The bromide “truth is stranger than fiction” is immortal now, and for science fiction fans, it might seem validated by internet lists of the strangest real planets observable in space. While unusual geographic conditions abound in those real worlds, no truly novel alien biology has yet to be discovered, let alone the thought-provoking and novel civilizations that science fiction authors have imagined. Fictional worlds also have the potential advantage of serving as easily communicated metaphors. So let’s go explore these worlds and the messages they have for us to contemplate.

Related: 10 Lesser-Known Sci-Fi Movies That Are Worth Your Time

10 Riverworld

Philip Jose Farmer wrote the novel that would be the origin of Riverworld in 1952, but the publisher went bankrupt before it could be released. By 1971, he had honed his craft sufficiently to rework the story into To Your Scattered Bodies Go and, in the process, win his third and final Hugo Award, the science fiction equivalent of the Best Picture winner for the Academy of Motion Picture Arts and Sciences.

To Your Scattered Bodies Go and its three sequels are the story of all 10 billion humans who have lived and died waking up on a new planet. It’s implied this happened because real-world adventurer/protagonist Richard Francis Burton interfered with the stasis condition of regenerating human bodies prior to reanimation, where they revolved around immense energized electric rods while floating in a vacuum. Conditions on Riverworld could pass for heaven, considering everyone is about 20 years old and naked while being dispensed all the food and other sustenance they could ever need through mysterious restocking holes in the ground. Plus, whenever someone dies, they reanimate nearby.

The main geographic feature of the new planet is an enormously long and wide river, which a determined Burton intends to explore to find out why humanity is in this fantastic, totally alien environment. Complicating things is the lack of metal ore, especially for such historical figures as Samuel Clemens, who, in the second novel, intends to build a river boat to explore the river. It’s an extremely dense, indulgent, yet oddly addictive series that has problematically lingered in the imagination of the science fantasy community to the extent that the Syfy Channel produced pilots for it in 2003 and 2010.^[1]

9 Flanimal World

Fresh from concluding the global phenomenon The Office for BBC 2 in 2004, Ricky Gervais and illustrator/stand-up comedian Rob Steen published a children’s wildlife book parody called Flanimals. The series would ultimately stretch four entries and begin production for a feature film adaptation by Illumination in 2009. About the most that ever came of this were clips for the ITV production.

The unifying theme of Flanimals is absurdist, maladaptive biological traits for creatures with a planet of their own that somehow came into being and thrived sufficiently to be documented and given Latin names. Many are senselessly violent (Grundits), with others practically helpless (Coddleflops and Puddloflajs, often victims of the Grundits).

A typical example is the Plamglotis, which has no legs, so it swallows its hands and arms so they can function as legs. However, because its mouth is now full, it cannot eat, which was the whole point of swallowing its arms in the first place. It’s a humorous metaphor for how Gervais claims the existential perspective of the books is that life is pointless. Always a good message for the children.^[2]

8 Lithia

In 1959, James Blish’s Hugo-winning novel A Case of Conscience posed a question that was extremely daring for Western readers at the time: What if humanity found an alien civilization living the ideal conception of a religious society, except that their views were purely secular? No belief in a higher power, afterlife, or concept of sin, and with it came notions such as karma. Furthermore, the Lithians are not simian, birdlike, or similar to a species humans generally associate with elegance or transcendence; instead, they are reptilian.

When Jesuit priest/world-class biologist and protagonist Ruiz-Sanchez brings the egg of one back to Earth, it hatches into Egtverchi, a Lithian who is innately disgusted by human civilization yet savvy enough with human psychology to instigate riots. Complicating the moral dilemma for Ruiz-Sanchez is that due to Lithia’s mineral richness, his colleagues are eager to invade Lithia for resource extraction, as its peaceful nature leaves it ripe for invasion.

Having set up such an intriguing, morally loaded premise for his story, Blish settles on a conclusion that probably wouldn’t make it past the editorial process today. Ruiz-Sanchez concludes that Lithia, the peaceful, kind, but nonreligious planet, must have been created by Satan to trick Earth’s religious adherents and resolves to perform a planet-wide exorcism on it.

It’s left ambiguous whether his ritual destroys Lithia in a bewildering validation of his religion or if reckless mining practices do. The only way this is a morally defensible conclusion, as reviewer Alex Howe noted, is to reconsider that the Lithians are too perfect to have emerged naturally and thus can only ever exist as an imagined ideal that should be put out of the reader’s mind, for which the exorcism ritual is also a metaphor.^[3]

7 Aura

One of the beauties of science fiction is how more intellectual, prestigious work sits right alongside the most lowbrow work in terms of influence and imagination. So it is that Mario Bava’s 1965 film Planet of the Vampires, a movie with as inauspicious a title as any film could be given. Bava himself poked fun at the cheapness of the production, saying the planet was made with “two plastic rocks” and that his method of obscuring that was “I filled the set with smoke.”

Yet the movie achieved a lingering level of popularity where such critical darlings as Nicholas Winding Refn was quoted in Variety as saying that the Alien series, from the original 1979 film through 2012’s Prometheus, was heavily influenced by this film.

When two human-piloted ships, the Argos and the Galliot, attempt to land on the unexplored planet of Aura, they crash some distance apart. The crew of the Argos almost kill each other because they’ve been possessed by entities unknown. When their crew arrives at the wreck of the Galliot, they find that the other crew was less fortunate when they were possessed by the same entities, for all hands are dead.

After burying the corpses, the Argos crew is in for the shock of seeing the bodies reanimated, and Argos crew members are found dead for good shortly after. Stranded, the Argos crew explores the planet and finds a crashed alien planet with the skeletons of monstrous aliens, who, it turns out, were also tricked into landing on Aura so that the natives could take control of them.

Undeniably, there are certain hurdles to being taken seriously today. For example, the spacesuits the Argos crew wears with black leather and yellow accents look like cyberpunk Tron cosplayers. Nevertheless, for its time, the notion of a planet of ghosts that takes over human minds was unique among science fiction, especially among science fiction films.^[4]

6 Midworld

Alan Dean Foster is unquestionably best known for writing novelizations and story treatments for the Star Wars and Star Trek franchises since the 1970s. As far as his original work goes, in 2020, he said that the original story he’d most like to see adapted is his 1975 novel of the eponymous planet, the fourth entry in a series called Humanx Commonwealth.

Midworld is uniquely teeming with life for a science fiction planet—and also uniquely deadly. It’s essentially a planet-wide rainforest, meaning a bewildering array of predatory flora and fauna. It’s divided into three main sections named by natives in ways that reflect the danger well: The Upper Hell (sky), Canopy (treeline), and the Lower Hell (ground).

