Which planet is similar to the Earth: name, description and features

Which planets are similar to Earth? The answer to this question can be approached differently. If the main criterion is to take, for example, the diameter and mass, then in the solar system, the closest to our space house is Venus. However, it is much more interesting to consider the question "Which planet is more like Earth?" In terms of the suitability of objects for life. In this case, within the solar system, we will not find a suitable candidate - we will have to take a closer look at the vast expanses of remote space.

Habitat Zone

The search for extraterrestrial life took people a long time. At first these were just conjectures, assumptions and conjectures, but as the technical capabilities improved, the matter began to shift from the category of theoretical problems to the field of practice and scientific cognition.

Criteria were defined for the space object to be potentially viable. Any planet similar to the Earth should be located in the so-called habitat zone. This term denotes a certain area around the star. Its main characteristic is the possibility of existence on the planet within its boundaries of water in a liquid state. Depending on the characteristics of the star, the inhabited zone may be located closer to it or slightly further, to have a greater or lesser extent.

Properties of the Luminary

Studies show that a planet that is similar to Earth and potentially suitable for life should rotate around a spectral-grade star from G to K and a surface temperature of 7000 to 4000 K. Such luminaries emit sufficient energy, are stable for a long time, their life cycle ends in Several billion years.

It is important that the star does not have a significant variability. Stability on both the Earth and in space is a pledge of a more or less peaceful life. Sudden outbreaks or long-term damping of the luminary can lead to the disappearance of organisms on the surface of the candidate in the twins of our planet.

Metallicity, that is, the presence of elements other than hydrogen and helium in the substance of the star, is another important property. At low values of this sign, the probability of the formation of planets is extremely small. A relatively high metallicity is possessed by relatively young stars.

Properties of planets

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

• Mass close to the Earth: such planets are able to hold the atmosphere, while plate tectonics on their surface are not as high as those of the "giants";

• Dominance in the composition of silicate rocks;

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

• Not too large eccentricity of the orbit, otherwise the planet will from time to time be too far from the star or approach it too close to it;

• A certain ratio of the slope of the axis and the speed of rotation, necessary for changing the seasons, the average duration of the day and night.

These and other parameters affect the climate on the surface of the planet, the geological processes in its interior. It should be noted that for different living organisms the necessary conditions may differ. The probability of encountering bacteria in space is much higher than that of mammals.

New Earth-like planets

Evaluation of all these parameters requires the availability of high-precision equipment that can not only calculate the location of the planet, but also to clarify its characteristics. Fortunately, modern equipment "knows" very much, and unstoppable research and development allows us to hope that in the near future people will be able to look even further into space.

Since the beginning of the century a fairly large number of objects have been discovered that are more or less suitable for life. However, it is not possible to answer the question of which planet is more like Earth than others, because more exact data is needed for this.

Controversial exoplanet

September 29, 2010, scientists reported the discovery of the Gliese planet 581 g, revolving around the star Glise 581. It is located at a distance of 20 light years from the Sun, in the constellation Libra. To date, the existence of the planet has not been confirmed. For five years since the opening, it has been reinforced several times with data from additional studies, and then it has been refuted.

If this planet exists, then, according to calculations, it has an atmosphere, water in a liquid state and a rocky surface. On the radius, it is close enough to our space house. It is 1.2-1.5 of the earthly. The mass of the object is estimated at 3.1-4.3 terrestrial. The probability of existence of life on it is as controversial as its very discovery.

First confirmed

Kepler-22 b - a planet similar to the Earth and opened by the Kepler telescope in 2011 (December 5). It is an object whose existence is confirmed. Characteristics of the planet:

• Rotates around a star of spectral class G5 with a period of 290 terrestrial days;

• Weight - 34.92 Earth;

• The surface composition is unknown;

• Radius - 2.4 terrestrial;

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

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

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

Recent discoveries

The "newest" planets, similar to the Earth, were discovered in the current year, 2015. This Kepler-442 b, located at a distance of 1120 light years from the Sun. It exceeds the Earth in size 1,3 times and is located in the zone of habitation of its star.

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

Finally, on July 23, 2015, Kepler-452 b. Was announced. The planet is located in the habitable zone of the star, very similar to our star. It is greater than the Earth by approximately 63%. The mass of Kepler-452 b is estimated by scientists to be 5 of the masses of our planet. Its age is also greater - by 1.5 billion years. The surface temperature is estimated at -8 ° C.

The existence of these three planets is confirmed. They are considered to be potentially livable. However, it is not yet possible to confirm or deny their habitability.

Further perfection of the technique will allow astronomers to study these worlds in more detail, and hence to answer the question of which planet is more like Earth.