space Shuttle.
Deep Space 1 is part of NASA's New Millennium Program, a group of missions designed to test and refine new space technologies. DS1 tests twelve new inventions, including a revolutionary ion propulsion system and a sophisticated software navigation system.
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Coldest Biome
Of all the kinds of ecosystems on land the coldest one is the tundra, found in the Arctic and at high elevations in the mountains. In these treeless regions, plants and animals are forced to survive on almost no available resources.
Because the climate is so harsh there is little extra energy for plants to put into large size or fancy flowers. They are generally small and grow only during a short part of the year. They have shallow roots because the soil is very shallow, resting on a layer of always-frozen ground called the permafrost.
Animals in the tundra are equally challenged. Many hibernate for almost the entire year, and some migrate when winter comes. Animal populations are subject to extreme population cycles, and the total mass of animal life is low compared to warmer biomes.
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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.
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Crack-Protected Hooves
The hooves of a galloping horse can hit the ground with more than the weight of the entire animal, yet they are made of keratin, the same protein that makes up your fingernails. How do they keep from cracking under the stress?
A horse's hoof is essentially a huge toenail. But unlike human toenails, it has an internal structure that stops cracks before they can grow, and even shunts them off to the edge of the hoof, thus trimming it efficiently by removing extra "flash" from the edges.
The keratin protein of the hoof has a "grain" like the grain of wood. Cracks tend to grow along that grain. If a crack develops, it moves along the grain until it comes to one of thousands of microscopic tubes that run through the hoof. Each tube is wound with layers of protein with differently-pointing grain, which redirect the crack along the tube to the edge of the hoof, where it harmlessly ends.
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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.
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Cross Your Fingers
The western tradition of crossing the first and second fingers as a way of "attracting" good luck is a holdover from the early history of Christianity, when there was great tension between Christians and non- Christians (called Pagans by early Christians).
Early Christians believed that it was important to honor their faith by making the sign of the cross, which is done by touching the body four times. But in the presence of Pagans this act might have given offense or even incited violence. So instead they made a "cross" by unobtrusively crossing their fingers, and many people still do it today.
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Deepest Dive
On January 23, 1960, Swiss adventurer Jacques Piccard and U.S. Navy Lt. Donald Walsh climbed into the bathyscaphe Trieste and began a dive that would go deeper into the ocean's waters than anyone has traveled before or since.
During a five-hour descent into the Challenger Deep off the Pacific's Marianas Islands, water pressure on the vessel, which had been jointly designed by Piccard and his father (explorer Auguste Piccard), rose to more than 16,000 pounds per square inch. Ultimately, they plunged to nearly 36,000 feet, some 7,000 feet deeper than Mt. Everest's height above sea level. To their surprise, they observed fish swimming about, which disappointed some scientists who had hoped to use the ocean's depths as radioactive waste disposal sites-- had they been found to be stagnant and devoid of life.
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Domesticated Insect
The silkworm moth (Bombyx mori) has been bred in captivity for thousands of years and probably no longer occurs in nature. During this time, like other domestic animals, it has evolved.
Today's silkworm moths are almost unable to fly, and cannot exist without human care. Each moth lives only a few days as an adult, and does not eat. After mating, females lay 300-500 eggs.
The caterpillars eat mulberry or osage orange leaves until they are ready to pupate. Then they enclose themselves in a cocoon made out of a single strand of silk about one kilometer long. Most silkworm pupae are destined to die, sacrificed so that their silk can be harvested.
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Durian
All across southeast Asia, people eat the durian or stinkfruit (Durio zibethinus). Westerners who try them are often astonished at the smell, which has been described as a blend of decayed onion, turpentine, garlic, Limburger cheese, and resin.
Although the flesh of the durian is sweet and mild, the aroma is so strong that many westerners cannot consume it without gagging. Eating it on commercial flights has been forbidden by several Asian airlines.
Yet the durian is enormously popular in Asia. In Thailand, it is called the King Of Fruits. This spiky-skinned, brownish green fruit, which can grow as big as a human head, is becoming available in the United States and Europe. Watch for it in gourmet supermarkets -- but be prepared!
