Are there planets similar to earth. What planet is similar to Earth: name, description and features. Exoplanets: what are they, types

What planets are similar to Earth? The answer to this question can be approached in different ways. If we take, for example, the diameter and mass as the main criterion, then in the solar system, Venus is closest to our cosmic home. However, it is even more fascinating to consider the question “Which planet is more like the Earth?” in terms of the habitability of objects. In this case, within solar system we will not find a suitable candidate - we will have to look at the boundless expanses of remote space.

People have been looking for alien life for a long time. At first, these were only hypotheses, assumptions and conjectures, but as technical abilities improved, the matter began to move from the category of theoretical problems to the field of practice and scientific knowledge.

Criteria were identified according to which a space object can be classified as potentially viable. Any planet similar to Earth must be located in the so-called habitable zone. This term refers to a certain area around the star. Its main characteristic is the possibility of the existence on the planet within its limits of water in a watery state. Depending on the characteristics of the star, the habitable zone can be located closer to it or a little further, have a huge or smaller extent.

Luminary properties

As studies show, a planet similar to Earth and potentially suitable for life should revolve around a star of spectral class from G to K and surface temperature from 7000 to 4000 K. Such luminaries emit a sufficient amount of energy, are stable for a long time, their current cycle ends in several billion years.

It is important that the star does not differ in significant variability. Stability both on Earth and in space is the key to a more or less calm life. Unexpected outbursts or prolonged fading of the luminary can lead to the disappearance of organisms on the surface of a candidate for twins of our planet.

Metallicity, that is, the presence of elements in the matter of a star in addition to hydrogen and helium, is another fundamental property. At low values of this attribute, the possibility of planet formation is extremely small. Relatively young stars have higher metallicity.

Planet properties

And why, in fact, only a planet similar to the Earth can be potentially habitable? Why are objects similar in size to Jupiter not included in this list? The answer lies in the optimal conditions for the development of living organisms. They are created specifically on planets similar to ours. The properties of Earth-like planets on which life can exist include:

a mass close to Earth's: such planets are able to hold an atmosphere, while plate tectonics on their surface is not as high as that of the "giants";

predominance in the composition of silicate rocks;

the absence of a dense atmosphere of helium and hydrogen, characteristic, for example, of Jupiter and Neptune;

the eccentricity of the orbit is not too large, otherwise the planet will at times be too far away from the star or too close to it;

a certain ratio of axial tilt and rotational speed, necessary for the change of seasons, the average length of day and night.

These and other parameters affect the climate on the surface of the planet, geological processes in its depths. You need to see that for different living organisms the necessary conditions may differ. The possibility of encountering microbes in space is even higher than that of mammals.

Evaluation of all these parameters requires high-precision equipment that can not only calculate the location of the planet, but also refine its characteristics. Fortunately, modern equipment "can" already do a lot, and the ongoing research and development allows us to hope that in the near future people will be able to look even further into space.

Since the turn of the century, quite a few great amount objects that are habitable to one degree or another. True, it does not seem likely to answer the question of which planet is more similar to the Earth, since this requires even more accurate data.

Controversial exoplanet

On September 29, 2010, scientists announced the discovery of the planet Gliese 581 g, orbiting the star Gliese 581. It is located at a distance of 20 light years from the Sun, in the constellation of Libra. To date, the existence of the planet has not been confirmed. In the five years since its discovery, it has been reinforced several times by data from additional research work and then refuted.

If this planet exists, then, according to calculations, it has an atmosphere, water in a watery state and a rocky surface. In radius, it is quite close to our space house. It is 1.2-1.5 of the earth. The mass of the object is estimated at 3.1-4.3 Earth. The possibility of life on it is as controversial as its very discovery.

First confirmed

Kepler-22 b is an Earth-like planet discovered by the Kepler telescope in 2011 (December 5). She is an object whose existence is confirmed.

Planet characteristics:

revolves around a G5 star with a period of 290 Earth days;
mass - 34.92 earth;
surface composition unknown;
radius - 2.4 Earth;
receives about 25% less energy from a star than the Earth receives from the Sun;
the distance to the star is about 15% less than from the Sun to the Earth.

The ratio of shorter distance and energy input makes Kepler-22 b a candidate for the title of a habitable planet. If it is surrounded by a fairly dense atmosphere, the temperature on the surface can reach +22 ºС. At the same time, there is an assumption that the planet in its composition is rather similar to Neptune.

Recent discoveries

The "newest" Earth-like planets were discovered in the current year, 2015. This is Kepler-442 b, located at a distance of 1120 light years from the Sun. It exceeds the Earth by 1.3 times in size and is located in the habitable zone of its star.

In the same year, the planet Kepler-438 b was discovered in the constellation Lyra (470 light-years from Earth). It is also close in size to Earth and located in the habitable zone.

