The world is still a lot unknown.
For many years, scientists puzzled by the study of the mysteries of our world, ranging from the crazy water flows in the ocean depths and ending with where did the oceans themselves.
10. The secret of moving rocks in Death Valley
From mid-1940-ies until recently, the Racetrack Playa, a dry lake with a smooth surface in Death Valley National Park USA, was home to the so-called moving stones. Over this mystery for a long time people were puzzled.
With years or even decades passing between each movement, there is an invisible force and moved hundreds of rocks on the ground, leaving long parallel traces. Each of the stones weighed about 300 kg.
As far as scientists know, the stones in motion no one saw. Thus, a team of researchers from the United States decided to deal with this issue in 2011. They set the camera time lapses and weather station to measure wind gusts.
They further set responsive to the movement of GPS tracking devices for 15 the rocks of the dried up lake. They could take 10 years or more before to get something, but the scientists were lucky. In December 2013, the team was in place when stones floated, and the mystery was solved.
Due to heavy rain and snow on the lake surface remained about 7 cm of water. Over night the water turned into thin sheets of ice that next day under the midday sun broke up into separate floating panel.
Have to wait for light wind around 15 km/h to “throw” stones across the surface of the lake, leaving traces of mud under the icy crust. Traces were visible months later, when the lake bed dried up.
The stones will only move under ideal conditions. Not too much wind, sun, water and ice. But not too little. Researchers believe that tourists could see it, not realizing what is happening. Really difficult to understand that the stone is in motion if all the rocks around it are also moving.
9. How giraffes manage to keep a vertical position, standing on such thin legs
The giraffe weighs an average of about 1000 kg, but this weight they have feet with a very thin and light bones. However, their legs don’t break and don’t get hurt.
In order to understand why this happens, researchers from the Royal Veterinary College studied the limbs of giraffes, donated by zoos in the European Union. The limbs belonged to an animal that died of natural causes in captivity or had been euthanized.
The researchers placed the limbs in a special frame and then used a pressure of 250 kg each to simulate the weight that wear these animals. Each limb remained strong and held upright without any problems. Actually, the legs of a giraffe, could withstand more weight.
The reason for this is the existence of a special ligament (fibrous tissue that holds bones together), which is located in the groove throughout the length of the Shin bone of an animal. These bones are similar to the metatarsal bone in the human foot and the metacarpal bone in our hand. Just a giraffe these bones are much longer.
Ligament alone does not generate any power. It provides passive support only the elastic tissue, not muscles. This reduces the rate of fatigue of the giraffe, because he does not have to use their muscles to hold the weight. This ligament protects the knee stop the giraffe from overload and from the breaks.
8. Singing Sands
Known 35 the sand dunes that emit a loud hum, sounding like a cello playing in low octaves. The sound can last up to 15 minutes, and you can hear it at the distance of 10 km with Some dunes sing from time to time, others daily. This occurs when a particular dunes roll grit.
At first, scientists thought that the origin of the sound is vibrations in the subsurface layers of the dunes. But then the researchers found that can recreate the sound in the laboratory, allowing sand to slide down an inclined plane. It turned out that singing sand, not dune.
The sound proceeded from the vibrations themselves grains of sand when they cascade and roll down the dune or an inclined plane in a lab.
The researchers then took up the study of why some singing sand dunes emit a series of notes at the same time. To do this, they took on the study of two sand dunes in South-West Morocco and South-East of Oman.
The Moroccan sand always given sound at a frequency of 105 Hz, the Omani same frequency from 90 to 150 Hz. The researchers found that the size of the grains responsible for the pitch of a note. The Moroccan was approximately the same (150-170 µm). They have consistently sounded like a g-sharp. The size of the Omani grains ranged from 150 to 310 microns, so their share fell a wider range: they can play all 9 notes.
When the researchers divided the grains by size, to test his theory, and it turned out different groups of grains of sand began to vibrate on the same frequency, reproducing the same note.
The speed of the moving sand also played a role. Close to each other the size of a grain of sand moving with the same speed, so over and over again consistently turned out the same sound. When the grains varied in size, they moved at different speeds, causing the range of music was wider.