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Elephant Birds
When humans first came to the island of Madagascar around 600 AD, it was home to the largest birds that ever lived, the giant, flightless elephant birds (Aepyornis maximus). The last one probably died about 800 years ago.
The liquid capacity of one elephant bird egg was about two gallons (7.5 liters), 180 times that of a chicken egg, possibly making it the largest single cell ever. An adult bird probably weighed about one thousand pounds (450 kilograms). Like their living cousins the ostriches, they were running birds with thick, muscular legs and vestigial wings.
The elephant birds were among many species of large animals that disappeared from Madagascar after humans arrived. Today, the island's animal life is much reduced. Destruction of habitat has eliminated many species, and many more are threatened.
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Expanding Universe
Astronomers see countless galaxies for billions of light years in every direction. The farther away a galaxy is, the faster it moves away from us. The whole universe is expanding. How do we know?
When an object moves away from an observer, the light from that object changes color, similar to the way a train whistle changes pitch if the train is moving away. This "Doppler shift" causes the light of receding galaxies to stretch out, becoming more reddish. Measuring this "red shift," astronomers can tell how fast each galaxy is receding.
If the universe is currently expanding, it makes sense that at one time it was much smaller. The "Big Bang" theory, which describes how the universe might have started in a stupendous explosion, is one possible explanation of how the universe began.
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Femtosecond Laser
The kind of laser cutter that causes the smallest amount of damage to the material surrounding the target is the femtosecond laser, developed in 1997 by a team at the Lawrence Livermore Laboratory.
The secret to the clean cuts of the femtosecond laser is the extremely short duration of its light pulses -- 50 to 100 femtoseconds (a femtosecond is one quadrillionth of a second). Because the pulse of light is so short, it only removes one layer of atoms with each pulse. These atoms are almost instantly vaporized and blown free of the target zone. By the time they are gone, the laser pulse is over and no further heat is added.
The femtosecond laser has applications ranging from cutting steel to performing delicate microsurgery operations. It was originally developed for use in disassembling nuclear weapon components, which must be done very carefully and precisely.
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First Domestic Animal
Throughout history, many kinds of wild animals have become domesticated (changed through breeding to live among humans). The first animal to become domesticated was also one of the smartest -- the dog.
Recent studies of the DNA of modern dogs show that dogs probably became a part of human society about 100,000 years ago in Africa, long before any other animals were living with people. How did these canine hunters come to live with our ancestors?
No one can say for sure exactly how it happened, but most experts agree that the first domestic canines were wolf pups, perhaps separated from their families by misfortune or by the actions of human tribes. As hunting companions, tame wolves would have been quite useful to early humans.
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First Newspaper
The first known newspaper was the free "Acta Diurna" (Daily Happenings), which was a hand-lettered gazette in ancient Rome, published from 59 B.C. to A.D. 222. It was mostly a record of what happened in political meetings.
The second newspaper was published about 1,300 years ago in China. It was called the "Tching-Pao" (News Of The Capital). The government used it to distribute news of events and decisions.
The first periodical publications with dated front pages were released in Europe in the 1620s. London's Morning Post began circulating in 1772. Then came the London Times, which is still being published today. Today, more than 600 million people buy a paper every day.
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First Stop Signs
You might think that stop signs were an offshoot of the invention of automobiles, but actually they were used centuries before in ancient Rome.
The Romans were great builders of roads, aqueducts, and other public works. Their dense city had many of the problems we have in our cities today, including air pollution, crowding, and heavy traffic. Coming to a stop at a busy corner makes sense whether your vehicle is a car or a horse-drawn chariot, and the Romans were smart enough to make it the law where appropriate.
Parking was also an issue in ancient Rome, and various laws addressed the problem. Improperly parked vehicles were subject to fines, just as they are today.
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Flame Zones
Take a close look at a candle flame. How many different zones does it have? From the wick outward and upward, first there is a transparent zone, then usually a blue zone, then a yellow zone, and possibly a short red one. Sometimes there is even a black zone after that one.
The transparent zone nearest the wick is where wax vapor steadily streams off the wick. There isn't enough oxygen in that zone for it to burn, because the steady stream of vapor keeps it out. But something else important happens here: the heat from the burning part of the flame starts breaking up the chains of carbon atoms in the wax. The long chains of carbon atoms immediately condense into extremely tiny particles of soot, which are carried into the main flame.