Finally, on July 23, 2015, the discovery of Kepler-452 b was announced. The planet is located in the habitable zone of the luminary, very similar to our star. She more earth by about 63%. The mass of Kepler-452 b is, according to scientists, 5 masses of our planet. Its age is also older - by 1.5 billion years. The surface temperature is estimated at -8 ºС.

The existence of these three planets is confirmed. They are considered potentially habitable. However, it is not yet likely to confirm or refute their habitability.

The upcoming improvement of technology will allow astrologers to study these worlds in more detail, and therefore answer the question of which planet is more like the Earth.

> > The most Earth-like planet

Second Earth: is there a twin of the Earth and what will be Earth-like planets systems? Description of candidates for the role of the second world with life and resettlement.

Tired of living on Earth? Do you want to pack a backpack and move to another world? Well, we have bad news. There is no second place in the solar system that doesn't kill you in a second.

You'll face hellish heat ice age, poisonous vapors and other inhospitable worlds. Almost the entire solar system is negatively opposed to the life that is found on Earth. But if you look for options, which place would be the best? And are there planets similar to Earth?

We need to find a world with similar gravity, composition, temperature and weather conditions. In general, the second Earth. Let's take a look at the contenders.

How is the planet most similar to Earth? Luna comes to mind first. Of course, this is not a planet, but an earthly satellite. But heavenly body located close. The moon is devoid of air, so you can not do without a spacesuit. Your bones will not be happy with low gravity because they will lose mass and become brittle. The temperature also jumps between hot and cold and there is no protection from cosmic rays.

If we consider satellites, then why not Titan?

It is the largest moon of Saturn. Reaches 15% of Earth's gravity, and the temperature can drop to -173°C. The pressure is higher than the earth, so you don’t have to equip the suit with special protection.

And what about Mars? The gravity of the Red Planet reaches 38% of the Earth's (terrestrial planet). So far we have no data on how this will affect the human body during a long visit. martian atmosphere represented by poisonous carbon dioxide and low pressure. The temperature mark varies from 35°C to -143°C. But the main problem is the lack of a magnetosphere, which means we will have to create protection from radiation.

Let's go to Venus! It seems like a real suicide. It is as if you are flying into an oven with a temperature of 462 ° C and a pressure 92 times higher than the earth (the most hot planet solar system). Around you there is a massive accumulation of carbon dioxide and clouds of sulfuric acid. However, gravity and the atmospheric layer protect from radiation.

Despite all the horror, there is one cozy place to live. In the clouds of Venus.

Yes, you just need to climb to a height of 50-60 km and you will find yourself in the usual conditions for the Earth. Around will still be focused carbon dioxide, but it is possible to equip special aircrafts like airships.

As you can see, it is extremely difficult to find planets similar to the Earth. So far, opinions about colonization differ. Most are focused on Mars, but thoughts of Venus also haunt. It remains only to observe where we go first.

The science

Scientists have discovered a mysterious planet outside our solar system, which is most similar in size and composition to the Earth, but on it too hot to sustain life.

The exoplanet was named Kepler-78b. Its orbit has puzzled astronomers - it is 20% wider, and the mass is 80% more than the earth, despite the fact that its density is the same as that of our planet.

The exoplanet is at a distance of about 1.5 million kilometers from the star. Kepler-78b orbits its star in about 8.5 hours. The temperature on the planet is about 2000 degrees Celsius, according to scientists.

The discovery was mentioned in two studies, the results of which were in turn published in the journal Nature.

Thanks to telescope Kepler astronomers have learned of thousands of exoplanets in our galaxy, many of them the same size as our planet. These planets revolve around stars like our Sun.

Although it is easy to measure the size of an exoplanet, it was quite difficult to find out its mass. Mass is an important parameter, since it allows you to find out the density of the planet, and therefore find out what this planet is made of.

Earth-like exoplanets

Kepler-78b is very interesting because this smallest exoplanet, in which scientists were able to find out the radius and mass with great accuracy.

By astronomical standards, this planet can be called a virtual twin of the Earth.

Scientists learn the size of an exoplanet, as well as the time it takes to orbit its star, by measuring the amount of light the planet blocks as it passes in front of the star.

After scientists measured the brightness of the planet Kepler-78b for 4 years at 30-minute intervals, the scientists found that the star's brightness dropped by .02% every 8.5 hours as the planet passed in front of its star.

secret planet

The planet Kepler-78b was discovered in September 2013 when it orbited a star similar to our Sun in the constellation Cygnus, approximately at a distance 400 light years from Earth.

Since its launch (March 2009), the Kepler space telescope has been able to detect nearly 3,600 potential exoplanets.

Two teams of scientists studied mass and density new planet. Team Andrew Howard (Andrew Howard) from University of Hawaii, calculated that the mass of the planet Kepler-78b is 1.69 times that of the Earth, while the data of the team of Francesco Pepe (Francesco Pepe) from University of Geneva, showed that the exoplanet has a mass of 1.86 times more.