Scientists still don’t understand why these sounds are similar to music. The main assumption is that the vibration of the moving grains of sand sinhroniziruete that “collects” the air particles together, thus working as a diaphragm in loudspeaker.
7. Pigeons Bermuda Triangle
It started in 1960-ies, when a Cornell University Professor studied the remarkable ability of pigeons to find their way home from unfamiliar places. He released the pigeons from various locations of the state of new York.
All the pigeons coped with the task, except those who were issued from the woods of Jersey hill. These birds were always getting lost on the way home. August 13, 1969 the only time they came back, the rest of the birds were disoriented and confused fly. The Professor was unable to explain why this happened.
Dr. Jonathan Hagstrum (Jonathan Hagstrum) of the U.S. geological survey believes he may have solved the mystery, although his theory is quite controversial.
“The behavior of pigeons, says that they use a kind of compass and map to tell them where they are relative to home.” Hagstrum believes the pigeons are using infrasound, low frequency sound, not audible to humans.
This type of sound may have been used in ancient soundscapes (audio scripts) to change the mental state of our ancestors during their participation in religious ceremonies.
Birds may use infrasound (which in this case is generated by small fluctuations in the Earth’s surface to deep ocean waves) as a homing beacon.
When the birds got lost in Jersey hill, the temperature and the wind “stole” the infrasound signal high into the atmosphere. Pigeons failed to catch him. However, on 13 August 1969, the air temperature and the wind was perfect, so the pigeons heard the sound and were able to return home.
6. A unique origin, the only active volcano in Australia
In Australia there is only one active volcanic zone that extends 500 km from Melbourne to mount Gambier. Over the last 4 million years, the volcano came to life about 400 times, the last occurred about 5,000 years ago.
Scientists puzzled than provoked by these eruptions in the world, almost devoid of volcanic activity. Now this secret is out. Most volcanoes on Earth were formed at the edges of tectonic plates that are constantly moving (a few inches per year) in the upper part of the mantle of the Earth.
But in Australia the differences in the “thickness” of the continent has led to the fact that the flow is directed into the lower part of the mantle with the aim of attracting heat to the surface. The combination with a drift to the North at 7 cm resulted in the formation of a hot point, that is a volcano, with magma.
“Worldwide there are about 50 such isolated volcanic regions, the principle of which we now can explain,” says Rhodri Davies (Rhodri Davies) from the Australian national University.
5. Fish that thrive in chemically polluted water.
In the period from 1940 to 1970-th years of the industrial enterprises of the USA dumped polychlorinated biphenyls (PCBs) as waste into the port of the city of new Bedford in Massachusetts. Soon, the U.S. Agency for environmental protection announced that the harbour is extremely polluted as the number of chemicals in the water four times higher than the safe level.
But the harbour remained until some time the biological puzzle that researchers are finally decided. In the water, full of toxic waste, felt great and multiplied the Atlantic killifish. This beautiful predatory fish throughout his life never leaves the place of birth more than a few hundred meters.
Usually when fish absorb PCBs, some of their elements become it is even more toxic than they were originally. However, killifish already got rid of this feature at the genetic level, halting the formation of toxins.
These fish have adapted to a specific type of pollution, but some scientists believe that this genetic change made them more sensitive to exposure to other pollutants.
In addition, apparently, these fish cannot live in a healthy environment, in clean water. Killifish are prey for striped bass, bluefish and other fish that we eat. Thus, despite the fact that killifish were able to develop immunity to the toxins PCBs, it can transfer toxic substances up the food chain, reaching up to man.
4. How are underwater waves
Underwater waves, also called internal waves, remain under the surface of ocean waters, hidden from our view. They raise the surface water of the ocean only a few inches, so often they can only detect the satellite.
The largest waves are born in the Strait of Luzon, between Taiwan and the Philippines. They can reach a height of 170 meters and move over large distances at a rate of several centimeters per second.
Scientists believe that it is important to understand how these waves are generated because they can play a crucial role in global climate change. Internal waves mix the cold and very salty water from the warm and less salty waters of the outer ocean. They carry a large amount of salt, heat and nutrients around the ocean.
This is the main method by which heat is transferred from the upper layers to the lower waters. Scientists have long wanted to unravel the mystery of how generated such a huge internal waves in the Strait of Luzon.