The blue zone is colored by the burning of a particular kind of molecular fragment called diatomic carbon (C2). The yellow zone is colored by the burning of the soot particles. If not all the soot burns, then the red zone forms from cooling soot particles, and you might even see the black zone which is smoke (large soot particles) in the process of condensing.
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Flying Car
In the 1930s a small winged automobile called the aeromobile was designed, and one was actually built. The aeromobile could fly through the air, but its performance, both on the ground and aloft, was not spectacular.
Now a new kind of flying car has been created that not only takes off vertically, but could also be the commuter vehicle of the future. Paul Moller's Skycar uses eight turbo engines to fly easily at 350 miles per hour (564 kph) using ordinary gasoline.
The Skycar is a new class of vehicle (called a volantor by Moller) that might make personal air transportation easier and safer than a ground trip. It could be equipped with a sophisticated computer autopilot that could safely fly its occupants to any destination, without human intervention.
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Flying In A "V"
Have you seen seagulls or migrating geese flying in a "V"? Through evolution, flocks of birds have spontaneously developed the best instinctive strategy for long-distance flight as a group.
Freeway drivers may be familiar with the "wake effect" that reduces gas usage when one follows just behind and to one side of a large truck. The "V" flying flock takes advantage of exactly the same effect.
By flying in a "V", birds minimize the energy used by the whole flock to get where it's going. Recent research shows that even the leader of the "V" benefits from the formation. A "V" flock of 25 birds can travel 70% farther than an unformed flock, and it also flies faster.
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Forest Fires
In many parts of the world, there were extensive forest fires long before humans came. These fires, set by lightning, were an important part of the forest ecosystem because they cleared out underbrush, making more room for large trees to grow and renewing the ecology.
The human policy of putting out forest fires as soon as possible has actually harmed some forest ecosystems. Unburned underbrush accumulates, so that when the forest finally does burn the fire's effects are far more severe, possibly burning all the trees instead of harmlessly burning only the undergrowth.
Modern forest management takes into account the importance of fire, and includes occasional "prescribed burns" as well as a more tolerant policy towards natural fires.
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Global Positioning System
One of the wonders of the modern world is that a handheld electronic instrument can tell you exactly where you are on the planet, including your altitude. This is the Global Positioning System (GPS), which uses a fleet of 24 satellites carrying extremely accurate clocks to aid navigation worldwide.
When a GPS receiver is activated, it listens on radio frequencies for signals from the GPS satellites. These signals contain precise information about each satellite's location in space, along with the exact time when that information was sent out.
When the receiver has time and location information from four different satellites, it uses its own computer to figure out where you are. By taking into account how long each signal took to travel at the speed of light and exactly when it arrived, the GPS unit can determine where you are.
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Hay fever
Many people experience sniffling, sneezing, and itchy eyes during certain times of year. This affliction, known as allergic rhinitis or "hay fever," was almost completely unknown until the last century or so. Today it affects one third of Americans and 40% of Australians.
Hay fever results from the body's reaction to particles carried in the air, including especially pollen grains and mold spores. Pollen and mold spore levels have not changed much in the last century, so why has hay fever become so widespread and severe?
No one knows for sure, but there are several theories. Fewer childhood infections may leave the body more sensitive to foreign particles, and increased pollution may make the situation worse. It may be that the body needs to be exposed to high levels of allergens in early life in order to learn how to "recognize" them so they don't cause problems later on.
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Highest Islands
The highest lake with islands larger than a big rock is Orba Co in Tibet. This extreme alpine lake has a surface that is 5,209 meters (17,090 feet) above sea level.
Tibet is also known as the "roof of the world." It is a rough, dry, cold plateau north of the Himalayalas, the world's highest mountains. It is bitterly cold in the winter and windy all year round. Rain and melted snow drain north into dozens of clear, blue lakes, four of which are considered sacred by local people.
There is very little vegetation in the stark, rocky landscape. The only trees are in the most sheltered valleys, and even those are often stunted. Yet for all its barrenness this land can be kind. Humans live near the lakes, where they grow healthy crops during the warm months.
