Potential Second Earth refers to those planets that share key characteristics with our own planet Earth also called the most Earth-like planets or another Earth planets. This includes a size similar to Earth, hinting at a rocky composition with a possible solid surface and atmosphere.
They reside within their star‘s habitable zone, the region where temperatures could allow liquid water, a vital ingredient for life as we know it, to exist. Ideally, it would contain elements like oxygen, carbon, and nitrogen, which are necessary for life and potentially point towards a rich and diverse atmosphere.
Scientists are constantly searching for these “second Earths,” hoping to find the right combination of size, location, atmosphere, and elements to support life beyond our own planet Earth.
Kepler-1649c (Potential Second Earth):
Kepler-1649c is an Earth-sized exoplanet, likely rocky, orbiting within the habitable zone of its star Kepler-1649. Kepler-1649c is a potential second earth.
Kepler-1649c’s Location & Distance from Earth:
Kepler-1649c resides in the constellation Cygnus, roughly 301 light-years away from Earth. That’s a staggering distance. One light-year is the distance light travels in one year, which is about 9.5 trillion kilometers.
Kepler-1649c’s Size:
Kepler-1649c is very Earth-like in size. Its radius is only about 1.02 times that of Earth, and its mass is estimated to be 1.2 times greater. This suggests it’s likely a rocky planet, similar to Earth and Venus in our solar system.
Kepler-1649c’s Habitable Zone:
An exciting aspect of Kepler-1649c is its location within the habitable zone of its star, Kepler-1649. Its star Kepler-1649’s radius is estimated to be roughly ¼ the radius of the Sun, It also has a lower mass compared to our Sun, coming in at around 0.198 times the Sun’s mass.
The habitable zone is the area around a star where liquid water could potentially exist on a planet’s surface. Kepler-1649c orbits its star at an incredibly close distance of only 0.0649 AU (Astronomical Units), its star is a red dwarf, which is fainter than our Sun. As a result, Kepler-1649c receives about three-quarters of the radiation Earth does from the Sun.
Kepler-1649c’s Tidal Locking:
A potential drawback is that due to its close proximity to its star, Kepler-1649c is likely tidally locked. This means one side of the planet always faces the star (dayside) and the other side is in perpetual darkness (night side). The day side would likely be scorching hot, while the night side would be very cold.
However, some scientists believe there could be a habitable zone between the two extremes, a region with temperatures that might allow liquid water to exist. Kepler-1649c takes only 19.5 Earth days to orbit its star, Kepler-1649. This is significantly faster than Earth’s orbital period of 365.25 days (or 1 year).
Kepler-1649c’s Composition:
Likely Rocky: Since Kepler-1649c is similar in size to Earth, scientists believe it’s likely a rocky planet, similar to Earth and Venus in our solar system. This means it’s probably composed mostly of heavier elements like oxygen, silicon, iron, and magnesium.
Uncertainty about Volatiles: The presence of lighter elements like hydrogen, carbon, and nitrogen, which are crucial for potential life as we know it, is unknown. These elements are often called “volatiles” because they can easily escape a planet’s gravity, especially at high temperatures.
Kepler-1649c’s Structure:
Possible Core-Mantle-Crust Structure: Given its rocky composition, Kepler-1649c might have a differentiated internal structure similar to Earth, with a denser core, a surrounding mantle, and a thinner crust.
Uncertain Mantle Composition: The specific composition of the mantle, whether it’s more like Earth’s solid mantle or the molten mantle of Venus, is unknown.
Kepler-1649c’s Atmosphere:
A major unknown is the composition of Kepler-1649c’s atmosphere. The atmosphere plays a crucial role in regulating a planet’s temperature and the potential for life. Without knowing its makeup, it’s difficult to say for sure if the surface could support life.
When and Who Discovered Kepler-1649c’s:
The first scientific description of Kepler-1649c was published in April 2020 in The Astrophysical Journal Letters. The lead author of the research paper is Andrew Vanderburg. It’s likely he led a team of researchers who analyzed data from NASA’s Kepler Space Telescope.
