Could There Be Another Planet Behind the Sun?

If you’ve read your share of sci-fi, and I know you have, you’ve read stories about another Earth-sized planet orbiting on the other side of the Solar System, blocked by the Sun. Could it really be there?

No. Nooooo. No. Just no.

This is a delightful staple in science fiction. There’s a mysterious world that orbits the Sun exactly the same distance as Earth, but it’s directly across the Solar System from us; always hidden by the Sun. Little do we realize they know we’re here, and right now they’re marshalling their attack fleet to invade our planet. We need to invade counter-Earth before they attack us and steal our water, eat all our cheese or kidnap our beloved Nigella Lawson and Alton Brown to rule as their culinary queen and king of Other-Earth.

Well, could this happen? Could there be another planet in a stable orbit, hiding behind the Sun? The answer, as you probably suspect, is NO. No. Nooooo. Just no.

Well, that’s not completely true. If some powerful and mysterious flying spaghetti being magically created another planet and threw it into orbit, it would briefly be hidden from our view because of the Sun. But we don’t exist in a Solar System with just the Sun and the Earth. There are those other planets orbiting the Sun as well. As the Earth orbits the Sun, it’s subtly influenced by those other planets, speeding up or slowing down in its orbit.

So, while we’re being pulled a little forwards in our orbit by Jupiter, that other planet would be on the opposite side of the Sun. And so, we’d speed up a little and catch sight of it around the Sun. Over the years, these various motions would escalate, and that other planet would be seen more and more in the sky as we catch up to it in orbit.

Eventually, our orbits would intersect, and there’d be an encounter. If we were lucky, the planets would miss each other, and be kicked into new, safer, more stable orbits around the Sun. And if we were unlucky, they’d collide with each other, forming a new super-sized Earth, killing everything on both planets, obviously.

Diagram of the five Lagrange points associated with the sun-Earth system, showing DSCOVR orbiting the L-1 point. Image is not to scale.  Credit:  NASA/WMAP Science Team
Diagram of the five Lagrange points associated with the sun-Earth system, showing DSCOVR orbiting the L-1 point. Image is not to scale. Credit: NASA/WMAP Science Team

What if there was originally two half-Earths and they collided and that’s how we got current Earth! Or 4 quarter Earths, each with their own population? And then BAM. One big Earth. Or maybe 64 64th Earths all transforming and converging to form VOLTREARTH.

Now, I’m now going to make things worse, and feed your imagination a little with some actual science. There are a few places where objects can share a stable orbit. These locations are known as Lagrange points, regions where the gravity of two objects create a stable location for a third object. The best of these are known as the L4 and L5 Lagrangian points. L4 is about 60-degrees ahead of a planet in its orbit, and L5 is about 60-degrees behind a planet in its orbit.

A small enough body, relative to the planet, could hang out in a stable location for billions of years. Jupiter has a collection of Trojan asteroids at its L4 and L5 points of its orbit, always holding at a stable distance from the planet. Which means, if you had a massive enough gas giant, you could have a less massive terrestrial world in a stable orbit 60-degrees away from the planet.

Grumpy Cat has the correct answer. Credit:
Grumpy Cat has the correct answer. Credit:

Well, it was a pretty clever idea. Unfortunately, the forces of gravity conspire to make this hidden planet idea completely impossible. Most importantly, when someone tells you there’s a hidden planet on the other side of the Sun, just remember these words:

Go ahead and name your favorite sci-fi stories that have used this trope. Tell us in the comments below.

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35 Replies to “Could There Be Another Planet Behind the Sun?”

  1. All the gravity arguments accepted we’ve also had satellites orbit the sun far out of the ecliptic as well as far ahead and behind the earth taking views behind the sun.

    No unexpected planets.

    But we do occasionally see the surprise comet or asteroid…. small stuff but exciting sometimes to look at.

  2. Mr. Cain,

    When I was in seventh grade, (many years before the advent of geosynchronous satellites) I wrote a story about this very subject for a class project. At the time I hadn’t heard of the possibility of another planet behind the sun and believed it was my original idea. Of course, time would prove that wrong.

    Over the many years that have passed I became a novelist writing mostly romance and some science fiction. The memory of my first fictional story from that seventh grade class kept calling to me to locate its whereabouts. Having been written presumably on notebook paper and never copied, (no Xerox machines in those days), I took to rewriting it based on memories from my childhood. Naturally, I added more to it, having experienced the Apollo missions, geosync satellites and political events of my lifetime. So here it is, my very first piece of fiction, modernized by age.

