How do you know that dark substance really exists?

How do we know that there is a dark matter?

Kide Kailas, 9

Dark A substance means a substance that has mass, that is, in everyday language, but cannot be seen with eyes or telescopes. Although the dark matter has not been discovered directly in other ways, its effect on gravity can be seen.

That effect can be detected when looking at, for example, stars and gas movements in our Milky Way and other galaxies. They move faster than possible if there was no dark matter.

The gravity created by the dark matter can also be seen by studying the light from the galaxies. In this case, it can be observed that the dark substance on the route causes the light rays to curve.

Based on computer models and calculations, it also seems that the structures of the universe could not have been formed as they have been formed without the effect of dark matter.

In addition, it has been found that the hot particle porridge, which filled the early universe, had small density differences. Calculations can be used to determine that the properties of those density differences are explained by the fact that most of the particle porridge has been a dark matter.

However, the ultimate certainty of the existence of a dark matter is only obtained if it can be detected directly in the laboratory in one way or another.

Matti Heikinheimo

university researcher, an adjunct professor of theoretical particle physics

University of Helsinki

When has words been invented?

Aatos Rajamäki, 5

Art come into languages ​​mainly by inventing, that is, someone begins to use a new word and its use spreads. We are unable to give a sure answer to when words have begun to be.

However, it is known that Neanderthal people have already had the ability to produce words. They were a genre that we were related to our modern humans that evolved about 400,000 years ago and lived about 40,000 years ago.

All oldest texts also contain words. For example, some words have been found in thousands of years old papyrus, or paprous spelling, and a stone object called Palermo’s stone.

It is usually impossible to answer exactly when any word has come into different languages. We know that many words like die, go, river and live, have existed for at least 6,000 years, but their first use is obscured.

From newer words, we can give more detailed answers. For example, inventing words related to technology development can be combined with the invention of a similar invention.

For example, the word microwave furnace has come to Finland in the 1980s. In the 21st century, the start of newer words, such as BIFFI, Wörtti and Veija, can be started in the 21st century.

Seppo Kittilä

university lecturer in general linguistics

University of Helsinki

How was electricity found?

Elias Uosukainen, 9

People have detected electronic phenomena for a very long time. Thousands of years ago, it was noticed that some substances received a wonderful power from rubbing. Greek philosopher Thales He reported about 2,600 years ago that he had coincidentally noticed that the wool yarns grabbed the amber as they were rubbed together.

People also found electricity in nature early. For example, lightning is a powerful electrical phenomenon. Some animals were also realized to produce electricity. For example, electric ancestors use electric shocks to prey.

However, went up to the 17th century until the English William Gilbert Developed the term of electricity from the word of the Greek amber. He was the first to write a serious scientific analysis of electricity.

Various experiments were used to investigate the essence of electricity. Among other things, glass balls were built, which were rotated by the crank. For example, when the glass rubbed a fabric cushion, it effectively came off electricity, which sparkled and could be moved from one place to another by means of a metal cable.

At the beginning of the 19th century, a so-called electric pair was invented, that is, learning how to use two different metals of metals to produce electricity. It generated constant electricity without rubbing!

It was also realized that the compass needle in the vicinity of the electric current along the metal cable turned, which was a sign of the so -called magnetic effect of electricity. In addition, it was noticed that rotating the magnets was made electricity. It helped decisively by constantly gaining joy from electricity in our everyday life.

Ari Sihvola

professor of electrical engineering

Aalto University

Are the bears sniffed with a hibernation?

Sebastian Fantato, 5

Bears They can snore while sleeping. They have snoring for the same reason as a person or, for example, a dog. The snoring sound is caused by vibration caused by the obstruction of the upper respiratory tract.

Man is most sensitive to his back, but the bears seem to be different. At the Kuusamo Great Fraud Center, it has been found that the bear snores most often in the side position and when the sleep is deep.

In the winter, however, the bear sleeps in his nest mostly in a light sleep. In this case, it does not snore much.

For example, bears in the Korkeasaari Zoo have not been found to be snoring in winter. They change the sleeping position from that, which indicates that the sleep state is not deep. The bear also hears the sounds near his nest and can react to the interference by moving to another place.

The female bear gives birth to puppies in winter. In the follow -up of the University of Oulu, there were noise sounds in the winter nest, where the mother and recently born puppies were staying. However, the sounds were not snoring either.

Even in Ähtäri Zoo, the nurses have not heard of the bears to snore properly, but quite loud of winter nests may sometimes sound.

Ilpo Kojola

Research Professor Emeritus

Natural Resources Center

Send the question, the full name and age of the questioner to [email protected]. The column is provided by Touko Kauppinen.