The density that the first team calculated is 5.57 grams per cubic centimeter, while the second team had a density of 5.3 grams per cubic centimeter.

Since each team recognizes certain errors, it can be said with certainty that scientists are right in their calculations. It is worth noting that the density of the Earth is 5.5 grams per cubic centimeter. This means that the new exoplanet may have the same composition as the Earth.

new planet

The new planet circles around its sun, gradually approaching it, and, approximately in 3 billion years her days will be numbered- the colossal gravity of the star will tear it to pieces.

By astronomical standards, the planet will become part of a star very soon. On Kepler-78b it will not be possible find alien life, due to too high a temperature on its surface.

And yet, the mass and density of the new planet, similar to the Earth, allow us to hope that somewhere there is a twin planet of our Earth, which has a similar size, composition and temperature on its surface.

According to Drake Deming of University of Maryland, the existence of Kepler-78b proves that, outside our solar system, planets similar in composition to Earth are not uncommon.

Deming alludes to new program NASA, called TESS (Transiting Exoplanet Survey Satellite). It will be a space telescope this moment developed by the Massachusetts Institute of Technology. For two years, his mission will be to find and study of unknown transiting exoplanets revolving around bright stars.

* The mass of the Sun is equal to 99.86% of the mass of our entire solar system. Everything else, including planets and asteroids, is only 0.14%.

* Jupiter boasts such a powerful magnetic field that every day it enriches the Earth's magnetic field with billions of watts.

* One day on Venus lasts 243 Earth days, despite the fact that the year lasts only 225.

* Mars boasts the largest volcano in our solar system. It is called "Olympus" and it stretches for more than 600 km, having a height of 27 km. It is worth noting that the peak of Mount Everest is at an altitude of 8.5 km.

* Our planet does not have a constant weight. According to scientists, every year the Earth becomes heavier by 40,000 -160,000 tons, but manages to drop about 96,600 tons, which means a loss of about 56,440 tons.

Comparative sizes of the Earth (right) and exoplanets (left to right): Kepler-22b, Kepler-69c, Kepler-452b, Kepler-62f and Kepler-186f. Illustration: NASA

Each discovered Earth-like exoplanet orbiting a solar-type star brings us one step closer to discovering a replica of our planet. The Kepler space telescope, the world's premier exoplanet hunter, has already discovered many potentially habitable worlds in our galaxy.To narrow down the search for a potentially habitable planet, Kepler searches for new objects in the so-called "life zones" - areas around stars where water can be in a liquid state, and, as a result, the temperature on a potential planet can also be favorable for maintaining life (as we know it).

In each star system, the "zone of life" has different sizes. Somewhere it is very extensive, somewhere narrower. In one system, the "zone" of life is located closer to the star, in the other further. The main factor, of course, is the star itself and its physical characteristics.

The last discovered "sister" of the Earth is the exoplanet "Kepler-452b", about which we are. Now, according to scientists, this exoplanet is the most similar to our planet. But there are other Earth-like exoplanets discovered earlier. And now, together we will recall which worlds most similar to the Earth were discovered before the discovery of Kepler-452b.

Exoplanet Kepler-186f as seen by an artist. Illustration: NASA Ames/SETI Institute/JPL-Caltech

The second most Earth-like exoplanet is considered to be Kepler-186f in the Kepler-186 system, located at a distance of 500 light-years from Earth in the constellation Cygnus. The size of the planet Kepler-186f exceeds the earth's by only 10%.

The planet is located at a relatively short distance from the star: its period of revolution around the parent star, which is a red dwarf of the spectral class M, is 130 Earth days. And at the same time, the exoplanet is on the far edge of the "life zone".

The energy received by Kepler-186f from its star is one third of the energy received by our planet from the Sun. At noon on the surface of the planet, the star Kepler-186 shines in about the same way as our Sun an hour before its sunset. The composition of the atmosphere may be broadly similar to that of the Earth's atmosphere; the temperature on Kepler-186f is probably the same as on our planet. But astronomers do not exclude the similarity with the atmosphere of Venus, so the temperature on the planet will be much higher.

Kepler 62 system. NASA Ames/JPL-Caltech illustration

Before the discovery of Kepler-186f, the exoplanet Kepler-62f occupied the leading place in the list of Earth's "twins". Calculations show that it is 40% larger than the Earth and has a circulation period of 267 Earth days. W the star of the system is "Kepler 62", 1200 light-years away from us in the constellation Lyra, 1/3 smaller than the Sun, colder than it and 5 times dimmer. However, the proximity of the exoplanet to the star makes the conditions on it more or less favorable for the development and maintenance of life.