They are difficult to see, although the relevant technique can detect the difference in density between the internal wave and its surrounding water. However, the researchers decided to test a 15-meter wave tank.
Internal waves generate pushing cold water from the bottom two tabs on the simulated seabed. It turns out that these huge internal waves are produced by the distance between the ridges in the Luzon Strait, not one feature on the ledge of the tall mountain.
“This is a very important missing piece of the puzzle in climate modeling,” says Thomas peacock (Thomas Peacock), a specialist at the Massachusetts Institute of technology. “To date, global climate models are not able to cover all these processes. You will get a different answer if you do not account for these waves.”
3. Why are zebras striped
There are many theories explaining the presence of Zebra stripes. Some believe that stripes is camouflage or a way to confuse the predator, others believe that the stripes help to regulate body temperature or to choose a partner.
Scientists from the University of California decided to find the exact answer. They learned about the habitats of different species and subspecies of zebras, horses and donkeys. Experts have collected data on color, location and size of the bands on the body of the Zebra.
They then mapped the habitats of tsetse flies, dragon flies and horseflies, added some other variables that are important for strategic analysis, and got the answer.
“I was amazed with the results,” says researcher Tim Caro (Tim Caro). “We see time and time again that the stripes on the body were more animals living in those parts of the world, where lived the larger number of flies.”
Zebras are more vulnerable to biting flies because their hair is shorter than in similar animals, such as horses. Blood-sucking flies bear the risk of deadly diseases, therefore, for the Zebra it is very important to avoid this.
Other researchers from the University of Sweden found that flies do not bite zebras in places where there are strips, just because of the fact that the strips are very correct width. If they were wider, then Zebra would not be protected. In this study, most flies were attracted to black surfaces, slightly fewer were drawn to the white and very few flies were attracted to striped.
2. Mass extinction of about 90 percent of all species on Earth
About 252 million years ago, roughly 90 percent of species on our planet has been destroyed in a mass extinction. It is an ancient detective suspects from asteroids to volcanoes. However, it appears that murderers cannot be seen without a microscope.
According to the researchers, the culprit was a single-celled microorganism called methanosarcina that absorbs carbon compounds to form methane as waste. This microbe lives today in garbage dumps, oil wells, and even in the intestines of cows.
In permyanka period, scientists believe, methanosarcina moved the transformation of the gene that allowed her to handle the acetate. After the incident, the microbe has learned to absorb large accumulations of organic matter from the ocean floor, containing acetate.
Shortly microbial population “exploded”, svergnuv huge amounts of methane into the atmosphere and much podkislit the ocean. Most of the plants and animals on earth were killed, along with fish and shellfish in the ocean.
But in order to reproduce so quickly, the microbes would need a Nickel. The researchers analyzed the sediments came to the conclusion that the desired amount of Nickel microbes “pozaranje” Siberian volcanoes.
“Armianskoe mass extinction of species is the only event that as never made a threat of extinction of all living things is very real,” says researcher Greg Fournier (Greg Fournier). “The lives of many, if not most, of the surviving groups of organisms hanging in the balance, and many managed to survive only by miracle.”
1. The origin of the oceans
Water covers about 70 percent of our planet’s surface. Originally, scientists believed that the Earth formed dry, the melted surface by impact of other objects from space.
The asteroid impact and “wet” comets supposedly brought water to our planet much later. “Some have argued that any water molecules that were present during the formation of the planet, or evaporated, or carried off into space,” explains the geologist Horst Marshall (Horst Marschall).
“Scientists believe that the surface water in the form in which they are present on the planet today, appeared much later – hundreds of millions of years later.” But a new study shows that during the formation of the Earth on its surface was still water, and in sufficient quantities for the development of life. This is true for other planets in our Solar system.
To find out when the water came to Earth, the researchers compared two sets of meteorites. The first set, the carbonaceous chondrites, the most ancient meteorites ever certain. They appeared around the same time as our Sun, before the formation of the planets.
The second set of meteorites believed to come from Vesta, a large asteroid formed in the same region as the Earth about 14 million years after the birth of our Solar system.
Both sets of meteorites with the same chemical composition and contain a lot of water. For this reason, researchers believe that the Earth formed with water on the surface of carbonaceous chondrites about 4.6 billion years ago.
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