Is it possible that there are other planets similar to Earth?
The possibility of finding another planet like Earth , with similar climatic and atmospheric conditions and capable of sustaining life as we know it, has gone from being a science fiction story to becoming a tangible reality.
Until a few years ago it did not seem possible to sustain life (at least similar to ours) on planets observable from Earth, which were the other planets of our own solar system. All of them are very far or very close to the sun, only the Earth and Mars are within what is called the "Habitable Zone" of the solar system.
Despite the fact that it is thought that, millions of years ago, Mars could have had a friendlier atmosphere and had the conditions to harbor life, today its surface is an arid and desolate steppe, formed mainly by iron oxide and other ferrous elements. .
The truth is that recent discoveries made thanks to modern super telescopes have opened our eyes to new Earth-like planets discovered so similar to our own that perhaps we could live on them in a completely natural way.
But what is the yardstick that determines whether a new planet is suitable for life or not?
What makes Earth habitable?
Our planet was not born with the conditions we enjoy today, in fact its current atmosphere is the result of millions of years of evolution, cycles and drastic climate changes.
The creation and evolution of stars and planets is a fascinating process! Be sure to read our article on galaxy and star formation.
Life and nature as we know it are the result of a long and complex period of mutual adaptation between living beings and the environment, which has made life flourish and evolve as we know it today.
Therefore, it had always been believed that finding another planet like Earth , with the specific conditions for survival that we humans require (pressure, oxygen, temperature, etc.), seemed very unlikely… Until now
In order for complex life forms to flourish on our planet, it had to adapt, change and cool down from the moment of its formation in order to meet the ideal conditions in its atmosphere.
perfect distance from the sun
Earth is the third planet in the orbit of our solar system and is located at an approximate distance of 150 million kilometers from the sun , which generates certain basic characteristics that allow life as we know it.
The temperature on earth is relatively stable, around 15°C in its atmosphere, which allows the planet to contain huge amounts of water in a liquid state and promote biochemical processes such as photosynthesis.
Let us remember that water was the breeding ground where the first unicellular life forms emerged billions of years ago, it is also the common element that sustains the life of all animals and plants.
Appropriate size
The size and density of the earth generate an adequate gravitational force, ideal for retaining a light and habitable atmosphere.
The earth's atmosphere is made up of light gases such as oxygen, which is vital for the respiration process of all animals.
If the planet were much denser in matter, then its gravitational pull would be so powerful that no life could exist on the surface.
On the other hand, if it were much smaller or less dense, then the lack of gravity would prevent objects from being able to remain anchored to the surface, as is the case on the moon.
Magnetic field
The magnetic field that surrounds the earth is the product of the constant movement of liquid metals found beneath the earth's surface.
The electromagnetic effect produced in the center of the Earth gradually expands towards the atmosphere, creating an invisible shield that allows the passage of sunlight, but protects us from the radiation brought by the solar winds, composed mainly of X-rays and gamma rays.
Presence of biomolecules
The surface of the earth is an environment rich in biomolecules that are essential to create and maintain complex life forms, such as humans and all animals.
We can find organic molecules in absolutely all the elements that make up our planet, including in the air we breathe, which is rich in oxygen.
Our planet is made up of a complex combination of more than 100 essential biomolecules; however, 96% of all its matter is made up of only: Oxygen, Nitrogen, Hydrogen, and Carbon.
Earth is a unique planet in our solar system!
Starting from the point of our favored position in the sun's orbital rings, we can obtain, as mentioned above, an atmosphere of temperate temperature, neither too cold nor too hot.
This is not the case with the other planets, which may be too cold or too hot to support extraterrestrial life (at least the life forms that we know of).
On the other hand, the earth was a "victim" of multiple asteroid collisions in the earliest stages of its formation, which is believed to have seeded the set of biochemical elements on the surface that allowed the proliferation of the first life forms in the planet. Water.
However, recent discoveries by NASA and the Russian Space Agency have suggested that there are 3 locations in our own solar system that could potentially harbor complex life forms.
The first of these is located beneath the surface of Mars, where samples obtained by the Mars Rover have found what appears to be a large cluster of water ice, with a molecular composition identical to that found on our planet.
Another promising scenario was discovered by the Cassini space probe and is located on Enceladus , one of Saturn's largest moons.
Enceladus is one of the giant planet's largest satellites and data collected since 2007 has yielded information about huge volumes of water frozen under its surface.
Many Russian researchers believe that, under the thick layer of ice, Enceladus hides a vast subterranean ocean that could undoubtedly support different forms of life, despite the low temperatures.
The last of the 3 potential locations is found in Europa, Jupiter's moon that Galileo Galilei discovered in the 17th century.
NASA scientists suspect that this moon could harbor vast oceans and atmospheric conditions conducive to life. To investigate, the agency will send the Europa Clipper Space Mission in 2023 to study the composition of water and the atmospheric conditions of this mysterious satellite.
There are other planets similar to Earth
Recent observations by NASA have made it possible for us to find Earth-like planets in other galaxies in our solar system.
In fact, not a single planet has been found with atmospheric characteristics similar to those of our home, 7 have been found!
In 2014, an entire solar system was discovered that appears to have conditions similar to those of our planet. These planets orbit a sun slightly different from our own and are now known as exoplanets.
This group of planets, called TRAPPIST-1, orbit around a super-cool dwarf star , which is about 10 times smaller than our sun, although it emits enough heat to overheat the first two planets in the system.
In this orbital system, planets 4, 5, and 6 are located within what is estimated to be the habitable zone. This means that one of them could be a planet similar to Earth in terms of temperature and atmosphere.
A planet equal to Earth?
The TESS (Transiting Exoplanet Survey Satellite) space telescope was launched into space in 2018 with a mission: to search for exoplanets in solar systems close to ours, with a 200-light-year sweep zone.
Among all the planets similar to Earth, this is the most surprising:
Among his many incredible discoveries, one stood out at the end of 2019: TOI 700 d , the most Earth-like planet discovered so far.
TOI 700 d is located within the habitable zone of its own star, at a relatively close distance from our galaxy, only 100 light-years. In addition, this planet has physical characteristics very similar to those of our planet and is only slightly larger.
Among the most interesting speculations about TOI 700 d, the most important is that there is a very high probability that this planet contains accumulations of surface water very similar to the Earth's oceans.
In addition, the planet must have an illumination very similar to that of our planet due to the distance of its orbit around its star, which is smaller than our Sun.