The foliage is so thick that many who live in the canopy never see the sky. To make matters worse, it’s also home to predators—called “clouders”—whose glowing undersides mimic the sky to mesmerize prey as it drifts down on them through foliage it had cleared out below. In the lower hell, there is such abundant bacteria that if a raft were dropped down there, it would dissolve within hours.

Yet perhaps the most intriguing aspect of the planet is what happened to humans that crashed on the planet centuries before the main action of the novel takes place: They evolved so that even their children have expert-level botanical knowledge to avoid the floral and animal traps that seemingly hide behind every branch of Midworld. They also have a bond from birth with small mammals called furcots that die at the same time as their human counterparts.^[5]

5 Lagash

Isaac Asimov’s 1941 classic short story “Nightfall”(reworked with Robert Silverberg into a full novel in 1990) was famously inspired by a discussion with John W. Campbell (author of Who Goes There, the story that became John Carpenter’s The Thing in 1982). The writers were discussing an opinion expressed by Ralph Waldo Emerson, regarding what would happen if humanity only saw stars once a millennium. Lagash is Asimov’s illustration of Campbell’s answer to that question.

Lagash orbits six stars, one consequence of which is that the planet is bathed in so much sunlight that nightfall only occurs every few millennia, which is known as the “long night.” Lagashians are thus innately afraid of darkness and yet enjoy the thrill of being exposed to it under controlled conditions, like an amusement park ride. So when the long night happens, spotty historical records show it always leads to an implosion of civilization. The records are spotty because madness seizes the planet.

However, a group of scientists has secured a bunker with plenty of torchlight to ride out the long night with their sanity intact. Yet when the time of crisis descends, they learn the lesson that those who think they have everything figured out often learn in the worst way.

For anyone curious, astronomer fans of the story have not been able to come up with an orbital model where darkness would be possible for a planet that orbits six suns to experience darkness every two millennia. Observatory of Bordeaux astrophysicist Sean Raymond drew up multiple orbital models. The longest interval between darkness for any of them was two months.^[6]

4 0099-4836/010-D

This is, by a wide margin, the least famous planet on this list. Indeed, the author of the 2006 short story “Gorge,” which features this planet, went by his internet alias “qntm” instead of his real name, Sam Hughes, when he commercially published this story for the collection Valuable Humans in Transit and Other Stories. And even with how dark some of the other stories in this collection are, this is easily the bleakest.

0099-4836/010-D is an anomalous planet that is so newly discovered it doesn’t even have a nickname. It has neither atmosphere nor impact craters. Indeed, its gray surface is unnatural in its perfect smoothness in geographic terms. When the Earth flagship Aspera Jaeyo begins scientific exploration, ominous problems immediately arise when the three drones dropped for exploration lose contact almost immediately, consumed by a “gray wave.”

Soon after, the gray wave comes for the fleet of ships themselves and consumes all but the fastest. It seems the gray world was not a regular sphere of rock but a vast collection of gray nanobots that had consumed the entire planet, an example of the “gray goo” scenario coined by Eric Drexler in 1986. They had been contained on the one planet only because they hadn’t learned what space travel was… until the explorers arrived.^[7]

3 Matryoshka Brains

Most of the planets on this list are purely meant for entertainment and philosophical value; they are not so concerned with scientific rigor. This entry, by contrast, was conceived with more basis in real-world science, though it may sound no less farfetched.

In 1997, Robert J. Bradbury published his proposal for planet-sized quantum computers for calculating problems beyond human, or even humanity’s, capacity. Here, “Matryoshka” refers to familiar matryoshka dolls, which nest inside each other in the same way Bradbury proposes that the processing units of planet-sized computers would need to be arranged for heat and energy distribution purposes. Extrapolating from contemporary trends and neural capacities, he forecasted that such megastructures would be viable by AD 2250.

This notion is still being studied in academic environments. However, as California Institute of Technology Professor Thomas Vidick told Vice in 2020, the interest tends to be more in working out how to fact-check the calculations of these hypothetical computers than drawing up blueprints to send to factories. Still, that means Robert Bradbury is much closer to seeing his imaginary planet become a reality than any of the other authors on this page.^[8]

2 Brethren Moons

Now it’s back to less highbrow science fiction because we’re going to be looking at the Dead Space video game series, which began in 2008. In the 25th century, mankind has achieved wide-ranging interstellar colonization, which runs into disaster when it begins encountering an ancient alien monolith called the black marker. Black markers emit an energy that brings dead tissue back to life and mutates it into hideous, violent monsters called necromorphs.

It turns out that this force is so powerful that it sends waves of reanimating power that wipe out entire planets. Furthermore, all the necromorphs on those planets will eventually form into city-sized hiveminds. From there, many form into entire rogue planet masses that are called both Blood Moons and Brethren Moons. The series has a particularly notable planetoid, but that will not be spoiled here. Belligerent zombie planets are perhaps the most over-the-top idea ever introduced in a mass-market work of science fiction and is surely the most creative answer for the notorious Fermi Paradox.^[9]

1 Solaris

To be adapted into a movie is something of an honor for any science fiction/fantasy book. Stanislaw Lem’s 1961 novel has the distinction of being adapted thrice: in 1968, 1972 and 2002. It’s not surprising because the concept of a literal living, conscious world is a captivating one, even if it’s not an evil zombie planet like one of the Brethren Moons.

What sets Lem’s premise apart most compellingly is that the planet Solaris is not just alive and capable of telepathic communication, but it’s something of a scientist. When Kris Kelvin is sent to a station orbiting the planet, Solaris sends him a simulacrum of his recently deceased wife to study his reaction. His reaction includes such violent acts as blowing the arrival from Solaris out an airlock, but Solaris merely replaces her with another, without any violent intent, like running an experiment with a replacement as a control.

It’s a singularly convincing example of science fiction making a world that’s both incomprehensibly alien yet so familiar. Life has a way of throwing us into situations where survival seems almost impossible. Yet, in those moments, both animals and humans find incredible ways to escape the clutches of death. Whether through quick thinking, clever strategies, or sheer willpower, these stories of survival are nothing short of awe-inspiring.^[10]

Our solar system is filled with a star, eight planets, some dwarf planets, and lots of comets and asteroids. A few centuries ago, people thought that more than eight planets existed out there. They erroneously labeled asteroids as planets, discovered nonexistent planets, and predicted the existence of some other planets.

Some of these predictions came true—like Neptune, which was discovered after its existence was predicted. However, many more have remained hypothetical. We believe that some of these planets could exist, while we know that others do not. Nevertheless, we should always keep our fingers crossed.

