It is unlikely that any other device will be able to take away the laurels of the "discoverer of planets" from the Kepler space observatory. Since its launch more than 10 years ago, the giant space telescope has discovered more than 4,000 planets.
And although the creators of Kepler did not intend their brainchild to search for life in space directly, the observatory managed to find about fifty planets on which life could potentially originate. And we will tell you about the most likely candidates according to NASA and the University of Puerto Rico.
10. Wolf 1061 c
The list of 10 potentially habitable planets opens with a "super-Earth." This is what scientists call planets that are very similar to Earth, only larger. The radius of Wolf 1061 c is one and a half times larger than Earth's, and its mass is 4.3 times that of Earth.
The planet is located just 14 light years from Earth, and its density, diameter, and temperature are just right for life to emerge. METI International is so confident that life exists on the “super-Earth” that every February, when the star system is visible through a telescope, they carefully study the sky in search of signs from aliens.
9. GJ 273 b
The star system, which contains another potentially inhabited planet, was discovered about 80 years ago. However, the existence of GJ 273 b became known much later – in 2013.
It is a large planet; its size is 2.5 times larger than Earth's. It is located right in the habitable zone and is presumably composed of solid rock. And the red dwarf around which it revolves is distinguished by its quiet nature and is not prone to violent outbursts of radiation that destroy all life.
True, in the current state of science it is impossible to know for sure whether there is life on GJ 273 b. But the uncertainty did not stop enthusiasts from launching a message into space addressed to this star system. The “package” packed in radio waves includes mathematical formulas and excerpts from musical works.
8. Kepler-442 b
This planet is located in the constellation Lyra, 1,200 light years away from Earth. Scientists at 97% are confident that Kepler-442 b is in the "habitable zone." It orbits a red dwarf, a small and dim star.
Kepler-442 b has a year of 112 days, and its axial tilt is too small for the planet to have seasons like Earth's. The planet is a "super-Earth" — its mass is about a third greater than Earth's.
There is a high probability that the planet's surface is solid and composed of rock; liquid water may even exist on it.
7. Proxima Cen b
Surprisingly, life may exist on the surface of one of the planets closest to us. The distance to Beta Proxima Centauri, which revolves around a small red dwarf, is 4.2 light years. However, despite such a small distance, little is known about it. It weighs slightly more than Earth, and makes a full revolution around its star in just 11 days.
Such closeness to the star has its downsides – most likely, the planet is always facing Proxima Centauri with only one side. So life, if it exists there, exists on a narrow strip between eternal day and eternal night. Also, the violent radiation flares with which the aging but still active star occasionally bombards the planet's surface do not add to optimism.
6. GJ 667 C f
In sixth place in the selection of planets that are theoretically suitable for life is the sixth planet of the smallest star in the three-sun system Gliese. It is probably one of the largest planets in the rating - three Earths could be "molded" from its mass!
And although GJ 667 C f receives 60% less starlight than Earth, it compensates for this with an increased influx of infrared rays. How favorable this is for the development of life is an open question.
5. Trappist-1 e
A lonely red dwarf in the constellation Aquarius has proven to be surprisingly generous with planets. To date, scientists have discovered as many as 7 planets that are strikingly similar in size to our Earth. And three of them are even potentially in the "habitable" zone!
By the way, it was not the Kepler telescope that discovered these planets, but its older brother, the Spitzer infrared telescope.
Scientists believe that the planet E Trappista-1 has a very high chance of having not only water, but even an entire ocean. In general, this planet is strikingly similar to Earth: in mass, radius, density, gravity and surface temperature. And it is not located very far away - about 40 light years from Earth.
However, according to the latest research, the chances for life to emerge on Trappist-1 version E are too exaggerated. It is located in the danger zone - there is too much carbon monoxide in the atmosphere for life of the Earth type to exist.
And other scientists, on the contrary, believe that the presence of traces of carbon monoxide in the atmosphere is an indicator of the presence of this very life. So you don't know who to believe.
4. Trappist-1 d
This is a small planet, the mass of which barely reaches two-thirds of the Earth. It is the smallest in the planetary system Trappist-1, but despite its size, about 5% of its mass is unstable. This means that it may have an atmosphere, oceans and even ice caps. However, according to the latest research, the atmosphere of version D may be more like that of Venus - dense and very hot.
3. GJ 3323 b
GJ 3323 b is located in the constellation Eridanus, 17.5 light years from Earth. It was discovered just two years ago, and very little is known about it, except that it is located in the habitable zone and is a "super-Earth." Its mass is twice that of our planet.
2. K2-72 e
This Earth-like, rocky planet is located in the constellation Goldilocks. Like many of the other planets on this list, it orbits an unnamed, aging red star. This is no surprise, since most stars in our universe are red dwarfs; they are the longest-lived of all.
The star K2-72 e will shine for many years after our Sun has gone dark. Although the planet is located in the habitable zone, it most likely only faces its star forever (like our Moon faces Earth). So life, if it exists, evolved on a small island between light and darkness.
1. Teegarden b
Probably the most habitable planet, Teegarden b, was discovered quite recently – in early 2019. There are two planets orbiting the star Teegarden in the constellation Aries, where conditions are similar to those on Earth. And it is located only 12 light years from the Sun.
Like other Earth-like planets that could potentially support life, it is in the “habitable zone” — not too far, not too close to its star. And of the 10 planets in our ranking, Teegarden b appears to be the most similar to our Earth, in terms of mass, density, and even possible surface temperature.
The only thing that is worrisome is the violent and furious radiation flares that red dwarfs emit from time to time. Powerful streams of radioactive particles are capable of destroying any life in their path.
How do scientists determine whether a planet can support life or not?
Our knowledge of the Universe is limited by the experience accumulated by humanity in the process of evolution. So scientists, determining whether life is possible on a particular planet, first of all focus on the planet Earth, which is well known to us. In their opinion, life is capable of originating on a planet if it meets the following criteria.
- Comfort zone.
The planet should not be very close or very far from its star. And, roughly speaking, it should not be too hot or too cold. - Point of support.
The planet must have a solid surface. A giant gas soup like Jupiter or Uranus is supposed to be a bad place for life to live. - Size matters.
The planet must be large enough to form a hot core. It is the core that creates the magnetic field around the planet, protecting its surface from harmful solar radiation. - Dense layer of the atmosphere.
Its thickness must be just enough to protect fragile living organisms from both radiation and foreign objects, and also to give them something to breathe. - Tiny inhabitants.
It is worth adding that possible life will most likely be microbial. Judging by the fact that the first microorganisms appeared on our planet about 4.25 billion years ago (and the planet itself arose about 4.54 billion years ago), the chances of populating the Universe with “living dust” are quite high. But whether it is capable of turning into something more is a completely different question.
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