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Hot Larvae
There are at least two kinds of flies whose larvae live in hot mineral springs. They are Ephydra brucei, whose larvae live in water above 112 degrees Fahrenheit (44 Centigrade), and Scatella thermarum, whose larvae thrive at 118 F (48 C), a temperature well above the pain threshold for human hands.
Ephydra brucei is a tiny black fly. It is a member of the family Ephydridae (the shore flies) whose other members include some of the flies that rise up in black clouds from seaweed at the beach. Its larvae feed on bacteria and algae.
Scatella thermarum adults live on and near mats of green algae floating in hot springs in Iceland. Their larvae live in the water below the algae, which flows up out of volcanic springs. They, too, feed on algae and bacteria.
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Hot Sloths
Sloths are among the slowest-moving mammals in the world. Part of the reason for this slowness is their diet: lots of green leaves.
Green leaves are not a very energy-rich diet, and they can be quite difficult to digest. All sloths have intestinal bacteria that help them break down the leaves they eat. Even so, it can take up to 100 hours to digest a full meal.
Some kinds of sloth have developed a habit that helps further: they bask in the sun, warming themselves up so the bacteria can do a better job on the leaves. If a sun-loving sloth is not able to find a sunny place, the bacteria can't do a good enough job on the leaves it eats, and the poor animal may starve to death even while eating plenty of food.
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Hungry Caterpillar
The egg of a polyphemus moth (Antheraea polyphemus) is the size of a sesame seed, and the caterpillar that emerges from it is even smaller. But it is a very hungry caterpillar, and it immediately sets to work.
Over the next 56 days, the tiny eater consumes its own weight in leaves over and over again, growing to 86,000 times its initial weight. If a seven-pound human baby were to grow that much, it would weigh about 300 tons.
After spending the winter in a cocoon, the adult insect emerges: a huge, brown and white moth with two striking eyespots. It is one of the world's largest moths, with wings spanning almost six inches (15 cm).
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Ice-Melting Robot
A new kind of robot is being built to explore a lake buried under four kilometers (2.5 miles) of Antarctic ice. Called a cryobot, it will slowly melt its way down into the ice until it emerges in the liquid water of Lake Vostok, near the South Pole.
When the cryobot reaches liquid water, it will attach itself to the underside of the ice, then release a smaller robot called a hydrobot. The hydrobot will swim around in the lake, taking measurements and reporting back to the cryobot.
Lake Vostok is one of the world's largest icebound bodies of water, about the size of North America's Lake Ontario. It has been locked under the ice for millions of years. Scientists hope to discover life in the lake, which may provide clues to the possibility of life in the icebound oceans of Jupiter's moon Europa.
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Io's Auroras
Jupiter is not the only body in the Jovian system that has an atmosphere with auroral displays. Brilliant, colorful auroras also happen over its moon Io. These are very exotic auroras, since they happen in a weird atmosphere of ionized sodium, oxygen, and sulfur dioxide.
The small, volcanic moon orbits close to Jupiter, in a belt of radiation so intense it could kill an unprotected human. In addition, there is a vast electric circuit between the moon and Jupiter, with a charge difference of some 400,000 volts.
Io's auroras are among the most brilliant and colorful in the Solar System. Because of the particle radiation and the huge electric current, Io's entire thin atmosphere is energized, causing it to emit a dazzling show of red, blue, and green lights.
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Largest Dolphin
Of all the aquatic mammals in the dolphin family (Delphinidae), the largest is the orca or killer whale (Orcinus orca), which can grow as long as 33 feet (10 meters). These large black and white animals are the top predators in the ocean, hunted only by humans and able to attack and kill even the largest whales.
Orcas are highly social and very intelligent. They form close groups (pods) of up to 40 individuals and hunt together, often cooperating to herd the prey. They communicate with clicks, whistles, and other sounds and can recognize each other by voice. Each orca's pattern of black and white markings is also unique.
Orcas are found throughout the world's oceans from the Arctic to the Antarctic, and are in no danger of extinction. In the Antarctic alone, there are an estimated 180,000 orcas.
