Over the last century, science provides answers to many questions that we are interested in all areas - from the complex issues of human and other organisms to the structure of how our universe formed. However, there are likely to always be things that some of them very important, which scientists will not be able to respond.

Physicist Brian Cox once said: "I have come to terms with the fact that there are things unknown - it is a driving force of science. The universe is billions of places where we have not been and do not know anything about that. And the fact that we know nothing about them, I was very worried about - I want to go out and about to find out as much as possible. This is the science. So if you can not come to terms with the uncertainty, then a scientist to be very difficult. I do not have the answers. I want to have the following questions, which I would like to find the answers. "

In website iflscience.com are 10 secrets that science can not solve.

Why do we sleep?

We know that people live on a daily clock, which determines our sleep cycle, but the answer to the question why this is happening, we still can not.

Sleep is the time during which the tissues of our bodies are up to date and perform other life-critical procedure. Sleeping, we spend a third of your life. Some other organisms sleep completely redundant, so why we need it?

There are few hypotheses, but in particular, none of them are unable to answer this question. Some scientists believe that some of awake animals developed an ability to protect themselves from predators. Others believe that some animals do not sleep because their bodies relax in other ways.

Where is lithium?

In the past, when the temperature was extremely hot, helium, lithium and hydrogen isotopes were synthesized in very abundant. Hydrogen and helium are very abundant and account for almost the entire mass of the universe, although it is only one-third of lithium-7, which we see.

There are plenty of explanations why this might happen. Some studies focused on the hypothetical boson, known as the AXIS.

Others believe that these particles are the nuclei of the stars with our telescopes can see. Anyway, now there are no theories that could explain the lack of lithium in the universe.

How does gravity work?

We all know that the moon's gravity causes tides on Earth, the Earth's gravity keeps us on the surface, and the Sun's gravity on our planet orbiting the time, but how many really know about gravity?

Gravity causes matter. Larger objects in the universe has the ability to bring themselves closer to other objects. Scientists know something about the effects of gravity, but do not understand why it is happening. Why atoms are mostly just empty space? Why force holding the atoms is different from gravity? Does gravity of particles? There are a lot of issues with the current understanding of physics can not understand.

Where is everyone else?

Measurable diameter of the universe is 92 million. light-years, which fills the billions of galaxies, stars and planets, but so far our available evidence indicates that life exists only on Earth.

Mathematically calculating the probability that we are alone in the universe is infinitely small. This is where all the others? This is known as the Fermi paradox and so far this has been brought about, and still pose a set of explanations, but the answer is still not here.

From what dark matter is made up?

Approximately 80 per cent. Mass of the universe is composed of Dark matter. This is - a very peculiar phenomenon, since this material does not reflect visible light.

Although dark matter has been discussed already 60 years ago, there is no direct evidence of its existence. Many scientists believe that dark matter consists of weakly interacting massive particles, which can be up to 100 times the mass of protons, but there are no indications of any of our existing facilities. Other dark matter candidates - Aksion, neturalinai and Fotini.

How did life started?

Where the origin of life on Earth? Those who rely on Alexander Oparino Prehistory broth (called. Primordial soup) theory says that the overflow of nutrients early Earth formed very complex molecules, and from them - life. This could be in deep ocean holes, clay, or under the ice. On some models, explaining that some could be influenced by volcanic activity.

Now the earth is dominated by DNA and the first forms of life, it is able to dominate and RNA. Scientists also believe that in the past could live without and other nucleic acids RNA and DNA.

Does life appeared only once, and it has evolved, disappeared and appeared again? There are people believe that life on our planet brought by meteorites or comets. So far, none of the hypothesis does not answer.

How does tectonic plate move?

This may sound a little strange, but the theory of moving tectonic plates, which are changing continents, causing volcanic eruptions and shaped mountains, approval was only recently.

Only in 1960. hypothesis, which refers to the Earth's mantle rocks hauled to the surface in the form of magma coming back later, was based on physical evidence. True, scientists are not completely sure what causes the movement of the plate boundaries were created.

How do animals migrate?

Many animals and insects migrate in order to avoid seasonal changes. Some routes stretching for thousands of kilometers in one direction, so that the animals find their way back?

Different animals use different navigation devices. Some of these are themselves able to use as a navigation device.

However, scientists fully known until then completely untrained animals know the exact flight itineraries.

Why is matter and antimatter?

According to our current understanding of particle physics, matter and antimatter are equal but opposite. When they collide, they must destroy each other and do not leave anything. Many of these collisions could take place in the early universe.

True, there were still a matter that would create billions of galaxies, stars, planets and everything else. There are many theories of mesons - short-lived subatomic particle composed of a quark or antiquark one. B-mesons decays faster than anti-B mesons, which could lead to B-mesons survived the crash in order to create a whole universe of matter. B, D and K mesons can also oscillate and become anti-particles.

What is dark energy?

Of all the scientific mysteries of dark energy is perhaps the most mysterious. Dark matter makes up about 80 percent. total weight and a hypothetical form of energy - dark energy, believed to be around 70 percent. Content of the Universe.

It is believed that dark matter is a consequence of the expansion of the universe, although there are still many mysteries about its apparent qualities. First and most importantly - what is it made of? Is it constant, or in different places of the universe is changing? Does this matter theory can be reconciled with Albert Einstein's theory of gravity, or it has to be transformed?