Astonishing Outer Space Facts That Challenge The Wildest Sci-Fi Scenarios
Although there's a sliding scale for how scientifically accurate science fiction can be, it can seem pretty fantastical no matter where on that scale it falls. While a story may not have lightsabers or phasers, it can still include some technology that seems like an absurdity until somebody actually figures out how to develop it.
But as unbound from reality as science fiction can seem, it's worth remembering that reality can get just as insane as figments of the imagination. And that's especially true in the vast reaches of space. The more humanity learns about space, the wilder the universe beyond Earth seems.
Earth is constantly getting hit by meteors
Although some people are lucky enough to catch a meteorite on camera as it falls to Earth, and a few are even luckier and find them when they land, these rare events hardly scratch the surface of how many of them end up in the planet's atmosphere.
According to Space.com, about 48.5 tons of space rock hit Earth every day. It's just that they're typically small enough to burn up in the atmosphere. For a meteorite to survive long enough to fall to Earth like the ones around this man's head did, it has to be at least 16 feet wide.
The Moon isn't as round as it looks
Although the Moon seems as round as the Earth when it's shown in pictures or at night, astronomers eventually figured out that its shape is more distorted than it seems. Rather than being perfectly spherical, it's actually closer to a lemon shape.
As for how that happened, the BBC reported that the most plausible current theory states that about 4 billion years ago, the Moon was more malleable due to its mostly liquid composition and closer proximity to Earth. This meant that its tides were stronger due to Earth's gravity and that it was spinning faster, which allowed its thin layer of crust to morph into a lemon shape before the satellite hardened over eons.
About one million Earths could fit in the Sun
According to Space.com, the Sun is large enough that it's possible to line up 109 Earths across its face, but that doesn't scratch the surface of how large it is. That's because if one were to hollow the Sun out, about 1 million Earths could likely fit inside.
With that in mind, it's easy to assume that the Sun is a colossus among stars, especially since nothing in the Solar System can compete with its size. However, the Sun is about average on the scale of how large a star can be.
An asteroid must be more than a mile wide to destroy Earth
Although it's not unusual for people to think deeply enough about the impact of certain asteroids to worry about one causing the Earth's destruction, it may provide some comfort to learn how unlikely an Armageddon-like situation is. As Space.com noted, an asteroid has to be at least 66 feet wide to shatter the windows around its area of impact.
Although they noted that the 525-foot Dimorphos asteroid could wipe out all life in a city the size of London and break windows throughout England if it fell to Earth, even a rock five times as large wouldn't be enough to destroy the world. Better yet, no such rocks are even close to being on a collision course with Earth.
Betelgeuse is 700 times larger than the Sun
Betelgeuse is a red giant star that's nearing the end of its life cycle (which means it will go supernova in about a million years), and to give an idea of just how big stars can get, it's about 700 times larger than the Sun. According to Space.com, that also means that it carries enough sheer energy to burn about 14,000 times brighter.
However, it might be just as staggering to learn that Betelgeuse isn't the largest star in the known universe either. That's because there are other red giants that are up to 100 times larger than the Sun in terms of diameter.
The core temperature of a star is mind-blowing
According to NASA, the hydrogen gas floating within a nebula has to reach the core temperature of about 15 million degrees Celsius (or 27 million Fahrenheit) before it can compress into the core of a star. When people report this fact, they often say that if a grain of sand got that hot, it could kill someone from 93 miles away.
However, astronomer Jishnu P Das broke this thought experiment down mathematically in a Quora response and found that given the difference in scale between the Sun and a grain of sand, a person could get within half a meter (1.5 feet) before they were in danger. Das also noted that the grain of sand would lose its heat extremely rapidly.
Uranus is weird in so many ways
According to NASA, Uranus is similar to other gas giants like Jupiter in that it doesn't have a solid surface, but it's cold enough that it's mostly composed of icy liquids rather than gases. It also appears to spin sideways, but that's because it rotates on a nearly 90-degree axis, which is possibly the result of a collision with an object the size of Earth sometime in the distant past.