    Another World
    Rick Bennette

    America took its first ride into space on May 5, 1961. Alan Shepard rode the Freedom Mercury capsule into space for a sum total of fifteen minutes. During the short sub-orbital flight, he barely had time to enjoy the view of space. Two months later, Gus Grissom rode the Liberty Bell Mercury capsule into orbit several times around the Earth, providing ample time to enjoy the view. Gus witnessed the sun dipping below the horizon for man’s first view of a sunset from space.
    It was nothing more than a faint dot above the disk of the sun. An optical illusion, he thought, created by the massive temperature of the sun’s surface bending light in the same manner as the hot sun creates a mirage of water on a long desert highway. Seeing the same dot in the same place two sunsets later, Gus began to wonder if this was really just a mirage, or was there something out there?

    Upon his return to Earth, Gus made some calculations based upon the conditions of his flight. At 280 miles above the Earth, his orbit wasn’t high enough to see an object where he imagined this one should be. The math alone couldn’t confirm his hunch.

    The following year NASA launched its first satellite into Geosynchronous orbit. That put the satellite into orbit 22,000 miles above the Earth. To an observer on the ground, the satellite would appear to be sitting still in space as it revolved around the equator at the same relative speed as the Earth below. This was done purposely so it could be used as a communications satellite to beam TV signals overseas. NASA had another mission piggybacked aboard that satellite. To look beyond the other side of the sun and either confirm or debunk Gus Grissom’s hunch.

    What lay beyond the sun was perplexing indeed. The satellite could not obtain a clear enough image to observe exactly what this object was. Whatever it might be, it was in orbit around the sun in the same plane as the Earth. From Earth, if it could be seen, it would be directly behind the sun. Which is why no one on Earth could see it, even with the best telescopes.

    Our government ordered the observation of this object classified. For years NASA was forced to keep their discovery a secret from the public. News of a suspected planet in the same orbit as Earth could cause sudden panic. Releasing this information might scare the public into fearing another planet was on a collision course with Earth.
    December of 1968 brought about the launch of Apollo 8. This was the first manned spacecraft to leave Earth orbit and head for the moon. NASA had yet another secret mission in mind.

    “As Apollo 8 flies around the back side of the moon, it won’t be visible from Earth,” the NASA mission commander explained to his staff. “At that point in lunar orbit we will launch a small probe from the Apollo command module. In addition to being an extremely efficient means of launching a probe, it also hides the mission’s origin from any prying eyes here on Earth.”

    It was a brilliant plan. At that point in history, we were in a moon race with the Russians. The entire world tuned in to every space launch, glued to their black and white TV screens by national pride. Sending a rocket to the sun directly from Earth would certainly draw unneeded attention and lots of questions. Piggybacking the tiny probe on Apollo 8 would allow the mission’s origin to remain undetected. The execution was so successful that subsequent probes were sent on every Apollo mission. This explains why NASA repeated sending Apollo spacecraft back to the moon. The fact the public lost interest in the Apollo missions after the first moon walk, only made it easier for NASA to hide the launches of these ‘solar’ probes. The real mission, of course, was to gather images and data from all these tiny probes to determine the nature of the planet on the far side of the sun. The probes didn’t reach the planet on the far side of the sun until after the last Apollo mission returned to Earth.

    Further Apollo missions were halted after it was felt enough probes had been launched. NASA blamed budget cuts for halting the remaining Apollo missions, but the reality was they had already obtained the information they set out to gather.

    What lay beyond the far side of the sun was another planet nearly the same as our own Earth. Sister Earth, as NASA affectionately referred to it, was discovered to be composed of the exact same elements as our own world. It was obvious to scientists the two worlds had been created about the same time, and from the same source. Its exact opposite orbit from Earth kept it hidden behind the sun from the vantage point of anyone on our own world.

    Images beamed down to Earth by NASA’s probes orbiting the sister planet showed a world that looked almost exactly like ours. Sister Earth was comprised of about one third land and two thirds water, much like our own planet. The differences, of course, were their land borders didn’t look like ours. A visitor to this world would not see land masses that looked like America, Africa and Europe, but would see totally different shapes.

    NASA scientists were eager to share this incredible discovery with the public. The government kept the information classified which meant, of course, the public would not be made aware of any such discovery. Men landing on the moon was fascination enough for the public, according to Uncle Sam. News of a new parallel world might cause perception of an astronomical disaster. The secret was kept at NASA.
    Naturally, after discovering a world so close in composition and proximity to our own, the next big question was of life. Finding life on another world would change human concepts of God and Creation. There was enough religious fighting already going on right here on Earth. Another life bearing world would surely set some humans to even more destructive behavior. The secret was maintained.