10 Vulcan

Vulcan is a hypothetical planet believed to lie between Mercury and the Sun. A few centuries ago, the planet was proposed after astronomers observed that Mercury had slightly changed its orbit with every revolution around the Sun.

In 1859, French astronomer Urbain-Jean-Joseph Le Verrier suggested that this was caused by the gravitational pull of an undiscovered planet lying between Mercury and the Sun. He called it Vulcan after the Roman god of blacksmithing. Le Verrier added that the planet could not be spotted because it was too close to the Sun.

A year later, amateur astronomer Edmond Modeste Lescarbault claimed to have spotted a small black dot near the Sun. Le Verrier said the dot was the planet Vulcan. Other astronomers later claimed to have spotted the elusive planet, although some insisted that they couldn’t see it.

Vulcan was soon considered the first planet of the solar system despite the lack of concrete evidence. This was probably because Le Verrier was an authority figure in astronomy. Thirteen years earlier, he had proposed Neptune after observing that an undiscovered planet was altering the orbit of Uranus. Besides, Vulcan’s existence was the only explanation for Mercury’s haphazard orbit.

This changed in 1915 when Albert Einstein’s Theory of General Relativity trashed every claim about the existence of Vulcan. Einstein said that massive objects like the Sun could bend time and space. Mercury’s orbit often changed because it was traveling through a “distorted space-time” caused by its closeness to the Sun.^[1]

9 Tyche

Tyche is a hypothetical planet lying somewhere in the Oort cloud at the edge of the solar system. The planet was proposed in 1999 by three astrophysicists from the University of Louisiana. The trio suggested that Tyche is the size of Jupiter, has three times the mass of Jupiter, and orbits the Sun once in 1.8 million years.

The astrophysicists proposed Tyche to explain the existence of long-period comets. These comets take over 200 years to complete an orbit round the Sun. Astronomers used to believe that long-period comets appeared from random locations in the solar system.

However, the astrophysicists say that the comets actually come from the Oort cloud and are flung toward the Sun by the gravitational force of Tyche. NASA used its Wide-field Infrared Survey Explorer (WISE) telescope to search for Tyche between 2012 and 2014. It found nothing.^[2]

8 Planet V

A barrage of asteroids hit the surfaces of Mercury, Venus, Earth, Mars, and the Moon 3.8 billion years ago. Scientists call that barrage the Late Heavy Bombardment (LHB). However, they cannot confirm where those asteroids came from.

Some scientists have suggested that the asteroids came from the remnants of Planet V, which lay between Mars and the asteroid belt that separates Jupiter from Mars today.

Scientists think that Planet V was smaller than Mars, which may explain why its orbit was heavily altered by the gravitational pull of Jupiter and other outer planets. Planet V soon became unstable and strayed into the asteroid belt, flinging asteroids toward Mars and the other inner planets. Planet V itself was later flung into the Sun or far into the solar system.

Alternatively, Planet V could have just steered clear of the asteroid belt and crashed into another planet. Some astronomers think it crashed into Mars and created the Borealis Basin, which covers 40 percent of Mars. If that happened, the asteroids that crashed into the inner planets were probably fragments flung into space during the collision.

Other astronomers say that the hypothetical Planet V never existed. They think that the LHB occurred after Jupiter and Saturn changed their orbits and flung asteroids from the asteroid belt toward the inner planets. Others say that the LHB was caused after the gravitational pull of Mars broke a large asteroid apart.^[3]

7 Theia

Scientists used to believe that the current Earth and Moon were created after a planet they called Theia slammed into an early Earth. The collision caused the smaller Theia to break up, sending fragments into space. One of these fragments became the Moon.

Scientists disproved this theory after tests on Moon rocks revealed that the Earth and Moon were made from the same material. These days, scientists believe that Theia slammed into an older Earth about 4.5 billion years ago. Both planets mixed together to create Earth. A fragment of Earth later broke off to form the Moon.^[4]

6 Phaeton

Astronomers believed there was an undiscovered planet between Mars and Jupiter until quite recently. The existence of the hypothetical planet seemed truer when Giuseppe Piazzi discovered what was considered to be planet Ceres in 1801. A year later, Heinrich Olbers discovered what was thought to be planet Pallas.

Olbers soon realized that Ceres and Pallas used to be part of the same planet. This belief was reinforced when planets Juno and Vesta were discovered. Ceres, Pallas, Juno, and Vesta were later reclassified as asteroids and considered remnants of a hypothetical planet called Phaeton.

Astronomers of the day thought that Phaeton had broken up and created the four large asteroids and every other one in the asteroid belt between Mars and Jupiter today.

Some astronomers thought that Phaeton had broken up after it exploded, was destroyed by Jupiter, or had smashed into another celestial body. Some think that this celestial body is Nemesis, a hypothetical star that was believed to be in our solar system.

However, today’s astronomers have disproved the existence of Phaeton. They say that the asteroids in the asteroid belt have always been asteroids. They were stuck between Mars and Jupiter and would have formed into a planet if it weren’t for Jupiter’s massive gravitational pull that kept them apart.^[5]

5 Nibiru

Nibiru is a hypothetical planet supposedly lurking somewhere in our solar system. While NASA says that it does not exist, conspiracy theorists insisted that it was real and would slam into the Earth in the year 2012.

For the record, Nibiru is also called Planet X and should not be confused with the hypothetical Planet Nine that is also called Planet X. We will get to Planet Nine shortly.

Nibiru was first proposed by Zecharia Sitchin in his 1976 book, The Twelfth Planet, where he claimed that it orbited the Sun every 3,600 years. Many years later, self-proclaimed psychic Nancy Lieder declared that aliens had warned her that Nibiru would slam into the Earth in 2003. Later, she changed the date to 2012.

In 2011, Comet Elenin passed by Earth and broke apart after flying too close to the Sun. Hard-liners insisted that the comet was planet Nibiru on its approach to crash into Earth. The fact that we are reading this article means that planet Nibiru probably doesn’t exist. Or it just missed Earth and will be returning in 3,600 years.^[6]

4 Planet Nine

Planet Nine is another hypothetical planet lurking somewhere in our solar system. Unlike Nibiru, NASA and astronomers from the California Institute of Technology think that Planet Nine could exist, although there is no verifiable evidence that it does. Astronomers speculated the existence of Planet Nine after observing the irregular orbits of five solar objects far beyond Neptune.