Kepler-1649c (Potential Second Earth) as compared to Earth:
Kepler-1649c Vs. Earth
| Feature | Kepler-1649c (Potential Second Earth) | Earth |
|---|---|---|
| Size (Radius) | 1.06 Earth Radii | 1 Earth Radius |
| Mass | ~1.2 Earth Masses (estimated) | 1 Earth Mass |
| Density | 5.54 g/cm³ (estimated) | 5.51 g/cm³ |
| Distance from Star | 0.0649 AU | 1 AU |
| Star Type | Red Dwarf | Sun (Yellow Dwarf) |
| Habitable Zone | Yes | Yes |
| Temperature (Teq) | 234 K (-39 °C, -38 °F) (estimated) | 288 K (15 °C, 59 °F) |
| Atmosphere | Unknown | Nitrogen-Oxygen rich |
| Tidal Locking | Likely | No |
Kepler-186f (Potential Second Earth):
Kepler-186f is an Earth-sized exoplanet orbiting within the habitable zone of its star, Kepler-186. Kepler-186f is a potential second earth.
Kepler-186f’s Location & Distance from Earth:
Kepler-186f is located about 580 light-years away in the constellation Cygnus. That’s a vast distance, making travel there with current technology nearly impossible.
Kepler-186f’s Size:
Kepler-186f is very Earth-like in size. Its radius is only about 1.1 times that of Earth, suggesting a rocky composition similar to our planet.
Kepler-186f’s Habitable Zone:
An exciting aspect of Kepler-186f is its location within the habitable zone of its star, Kepler-186. Its star Kepler-186’s radius is estimated to be roughly 0.52 times the radius of the Sun. Our Sun’s radius is about 695,500 kilometers, so Kepler-186’s radius would be around 360,000 kilometers.
Kepler-186’s mass is estimated to be around 0.54 times the Sun’s mass. In other words, it’s about half as massive as our Sun. Kepler-186f orbits its star at a distance of about 0.43 AU (Astronomical Units). This sweet spot allows liquid water to potentially exist on the surface.
Kepler-186f’s Tidal Locking:
There’s a possibility Kepler-186f is tidally locked, meaning one side always faces the star and the other is in perpetual darkness. However, some scientists believe a habitable zone might exist between the extremes, where temperatures could support liquid water. Astronomers estimate Kepler-186f’s orbital period to be somewhere between 13 and 90 days.
Kepler-186f’s Composition:
Likely Rocky: Since Kepler-186f is similar in size to Earth (roughly 1.1 times the radius), scientists believe it’s likely a rocky planet, similar to Earth and Venus in our solar system. This suggests it’s probably composed mostly of heavier elements like oxygen, silicon, iron, and magnesium.
Uncertainty about Volatiles: The presence of lighter elements like hydrogen, carbon, and nitrogen, crucial for potential life as we know it, is unknown. These elements are often called “volatiles” because they can easily escape a planet’s gravity, especially at high temperatures.
Kepler-186f’s Structure:
Possible Core-Mantle-Crust Structure: Given its likely rocky composition, Kepler-186f might have a differentiated internal structure similar to Earth, with a denser core, a surrounding mantle, and a thinner crust.
Uncertain Mantle Composition: The specific composition of the mantle, whether it’s more like Earth’s solid mantle or the molten mantle of Venus, is unknown.
Kepler-186f’s Atmosphere:
The existence and composition of an atmosphere on Kepler-186f are mysteries. An atmosphere is crucial for temperature regulation and potentially life support, but its characteristics are unknown.
When and Who Discovered Kepler-186f:
Kepler-186f was discovered in 2014 by a team analyzing data from NASA’s Kepler Space Telescope. The lead author was Andrew Vanderburg.
Kepler-186f (Potential Second Earth) as compared to Earth:
Kepler-186f Vs. Earth
| Feature | Kepler-186f (Potential Second Earth) | Earth |
|---|---|---|
| Size (Radius) | 1.11 Earth Radii | 1 Earth Radius |
| Mass | Unknown (likely more massive) | 1 Earth Mass |
| Density | Unknown | 5.51 g/cm³ |
| Distance from Star | 0.40 AU | 1 AU |
| Star Type | Red Dwarf | Sun (Yellow Dwarf) |
| Habitable Zone | Yes (outer edge) | Yes |
| Temperature (Teq) | Estimated to be similar to Earth | 288 K (15 °C, 59 °F) |
| Atmosphere | Unknown, but presence of CO2 could regulate temperature | Nitrogen-Oxygen rich |
| Tidal Locking | Unknown, possibility exists | No |
Kepler-452b (Potential Second Earth):
Kepler-452b is a super-Earth exoplanet orbiting within the habitable zone of its star, Kepler-452. Kepler-452b is a potential second earth.