Due to its long rotation period around the Sun, half of Uranus plunges into a dark winter for 21 years at a time. It also has a lopsided magnetic field around it that's apparently shaped like a corkscrew. This means that the kind of aurora events (like Earth's Northern Lights) that happen on other planets don't occur around Uranus's poles as they do on other planets.
The most volcanic object in the Solar System orbits Jupiter
Although Earth's volcanic activity has devastated some of its civilizations for centuries, it doesn't hold a candle to the number of active volcanoes on Io, one of Jupiter's moons. According to a 2023 study in Nature Astronomy, at least 266 volcanos have been erupting at once, and researchers have drawn an interesting conclusion from the measure of its heat flow.
Tracking this flow and noting that Io's poles are unusually warm has led researchers to suggest that Io's surface is sitting on a global ocean of magma. After all, it isn't just Earth that tends to have cold North and South poles.
The length of a "year" depends a lot on the planet
Considering the difference in distance between each planet and the Sun, it stands to reason that there would be some variance in how long each of them takes to orbit the Sun. However, the difference between Mercury's orbit and Neptune's orbit is not only a matter of years but well over a hundred years.
According to the National Radio Astronomy Observatory, it's not just the distance that affects the term of a planet's orbit but also its speed. This is likely influenced by the Sun's relative strength of gravitational pull, but the planets closest to it also move faster than the ones further away.
Astronauts' brains work slower in space
Microgravity environments have a wide variety of unnerving effects on the human body, but the brain apparently isn't immune to the ravages of space either. According to the Indiana University School of Medicine, this phenomenon is called "space fog" and can make astronauts feel disoriented and experience a reduction in their cognitive ability.
It's unknown what exactly causes space fog, but the most plausible theory is that the dramatic shifts in gravity astronauts experience as they're launched into space are giving them a severe form of motion sickness. In some cases, it's severe enough to cause mood swings and vomiting. It's possible that the radiation exposure that comes from going into space is also a factor.
Pluto wasn't even a planet for a full rotation
According to the Library of Congress, the earliest known date for the discovery of Pluto was August 20, 1909. After a great deal of debate and consideration since its discovery, Pluto was ultimately delisted from its former status as the ninth planet in the Solar System in 2006.
But while this timeframe is long enough for several generations to pass, this 97-year period accounts for less than half the time it takes for Pluto to orbit the Sun once. This means that Pluto was not only discovered and delisted within a single revolution but that it would have 151 years to go before that revolution was completed. That's right, it takes Pluto almost 248 to orbit the Sun.
Saturn is less dense than water
According to Wired, the density of water is about 62.4 pounds per cubic foot, while Saturn's density is typically measured at about 43 pounds per cubic foot. Given these facts, it's common for people to assume that if someone were to find a big enough bathtub to fit Saturn, Saturn would float in it.
However, Wired science blogger Rhett Allain argued against this, reminding readers that while Saturn may not be very dense, it still has a core. Since that core has to be dense for the planet to exist at all, it's more likely that if Saturn were somehow submerged in water, that core would sink while the rest of Saturn would collapse and dissipate.
There are neutron stars that can spin 2000 times a second
Although many people recognize neutron stars as the possible aftermath of a massive, star-killing supernova, it's less widely known that these waste products are constantly and rapidly spinning. According to Science, that's especially true for the supremely compact variations of these phenomena called millisecond pulsars.
While studying the behavior of a millisecond pulsar called SAX J1808.4-3658 (which admittedly isn't the catchiest name), scientists found that it could spin at a rate of 24,060 revolutions per minute. That means that in the time it takes to read this sentence, SAX J1808.4-3658 spins about 2,000 times.
Space both is and isn't completely silent
When space is depicted in a fictional setting, it's typically a mark of a writer paying attention to real science when it's characterized as a vacuum without any sound at all. However, the truth of this depiction depends on where in space somebody is. According to the BBC's Sky At Night Magazine, the sound is a pressure wave that needs a medium such as a solid, gas, liquid, or plasma to be heard.
