Is there life in the Universe: Earth-like planets

For hundreds of years humanity has been in search of new life on other planets. In the twentieth century, the world made enormous discoveries in space, expanding knowledge. However, we know so little about neighboring and distant planets that most discoveries lie ahead of us.

Earth is the most beautiful planet in the solar system, it has life. Our celestial body is inhabited by animals, birds, insects, there are oceans, seas, a rich world of flora. Let's talk about other planets in the universe that are similar to Earth.

Exoplanets: what they are, types

Space exploration is not limited to gaining knowledge of the solar system, in which only eight planets have been discovered. Astronomers around the world aim to discover other celestial bodies clustered around other gas balls in the universe.

The discovery of a distant planet is a difficult task, since a celestial body of this type does not shine, it is difficult to detect it. Exoplanet is called a planet outside the solar system. At the end of 2018 with the help of modern technical means man discovered:

• 2,935 star systems;
• 3934 exoplanets.

More than a thousand more celestial bodies are candidates for inclusion in the list. Work is underway to locate bodies whose surface conditions are close to Earth:

• temperature control;
• sizes;
• mass.

Interest in Earth-like bodies is great, as they could be the future home of Earthlings. Every new Earth-like planet discovered is carefully studied. So far, no planet has been found that possesses conditions suitable for life.

Star systems are common in the universe, of which the Solar System is an example. It is not known what the process of origin of celestial bodies is. It is now reliably known that the center of the systems is a star around which the planets orbit.

American astrophysicist David Sudarsky created a system for classifying exoplanets by their appearance. This allowed us to clearly divide discovered celestial bodies into two groups, despite the minimal knowledge about them:

• terrestrial type (with a solid body);
• gas type.

It is noteworthy that astrophysicists estimate that there are 100 billion planets in the Milky Way galaxy that humanity does not know about. It remains to be seen whether they are suitable for life.

Discovery of exoplanets

Observing the positions of the stars nearest to us, astronomers around the world have tried to find planets similar to Earth. The first attempts date back to 1855. The first extrasolar planet similar to our own discovered by scientists from Canada in 1988 near the double gas ball Gemma Cephea A. In 2002, the discovery was recognized by the astronomical community.

One year later, a brown dwarf was found; the discovery was recognized in 2002.

Detecting galaxies and stars does not pose serious difficulties. This is not the case with planetary objects. Having no bright light, luster, located hundreds of light years from Earth, they remain unexplored. There are six ways to discover an exoplanet:

1. direct observation through telescopes;
2. astronomical;
3. pulsar radio monitoring;
4. spectrometric calculation of the radial velocity of a star;
5. transit method;
6. microlensing (another star is used as a lens).

The most popular and effective method is the transit method, which consists in observing the planets passing through the disc of their star.

Exoplanets have names similar to the names of their stars with separately assigned letters, which distinguish them from each other.

The first Earth-like planets studied

Not all discovered objects of celestial bodies resemble Earth. In the next decade, thousands of distant planets will be discovered, perhaps finding one where living conditions are as close to those here as possible.

Let's take a look at the list of the most Earth-like planets.

Kepler-62 f

A planet orbiting the gas ball Kepler 62, part of the constellation Lyra, was found by the Kepler telescope, from which it is named.

• Opening date: 2013;
• star: orange dwarf Kepler 62;
• detection method: transit.

Together with the body with the number f, the planets Kepler 62 e and Kepler 62 b were found.

Kepler-62 f is 40% larger than Earth's. The origin occurred 7.5 billion years ago. For comparison, our world is 4.5 billion years old. The axis tilt is stable and the temperature regime is similar to Earth's. Astrophysicists speculate the presence of life on the surface.

Gliese 581 g

A red dwarf from the constellation of Libra has a satellite planet located 20 light-years from Earth and is similar to it.

• Date of opening: 29.09.2010;
• star: red dwarf Gliese 581;
• detection method: spectrometric calculation of stellar velocity.

It originated 7-11 billion years ago. Since the discovery was preceded by calculations, astronomers from the European Southern Observatory checked the spectrograph data again and questioned the existence of Gliese 581 g.

There is still no consensus on this. If the planet exists, its size is two the size of the Earth, the average temperature is -10 to - 30°C. It is turned to the red dwarf by one side.