Astronomers think that Planet Nine is the same size as Uranus or Neptune, has a mass 10 times that of Earth, and is 20 times farther from the Sun than Neptune. They believe that Planet Nine takes 10,000–20,000 years to complete a revolution around the Sun.^[7]

3 Counter-Earth

In the fourth century BC, Greek philosopher Philolaus proposed the existence of a planet that he called Counter-Earth. He believed that Counter-Earth was always on the opposite side of the solar system from Earth. This meant that the Sun, Earth, and Counter-Earth would always be on the same line.

Philolaus believed that Counter-Earth was invisible from Earth because Counter-Earth was always obscured by the Sun. Today, we know that it could have never existed. If it had, we would have seen it from Earth because every planet in the solar system is affected by the gravitational pull of other planets.

The gravitational pull of Mercury and Venus would have altered the orbit of Counter-Earth and shifted it from its position on the opposite side of the solar system. This would have made it visible from Earth. Counter-Earth would have strayed closer to Earth over time, and both planets would have eventually met.

One of two things would have happened when they met. Earth and Counter-Earth could have collided to form a new Earth. Or they could have missed each other. If they had, their gravitational pulls would have been so great that they would have been thrown into new orbits.^[8]

2 An Unnamed Planet

Planets are often unstable after their creation. They will frequently change orbits because their orbits are continuously altered by the gravitational pull of other planets. In 2005, three groups of researchers used this theory to propose the Nice Model of the formation of the solar system.

In the past, the gravitational pull of other planets made Uranus and Neptune swap orbits and sent Jupiter and Saturn farther away from the Sun. Jupiter also supposedly moved closer to the Sun before returning to the outer solar system.

The Nice Model was accepted as true until it was partly disproved in 2011. At that time, some scientists said there had to be a fifth planet between Mars and Jupiter for it to be true. However, they added that the planet was probably flung out of the solar system by the gravitational pull of either Saturn or Jupiter.

In 2015, other scientists disproved the Nice Model because it did not explain the creation of the inner planets (Mercury, Venus, Earth, and Mars). They said that Jupiter would have cleared the inner planets, particularly Mercury and Mars, if it had ever strayed into the inner solar system.

The four inner planets would have formed long after the four outer planets if the Nice Model were true. Or they could be the survivors of Jupiter’s apocalypse. This means that the other inner planets were flung farther into the solar system along with one or two planets from the outer solar system.^[9]

1 Tiamat

The Sumerians believed that a planet called Tiamat lay between Mars and Jupiter. However, there is some debate about where this planet is today. In his book, Dark Matter, Missing Planets and New Comets, Tom van Flandern claimed that the planet was destroyed 65 million years ago and became the asteroid belt.

Zecharia Sitchin disputed this in his books The Twelfth Planet and The Cosmic Code. Instead, he declared that Tiamat had changed orbit and is now Earth. Sitchin said that Tiamat changed orbit after colliding with a hypothetical planet called Marduk and its three moons.

Sitchin claimed that the collision formed a new planet that broke in half. Two chunks of it moved closer to the Sun to become the Earth and the Moon while leftover debris became the asteroid belt. Sitchin added that Tiamat’s former moons were also flung into new orbits. He believes that one of the moons crashed into Mars and created the great rift.^[10]

Unlike Earth, every new planet we have discovered has been hostile to us. Some could become habitable if we figure out the answers to a few problems, like the unavailability of oxygen and water. Others would still be unsuitable for human life.

These deadly planets are ready to kill any creature that strays too close or tries to develop on them. Most of the planets on this list are not just too hot or cold. They have more terrible conditions that will never support life.

10 HD 189733b

In 2005, astronomers discovered a Jupiter-sized exoplanet, HD 189733b, with a distinctive Earthlike blue tint 63 light-years away. However, unlike Earth, HD 189733b was not blue because of its seas and oceans. Instead, the color came from its silicate-rich clouds.

HD 189733b is also deadly. The first problem is the 8,700-kilometer-per-hour (5,400 mph) winds that blow across the exoplanet. That is seven times the speed of sound, which is insanely fast. For comparison, peak sustained winds of the notorious Hurricane Katrina blew at 280 kilometers per hour (175 mph).

Then there is the rain. The silicate-rich clouds of HD 189733b cause rain of molten glass to fall from the skies. That rain does not fall straight down because of the superfast winds we just talked about. Instead, this strange precipitation falls sideways.^[1]

Even if we somehow found our way around that, we would still need to deal with the high temperatures on the exoplanet. HD 189733b is so close to its star that it is ridiculously hot. To put that in better perspective, it is so near to its sun that HD 189733b completes a revolution around its star in just 2.2 Earth days. Interestingly, a day on this exoplanet is also 2.2 Earth days long.

The gravitational interaction between a planet and its star can cause a planet to have a day and year of the same length if the planet becomes tidally locked to its star, just as our Moon is tidally locked to the Earth. This means that the planet rotates on its axis in the same amount of time that it takes to complete one revolution around its star. (Rotations cause days and nights, and revolutions cause years.)

A tidally locked planet always keeps the same side toward its sun. So, one side is condemned to nonstop daytime while the other has perpetual nighttime.

9 CoRoT-7b

In February 2009, astronomers operating the Convection, Rotation and Planetary Transits (CoRoT) satellite discovered a new exoplanet in the Monoceros constellation 480 light-years away from Earth. They called it CoRoT-7b.

CoRoT-7b is a rocky, Earthlike exoplanet even though it used to be a Saturn-sized hot Jupiter—a term used to describe the huge, gas-filled planets outside our own solar system with tight orbits around their stars. Despite having a rocky surface that could support life, CoRoT-7b is not the place to be.

For starters, its atmosphere is filled with minerals that form rock clouds. These clouds send pebbles and small rocks falling from the skies as if they were rain. Even if humans managed to survive that, they would be destroyed by the insanely hot surface temperature of the exoplanet.

Our own Earth is 60 times farther from our Sun than CoRoT-7b is from its star. In the daytime, the star in the skies of CoRoT-7b appears 360 times bigger than our own Sun looks from here on Earth. Talking about daytime, CoRoT-7b may also be tidally locked to its star. A day and a year are just 20.4 hours long.^[2]

As you may have guessed, this means that half the exoplanet permanently faces its star. The surface temperature of that side is between 1,980 degrees Celsius (3,600 °F) and 2,300 degrees Celsius (4,220 °F), which is enough to melt rock. Astronomers believe that the rocks on the side facing the sun are molten because they can’t remain solid at that temperature.

8 KELT-9b

Exoplanet KELT-9b is the hottest planet we have ever found. The temperature of its star is around 9,700 degrees Celsius (17,500 °F), which is almost two times the 5,480-degree-Celsius (9,900 °F) surface temperature of our Sun. The daytime temperature on the exoplanet hovers around 4,300 degrees Celsius (7,800 °F), which is still insanely hot. Most stars in the universe do not even come close.