    It wasn’t much longer before Russian cosmonauts discovered the sister planet on their own. When knowledge of it was made public, they tried to take credit for its discovery. Our government then released its own information, laying proper claim to the discovery having been made years before the Russians knew about it. The mistrust between the two countries drew even more attention from the public than the actual discovery of the planet itself. There was no wide spread fear and panic as had been predicted. In fact, most people didn’t even believe the existence of a parallel world was real. Scientists, of course, were elated and could not wait for a manned mission. They named the planet Earth Too, purposely spelling it t-o-o.

    By now, scientists knew the atmosphere of Earth Too was close to the same composition of oxygen and nitrogen as the air on our own planet. Nothing in the atmosphere was discovered that would be poisonous to humans. Because of this, a mission to Earth Too would be a much more practical mission then sending men to the cold, dry, oxygen deficient desserts of Mars.

    On a summer day in 1981, scientists made the discovery of a life time. One of the newer probes orbiting Earth Too landed and beamed back the first images of life on another world. No longer were we privy to being the only home of living organisms. Observations included birdlike creatures and terrestrial animals that mimicked some of the species seen here on Earth. No human forms of life had been observed, but still, it was a monumental discovery that once again brought humanity together for one brief moment in time. It was a discovery significant enough to prompt funding for future manned missions. Russian scientists were so eager to share in our discovery they put forth massive amounts of funding toward future manned missions.

    In the summer of 1985, one American astronaut and one Russian cosmonaut synchronized their steps to set foot on Earth Too at the exact same time, in order that neither country could lay claim to placing the first man on another planet. It was truly a joint effort that once again united the population of Earth for another historic moment in time.

    While scientists at NASA were rejoicing in their new discoveries, three Americans and three Russians were exploring our sister world dressed not in space suits, but as casually as any hunter in the woods here on Earth. It was uncanny, they said, to release the seals of their space suits and breathe the air of another world for the first time. The surroundings appeared so familiar, it seemed almost as if the spacecraft had simply been dropped in a foreign country right here on Earth.

    Carrying two captured animals back to the spacecraft for the ride back to Earth, the men heard what sounded like something larger following them. As they exited the wooded area and traversed the level ground back to the spacecraft, they soon realized they were being pursued by a species larger than themselves. They made a mad dash up the ladder. One unfortunate cosmonaut lost the battle to the larger pursuer. He was savagely clawed to death and dragged back into the woods. The remaining five men were in shock. They were preparing to go back into the woods to retrieve their comrade, but came to realize there might not be much left to retrieve. Still, they could not leave a man behind.

    Enough time had passed to give themselves a modicum of safety. At least now they knew the danger and could be prepared. As they opened the door to step down the ladder, they changed their minds as multitudes of bear-like animals gathered around the spacecraft as if waiting for their next meal to emerge. Once they realized the men were inside, they began clawing at the thin walls of the spacecraft in an attempt to gain access. The decision was made to depart Earth Too at once. The rocket blast would certainly frighten off the creatures.
    Ascending to rendezvous with the command module, it became evident the crew was facing two problems. The skin of the spacecraft had been breached. The air was slowly leaking out, necessitating the wearing of space suits in flight. Worse than that was some of the flight control nozzles had been compromised during the attack. It was becoming difficult to correctly orient the spacecraft to the orbit of the command module. It would be like trying to drive your car if the steering wheel could only make right turns.

    The extra fuel needed to compensate for the diminished flight control was beginning to make its cost well aware to the crew. There wasn’t enough fuel to maneuver for correct orientation for a solid docking procedure. Coasting through orbit based on their final engine burn finally brought them within range of the command module. Unlike the Apollo missions where one astronaut stayed behind in the command module, this mission allowed the docking procedure to be controlled entirely from the landing module. The two spacecraft eventually slowly came together like a rolling grocery cart and a car in a parking lot. The impact caused the command module to pitch into a rolling motion as the landing module bounced off and slowly receded.
    One of the American astronauts quickly exited the spacecraft with a 100 foot line in tow. He pushed off from the outer surface by foot, just fast enough to catch up to the retreating command module. Slowly he floated in space toward the target, tow line firmly in hand. Two feet away he ran out of tether. He reached out his arm in a last ditch effort to grab hold. He was only drifting a fraction of a mile an hour. His arm was just long enough to touch the module but there wasn’t anything to grab on to. The resulting bump was just enough to send him backwards as if in slow motion. With nothing left to push or pull against, he grabbed the tether and reeled himself back into the landing module to try again.

