Which planet is more similar to the earth? Scientists have found “another Earth.” Where the sun sets twice
ALL PHOTOS
NASA specialists have immediately discovered seven analogues of planet Earth around the recently discovered star TRAPPIST-1 in the constellation Aquarius. These celestial bodies both in size and mass similar to the Earth. Moreover, three of the seven planets are located in the center of the “life zone” and presumably have water and a thick atmosphere.
Experts announced the sensational discovery during a press conference, which was broadcast live on NASA's official website. In addition, the journal Nature wrote about the breakthrough discovery of astronomers.
“This discovery could be a significant step in the search for habitable environments and places that support life,” NASA emphasized, commenting on the discovery of planets in the TRAPPIST-1 star system, 40 light years away from Earth.
All discovered planets They are similar in size to the Earth - their radius ranges from 0.7 to 1.08 of the radius of our planet, and their mass ranges from 0.41 to 1.38. Accordingly, their density is equal to or slightly lower than the earth’s. This indicates their rocky nature or that they are ocean planets.
Unlike Earth, the "seven sisters" orbit TRAPPIST-1 in a very close orbit. On these planets, the year lasts from one and a half days to about two weeks.
Moreover, the last planet of the system, TRAPPIST-1h, is located approximately four times closer to the star than Mercury approaches the Sun.
As for the probability of the development of life, the three central planets that most claim this role are d, e and f.
According to the Emory Trio scientist from the Astronomical Institute in Cambridge, the greatest chance of the emergence of life is on planet f, whose climate is mild and cool enough for water and organic matter to exist on it.
In May 2016, astronomers from the American university MIT announced the discovery of an unusual star system - TRAPPIST-1, located only 40 light years away from Earth towards the constellation Aquarius, recalls RIA Novosti.
Even then, scientists suggested that the three planets orbiting this red dwarf were located inside the “life zone”, where water could exist in liquid form, and their mass was presumably comparable to that of Earth.
Scientists later studied the spectrum of rays from the star TRAPPIST-1, which passed through the air shells of the planets on their way to Earth, and discovered that these were rocky planets similar to Earth. In addition, hints were found of the presence of water, oxygen and carbon dioxide in their atmospheres.
However, until recently, not all astronomers agreed that these planets really exist. Critics noted that the periodic decreases in the brightness of the star, by which they were discovered, could be generated by an invisible star - the TRAPPIST-1 satellite.
Astronomer from the University of Liege Michel Gillon, meanwhile, cautioned that the discovery of a family of seven planets does not yet allow us to talk about how often multiplanetary star systems similar or similar to the Solar System are found in our Galaxy.
"Here we are dealing with a relatively rare type of star, one of the coolest and quietest objects Milky Way. We do not expect analogues solar system can arise from such stars - they simply do not have enough building materials for large planets like Jupiter or Saturn to arise in them. Therefore, we have not yet found analogues of the Solar system in red dwarfs and are unlikely to find them,” he explained.
While working with the European Southern Observatory (ESO) high-precision spectrograph HARPS, a team of researchers discovered a small exoplanet orbiting the red dwarf star Ross 128. Astronomers believe its size and surface temperature are very close to Earth's. What's even more interesting is that Ross 128 b is located just 11 light-years from the Solar System, making it the second closest exoplanet to us after Proxima b.
A quiet star and a promising planet
“This discovery was made possible by a decade of monitoring HARPS (High Accuracy Radial velocity Planet Searcher) data, coupled with the most modern methods information analysis,” says Nicola Astudillo-Defrou from the University of Geneva, co-author of a paper on the new discovery. “Until now, only HARPS has demonstrated such measurement accuracy, and for 15 years it has remained the best planet hunter in the world,” he assures.
The team notes that most red dwarfs experience intense solar flares, which usually literally blow the atmosphere off the planets and bombard them with solar radiation. However, Ross 128 is an unexpectedly “quiet” star that does not exhibit such activity. As a result, its planets may be the closest point to our planet for the colonization of other star systems. This is the particular importance of the discovery: if in the case of the well-known Proxima b, an aggressive star could destroy the planet’s atmosphere and turn it into a rocky desert, then Ross 128 b gives humanity hope for cosmic expansion.
Opening value
Ross 128 b's orbit is 20 times closer to the star than the distance between Earth and the Sun, but the planet receives only 1.38 times more solar radiation. As a result, the temperature on its surface is not very different from our planet: in the coldest points it does not fall below -60 o C, and in the hottest points it does not rise above 20 o C. However, scientists are not yet sure whether the planet is included in this called " Goldilocks zone"- the region around the star, the conditions of which allow water on planets to exist in a liquid state.
“Thanks to powerful modern telescopes, in 10 years we will be able to see new planet and describe its atmosphere. Currently, we only have theoretical models, and therefore cannot say with certainty whether liquid water exists on the surface of Ross 128 b,” explains Nikola in an interview with Futurism.