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Largest Herb
An herb is a vascular plant (a plant with water-carrying vessels) that does not have woody tissue (stem tissue in which the cells have died but still carry water). The largest herb in the world is the banana plant (Musa sapientum), a crop grown in tropical countries around the world.
Banana plants have leaves up to four meters long (12 feet) that emerge from an underground corm. The bananas are formed in a large bunch called a hand that forms on the end of a sturdy stem. The fruits of domestic bananas do not contain viable seeds; the plants are reproduced by dividing the corm or by growing tiny plantlets in laboratory tissue cultures.
The average American eats 28 pounds (13 kg) of bananas in a year, more than any other fruit. Worldwide, about 60 million tons of bananas are produced each year. An acre of banana plants can produce as much as seven tons of fruit in a year.
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Largest Pipe Organ
Built between 1929 and 1932, the largest pipe organ in the world is the Atlantic City Convention Hall Organ, in Atlantic City, New Jersey, USA. According to the Guinness Book of World Records, it is also the largest and loudest musical instrument ever constructed.
The monster music maker has 336 stops (tuned sets of pipes that form musical voice settings), and is powered by blowers totaling more than 600 horsepower. The exact number of pipes is not known; the quoted figure is 33,112 but some experts estimate the number at more than 32,000.
The main playing console, which is surrounded by art-deco columns with stylized flames on top, boasts seven keyboards and rank upon rank of stop controls. There are six large foot pedals and dozens of small ones. The pipes are located in chambers that fully surround the auditorium, so the audience is completely immersed in the musical experience.
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Largest Telescope
Until 1993, the largest light telescope in the world was the 200-inch (5-meter) Hale Telescope at the top of Mt. Palomar in southern California. With its huge single-piece glass mirror, it was a tremendous feat of engineering.
In 1993, the gigantic 400-inch (ten-meter) Keck I Telescope was completed. At the top of Hawaii's dormant Mauna Kea volcano, it is eight stories tall and weighs 300 tons. In 1996 its twin, the Keck II, was brought online.
Instead of a single continuous mirror, each Keck Telescope has thirty-six thin hexagonal segments that can be individually aligned for maximum accuracy. With its huge collecting area, each Keck can gather forty thousand times as much light as the telescope that Galileo used.
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Lasers
Laser stands for "Light Amplification by Stimulated Emission of Radiation." A laser beam is produced when light bounces back and forth between two mirrors with a special medium (gas, liquid, or solid) between them. As it bounces, the light triggers energized atoms in the medium to release more light, some of which leaks out through one of the mirrors to produce the laser beam.
A laser beam is special because all the photons (discrete "particles" of light energy) in the beam are vibrating in exactly the same lockstep way. The beam is tightly focused and perfectly aligned because all the photons are "marching in phase" like soldiers in a troop.
In an ordinary beam of light, the photons vibrate every which way. Because laser photons are in phase, the beam can stay aligned for very long distances and it can be focused down to a very tiny spot without losing its alignment.
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Making Protein
One of the most important tasks of any living cell is making the protein molecules that form its internal structures, trigger important chemical reactions, and fill many other roles. How are protein molecules made?
Protein molecules are assembled from simple molecules called amino acids by molecular machines called ribosomes, themselves made largely out of protein. A ribosome starts making a protein by catching the end of a molecule called messenger RNA, which contains the coded instructions to make the protein.
The messenger RNA (which was created by reading DNA in the cell's nucleus) feeds through the ribosome like a ribbon, and as it feeds through its code is read. The ribosome recognizes the pattern of code, and adds the appropriate amino acids to the partially completed protein. When the protein molecule is finished, it is released and the ribosome can begin building another one.
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Most Tornadoes
The country with the most tornadoes is the United States, where about 800 twisters touch down every year. Most of them happen in the central plains states ("Tornado Alley"), where gigantic "supercell" thunderstorms sweep across the landscape, fed by moisture from the Gulf Of Mexico colliding with cooler, dryer air from the Rocky Mountains.
The second place winner for most tornadoes is Australia, where a few hundred form every year. They also happen sometimes in the plains of Asia.