    With no means of maneuvering the spacecraft and no means of reaching the command module, the five men watched as their ride back home drifted slowly away. Acknowledging their inevitable fate, they honored each other for a mission well done. They radioed condolences back to their families on Earth. One by one, the five of them succumbed to a peaceful transition into eternal sleep brought about by oxygen deprivation. The world honored those first six first men who made the first contact with extraterrestrial life. As adversity often brings about unforeseen good, the Americans and the Russians vowed to work in cooperation to return one day and try again. It wasn’t long after when in 1987, President Reagan made his infamous speech to Russian President Gorbachev that signaled the end of the cold war, “Mr. Gorbachev, tear down that wall.”

    The End

    More of my work can be seen on Amazon.
    Rick Bennette

    1. Rick, your story has problems with geometry. Since the Sun is exactly halfway between the Earth and Earth, too, the astronaut would have to be two solar diameters away from the Earth to see the other planet. The Sun’s diameter is a whopping 432,450 miles. Ignoring the diameter of the Earth (which is so much smaller than the Sun and you did say he saw the entire planet above the limb of the Sun so the correction for the Earth’s diameter does not apply, anyway), the astronaut would have to be at least 865K miles away from the Earth, in any perpendicular direction from the line connecting the Earth and Sun. This is about 3 1/2 times further than the Moon. The orbit of Gus’ Mercury capsule was far too low and a satellite in a geosynchronous orbit is also far too close.

      Your allusion to a visual distortion akin to mirages also falls short. Mirages work in the desert because hot air has a different refractive light index than cold air. Since there is no air in space, there would be no mirages. (Although they can be formed by massive gravitational objects, but not within our Solar System.)

      Finally, I’m not too sure the visitors’ radio waves would be able to pass through the Sun to be detected back on Earth. A direct line of signt is needed for the receivers back on Earth to detect their transmission from Earth, too. And, as I’ve explained, the Sun is so big it would block any transmission in low Earth, too orbit, particluarly if the craft is still in the atmospenere (60-100 miles).

      Your science mistakes would be easily forgiven for a seventh grader in a literary composition but they should be cleaned up for a piece in a science forum.

  3. John Norman’s “Gor” sword-and-sorcery series was centered on this sort of other-Earth on the opposite side of the Sun, full of heroic barbarian adventures to be had by a space-traveling professor. I loved them when I was an impressionable teenager.

    I’d post a full copy of the series here but that’d eat up way too much of the comments. 😉

    1. Nah. Seems like amateur open-mic night when aged conjecture supplants stories about actual advances in astronomy/rocketry, so you Go for Gold Jase (apologies to our UT publisher). 🙂

  4. There is a movie called “Journey to the Far Side of the Sun” with this exact premise. However, it goes even further and assumes that everything on that planet (people, plants, geography, etc) is an exact duplicate of this Earth except that things go “backwards”. So clocks run counter-clockwise, for example.

    A weird movie and obviously ludicrous but kind of fun when I watched it as a kid.

    1. I see this came out in 1969, two years after my original story. I heard such a film existed but I never knew the title. I’ll have to see this movie. I just saw the trailer on Youtube and it looks like a truly “B” rated film, even by 1969 standards.

  5. I have always loved this idea – a perfect duplicate Earth on the other side of the sun. Of course it’s impossible but I enjoyed reading your reasoning why in this article. Of course there used to be something similar billions of years ago. It wasn’t an exact duplicate of Earth plus it was significantly smaller (or larger). Eventually this other “planet” did catch up to the Earth (or the Earth caught up to it) and there was a massive collision. The result, of course, was the Earth-Luna system. This is how our moon was formed.

  6. I’ve heard of a “Planet X” theory; that there is a large Jupiter-sized “planet” on an orbital-period of a few thousand years or so that buzzes our solar system after a blind approach from ‘behind’ the Sun. Some theories suggest it’s more just a comet (some thought ISON and Hale-Bopp might’ve been it), others say it’s the home of a whole alien-world of our eternal guardians or creators or slave-barons of the human condition or whatever. Most suggest it’s the sort of event that could at least explain Earth’s periodic pole-shifts and continental changes.

    Interestingly earlier this year astronomers predicted that either one large or two smaller yet-undiscovered additional planets must be present in our solar system in order to account for certain orbital behaviors of further-out objects. And just the other day there was a report that a whole other star (actually a whole binary system) made a pass through our solar system just 70,000 years ago or so, and we have yet to determine how it might’ve disturbed the Oort Cloud and what that could mean for the future of our home. I mean, that’s insane! Add-in our crazy age of global climate change and you have all the makings of a summer blockbuster at the box office..