Kepler-452b’s Location & Distance from Earth:
Kepler-452b is located about 1,400 light-years away in the constellation Cygnus. This vast distance makes traveling there with current technology nearly impossible.
Kepler-452b’s Size:
Kepler-452b was one of the first discovered to be within the habitable zone of a sun-like star. It’s larger than Earth, classified as a “super-Earth” with a radius estimated to be about 1.8 times that of Earth. This suggests a rocky composition, similar to our planet.
Kepler-452b’s Habitable Zone:
An exciting aspect of Kepler-452b is its location within the habitable zone of its star, Kepler-452. This zone is the region around a star where temperatures could potentially allow liquid water to exist on the surface, a key ingredient for life as we know it. Its star Kepler-452’s radius is estimated to be slightly larger than our Sun.
It’s about 1.1 times the radius of the Sun. The mass of Kepler-452 is also a bit higher compared to our Sun. Estimates suggest it’s around 1.03 times the Sun’s mass. The orbital distance of Kepler-452b is estimated to be 1.04 AU (Astronomical Units).
Kepler-452b’s Tidal Locking:
The possibility of Kepler-452b being tidally locked is not yet confirmed. However, it’s a possibility for planets close to their stars. If tidally locked, one side would always face the star (dayside) and the other would be in perpetual darkness (night side). Astronomers estimate Kepler-452b’s orbital period to be around 385 days.
Kepler-452b’s Composition:
Likely Rocky: Given its size, estimated to be 1.8 times Earth’s radius, Kepler-452b is likely a rocky planet similar to Earth and Venus in our solar system. This suggests it’s probably composed mostly of heavier elements like oxygen, silicon, iron, and magnesium.
Uncertainty about Volatiles: The presence of lighter elements like hydrogen, carbon, and nitrogen, crucial for potential life as we know it, is unknown. These elements are often called “volatiles” because they can easily escape a planet’s gravity, especially at high temperatures.
Whether Kepler-452b has enough volatiles to support a significant atmosphere or life as we know it remains a mystery.
Kepler-452b’s Structure:
Possible Core-Mantle-Crust Structure: Given its likely rocky composition, Kepler-452b might have a differentiated internal structure similar to Earth, with a denser core, a surrounding mantle, and a thinner crust.
Uncertain Mantle Composition: The specific composition of the mantle, whether it’s more like Earth’s solid mantle or the molten mantle of Venus, is unknown.
Kepler-452b’s Atmosphere:
The existence and composition of an atmosphere on Kepler-452b are mysteries. An atmosphere is crucial for temperature regulation and potentially life support, but its characteristics are unknown.
When and Who Discovered Kepler-452b:
Kepler-452b was discovered in 2015 by NASA’s Kepler Space Telescope. The discovery was a significant milestone in the search for exoplanets and sparked excitement due to its size and location within the habitable zone.
Kepler-452b (Potential Second Earth) as compared to Earth:
Kepler-452b Vs. Earth
| Feature | Kepler-452b (Potential Second Earth) | Earth |
|---|---|---|
| Size (Radius) | 1.63 Earth Radii | 1 Earth Radius |
| Mass | 5 times Earth Mass (estimated) | 1 Earth Mass |
| Density | Likely lower than Earth (estimated) | 5.51 g/cm³ |
| Distance from Star | 1.04 AU | 1 AU |
| Star Type | Sun-like (G2) | Sun (Yellow Dwarf) |
| Habitable Zone | Yes | Yes |
| Temperature (Teq) | No direct measurement, modelling suggests potentially habitable | 288 K (15 °C, 59 °F) |
| Atmosphere | Unknown | Nitrogen-Oxygen rich |
| Tidal Locking | Unknown, possibility exists | No |
TOI-700 e (Potential Second Earth):
TOI-700 e is a recently discovered Earth-sized exoplanet orbiting within the habitable zone of its star, TOI-700. TOI-700 e is a potential second earth.