Which planets are similar to Earth? The answer to this question can be approached in different ways. If we take, for example, diameter and mass as the main criterion, then in the solar system Venus is closest to our cosmic home. However, it is much more interesting to consider the question “Which planet is more like Earth?” from the point of view of the suitability of objects for life. In this case, we will not find a suitable candidate within the Solar System—we will have to take a closer look at the vast expanses of distant space.
Habitable zone
People have been searching for a long time. At first these were just guesses, assumptions and conjectures, but as technical capabilities improved, the matter began to move from the category theoretical problems into the field of practice and scientific knowledge.
Criteria were outlined by 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 specific area around a star. Its main characteristic is the possibility of the existence of liquid water on the planet within its boundaries. Depending on the characteristics of the star, the habitable zone may be located closer to it or a little further away, and have a larger or smaller extent.
Properties of the luminary
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 a surface temperature from 7000 to 4000 K. Such luminaries emit a sufficient amount of energy, are stable for a long time, their life cycle ends in a few billion years.
It is important that the star does not exhibit significant variability. Stability both on Earth and in space is the key to a more or less calm life. Sudden flares or long-term extinctions of the star can lead to the disappearance of organisms on the surface of a candidate twin of our planet.
Metallicity, that is, the presence of elements other than hydrogen and helium in the star’s matter, is another important property. At low values of this feature, the probability of planet formation is extremely low. Relatively young stars have higher metallicity.
Properties of planets
Why, in fact, can only a planet similar to Earth 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 precisely on planets similar to ours. Properties of Earth-like planets on which life can exist include:
a mass close to that of the Earth: such planets are able to retain an atmosphere, while the plates 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, of Jupiter and Neptune;
the orbital eccentricity is not too large, otherwise the planet will from time to time move too far from the star or come too close to it;
a certain ratio of axis tilt and rotation 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 and geological processes in its interior. It should be noted that for different living organisms the necessary conditions may vary. The likelihood of meeting bacteria in space is much higher than mammals.
Assessing all these parameters requires high-precision equipment capable of not only calculating the location of the planet, but also clarifying its characteristics. Fortunately, modern equipment can already do a lot, and 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 beginning of the century, a fairly large number of objects have been discovered that are, to one degree or another, suitable for life. True, it is not possible to answer the question of which planet is more similar to Earth than others, since this requires even more accurate data.
Controversial exoplanet
On September 29, 2010, scientists announced the discovery of the planet Gliese 581 g, orbiting a star. It is located at a distance of 20 light years from the Sun. 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 additional research and then refuted.
If this planet exists, then, according to calculations, it has an atmosphere, liquid water and a rocky surface. In terms of radius, it is quite close to our cosmic home. It is 1.2-1.5 of the earth's. The mass of the object is estimated at 3.1-4.3 Earth's. The likelihood of life existing on it is as controversial as its discovery itself.
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 has been confirmed. Characteristics of the planet:
Which planets are similar to Earth? The answer to this question can be approached in different ways. If we take, for example, 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 Earth?” from the point of view of the suitability of objects for life. In this case, we will not find a suitable candidate within the Solar System—we will have to take a closer look at the boundless expanses of distant space.
People have been searching for alien life for quite some time. At first these were only hypotheses, assumptions and speculation, but as technical abilities improved, the matter began to move from the category of theoretical problems into the field of practice and scientific knowledge.
Criteria were outlined by 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 specific area around a star. Its main characteristic is the possibility of existence on the planet within its boundaries 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.
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 a surface temperature from 7000 to 4000 K. Such luminaries exude 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 exhibit significant variability. Stability both on Earth and in space is the key to a more or less peaceful life. Unexpected flares or long-term attenuation of the star can lead to the disappearance of organisms on the surface of a candidate for our planet’s twins.
Metallicity, that is, the presence of elements other than hydrogen and helium in the star’s matter, is another fundamental property. At low values of this feature, the possibility of planet formation is extremely small. Relatively young stars have the highest metallicity.
Properties of planets
Why, in fact, can only a planet similar to Earth 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. Properties of Earth-like planets on which life can exist include:
a mass close to that of the Earth: such planets are able to retain an atmosphere, while the plate tectonics on their surface is not as high as that of the “giants”;
predominance of silicate rocks in the composition; the absence of a dense atmosphere of helium and hydrogen, characteristic, for example, of Jupiter and Neptune;
the orbital eccentricity is not too large, otherwise the planet will at times move too far from the star or come too close to it;
a certain ratio of axis tilt and rotation speed necessary for the change of seasons, the average length of day and night.
These and other parameters influence the climate on the surface of the planet and geological processes in its interior. You need to see that the necessary conditions may differ for different living organisms. The possibility of meeting microbes in space is even higher than mammals.
Assessing all these parameters requires high-precision equipment capable of not only calculating the location of the planet, but also clarifying its characteristics. Fortunately, modern equipment can already do a lot, and 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 beginning of the century, quite a huge number of objects have been discovered that are, to one degree or another, suitable for life. True, it does not seem likely to answer the question of which planet is most similar to 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 20 light-years from the Sun, in the constellation Libra. To date, the existence of the planet has not been confirmed. Over the five years since its discovery, it has been supported several times by data from additional research work, and then it was refuted.