Tornadoes can happen in any country that gets thunderstorms, but they require very special conditions. A heavy layer of cool, dry air must flow above a layer of warm, moist air, and there must be a certain twist to the air currents to start the vortex spinning.
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Moths and Bats
In the course of evolution, hearing ability has arisen several times in moths. Some moths have special membranes near the base of their wings, while others have sound detecting organs on their legs, heads, or bodies.
The first hearing moths appeared about 50 million years ago, right around the time bats first began using echolocation. This is no coincidence. Moth ears are especially sensitive to the ultrasonic sounds bats emit, and their behavior helps them escape the agile predators.
When a flying moth hears the sharp squeak of an approaching bat, it responds by suddenly veering off in an unpredictable direction. It might dive straight down, scoot sideways, or suddenly spin in a loop. To catch the moth, the bat has to react very quickly.
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Mushroom Clouds
Atomic blasts are not the only kinds of explosions that create mushroom clouds. Any explosion large enough will create a mushroom cloud if it happens close enough to the ground. What forms the mushroom shape?
When the blast begins it is a nearly perfect sphere. But the spherical blast front soon encounters the ground and begins to vaporize it. Because of the way the blast hits the ground, it usually creates a parabolic crater with the greatest curvature in the deepest, central part.
Similar to the way parabolic telescope mirrors focus light, the crater focuses the blast wave and redirects it straight up, forming the vertical "stem" of the mushroom cloud. Eventually the stem loses energy and flattens out against the resistance of air layers higher in the atmosphere, forming the "cap" of the cloud.
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Oldest Board Game
The oldest board game still played today is Go, a game with only a few very simple rules but such complex strategy that many players dedicate their entire lives to its mastery.
The game is played on a plain grid of black lines, where two players alternate placing black and white "stones" on the intersections, simultaneously trying to capture one another's stones, avoid capture of their own stones, and surround territory.
The aesthetics of the game are as important as the game itself. The best boards are thick, solid pieces of yellow hardwood; the best stones are made from slate and clamshells; the stones are kept in elegant wooden bowls. Although most people play with much less expensive boards and stones, it is possible to spend many thousands of dollars on a nice Go set.
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Oldest Viable Seeds
The oldest known viable seeds were found in 1954 in a lemming burrow in Canada's frigid Yukon. The burrow, which was buried in silt and sediment, had been frozen since the last ice age.
The arctic tundra lupine seeds (Lupinus arcticus) were found with lemming remains that were at least 10,000 years old. When they were placed in favorable conditions, several seeds sprouted within 48 hours. One of the plants later bloomed.
Other cases of extremely old seeds that sprouted include a 3400-year-old bean from the tomb of Tutankhamun and water lily seeds that were found with a canoe that had been buried in a bog near Tokyo for more than 3000 years.
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Owls and Snakes
Screech owls (Otus species) commonly place blind snakes (Leptotyphlops dulcis or related species) in their own nests while their hatchlings are being raised. The snake, which normally lives underground, does not bother the chicks and seems to survive nicely.
Why do owls put snakes in their own nests? No one knows for sure, but the snakes in the nests live on small arthropods (fleas, mites, and other nest parasites), and chicks reared with the snakes seem to do better than those without. Since the owls must go to some trouble to find the tiny burrowing reptiles, it must be worthwhile to have them around.
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Pendulum Clock
Although the Italian inventor Galileo Galilei studied the motion of pendulums in 1592, and actually designed a pendulum clock, he never built one. It was not until 1656 that the Dutch scientist Christiaan Huygens built a working clock regulated by a freely swinging pendulum.
Huygens' pendulum clock was revolutionary. Its error was less than one minute per day, and later refinements brought the accuracy within ten seconds per day. Improvements continued over the next century, including compensation for temperature changes and other environmental error sources. The most accurate pendulum clocks now keep time to within one hundredth of a second per day.
Pendulum clocks were the most accurate timekeepers until the development of the electronic quartz oscillator in the 1930s.
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Play-Doh
For more than 40 years kids have been making monsters, dogs, people, and shapeless blobs out of Play-Doh, a curiously aromatic stuff that comes in different colors. Today it's a multi-million dollar product made by Hasbro, but how did it get started?