TOI-700 e’s Location & Distance from Earth:
TOI-700 e is located in the constellation Dorado, roughly 101.4 light-years away from Earth. Traveling such a vast distance with current technology is beyond our capabilities.
TOI-700 e’s Size:
TOI-700 e is exciting because it’s similar in size to Earth. Its radius is estimated to be about 0.95 times that of Earth, suggesting a rocky composition.
TOI-700 e’s Habitable Zone:
TOI-700 e resides within the habitable zone of its star, TOI-700. This is the region where temperatures could potentially allow liquid water to exist on the surface, a key ingredient for life as we know it. Its star TOI-700’s radius is estimated to be about 0.4 times the radius of the Sun. This means it’s a much smaller star, cooler and fainter.
The mass of TOI-700 is also significantly lower compared to our Sun. It’s estimated to be around 0.4 times the Sun’s mass. TOI-700 e is quite close to its star, orbiting at a distance of only 0.0134 AU (Astronomical Units). While this seems close, remember that 1 AU is the average distance between Earth and the Sun. So, TOI-700 e is much closer to its star than Earth is to our Sun.
TOI-700 e’s Tidal Locking:
TOI-700 e is likely tidally locked to its star. This means one side of the planet always faces the star (dayside) and the other side is in perpetual darkness (night side). Some scientists believe there could be a habitable zone between the extremes, where temperatures might support liquid water. It takes an estimated 27.8 days to complete one orbit.
TOI-700 e’s Composition:
Likely Rocky: Since TOI-700 e is similar in size to Earth (roughly 0.95 times the radius), scientists believe it’s likely a rocky planet, similar to Earth and Venus in our solar system. This suggests it’s probably composed mostly of heavier elements like oxygen, silicon, iron, and magnesium.
Uncertainty about Volatiles: The presence of lighter elements like hydrogen, carbon, and nitrogen, crucial for potential life as we know it, is unknown. These elements are often called “volatiles” because they can easily escape a planet’s gravity, especially at high temperatures. Whether TOI-700 e has enough volatiles to support a significant atmosphere or life as we know it remains a mystery.
TOI-700 e’s Structure:
Possible Core-Mantle-Crust Structure: Given its likely rocky composition, TOI-700 e might have a differentiated internal structure similar to Earth, with a denser core, a surrounding mantle, and a thinner crust.
Uncertain Mantle Composition: The specific composition of the mantle, whether it’s more like Earth’s solid mantle or the molten mantle of Venus, is unknown.
TOI-700 e’s Atmosphere:
The existence and composition of an atmosphere on TOI-700 e are mysteries. An atmosphere is crucial for temperature regulation and potentially life support, but its characteristics are unknown.
When and Who Discovered TOI-700 e:
Astronomers discovered four planets in this system orbiting the star TOI-700, called TOI 700 b, TOI 700c, TOI 700 d, and TOI-700 e. TOI-700 e was a recent discovery, announced in January 2023. The team responsible for its identification likely belongs to the NASA research group studying data from the Transiting Exoplanet Survey Satellite (TESS).
TOI-700 e (Potential Second Earth) as compared to Earth:
TOI-700 e Vs. Earth
| Feature | TOI-700 e (Potential Second Earth) | Earth |
|---|---|---|
| Size (Radius) | 0.95 Earth Radii | 1 Earth Radius |
| Mass | 0.818 Earth Masses | 1 Earth Mass |
| Density | Likely similar to Earth (estimated) | 5.51 g/cm³ |
| Distance from Star | 0.0134 AU | 1 AU |
| Star Type | M-dwarf | Sun (Yellow Dwarf) |
| Habitable Zone | Yes | Yes |
| Temperature (Teq) | No direct measurement, modelling suggests potentially habitable | 288 K (15 °C, 59 °F) |
| Atmosphere | Unknown | Nitrogen-Oxygen rich |
| Tidal Locking | Possible | No |
TOI-715 b (Potential Second Earth):
TOI-715 b is a recently discovered (2023) super-Earth-sized exoplanet orbiting within the habitable zone of its star, TOI-715. TOI-715 b is a potential second earth.
TOI-715 b’s Location & Distance from Earth:
TOI-715 b is a super-Earth exoplanet located in the constellation Pictor, roughly 137 light-years away from Earth. Traveling such a vast distance with current technology is far beyond our capabilities.
