Our Home's 13 Distant Cousins: Earth-Like Planets
- Mar 22
- 6 min read
Our search for extraterrestrial life is accelerating every day, and our questions multiply with each discovery of a planet in the habitable zone. So, how many Earth-like planets have been discovered so far? As Galaxy Explorer, I have compiled a list of planets similar to Earth for you:
Now let's get to why these planets have the potential to support life. Fasten your seatbelts, because we’re about to look far beyond Earth, perhaps toward the new worlds where we might one day begin to live!
The 13 Most Well-Known Earth-Like Planets
Kepler-22b
Kepler-22b is the first planet that comes to mind for anyone familiar with Earth-like planets. This planet is a super-Earth, 2.4 times the size of Earth. Its structure is still unknown, so its atmosphere and internal composition remain uncertain. However, based on its distance from its star, it is believed to be in the habitable zone and capable of hosting liquid water. It was discovered using the Kepler space telescope.
Discovery Date: 5 December 2011
Diameter: 30,581 km
Distance from Earth: 600 light years
Orbital Period: 290 days
Surface Temperature: 22°C
Kepler-62f
Kepler-62f, larger than Earth but smaller than Neptune and Uranus, is one of the planets in the habitable zone of the Kepler-62 star system. About 40% larger than Earth, it is believed to be either a terrestrial or an ocean planet. It was discovered using the Kepler space telescope.
In 2016, researchers at the University of California, Los Angeles, conducted various tests assuming Kepler-62f has an atmosphere similar in thickness to Earth's and reported that the planet could be habitable. Studies published in 2018 also suggest that Kepler-62f could have a climate similar to Earth’s.
Discovery Date: 18 April 2013
Diameter: 17,966 km
Distance from Earth: 1,200 light years
Orbital Period: 267 days
Surface Temperature: 11-17°C
Kepler-62e
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Kepler-62e, another member of the Kepler-62 star system, is a super-Earth about 60% larger than Earth. Due to the excess radiation it receives from its star, it is thought to experience a runaway greenhouse effect, making it very hot; however, this remains a hypothesis. Its composition is also not fully known—it could be a terrestrial or an ocean planet. It was discovered using the Kepler space telescope.
Discovery Date: 18 April 2013
Diameter: 20,515 km
Distance from Earth: 1,200 light years
Orbital Period: 122 days
Surface Temperature: Estimated 77°C
Kepler-186f
Kepler-186f, nearly the same size as Earth, orbits at the outer edge of the habitable zone of a red dwarf star located 500 light-years away from us. Its surface temperature and composition are not precisely known. However, its position in the habitable zone suggests that it may have a thick atmosphere containing enough carbon dioxide to produce liquid water. Therefore, if the surface temperature is close to 0°C, there is a possibility that life could exist on Kepler-186f.
Discovery Date: 17 April 2014
Diameter: 14,908 km
Distance from Earth: 500 light years
Orbital Period: 130 days
Surface Temperature: Unknown
Kepler 283c
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Kepler-283c, with a mass 3.97 times that of Earth, orbits within the habitable zone of its star. Although most of the planet’s parameters are unknown, its orbit suggests that it could contain liquid water. It was discovered using the Kepler space telescope.
Discovery Date: 2014
Diameter: 11,595 km
Distance from Earth: 1,527 light years
Orbital Period: 92.7 days
Surface Temperature: Unknown
Kepler-442b
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Kepler-442b, three years after its discovery, was considered the most habitable exoplanet as of July 2018, without being tidally locked. One of the main reasons is its distance from its star and its orbital parameters, which are similar to Earth's. While its atmospheric composition and the presence of liquid water on its surface are still unknown, a study published in 2015 claimed that Kepler-442b, along with two other exoplanets, is among the most habitable exoplanets in the universe.
Discovery Date: 6 January 2015
Diameter: 17,074 km
Distance from Earth: 1,100 light years
Orbital Period: 112 days
Surface Temperature: Unknown
Kepler-452b
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It is not yet known whether Kepler-452b is a terrestrial planet, but based on its size, it is thought to have a rocky composition. Its star has characteristics very similar to our Sun, and the planet orbits within the star’s habitable zone. However, because its star is in an evolutionary phase, Kepler-452b receives about 10% more energy than Earth, suggesting it could experience a runaway greenhouse effect similar to Venus. Nevertheless, since it is about 50% larger than Earth, it is believed that the effects of greenhouse gases are delayed by roughly 500 million years, allowing it to potentially retain its oceans.