It happened in Cincinnati, Ohio in the 1950s, and involved a young man named Joe McVicker. McVicker's sister-in-law was a schoolteacher who wanted softer clay for her young students, who were having trouble molding the hard, water-based mineral clay that was used in schools at that time.
McVicker took the request to a biochemist named Tin Liu at his father's soap and chemical company. Starting with a soft, gooey substance used to clean wallpaper, Tin Liu came up with Play-Doh. McVicker marketed the result, and became a millionaire by the time he was 27. No one seems to know what happened to Tin Liu, who seldom gets credit as Play-Doh's actual inventor.
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Popsicles
Until 1905 the world had no Popsicles. It was in that year that 11-year old Frank Epperson of Oakland, California invented the popular treat by accident.
He had mixed up some powdered soda pop, but he left the cup outside with the stirring stick still in it. That night there was a record frost. When Frank went outside the next morning, there was his cup with the soda pop frozen solid. He grabbed the stick and the frozen pop came out of the cup in one piece. Eighteen years later Epperson started selling "Eppsicles."
The Eppsicle was eventually called the Popsicle, a trademarked name for what is also known as an ice pop. Today they are sold on thin hardwood sticks, and they have evolved into hundreds of varieties including chocolate dipped ice cream pops (Creamsicles), with or without sprinkles.
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Pure Ocean Sound
Scientists have been puzzled by strange sounds echoing through the Pacific Ocean. The mysterious "T waves" are among the purest sounds heard in nature, usually with a single frequency of 3-12 cycles per second.
Blasting for seconds to minutes at a time, these strange sub-bass rumblings were recorded especially often in 1991 and 1992. Where do the mysteriously pure tones come from?
The source is now thought to be an undersea volcano in the South Pacific. When it erupts, it creates a column of steam bubbles that acts as a resonator (like an organ pipe) to create the deep, pure sound. According to calculations, the distance between the top of the volcano and the surface of the ocean (130 meters / 426 feet) is just right to produce the frequencies heard.
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Quadruplets Animal
Female nine-banded armadillos (Dasypus novemcinctus) always bear their young in batches of four identical quadruplets. Each fertilized egg divides into two eggs, and each of those divides once more before all four eggs become embryos that develop into baby armadillos.
Other species of armadillos also have unusual birth habits. Some always give birth to identical duodectuplets (twelve identical babies).
Armadillos are small insect-eating mammals with articulated, leathery shells covering their backs. They live in tropical areas because they are not good at retaining heat. The nine-banded species is now spreading rapidly north from the southern United States.
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Seawater Composition
Other than the hydrogen and oxygen that make up the water molecules, the most plentiful element in seawater is chlorine, mostly in the form of the chloride ions (charged atoms) that make up one half of the salt (mostly sodium chloride) dissolved in the water.
The other half of the dissolved salt is mostly composed of sodium ions, but there are also ions of potassium and other metals that combine with the chloride ions to form various kinds of salt. In general, for every hundred molecules of water there is about one ion of chloride and one ion of sodium.
Seawater also contains hundreds of other kinds of atoms and ions, including magnesium, calcium, bromide, carbonate, sulfur, iron, silicate, and dissolved gases such as oxygen, nitrogen, and carbon dioxide. In trace amounts, there are even small amounts of gold, silver, uranium, copper, tin, and many other rare metals.
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Self-splicing Proteins
Most protein molecules are complete as soon as they come out of the ribosomes where they are made. But there are some kinds of protein molecules that actually modify their own structure by clipping out a segment and fusing together the two remaining pieces.
These self-modifying proteins contain special sequences of amino acids called inteins. An intein naturally folds into a shape that snaps itself right out of the host molecule, while neatly joining the severed ends.
No one knows why proteins sometimes contain self-removing inteins, but scientists are excited by the research possibilities. By studying inteins they may be able to design other kinds of self- modifying molecules, and may gain insights into various biological processes.
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Slowest Pulsar
A pulsar is a spinning neutron star that casts a tight beam of electromagnetic energy around the Galaxy like a searchlight. Until recently, it was thought that in order to create the beam of energy a pulsar had to spin at least several times each second. But a newly discovered pulsar, called PSR J2144-3933 spins only once every 8.51 seconds, making it the slowest pulsar known.