As you read this, KELT-9b is so hot that its hydrogen-rich atmosphere is boiling and escaping into space and right into star KELT-9, around which the exoplanet rotates. Star KELT-9 is huge, reaching three times the size of our Sun. Exoplanet KELT-9b is two times the size of Jupiter and three times heavier.

The extreme temperatures are caused by the relatively short distance between KELT-9 and KELT-9b. Both are so close that the exoplanet completes an orbit in just 1.5 days. Mercury is 10 times farther from our Sun than KELT-9b is from KELT-9.

Astronomers believe that exoplanet KELT-9b will lose its entire atmosphere to star KELT-9 in just 200 Earth years. By that time, KELT-9 will have become so big that it could be touching the exoplanet. However, astronomers do not think that the exoplanet will slam into the star.^[3]

7 WASP-121b

WASP-121b is one weird exoplanet. To begin, it is not spherical but looks more like a football. We mean American football and not the more popular one that Americans call soccer. But the shape is not what makes WASP-121b deadly. Instead, the problem is the exoplanet’s nearness to its star.

WASP-121b is so close to its star that temperatures hover around 2,540 degrees Celsius (4,600 °F). Solid or liquid objects cannot form there, and everything just remains in a gaseous state. This includes its metallic atmosphere, which is filled with iron and magnesium gases. Worse, the exoplanet is losing this atmosphere to its star, just like KELT-9b.

Curiously, the closeness to its star is the same reason that WASP-121b is stretching out of shape. The star is able to exert a heavy gravitational pull on the exoplanet. WASP-121b cannot resist the pull because it has a weak gravitational force. It manages to partly resist, though, causing it to bend out of shape.^[4]

6 Upsilon Andromedae b

Upsilon Andromedae b is one strange exoplanet that rotates around the star Upsilon Andromedae A, which is 44 light-years away from Earth. The exoplanet is too close to its sun, completing an orbit in just 4.6 days. As you may have guessed, this suggests that it is tidally locked, with one side permanently facing the sun and one unbelievably hot.

Interestingly, the hottest area, the “warm spot,” does not face the star. Instead, it is on the side that never receives sunlight. This discovery puzzled astronomers because the side facing the star should be hotter. Astronomers believe that things are a bit different here because the wind transfers the heated air to the opposite side of the exoplanet.

Here is one theory as to how that works. The heat from the star Upsilon Andromedae hits the side of exoplanet Upsilon Andromedae b that is facing the sun, causing the air to heat up. When that air becomes hot enough, the wind transports it to the opposite end of the exoplanet.

At the same time, the wind transports the cooler air at the opposite end to the side facing the sun. Then the process continues. The continuous switch means that the side shielded from the sun has a reliable flow of hot air while the side facing the sun has much cooler air.^[5]

5 OGLE-2005-BLG-390Lb

OGLE-2005-BLG-390Lb is a rocky exoplanet with a very thin atmosphere located right in the middle of our own Milky Way. All three factors made astronomers suspect that it could contain life when it was discovered. However, they now believe that it does not due to the exoplanet’s super-low temperature.^[6]

The surface temperature on OGLE-2005-BLG-390Lb is around -220 degrees Celsius (-364 °F), which is too low to support life as we know it. For comparison, by some accounts, the lowest temperature ever recorded here on Earth is -97.8 degrees Celsius (-144 °F). The temperature was recorded in an area of ice-cold Antarctica that has never seen sunlight. An attempt to breathe in that area will destroy our lungs and cause instant death.

4 TrES-2b

TrES-2b is the darkest planet out there. It is so black that coal will appear lighter if both were ever placed side by side. TrES-2b is the size of Jupiter and located in the Draco constellation 750 light-years away from Earth. Its star is GSC 03549-02811, which is almost like our Sun.

TrES-2b is black because its atmosphere absorbs over 99 percent of the light it receives from the sun. Astronomers believe that the exoplanet reflects so little light because its atmosphere is filled with vaporized sodium and potassium or gaseous titanium oxide.

Nevertheless, being black does not mean that the exoplanet is cool. In fact, its atmospheric temperatures reach over 980 degrees Celsius (1,800 °F). This extremely high temperature causes some parts of the exoplanet to emit a red glow, just like burning coal or electric stove coils. Astronomers also suspect that the exoplanet is so close to its star that both are tidally locked.^[7]

3 OGLE-TR-56b

Planet OGLE-TR-56b lies in the Sagittarius constellation 5,000 light-years away from Earth. It is one of the “hot Jupiters” we talked about earlier. Hot Jupiters are often formed farther out in their stellar systems and later move closer to their stars.

Planet OGLE-TR-56b has already moved too close to its own star.^[8] It is so near that a year is 29 hours long, and the exoplanet’s surface temperature reaches 2,000 kelvins. Over there, the clouds are not made of water but of vaporized iron. Rain falls to the ground as hot liquid iron.

2 Venus

Deadly planets do not only exist outside our solar system. We have one lurking nearby, too. Without a doubt, Venus is the deadliest planet in our solar system thanks to its sulfur dioxide–rich clouds. Those clouds prevent useful sunlight from reaching the planet’s surface and stop deadly carbon dioxide from leaving the atmosphere.

The surface of Venus is filled with volcanoes that emit large amounts of heat and carbon dioxide. The large deposit of carbon dioxide makes Venus poisonous for humans. The thick clouds also trap heat and gas, making the planet lethally hot. Temperatures reach a hostile 467 degrees Celsius (872 °F).

The hot temperature remains constant all over the planet—even at the poles. Other hot planets are often cooler at the poles. Venus also retains this high temperature every day of the year. Even the nights are as hot as the days. Researchers think that Venus would be similar to Mercury if Venus did not have these clouds.

Interestingly, it also rains and snows on Venus, although things are quite different than what occurs on Earth. The snow is not made of liquid but of galena and bismuthinite metals. Rainfall is composed of deadly sulfuric acid. However, the high temperature on the planet means that rain never touches the ground. Instead, it evaporates midway to form another cloud.^[9]

1 Proxima b

Proxima b looked promising when it was discovered. It orbits Proxima Centauri, a red dwarf star 4.24 light-years away from Earth. The exoplanet interested astronomers who thought that it had water and Earthlike properties. However, they soon discovered that they were wrong.

Proxima b is so close to Proxima Centauri that the exoplanet completes an orbit in 11.2 days. It is also tidally locked, leaving one side deadly hot and the other fatally cold and frozen. Between the two is a middle ground that is more temperate. However, that region is unlikely to support life because of Proxima Centauri.