TOI-715 b’s Size:
TOI-715 b is larger than Earth, classified as a super-Earth. Its radius is estimated to be about 1.5 times that of Earth. This suggests a rocky composition, similar to Earth and Venus.
TOI-715 b’s Habitable Zone:
An exciting aspect of TOI-715 b is its location within the habitable zone of its star, TOI-715. This zone is the region around a star where temperatures could potentially allow liquid water to exist on the surface, a key ingredient for life as we know it. Its star TOI-715’s radius is estimated to be significantly smaller than our Sun.
It’s likely around 0.3 times the radius of the Sun. This means it’s a much smaller and cooler star. The mass of TOI-715 is also considerably lower compared to our Sun. Estimates suggest it’s about 0.4 times the Sun’s mass. TOI-715 b is quite close to its star, orbiting at a distance of only 0.083 AU (Astronomical Units).
TOI-715 b’s Tidal Locking:
The possibility of TOI-715 b being tidally locked is not confirmed yet. However, it’s a possibility for planets close to their stars. If tidally locked, one side would always face the star (dayside) and the other would be in perpetual darkness (night side). Astronomers estimate TOI-715 b’s orbital period to be somewhere around 10 days.
TOI-715 b’s Composition:
Likely Rocky: Given its size, estimated to be 1.5 times Earth’s radius, TOI-715 b is likely a rocky planet similar to Earth and Venus in our solar system. This suggests it’s probably composed mostly of heavier elements like oxygen, silicon, iron, and magnesium.
Uncertainty about Volatiles: The presence of lighter elements like hydrogen, carbon, and nitrogen, crucial for potential life as we know it, is unknown.
These elements are often called “volatiles” because they can easily escape a planet’s gravity, especially at high temperatures. Whether TOI-715 b has enough volatiles to support a significant atmosphere or life as we know it remains a mystery.
TOI-715 b’s Structure:
Possible Core-Mantle-Crust Structure: Given its likely rocky composition, TOI-715 b might have a differentiated internal structure similar to Earth, with a denser core, a surrounding mantle, and a thinner crust.
Uncertain Mantle Composition: The specific composition of the mantle, whether it’s more like Earth’s solid mantle or the molten mantle of Venus, is unknown.
TOI-715 b’s Atmosphere:
The existence and composition of an atmosphere on TOI-715 b are mysteries. An atmosphere is crucial for temperature regulation and potentially life support, but its characteristics are unknown.
When and Who Discovered TOI-715 b:
TOI-715 b was a recent discovery, announced in January 2024 by a team of researchers likely affiliated with NASA. The discovery was based on data from the Transiting Exoplanet Survey Satellite (TESS).
TOI-715 b (Potential Second Earth) as compared to Earth:
TOI-715 b Vs. Earth
| Feature | TOI-715 b (Potential Second Earth) | Earth |
|---|---|---|
| Size (Radius) | 1.55 Earth Radii | 1 Earth Radius |
| Mass | ~3.02 Earth Masses (estimated) | 1 Earth Mass |
| Density | Unknown (potentially lower than Earth) | 5.51 g/cm³ |
| Distance from Star | 0.083 AU | 1 AU |
| Star Type | M-dwarf | Sun (Yellow Dwarf) |
| Habitable Zone | Yes | Yes |
| Temperature (Teq) | No direct measurement, potentially similar to Earth | 288 K (15 °C, 59 °F) |
| Atmosphere | Unknown | Nitrogen-Oxygen rich |
| Tidal Locking | Unknown, possibility exists | No |
Other Potential Second Earth Planets:
Apart from these planets, Mars in our solar system is a potential candidate for Second Earth. Exoplanets like Proxima Centauri b, GJ 273b, Tau Ceti e, K2-18b, Kepler-438b, Kepler-442b, Kepler-22b, Kepler-69c, and Kepler-62f are potential candidates for Second Earth.
Conclusion:
The search for a second Earth is a work in progress, but with ongoing discoveries and advancements in telescopes and space exploration technology, we’re getting closer to finding another world that could support life.
The search for a second Earth is a thrilling exploration of our place in the universe. While we haven’t found a perfect match yet, the ongoing discoveries unveil a diverse and captivating collection of exoplanets, keeping the possibility of life elsewhere very much alive.