Pulsars are thought to generate their energy beams through the reactions of electrons and positrons (anti-electrons) produced by the star's gigantic magnetic field.
But PSR J2144-3933 is not spinning fast enough to make an energy beam by that process, according to the scientists. Its energy source remains unknown, and the scientists continue to watch it carefully, hoping for more clues.
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Snowballs
When you make a snowball, you squeeze together a scoop of snow and it clumps into a semi-solid mass. Why does it do that? Do the snowflakes get caught on one another? How does the snowball hold together?
The pressure you apply when you pack the snowball melts a small fraction of the ice. When you release the pressure, that melted ice re-freezes, holding the whole ball together. The same thing happens when an ice skater skates: there's a thin layer of liquid water under the skate blade, formed by the increased pressure there.
When it's extremely cold, snowballs are hard to make, and it's harder to skate on the ice. That's because the colder the ice is, the more pressure it takes to melt it.
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Spitting Spider
The spitting spiders (several species in the genus Scytodes) are the only true spiders that have silk glands in their heads.
A spitting spider hunts at night and moves very slowly. When it sees a prey insect (which is resting for the night) it measures the distance with its legs and then quickly spits out two zigzag threads of poisonous silk, covering the prey. The spitting action happens in 1/600 second, before the prey has a chance to escape.
There are several species of spitting spiders around the world. In the Philippines there is a species that can spit its silk up to 6 centimeters (2.4 inches) and specializes in capturing jumping spiders, among the fastest and smartest spiders of all.
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Starfish Eyes
From the look of it, you might think that a starfish has no eyes. But in fact, it has an eye on the end of each arm. Most starfish have five arms, so they also have five eyes, but some starfish have as many as twenty arms (or more), and as many eyes.
The very simple eyes of a starfish are unable to form images. Each eye is a tiny spot of red pigment that is sensitive to light. Nerves run from the pigment spots to the starfish's central nerve ring.
The signals from the eyespots affect the animal's behavior, enabling it to avoid light that is too bright and change its light preferences according to the time of day, water chemistry, and other factors. Since a starfish has no brain, it would not be able to make much use of images, even if its eyes were able to form them.
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The Tongass
The largest unbroken temperate rain forest in the world is the Tongass in southeast Alaska. It is 17 million acres of magnificent wilderness with abundant birds, bears, and other life. How wild is it? Surrounded by the Tongass, the city of Juneau (Alaska's capital) is accessible by ferries or by air, but not by roads.
The Tongass was extensively logged until the early 1990s, when the lumber mills began to shut down. Today, almost the entire region is protected from further development or exploitation, and many groups act to further that protection.
Temperate rain forests (those outside the tropics) look different than tropical rain forests. Dominated by coniferous trees, they grow more slowly but have a larger biomass (total mass of living matter) than tropical rain forests.
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Thin Crust
Most of the Earth is made of relatively heavy rock and metal. The crust is a layer of lighter material that floated to the top when the planet was still almost all molten. It makes up only 1% of the total volume of the planet.
The crust varies in thickness, from five kilometers (three miles) under the deepest parts of the ocean to 70 kilometers (43 miles) under the highest continental mountain ranges. How thin is it, compared to the planet's size?
Imagine that the Earth is the size of an orange. Under the deepest oceans, the crust would be thinner than tissue paper, while under the biggest mountain ranges it would be about as thick as construction paper.
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Useless Bone
Everyone has a bone that serves no purpose we know of. It's the coccyx [KOK-siks], a small triangular bone at the very end of the spine.
Millions of years ago, our distant ancestors had tails that helped them balance while they moved around in the trees, much like today's tailed monkeys. When they moved from the trees out onto the grasslands of Africa, our prehuman ape ancestors began to stand upright, and the tail diminished to a tiny stump, and then to nothing at all. But the bone that was in the tail is still with us, even though there are no muscles attached to it.
Such a left-over of a once-useful organ is called a vestigial [ves-TIJ-yul] organ. Another organ that may be vestigial is the appendix, a small extension of the intestine that may have once helped filter toxins from our food.
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