    Obviously an earth-like planet orbiting exactly opposite of us from the sun is silly, but it seems like the more we learn about the universe the more we realize how little we still know. But that’s fine- imagination might not be so fun otherwise 🙂

    1. mister_e, good point – so many people like to stand behind the “proven science” cloak. The outer planets orbits are all impacted by some gravitational presence. There is truly only theories about what may be out there. I don’t personally believe in a strange elliptical orbit and a planet Nibiru, but I do respect the fact that there are anomalies that cannot be explained. Regardless of the matter of fact style of Dr. deGrasse Tyson, we are still infants in understanding the big picture.

  7. It may just mean our existence in the sun(son) has been getting back doored> and you know what that means and by whom.

  8. Obviously with all the technology we have today, it’s downright silly to believe another “earth” exists behind the sun. It isn’t even believable as science fiction. But up until the summer of 1963 when the first geosynchronous satellite was launched, no one could disprove such a theory based upon direct observation. Then again, we all believed at one time, and not too long ago, that Pluto was the farthest object from the sun in our own solar system. Just because a fact isn’t readily believable, or just because we can or can not prove the existence of something in space, doesn’t make for bad sci-fi in and of itself. It is the quality of the film that determines good sci-fi. We all knew the history of Apollo 13, yet the movie proved to be a big hit. That’s because it was well made.

  9. I recall a t.v.pilot movie about 3 lost astronauts crashing on another earth behind the sun,exactly like earth except run by a communist gov’t called “the perfect order”.and I always wondered where “land of the giants “was.

  10. With the advanced dection equipment at NASA’s disposal, dectecting a planet playing hide& seek would be relaticely easy. Even for a fool such as I. It could easlily be found via the tell tale magnetic planetary thumb print surrounding this wisp-o-da-wil. Futhermore, the Sun has no Back side to speak of. Thanks.

  11. To my astonishment, no one has mentioned the last season-and-a-half or so of the brilliantly infantile Canadian sci fi serries LEXX as using this trope.

    The mirror planet was actually two planets locked in tight orbit – Water and Fire – and served as an allegorical stand in for heaven and hell.

    Of course, many a cleavage was given a censor-friendly airing.

  12. (spoiler alert) As I remember the movie “Journey to the Far Side of the Sun” the planet was a second Earth, which was the complete opposite to the first Earth. The astronaut crash landed, reported back to NASA, who then rebuilt another craft to go back to the orbiting mother ship, then each astronaut will return to his own Earth. The movie ended when the returning craft reconnected to their mother ship and exploded due to the wrong electrical polarity of the rebuilt returning craft.

  13. get your heads out of the sand people!Planet X is coming our way from behind the sun.The ancients described it as the winged planet.The Bibles book of Revelation describes what effect it will have on the Heavens,on our planet,and mankind!!!!!!!!! google it!

    1. Nope, there is no Planet X waiting to pop out from behind the Sun and kill us. Conspiracy theorists have predicted that hundreds of times before, and were always wrong.

      And if it’s behind the Sun now, why didn’t we see it six months ago when we were on the other side of the Sun?

      Astronomers have instruments sensitive enough to measure the mass of asteroids from their tiny gravitational perturbations on Mars, and you think they could have somehow missed a major planet zooming towards us? Come on, be realistic.

  14. This is not new. The theory of the counter-earth was proposed by the Pythagorean philosopher Philolaus in the fifth century BCE. But you wouldn’t know that, would you, O child of yesterday?

  15. In the words of Douglas Adams … “There is another theeory that states this has already happened”…

    Current thinking states that the Earth was in collision with a planetary-sized body called Thea, which merged and splashed off what is now our moon. It is POSSIBLE that this was an object which shared Earth’s orbit and eventually collided with us. The result of such a collision would be similarly catastrophic.

    As for my favourite “Counter-Earth” Sci-Fi – there’s either John Norman’s “Gorean Cycles of Counter-Earth” books, or Doctor Who – the Cybermen originally came from Mondas which was a “Counter-Earth”.

    1. I loved this series of books. They came out with two different publishing dates…One with covers that looked like Frazetta art. I regularly used the name Marlenus of Ar as my hacker name back in the 80s!

  16. I seem to remember that there was a short story by PK Dick called “The grass is always greener” in which a counter earth was far more evolved than ours because it only had one religion! I can’t seem to find this story any more though!

  17. Ok, I’m not good at all the sciency stuff, but isn’t this is a no-brainer? Do we really need the L1 to L5 stuff? Just look at any snapshot from just about every probe we ever sent that turned its camera back on our planet and solar neighborhood. Isn’t every dot accounted for?

  18. If a small enough object can exist in orbit around the sun at L3, how large can this small object be? Pluto sized? Moon Sized? If there is no planet at L3, can’t there be a dwarf planet?

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