“To detect at least primitive life”: a Russian scientist on the possible habitability of planets

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The moon Enceladus is very interesting.

Despite its tiny size, only about 500 km in diameter, it resembles a planet in shape.

It was first explored by the Cassini interplanetary station, which was launched in 1997 by NASA to study Saturn.

When the apparatus flew between the Sun and the satellite, it captured its surface.

The moon was covered in ice and had no craters.

Consequently, scientists assumed that the ice is constantly being renewed and estimated that the age of the ice sheet is about 300,000 years.

This is very little, considering that the age of the solar system is 4.57 billion years.

The device circled Enceladus and captured the so-called "champagne splashes" - water splashing onto the surface through ice cracks.

This effect is observed due to the fact that heat is released inside the planet due to the constant "tides" caused by the giant Saturn.

As a result, the ice melts at the bottom and cracks at the top.

Apparently, at the satellite, the volume of melted water is a whole sea.

This water periodically splashes on the surface.

Approximately the same picture for the largest satellite of Jupiter - Europa, since it is also covered with ice.

However, no similar water fountains have been found on it yet.

Thus, Enceladus is the most reliable place in the solar system where there is liquid water, and it is one of the targets of interplanetary missions.

In the flying droplets, scientists are trying to find complex organic molecules. 

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— In fact, scientists do not know exactly how life is formed in the universe.

It was not possible to obtain microorganisms artificially in the laboratory.

There is no theory of the origin of life.

But there are facts that scientists can rely on.

In particular, the most common organisms on Earth have a protein base, and oxygen serves as the main oxidizing agent for protein.

Therefore, astrophysicists and astronomers hope to find life outside the Earth where there are conditions similar to those on Earth.

It is not known if there was once life on Mars.

It is possible that it was, at least in primitive forms.

On this planet, the temperature is high enough for life, but the carbon atmosphere is very rarefied.

Therefore, there cannot be a complete analogue of earthly life now.

• Image of Mars, illustration

• Gettyimages.ru

This question is now of interest to many, and Mars is being carefully studied.

Venus attracts similar attention from scientists.

But most likely for the opposite reasons.

Venus is very similar to Earth in its physical characteristics.

The planets have close orbits - they are neighbors and both are not far from the Sun.

However, the temperature on Venus reaches 500 ° C, due to the catastrophic greenhouse effect.

In such conditions life of the terrestrial type is impossible.

Other forms of life have been proposed, such as those based on silicon.

There are a number of theories and hypotheses that explain the possibility of the existence of life forms that are partially or completely biochemically different from those that arose on Earth.

For example, such differences include the replacement of carbon in the molecules of organic substances with other atoms, or the replacement of water as a universal solvent with other liquids.

For example, on Earth there is such a plankton - radiolaria, a single-celled creature whose skeleton consists of silicon.

Jupiter's moon Europa can also be a potentially life-bearing space object.

However, there is no direct evidence that there is water there.

For its detailed study, spacecraft still need to be sent.

When researchers look for life on other planets, it is important to understand that the conditions under which it can arise must last on them for at least 1 billion years.

Approximately so much time it took the Earth to cool down and complex molecules could form on it.

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- All planets are theoretically divided into two groups: planets-oceans, covered with oceans and islands, and planets with a solid surface.

Scientists understand that life originates on a planet with oceans.

They are using computer technology to simulate the formation of Earth-like planets, which are also called exo-Earths.

It seems that our planet is unique, but no.

There are at least 100 billion stars and planets in the Milky Way.

And potentially similar to the Earth, too, billions.

Why are astronomers around the world looking for extraterrestrial life?

“The question of whether other worlds exist is one of the most important.

As I said, there are billions of Earth-like planets in our galaxy.

We know exactly the age of the Earth - it was formed at about the same time as the Sun.

Our galaxy is at least 10 billion years old.

And in it, many planets are much older than the Earth.

And the question arises, is there really no intelligent life on any of them?

It is also important that one must distinguish between primitive life and intelligent life.

In my opinion, intelligent life can be characterized as follows: with each generation of a species, the amount of knowledge of the next generation becomes greater than that of the previous one.

If there is no accumulation, then it is primitive life.

• Image of Venus, illustration

• Gettyimages.ru

Civilizations of our planet for several thousand years.

And since the beginning of technological progress, several hundred years have passed.

Recently, people only came up with steam engines, and now they are dreaming and developing nuclear space engines.

And a paradox arises: between the rapid development of our civilization and those billions of years that civilizations have billions of years older than us.

This is the so-called Fermi paradox or the paradox of the Great Silence of the Universe, or the absence of cosmic miracles.

Where are our so-called “brothers in mind”, because their civilizations should be even more developed, they could already travel all over the Galaxy.

Other worlds also had much more time to develop than ours.

Every time, astronomers use the latest telescopes to look for hints of other civilizations.

But they don't find it.

So far, scientists are trying to detect at least primitive life in space.

However, if such a find is made, it will not necessarily give cause for joy.

• Milky Way

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Perhaps this will lead to a revision of our views on nature, as was the case with the theory of relativity.

Accordingly, it is rather difficult to perceive something new both for the scientific community and for the society.

I believe that in the next 20-30 years humanity may well discover traces of primitive life on planets in our galaxy.

Of course, the first task facing researchers is to fly to these exoplanets and study them with powerful telescopes.

- Not so long ago 

- Even 10-20 years ago, the prevailing view in scientific circles was that all the water on Earth is the result of the fall of meteorites and comets.

Comets are mostly made of rocks, dust, dirt, but they also contain pieces of ice. 

However, today it is difficult to say that meteorites and comets formed oceans on the planet.

The fact is that they usually fall on Mercury and Venus, but a similar situation did not arise there.

For example, the Tunguska meteorite, most likely, consisted entirely of ice; after the fall, only steam remained from it, which subsequently settled.

However, the question of the appearance of water on Earth remains open.

After all, our planet is stone, and it does not imply the initial presence of water.

It is possible that the first microorganisms were brought to Earth with such comets.

If meteorites and comets fly past us, carrying ice blocks with them, then why not consider this option.

• Gettyimages.ru

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- The nearest exoplanet was discovered in the Proxima ("Nearest") star system in the constellation Centaurus - at a distance of 4 light years from Earth.

One of the stars is a red dwarf, and it is 5 times smaller than the Sun.

Its luminosity is also very small, 10 thousand times less than the sun.

An exoplanet on which life is possible must be located very close to the star.

However, there is a big problem with red dwarfs - they constantly flare up.

Our Sun also shows variable activity once every 11 years.

At the same time, the energy sent by the Sun to the Earth changes by less than a percentage.

Imagine if the luminosity of the Sun changed 100 times?

This is exactly what happens to red dwarfs.

Their emissions can be deadly and destroy any organic life forms on the surface of the planet.

Therefore, it is rather difficult for even primitive life to arise there.

A few years ago, engineers from the NASA space agency discussed plans to send tiny probes to the nearest star, accelerated by a powerful laser located near the Earth.

Theoretically, such probes can be accelerated to the speed of light.

If the devices reach a distant planet, they will be able to send all the information received to Earth.

However, this project is still under big question.

• Space Observatory "Kepler"

• Gettyimages.ru

The Kepler spacecraft, launched by NASA in 2009, has already discovered many exoplanets in the constellation Cygnus.

They are all at a distance of 10-20 light years from Earth.

These are the planets that need to be studied and spacecraft launched to them.

After all, they could have civilizations or the remnants of ancient civilizations that simply exterminated the "strangers", and then some other climatic catastrophe occurred.