Discovery Date: 23 July 2015
Diameter: 19,113 km
Distance from Earth: 1,400 light years
Orbital Period: 385 days
Surface Temperature: Estimated either -20 or 10°C
Kepler-1649c
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Kepler-1649c, located in the system of the dwarf star Kepler-1649, is estimated to be a terrestrial planet. Little is known about this Earth-like planet orbiting within its star’s habitable zone. Since we have no information about its atmosphere or climate, it is unknown whether it has liquid water on its surface. Additionally, because its star is thought to experience frequent stellar flares, it is also speculated that the planet may lack a substantial atmosphere.
Discovery Date: 15 April 2020
Diameter: 12,744 km
Distance from Earth: 301 light years
Orbital Period: 19.53 days
Surface Temperature: Unknown
Proxima Centauri b
Proxima Centauri b, orbiting the red dwarf Proxima Centauri—the closest star to the Solar System—is also known as the nearest Earth-like planet to us. Compared to Earth, the exoplanet receives about two-thirds of the energy from its star. There are two scenarios regarding its atmosphere: the first involves water on the planet condensing and hydrogen escaping into space, leaving oxygen and/or carbon dioxide in the atmosphere; the second suggests that the planet retains a primitive hydrogen atmosphere or formed farther from its star, preventing the loss of water.
Although the initial amount of water on Proxima Centauri b is unknown, calculations suggest that during the first 100–200 million years after the planet’s formation, it may have lost the equivalent of about one ocean due to early stellar radiation. What happened after this period is less clear. The planet may have continued to lose significant amounts of atmospheric gas, becoming a dry, airless world, or it could have retained most of its atmosphere, preserving surface liquid water and potentially reaching a state capable of supporting life.
Discovery Date: 24 August 2016
Diameter: 13,124 km
Distance from Earth: 4.2 light years
Orbital Period: 11 days
Surface Temperature: Unknown
TRAPPIST-1f
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TRAPPIST-1f is known to be within or just outside the habitable zone. Observations suggest the presence of liquid water. Additionally, simulations indicate that this Earth-like planet is composed of about 20% water, significantly more than Earth. However, the exoplanet is tidally locked: one side always faces its star while the other remains in darkness. Liquid water is most likely to exist in the area between these two extreme zones, which we call the “terminator” or “twilight zone.”
Discovery Date: 22 December 2017
Diameter: 13,315 km
Distance from Earth: 40.7 light years
Orbital Period: 9.2 days
Surface Temperature: Unknown
TRAPPIST-1e
TRAPPIST-1f is part of the same star system as TRAPPIST-1, orbiting within the habitable zone on an inner orbit. This exoplanet has been confirmed to be terrestrial and is cool enough for liquid water to accumulate on its surface. According to models from the University of Washington, its atmosphere is not dense or thick enough to be harmful to life.
Discovery Date: 22 February 2017
Diameter: 11,595 km
Distance from Earth: 40.7 light years
Orbital Period: 6.1 days
Surface Temperature: Unknown
Gliese 581d
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When Gliese 581d was first discovered, it was thought to be outside the habitable zone of its star. However, in 2009, recalculations of its orbit and simulations conducted by French researchers in 2011 showed that the planet could have temperatures and sufficient atmospheric pressure to allow liquid water on its surface.
On the other hand, Gliese 581d receives about 30% of the light from its star compared to Earth, which suggests that the planet could be too cold to support liquid water. However, if the planet’s atmosphere produces enough greenhouse effect, this would not be an issue, as the greenhouse effect directly impacts surface temperature and, unless excessive, can create conditions suitable for life.
Discovery Date: 24 April 2007
Diameter: 28,032 km
Distance from Earth: 20.4 light years
Orbital Period: 67 days
Surface Temperature: Unknown
Gliese 667 Cc
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In the early days after its discovery, Gliese 667 Cc was thought to be a potentially habitable planet. Being tidally locked, it was believed that if liquid water existed along its “terminator” or twilight zone and the atmosphere was sufficiently thick, large areas of the planet could support life. However, a 2013 study found that this exoplanet experiences tidal heating 300 times greater than Earth. Tidal heating is the heat generated as a planet orbits its star and rotates, which spreads across the surface and is especially intense for bodies in elliptical orbits. On Gliese 667 Cc, this extreme tidal heating reduces its likelihood of being a habitable planet.
Discovery Date: 2011
Diameter: 19,622 km
Distance from Earth: 22 light years
Orbital Period: 28 days
Surface Temperature: Estimated 5°C
