Eight mysteries solved by scientists

THE PHENOMENON OF HUMAN GROWTH

With each generation people become taller and taller. This natural phenomenon has been recently studied and described in detail by scientists using the example of the Dutch, the tallest nation on Earth. Over the last 200 years the Dutch have grown by about 20 cm: the average height of men was 1.84 m and 1.71 m for women. Trying to understand the reasons for such a rapid growth of the nation, a team of specialists analyzed a database of 94,516 residents of the three northern provinces of the country. In the attention of scientists got only people over 45 years old who were born in the Netherlands from the parents of the Dutch. It turned out that in the period from 1935 to 1967 the most children were born to taller men. Women chose taller partners because height was associated with better health, education and income. The growth spurt demonstrated by the Dutch can serve as a clear example of human evolution in action and proof that it is not over yet, the scientists say. "This study proves that the human population is still subject to natural selection," said Yale University biologist Stephen Stearns.

 

CRAWLING STONES

The self-moving stones that literally "crawl" across a dried-up lake in Death Valley, a national park in the United States, have been under the scrutiny of scientists since the late 1940s. During this time there was a lot of hypotheses explaining the geological phenomenon: about hurricane winds, the impact of magnetic fields, anomalous zone, there was even the assumption that the stones move the employees of the park. There were always more questions than answers. Can the wind move a boulder weighing up to 350 kg at a distance of 200 m? Why do the stones move chaotically, without any general direction? Why do some of them remain motionless? And where, finally, do the boulders, of which only traces remain, disappear to?

 

In 2011, a team of researchers from the Scripps Institution of Oceanography began an experiment. Scientists set up a weather station in Death Valley and brought 15 boulders equipped with GPS receivers to the lake - the national park authorities prohibited experimenting with native rocks in Death Valley. The three-year observation allowed to confirm one of the earlier hypotheses: the stones roll under the action of the wind, and it happens only in the winter, when during frosty nights the ice crusts are formed on the boulders, acting as a sail. In parallel, the researchers managed to whitewash the tourists in the eyes of the park rangers who believed that the empty paths from the stones prove that visitors steal valuable "exhibits". The researchers convinced them that these were just traces of melted ice.

 

LIVE AND COLORED RAINS

Rains of shrimp, fish, frogs, spiders, worms, or birds are rare natural phenomena that have frightened people in ancient times and continue to confuse them today. For example, in May this year precipitation in the form of a million small spiders "fell" in the Australian town of Goulburn in New South Wales, and was considered by some residents as a sign of the end of the world soon.

Fortunately, people of science have found an explanation for the "live" rains - most scientists agree that water tornadoes and whirlwinds are to blame, snatching animals from their habitat and transporting them over vast distances. As for fish, they don't always fall from above: some species can crawl on land and even breathe with their lungs, such as the double-breathing protopteran fish. The likelihood of dead birds falling from the ground increases during New Year's celebrations, when thousands of firecrackers and fireworks explode in the sky.

Another natural phenomenon, colored precipitation, is still causing panic in the cities of the world. In India in 2001, it rained blood for two months. In the Saratov region, orange snow recently fell. Scientists are quick to react to such anomalies and find explanations: particles of African sand from the Sahara Desert were found in the Russian snow, and local lichen spores were found in the rain.

 

BIRD MURMURATION

The incredibly spectacular flight of flocks of starlings is scientifically called murmuration. This phenomenon, which looks more like a dance or air show because of the amazing celestial figures appearing in the sky, has been one of the main mysteries for ornithologists. Scientists have had several hypotheses about how and why thousands of birds gather in huge flocks and make shows in the sky. Some experts believed that such flights are necessary for the birds to exchange information about where to fly and where the food is. Others believed that the dances help the starlings protect themselves from enemies by misleading and intimidating them. Even sophisticated algorithmic models did not help explain this natural phenomenon. However, last year, scientists from Warwick University in the UK made an important discovery: they explained the phenomenon of murmuring starlings using the dynamics of dark and light spots in a flying flock. It was observed that each starling in a giant flock takes a position so that light falls on it from all sides - this makes it possible to draw maximum information as it flies. All figures and changes in the mass "dance" occur due to the fact that starlings maintain this state - the ultimate transparency, changing position depending on the sunlight.

Scientists built a computer model of murmuration and verified that the movements and figures of the flock resemble the natural movements of starlings in nature, which confirms the correctness of the new algorithm.