Kepler 62 e

This celestial body was found near the same orange dwarf as the one described above, which is one part of the constellation Lyra, with an approximate age of 7 billion years.

• Opening date: 2013;
• star: orange dwarf Kepler 62;
• detection method: transit.

Astronomers suggest the presence of life and the existence of a huge ocean, not unlike the Earth's world ocean. Distance to Earth - 1200 light years, the size (1.5 times the diameter of the Earth) suggests the presence of an atmosphere. The distance from the planet to the star is similar to the position of Earth in relation to the Sun.

Presumably the average temperature is +15°C. The task of future astrophysicists is to calculate the atmosphere of Kepler 62 e. Astronomers believe that the planet has life at least at the level of single-celled organisms. This exoplanet, which resembles the Earth the most.

Gliese 667 cc

Distant from us by 22.7 light years, Gliese 667 is located in the constellation of Scorpio.

• Opening date: 11/29/2011;
• star: Triple Gliese 667 (two orange dwarfs with one red dwarf);
• detection method: spectrometric calculation of stellar velocity.

It orbits around the stellar trio for 28-29 Earth days. The mass exceeds the Earth's in 3,5-4 times. The University Laboratory in Puerto Rico has concluded that the average temperature is +27°C, conditions similar to our own. Exoplanet turned to Gliese 667 one side. There is reason to believe that there is life on the planet.

Kepler 22 b

Kepler 22 is located in the constellation Swan. NASA's Kepler telescope found it first, so it was decided to name the planet after him. Confirmation of its existence was made by eliminating falsehoods.

• Date of opening: 05.12.2011;
• star: single star of spectral class G;
• detection method: transit.

Kepler 22b is an Earth-like planet 620 light years distant from the Earth, which makes a revolution around the star in 290 Earth days. Its size and structure are unknown.

These are the most famous exoplanets similar to our own. Let's talk about new discoveries and find out how many Earth-like planets exist.

New exoplanets

Every year astronomers find Earth-like planets in the universe. There is a term "habitable zone," which means the region of space gaps between a planet and a star within which any of the life forms can exist.

All of the planets described above belong to a single class, called Super-Earth. Such exoplanets have a mass greater than ours, but much smaller than gas giants. The maximum size is 10 Earth masses. The mass parameter was not chosen by chance, it is related to the ability of the planet to hold the atmosphere.

Astrophysicist M. Hippke used the example of Kepler 22b to explain the inability of other life forms to leave such a planet because of its large mass. Its gravity is superior to Earth's, and it requires hundreds of tons of fuel to send small objects into space.

Proxima Centauri b is our closest exoplanet

The red dwarf Proxima Centauri is the closest star to the Sun. Proxima b was discovered in 2016 at a distance of 4.22 light-years from our planet. Astrophysicists are interested in nearby celestial bodies because they are easier to study.

The planet Proxima b has a mass 1.27 times greater than the Earth's. It makes a complete orbit for 11 days. It is assumed that the radius of the planet Proxima b is 10% greater than the Earth's. The existence of living organisms on the surface is not excluded. However, the radiation background on it is high.

Colonization of nearby exoplanets: timing, obstacles

The discovery of other planets in space allowed astronomers to talk about the existence of extraterrestrial life, to put forward theories about the formation of planets.

At the moment, scientists are deciding which planet to choose for colonization. The main obstacles to the implementation of space travel:

• a great distance;
• unknown conditions and presence of atmosphere (radiation background, lack of water, high and low temperatures);
• complex calculations (the flight of the spacecraft will need to accurately calculate the orbital passage, correlate it with the orbital rotation of the exoplanet, and take into account the time of approach).

Analyzing this data, it becomes clear that it is necessary to start with the planet closest to Earth. For this reason, they are increasingly talking about the colonization of Mars.

Plans for the near future

Colonization of space is still an area of science fiction. The discovery of planets similar to our own does not give a reason to undertake an interplanetary mission in the foreseeable future. Humanity's immediate goal is to establish a permanent base on Mars to study the planet itself and its satellites. The flight to the red planet will take 70-80 days. Conditions are similar to Earth, so attempts to send a mission will be made in the next decade.

Looking at videos from space, photos taken by astronauts, flying vehicles, you realize how big this world is. Similar planets to ours exist, and living organisms will be found.