As we mentioned earlier, Proxima Centauri is a red dwarf. One characteristic of such stars is their tendency to release solar flares every two to three months that strike the planets orbiting around the stars. Those flares would destroy the ozone layers of those planets, making them vulnerable to ultraviolet radiation from the stars.

We observed one such event on March 24, 2017, when Proxima Centauri released a solar flare toward exoplanet Proxima b. The flare was so intense that the star became 1,000 times brighter within 10 seconds. Proxima b received 4,000 times the radiation that reaches the Earth from solar flares. That is bad for anything living on the exoplanet.^[10]

It’s a small world after all. That was the conclusion reached at an August 2006 meeting of the International Astronomical Union. And while only 424 of an eligible 9,000 voting members participated, it amounted to a planetary eviction notice for Pluto.

But the meeting did more than reduce the solar system from nine full-fledged planets to eight. It also created an entirely new classification of celestial bodies. Let’s explore our solar system’s five little wonders: the dwarf planets.

10 Hypothetical Planets That Could Exist In Our Solar System

10 Ceres: So Nice They Classified It Twice

Despite being the smallest of the five dwarf planets, Ceres was the first one discovered. The reason is that Ceres, located in the Asteroid Belt between Jupiter and Mars, is by far the closest. So even though it’s the dwarfiest dwarf, Sicilian astronomer Giuseppe Piazzi spotted it back in 1801 – more than a century before Pluto made its planetary presence known.

Calling Ceres a planet – even of the dwarf variety – seems generous. At only 950 km in diameter, its mass is just 0.015 percent of Earth’s and 14 times less than Pluto. In fact, Ceres is so minuscule that it’s ALSO classified as an asteroid; though in Ceres’ defense, it is the largest asteroid in the solar system.

Ceres is a boulder among relative pebbles: it comprises a full quarter of the Asteroid Belt’s total mass and, unlike its neighbors, has a nearly round body and likely has water ice beneath its crust. Supporting this assertion, in 2014 the European Space Agency’s Herschel Space Observatory detected water vapor spewing from two different areas of Ceres – possibly from ice volcanoes, which is pretty awesome.

Ceres is distinct enough from its surroundings that it was bestowed dwarf planet status in 2006. It is named for the Roman goddess of harvests – which is also how breakfast cereal got its name.^[1]

9 Mission to Ceres: A Trip Back in Time

Ceres is a still-intact survivor from the earliest days of the solar system, some 4.6 billion years ago, so studying its characteristics provide revelations into the solar system’s basic building blocks. In 2007, NASA launched an ambitious mission to comprehensively map Ceres (and Vesta, the next-largest object in the Asteroid Belt) by placing a spacecraft in orbit around it. Dubbed the Dawn Mission in honor of its origins-centric intentions, the spacecraft reached Ceres in March 2015.

The intel gathered indicates Ceres likely formed farther from the sun and migrated into the inner solar system; this assertion was drawn because Ceres’ surface composition includes large amounts of condensed ammonia, which requires the outer solar system’s colder temperatures to form. The mission also found an abundance of water, including a rocky mantle with water-rich rocks (such as clays) and an icy outer shell.

Scientists were particularly intrigued by Ceres’ organics – the building blocks of life. A specific carbon-hydrogen chain of organics was discovered in one of Ceres’ deepest craters, suggesting the material initially formed in its once-deep ocean.

Adding to the excitement is evidence that Ceres was geologically active relatively recently. This is supported by its glittering array of more than 300 bright features, called faculae, that gleam atop an otherwise dark landscape. The brightest of these contains the largest deposit of carbonate minerals ever seen outside Earth. This suggests briny water rose to Ceres’ surface in the recent past and deposited salts – a sign of a healthy, “living” planetoid.^[2]

8 Eris: A Misjudged Nail in Pluto’s Grave

One of the reasons Pluto got demoted in 2006 was the discovery of Eris a year earlier (to this day, the two still don’t speak). When astronomers found Eris in January 2005, it was initially pronounced the largest dwarf planet yet; its diameter was estimated at 2,300-2,400 km, making it 27% more massive than Pluto. This prompted the International Astronomical Union (IAU) to reconsider its definition of a planet – the first demerit in Pluto’s loosening grasp on full planethood.

The problem is… well, they were just wrong. Further observation suggested that Eris is actually slightly smaller than Pluto. Unfortunately, this wasn’t realized until 2010 – four years after Pluto got the boot. Oops. Fortunately, sheer mass wasn’t the prime reason Pluto was downgraded – more on that later.

Back to Eris, which has a wild streak to it. For one, its orbit is very erratic, crossing Pluto’s and nearly intersecting Neptune’s in an oddball, oval-shaped journey that takes Eris and its moon, Dysnomia, 557 years to circle the sun – more than twice as long as it takes Pluto. In doing so, Eris dips in and out of the Kuiper Belt, a band of mostly asteroid-sized bodies beyond Neptune occupied by each dwarf planet except Ceres.

The surface of Eris likely consists of nitrogen and methane dispersed in an extremely thin, one-millimeter layer. Some scientists think that what we see as Eris’ surface actually is its condensed atmosphere, which potentially expands into gas when the planetoid is closer to the sun.^[3]

7 The Tenth Planet?

The preceding entry discusses how Eris’ discovery led to a re-examination of how planets were classified, starting Pluto’s yearlong slide to demotion. But that outcome wasn’t inevitable; another distinct possibility was adding Eris as the solar system’s tenth full-fledged planet. Unfortunately for Pluto, the debate descended into the IAU rewriting its definition of a full planet, and one criteria – the ability of a celestial body to clear its surroundings through gravitational dominance – was met by neither Eris nor Pluto.

For that reason, on August 26, 2006, Pluto was demoted and a new designation, “dwarf planet,” created. Along with Pluto, Eris and Ceres were given this classification as well, with many dubbing Eris “The First Dwarf” because its discovery led directly to this specified category.

In fact, Eris’ disruptiveness is espoused in its very name. When initially discovered in 2005, it was unofficially called Xena. But given its divisive impact on both the IAU and third-grade science projects, the planetoid was renamed to honor the Greek goddess of discord.

“[Eris] stirs up jealousy and envy to cause fighting and anger among men,” explains Mike Brown, a professor of planetary astronomy at the California Institute of Technology. As legend has it, after being snubbed for a wedding invitation, Eris spitefully started a spat among goddesses that led to the Trojan War.