If this planet exists, then, according to calculations, it has an atmosphere, watery water and a rocky surface. In terms of radius, it is quite close to our cosmic home. It is 1.2-1.5 of the earth's. The mass of the object is estimated at 3.1-4.3 Earth's. The possibility of life existing on it is as controversial as its discovery itself.
Kepler-22 b is an Earth-like planet discovered by the Kepler telescope in 2011 (December 5). She is an object whose existence has been confirmed.
Characteristics of the planet:
orbits a star of spectral class G5 with a period of 290 Earth days;
mass - 34.92 Earth;
surface composition is unknown;
radius - 2.4 Earth;
receives about 25% less energy from the star than the Earth 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 surface temperature can reach +22 ºС. At the same time, there is an assumption that the planet is more similar in composition to Neptune.
The “newest” Earth-like planets were discovered this year, 2015. This is Kepler-442 b, located at a distance of 1120 light years from the Sun. It is 1.3 times larger than Earth 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 is 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 a star very similar to our star. It is about 63% larger than Earth. The mass of Kepler-452 b is, according to scientists, 5 times the mass of our planet. Its age is also older - 1.5 billion years. The surface temperature is estimated at -8 ºC.
The existence of these three planets has been confirmed. They are considered potentially suitable for life. However, it does not yet seem likely to confirm or deny 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 similar to Earth.
Comparative sizes of Earth (right) and exoplanets (from left to right): Kepler-22b, Kepler-69c, Kepler-452b, Kepler-62f and Kepler-186f. Illustration: NASA
Each discovery of an 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 main exoplanet hunter, has already discovered many potentially habitable worlds in our galaxy.To narrow the search for a potentially habitable planet, Kepler is searching for new objects in so-called "life zones" - areas around stars where water may exist in a liquid state, and, as a result, the temperature on a potential planet may also be favorable to support life (the one we know).
In each star system, the “life zone” has different sizes. In some places it is very broad, in others it is narrower. In one system the “zone” of life is located closer to the star, in another it is further away. 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”, which we are talking about. Now, according to scientists, this exoplanet is the most similar to our planet. But there are other Earth-like exoplanets that were discovered earlier. And now, together we will remember which worlds most similar to Earth were discovered before the discovery of Kepler-452b.
Exoplanet Kepler-186f as imagined 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 500 light-years from Earth in the constellation Cygnus. The size of the planet Kepler-186f exceeds that of Earth by only 10%.
The planet is located at a relatively short distance from the star: its orbital period around the parent star, which is a red dwarf of spectral class M, is 130 Earth days. And at the same time, the exoplanet is located on the far border of the “life zone”.
The energy received by Kepler-186f from its star is a third of the energy our planet receives from the Sun. At noon on the surface of the planet, the star Kepler-186 shines about the same as our Sun an hour before it sets. Composition of the atmosphere in general outline may be similar to the composition of the Earth's atmosphere; the temperature on Kepler-186f is probably the same as on our planet. But astronomers do not exclude similarities with the atmosphere of Venus, therefore the temperature on the planet will be much higher.
Kepler 62 system. Illustration by NASA Ames/JPL-Caltech
Before the discovery of Kepler-186f, the leading place in the list of Earth “twins” was occupied by the exoplanet Kepler-62f. Calculations show that it is 40% larger than the Earth and has an orbital period of 267 Earth days. Z The star of the system is “Kepler 62”, 1200 light years away from us in the constellation Lyra, 1/3 smaller than the Sun, cooler 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. Illustration by NASA Ames/JPL-Caltech
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 habitable zone, and its orbital period is 242 Earth days.
In addition, the mother star of the Kepler 69 system belongs to spectral class G. It is very similar to the Sun: its mass is 93% of the mass of the Sun, and its luminosity is 80% of the Sun.
Exoplanet Kepler-22b. Illustration NASA/Ames/JPL-Caltech
Even earlier, the exoplanet Kepler-22b was considered an ideal twin of the Earth. It was the first exoplanet discovered in the "life zone" by the Kepler telescope mission. And among the announced planets, “Kepler-22b” is a real “sumo wrestler”.
The diameter of the exoplanet is 2.4 times greater than that of Earth. It has not yet been established whether this planet has a rocky surface, or is covered with water, or perhaps consists of gas. The exoplanet was discovered almost immediately after Kepler observations began 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 from earthlings was sent using the RT-70 radio telescope, but it will not arrive 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 were discovered using the “hunter telescope.” In 2011, astronomers announced the discovery of "Gliese 667Cc" using the 3.6-meter telescope owned by the European Southern Observatory.
The planet is located just 22 light years from us. It is about 4.5 times more massive than the Earth. It orbits around a red dwarf in the “life zone” at a short distance from the star - the orbital period is 28 Earth days. Thus, the planet is highly exposed to 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 exoplanet's diameter and density still remain a mystery to astronomers.
Thus, the following chain is clearly visible - every discovered Earth-like exoplanet is the closest “twin” of our planet, which in turn confirms what we started this material with: “ Each discovery of an Earth-like exoplanet takes us one step closer to discovering a replica of our planet."