Kepler 69 system. NASA Ames/JPL-Caltech illustration

At the same time (the first half of 2013), another interesting exoplanet was announced - Kepler-69c, but it is 70% larger than our planet! In a sense, this is bad news, because, according to scientists, the larger the "super-Earth", the less likely it is to find life on it. But there is also good data: the exoplanet is located in the zone of life, and its period of revolution is 242 Earth days.

In addition, the parent star of the Kepler 69 system belongs to the spectral class G. It is very similar to the Sun: the mass is 93% of the mass of the Sun, and the luminosity is 80% of the Sun.

Exoplanet Kepler-22b. NASA/Ames/JPL-Caltech illustration

Even earlier, the Kepler-22b exoplanet was considered an ideal twin of the Earth. It was the first exoplanet discovered in the "life zone" as part of the mission of the Kepler telescope. And among the voiced planets, "Kepler-22b" is the real "sumo wrestler".

The exoplanet is 2.4 times larger than Earth. It has not yet been established whether this planet has a rocky surface, or is covered with water, or maybe it consists of gas. The exoplanet was discovered almost immediately after the start of observations by Kepler in 2009.

And one more interesting fact about "Kepler-22b": December 21, 2012 to this planet, containing information about the world around us and greetings to potential extraterrestrial civilizations. The message of earthlings was sent using the RT-70 radio telescope, but it will not come soon - the exoplanet is 600 light-years away from our planet.

Visual similarity of Earth (left) and Gliese 667Cc (right) - computer model.

Meanwhile, not all Earth-like exoplanets have been discovered using the "telescope-hunter". In 2011, astronomers announced the discovery of "Gliese 667Cc" using the 3.6-meter telescope owned by the European Southern Observatory.

The planet is only 22 light years away. It is about 4.5 times more massive than the Earth. Rotates in orbit around a red dwarf in the "life zone" at a small distance from the star - the period of revolution is 28 Earth days. Thus, the planet is strongly affected by the star's radiation. And at the same time, it receives only about 90% of the energy that we receive from our Sun. Unfortunately, the diameter and density of the exoplanet is still a mystery to astronomers.

Thus, the following chain is well traced - each discovered Earth-like exoplanet is the closest "double" of our planet, which in turn confirms what we started this material with: " Each discovered Earth-like exoplanet brings us one step closer to discovering a replica of our planet."

What planets are similar to Earth? The answer to this question can be approached in different ways. If we take, for example, the diameter and mass as the main criterion, then in the solar system, Venus is closest to our cosmic home. However, it is even more fascinating to consider the question “Which planet is more like the Earth?” in terms of the habitability of objects. In this case, we will not find a suitable candidate within the solar system - we will have to look at the boundless expanses of remote space.

Planet properties

a mass close to Earth's: such planets are able to hold an atmosphere, while plate tectonics on their surface is not as high as that of the "giants";

predominance in the composition of silicate rocks; the absence of a dense atmosphere of helium and hydrogen, characteristic, for example, of Jupiter and Neptune;

the eccentricity of the orbit is not too large, otherwise the planet will at times be too far away from the star or too close to it;

a certain ratio of axial tilt and rotational speed, necessary for the change of seasons, the average length of day and night.

Since the beginning of the century, a fairly huge number of objects have been discovered that are more or less suitable for life. True, it does not seem likely to answer the question of which planet is more similar to the Earth, since this requires even more accurate data.

Controversial exoplanet

On September 29, 2010, scientists announced the discovery of the planet Gliese 581 g, orbiting the star Gliese 581. It is located at a distance of 20 light years from the Sun, in the constellation of Libra. To date, the existence of the planet has not been confirmed. In the five years since its discovery, it has been supported several times by the data of additional research work, and then refuted.

Kepler-22 b is an Earth-like planet discovered by the Kepler telescope in 2011 (December 5). She is an object whose existence is confirmed.

Planet characteristics:

revolves around a G5 star with a period of 290 Earth days;

mass - 34.92 earth;

surface composition unknown;

radius - 2.4 Earth;

receives about 25% less energy from a star than the Earth receives from the Sun;

the distance to the star is about 15% less than from the Sun to the Earth.

In the same year, the planet Kepler-438 b was discovered in the constellation Lyra (470 light-years from Earth). It is also close in size to Earth and located in the habitable zone.

Finally, on July 23, 2015, the discovery of Kepler-452 b was announced. The planet is located in the habitable zone of the luminary, very similar to our star. It is larger than the Earth by about 63%. The mass of Kepler-452 b is, according to scientists, 5 masses of our planet. Its age is also older - by 1.5 billion years. The surface temperature is estimated at -8 ºС.

The existence of these three planets is confirmed. They are considered potentially habitable. However, it is not yet likely to confirm or refute their habitability.

The upcoming improvement of technology will allow astrologers to study these worlds in more detail, and therefore answer the question of which planet is more like the Earth.