“She’s quite a fun goddess, really,” Brown adds. Pluto might use a different adjective.^[4]

6 The Potato-Shaped Dwarf

Another Kuiper Belt native is Haumea, whose standout characteristic is its distinct flattened shape. This is because Haumea is one of the fastest rotating large objects in the solar system, and the force generated by this spin distorts the planetoid into an oblong potato shape resembling more an American football than a European one.

The days fly by on Haumea, which completes a full rotation every four hours. That’s astonishingly fast in astronomical terms, leaving scientists to speculate that a massive impact billions of years ago may have initiated Haumea’s speedy spin and, in the process, also created its two moons, Namaka and Hi’iaka. (Haumea is named for the Hawaiian goddess of fertility, her moons for the goddess’ mythological daughters.)

Haumea has another feature that sets it apart from its siblings: rings. Scientists announced the discovery in 2017 after watching Haumea pass in front of a star, making it the first known Kuiper Belt object with rings.

Other than that, though, Haumea is a bit of a mystery. NASA’s website admits that very little is known about the dwarf planet’s atmosphere and surface. It’s roughly the same width as Pluto, and takes slightly longer (285 years) to orbit the sun. Still, what is known about Haumea already distinguishes it from its fellow dwarves.^[5]

10 Ways Earth Once Looked Like An Alien Planet

5 Makemake Finishes What Eris Started

Another proud Kuiper Belt denizen is Makemake, which also played an important role in Pluto’s expulsion from the fraternity of full-fledged planets. Much of this has to due with timing; like Eris, Makemake was discovered in early 2005, and helped lead the IAU to rethink its definition of a planet.

As mentioned earlier, scientists initially – and erroneously – believed Eris was larger than Pluto, leading to its short-lived consideration for full planet status. Unfortunately for them both, one of the factors that settled this dispute was the discovery of Makemake just two months after Eris. Unlike comparisons between Eris and Pluto, no such size-related case could be made for the miniscule Makemake, which was clearly far smaller than both.

With Makemake, scientists had an object that clearly wasn’t large enough to be called a planet. And once it became clear that Pluto acted more like Makemake than, say, Mars, the writing was on the wall. There were now three small planet-esque objects in roughly the same place – the Kuiper Belt – acting similarly. This led directly to the assertion, ratified in 2006, that only objects that “clear its neighborhood” through gravitational dominance can be called full planets.

None of the three met this criteria. Eris’ application for planethood was denied, and Pluto lost its position entirely. Thanks a lot, Makemake.^[6]

4 Make Way for Makemake

Of course, Makemake is more than a bad-ass foil for wannabe planets. Makemake outshines its more massive sibling Eris as the second-brightest object in the Kuiper Belt; only Pluto is brighter. And despite taking 305 Earth years to circle the sun, a day on Makemake lasts about 22 1/2 hours – very similar to days for us Earthlings and our closest celestial neighbor, Mars.

As best astronomers can tell from so great a distance (Makemake is some 6,847,000,000 km from the sun, which is just 150 million km away from us – a stellar stone’s throw), the planetoid is reddish-brownish in color, like Pluto. Its surface appears to be teeming with ethane, as well as large pellets of frozen methane.

Makemake also has a miniscule moon. Officially named S/2015 (136472) 1 and mercifully nicknamed MK 2, the satellite’s radius is estimated to be just 80 km. (For the record, the solar system’s smallest moon is Deimos, one of Mars’ two moons, whose diameter measures only 11 km.) MK 2 is approximately 1,300 times fainter than Makemake – so difficult to spot that NASA still deems it a “provisional” moon.

Finally, Makemake got its very odd name in very odd fashion. For whatever reason, its discoverer nicknamed his finding “Easterbunny.” When it was time to give the dwarf a proper name – after a deity, like its celestial siblings – they chose Makemake, the creator god of the Rapa Nui people of… you guessed it: Easter Island.^[7]

3 Pluto Was Just Waiting to Be Picked Off

Finally we come to Pluto, the little planet that could…n’t. Despite enjoying three-quarters of a century as a full-fledged planet, Pluto was unceremoniously booted from the big brotherhood thanks to the combined efforts of Eris and Makemake, as explained above.

It all started out so well for the little guy. Pluto was discovered in February 1930 by American astronomer Clyde William Tombaugh – the culmination of years of predictions by fellow scientists of a ninth planet’s likely existence. Pluto then became the only planet named by an 11-year-old girl, when Venetia Burney of Oxford, England said the new discovery should be named for the Roman god of the underworld. Subsequently, Pluto’s five moons also were named for figures associated with Pluto; its largest satellite, Charon, honors the River Styx boatsman who ferries fresh souls to the underworld.

But here’s the rub: scientists found Pluto under biased pretenses. They were actively seeking a ninth planet, and were all too happy to bestow this title upon their treasured finding. This, despite Pluto being just 2,250 km wide – approximately half the width of the United States. Charon further complicated matters: when it was discovered in 1978, it soon became clear that Pluto’s largest moon was fully half as massive as the then-planet itself. The problematic result was that their fairly equal gravitational forces caused the two to orbit each other like a double-planetary system. That’s not a moon, it’s a partner.

So really, Pluto was just waiting to get plucked off the planet list for decades. Eris could very well have been the ninth planet for 75 years had it been found first.^[8]

2 Still, Pluto is the Least Dwarfy Dwarf

Despite not measuring up to the likes of Neptune, Uranus or Mercury – or even seven of the full planets’ moons, including our own – Pluto is still a standout in its category.

For starters, Pluto is the largest dwarf planet – a distinction temporarily forfeited to Eris, then reclaimed once astronomers realized Eris wasn’t as big as initially thought. Pluto is also by far the brightest in its class, outshining runner-up Makemake. It also travels along an eccentric, distinguishingly inclined orbit; at times during its 248-Earth-year journey around the sun, Pluto is actually much closer to its star than Neptune, the furthest planet proper.

We also have far more information about Pluto than the other dwarfs. This is because in January 2006 – seven months before Pluto officially lost its status as a full-fledged planet – NASA’s New Horizons spacecraft set out to explore the distant world. The spacecraft reached Pluto in July 2015 and, among other discoveries, found mountains made of ice that may float atop a layer of nitrogen ice.

New Horizons also turned its attention to Pluto’s largest moon, Charon, where it noticed a north pole covered with reddish material that likely escaped Pluto’s on again-off again atmosphere that forms and dissolves depending on the planetoid’s distance from the sun.^[9]

1 A Distant Dwarf?

In 2003, three years before Pluto got demoted to the planetary junior varsity squad, a trio of researchers discovered what at the time was the coldest, most distant known object in the solar system. In honor of its frigidness – scientists believe the temperature there never rises above -400° Fahrenheit – they named their finding Sedna, after the Inuit goddess of the sea who, legend has it, dwells in the depths of the Arctic Ocean.

Well beyond the Kuiper Belt that four of the five dwarf planets call home, Sedna is so far away that it’s barely in the solar system – some 130 billion kilometers away. (For context’s sake, the sun is a mere 146 million kilometers from Earth.) Following an odd elliptical orbit, it takes Sedna roughly 10,500 Earth years to orbit the sun. That’s staggeringly long.

Not so staggering, however, is Sedna’s size, which is estimated at between 1300-1770 km in diameter – about 75% that of Pluto. Still, as dwarf planets go that’s not disqualifyingly tiny. So the only reason Sedna hasn’t become the sixth dwarf is something called hydrostatic equilibrium – a stabilizing balance of force pressing both upwards and downwards. Sedna is too far away for this to be measured using current technology, so for now it’s stuck at “minor planet” status, which seems totally unfair in my scientific opinion. Penalizing Sedna for our technological shortcomings is typical Earthling arrogance.^[10]

Top 10 Deadliest Planets In The Universe

Is there another planet like earth? Science has seen astonishing growth in the past 5 decades and our knowledge of Space is increasing daily and we are discovering new planets, stars, black holes and many more things. Our curiosity for exploring space is increasing day by day and some reports says that there are around 300 million habitable planets in our Milky Way Galaxy alone. In 2021, there are 4843 confirmed exoplanets. Here, below we have mentioned 10 earth like planets that could be the future earth. We have not given any specific order to the planets because each one is unique.

The 10 Most Earth-like Alien Planets:

10. TOI 700 d

TOI 700 d is an exoplanet located in the habitable zone of its star TOI 700 which is a cool ‘M DWARF’. Located 100 light years away in the Dorado Constellation. The TOI 700 is only 40% of Sun Mass and size and only half of its surface temperature. The star doesn’t show any signs of harmful “stellar flares” that would make life impossible on orbiting planets.

TOI 700 d is a tidally locked planet which means that one side always faces the star and the other lives in darkness every time. The planet is probably known to be rocky and is 20% larger than earth and receives 86% light from the star in comparison to earth receives from the Sun.

See also the list of 10 Upcoming Space Events.

9. TRAPPIST-1e

The TRAPPIST-1 is a dwarf planet nearly 40 light years away. Seven Known earth like planets in this star system and the full system was discovered in 2017. It is the only known solar system which has 7 earth like planets orbiting a single star. There are 3 habitable planets in this system and all three are probably known to be rocky planets.

The TRAPPIST-1e is most likely similar to earth in terms of size, mass and temperature. TRAPPIST-1e has 93% surface gravity of earth and is probably known to support liquid water and terrestrial life. The other planets in the solar system are known to be completely water worlds or covered with thick Ice sheets.

8. Proxima Centauri B

Proxima Centauri B is an exoplanet located in the habitable zone of its red dwarf star Proxima Centauri; Which is the closest star to our Sun and belongs to a triple star system. Proxima Centauri is located just 4.25 light years away from us. The star is so dim that you can’t see it from naked eyes even though it is the closest star known to the Sun. Proxima Centauri B is known to be the earth like planets but the chances of maintaining life on the planet is slim. As the exoplanet gets 2000 times more Stellar Winds from its parent star in comparison to earth.

The planet is supposed to be tidally locked to its parent star and one side might be freezing cold and the other side extremely hot.

See also the list of 10 Strange and Mysterious Planets Outside the Solar System.

7. ROSS 128 b

Ross 128 b is an exoplanet orbiting the red dwarf star Ross 128, located 11 light years away from us. The exoplanet is considered one of the best suitable candidates for future earth. As it is only 35% more massive than earth and only 38% more star light which makes it suitable to host liquid water and also an atmosphere. The host star Ross 128 is only 17% mass and 20% radius of our Sun. The exoplanet Ross 128 b is located very close to its star and completes its orbit around the star in about 9.9 days.

6. GLIESE 581g

Gliese 581g is another habitable exoplanet located 20 light years away from us. But there is a doubt in the existence of the planet. In order to confirm the existence of a planet, two independent studies need to be conducted and the first study was conducted in 2010. The planet orbits around its parent star Gliese 581 which is a dwarf star and is much cooler than our Sun. Some research marks the existence of the planet and some don’t. So let’s wait for more accurate research in future.

5. Kepler-22b

Kepler-22b is an exoplanet located 600 light years away from us confirmed in December 2011. It was the first confirmed exoplanet in the habitable zone. It is 2.4 times larger than earth and it also orbits a sun-like star with a suitable temperature of 72° F (22° C) which makes it a suitable planet for living. Scientists have a doubt whether the planet is watery, gaseous or rocky but they have confirmed the cloudy atmosphere. As it is almost twice the size of earth and we can expect a very rocky core.

See also the list of 10 Most Potentially Habitable Planets For Humans.

4. Kepler 452b

Kepler 452b is an exoplanet which orbits a G2 type star and is located in the habitable zone whose mass it can hold liquid water on its surface. The exoplanet is 60% larger than earth and considered to be rocky.  The exoplanet completes an orbit in 385 days and the exoplanet is slightly older than our Earth. It is known to be the most suitable habitable planet like Earth and also an older cousin to the Earth. The Parent star is 1.5 billion years older than our Sun and 10% larger. The exoplanet is located 1400 light years away from us in the Cygnus Constellation.

3. Kepler 186f

The exoplanet is 500 light years away from the Cygnus Constellation. Kepler 186f is also known as second earth and it is only 10% larger than earth. It lies in the habitable zone of its parent star. This exoplanet might have a suitable temperature to hold liquid water on its surface. The planet completes an orbit in 130 days and receives ⅓ light from its star in comparison to light earth receives from the Sun.

2. KOI 7711.01

The KOI 7711.01 is another candidate to host life. It is located 1700 light years away and Orbits a Sun like star. It is located in the habitable zone and can hold liquid water. But scientists are still confused what kind of atmosphere it has. Also, the exoplanet is 30% larger than our Earth.

See also the list of 10 Conceptual Spacecraft Engines.

1. Kepler 62e

Kepler 62 is a solar system located 990 light years away from us. And the Kepler 62e comes in the habitable zone of its parent star. It is known to be a water world. Also, it is about 1.6 times the size of earth. And it is assumed that the exoplanet has cloudy skies and a warm temperature. It Orbits its star in 122 days. We can also call it a mini Neptune. As most of the part is covered with water with minimal land area, making it more interesting to look at.