If there's no medium for that wave to travel through, there's no sound. Although this means that vacuums are silent, it's also true that not as much space qualifies as a true vacuum as people may think. Within galaxies, nebulae, plasma waves, and gravitational waves, there's enough material to carry some sound at least.
Mars has blue sunsets
Regardless of the planet in question, scientists will attest that the color of a sunset has more to do with the atmosphere of that planet than the Sun itself. And that's just as true of the array of warm colors seen in Earth's sunsets as it is of the oddly blue ones seen while standing on the surface of Mars.
According to NASA, this is because there's fine dust wafting through the Martian skyline that's large enough to make the Sun's blue light punch through quicker than the other colors. As Mark Lemmon of Texas A&M University further explained, "When the blue light scatters off the dust, it stays closer to the direction of the Sun than light of other colors does. The rest of the sky is yellow to orange, as yellow and red light scatter all over the sky instead of being absorbed or staying close to the Sun."
There are storms on Neptune as big as the Atlantic Ocean
According to NASA, Neptune has a habit of forming dark vortexes that form in the planet's northern hemisphere before they typically drift down around the equator and vanish. However, these storms are ultimately pretty unpredictable in terms of when they'll disappear and where they'll go once they form.
For instance, one vortex that formed in 2018 was wider than the Atlantic Ocean and when it started its usual course down the planet's surface. However, this storm suddenly changed direction in August 2020 and headed back north right before it was supposed to enter its "kill zone." In the 30 years that the Hubble space telescope has observed these storms on Neptune, one has rarely — if ever — exhibited this behavior.
Neil Armstrong's footprints are still on the Moon
Each time an astronaut walks on the Moon, they leave footprints like this one. And while the Sun's light has a way of damaging images like flags or photographs left on the Moon over time, the same is unlikely to be true for even Neil Armstrong's footprints.
As the BBC reported, one of the only ways that one of these footprints could wear away is if another astronaut vandalized them. Because the Moon's atmosphere is so slight and doesn't feature any wind or rain, it is expected to take millions of years before these footprints wear away from the Moon's surface.
Mars isn't as red as it seems
Considering it looks that way both from Earth and from its own surface, it's not surprising that Mars is often called "the red planet." But while its surface and atmosphere look that way, it's only due to how dusty it is. According to Forbes, Mars' dust has a way of absorbing red light in the Sun's rays more than it does on Earth, which is amplified by how much thinner the Martian atmosphere is.
As for the surface, the ground on Mars is covered in similar dust that's rich in iron. And the oxidation of that iron leads to rust on Mars just as it does on Earth. However, that layer of dust is also only a few millimeters thick, so if someone were to dig a shallow trench across a patch of Martian ground, that ground would no longer be red.
The center of the Milky Way tastes like raspberries
As The Guardian reported in 2009, astronomers used a radio telescope to comb through a large cloud of dust at the center of the Milky Way galaxy (in which the Solar System lies) in search of amino acids, which would suggest the capacity to form life on other planets. But while they didn't find such a substance there, they did find significant quantities of the chemical ethyl formate.
Although it tends to smell like rum, ethyl formate is also the chemical that gives raspberries their flavor, which means some of this cloud would taste like berries if it could be eaten. But since that cloud also contained just as much of the lethal chemical propyl cyanide as it does ethyl formate, eating that cloud would be a really bad idea.
The Milky Way is on a collision course with Andromeda
According to NASA, astronomers are certain that the Milky Way galaxy and the Andromeda galaxy are heading toward each other, with Andromeda moving 2,000 times as fast as humanity's home galaxy. There's also a chance that before this collision happens, the Milky Way will run into Andromeda's smaller sister galaxy, the Triangulum, first.
However, as violent as this sounds, there are multiple reasons why people don't need to worry about it. Although the Solar System's position is likely to radically change as a result of this collision, it's not close enough to the affected edge of the Milky Way to be destroyed by it. And even if it was, Andromeda is about 2.5 million light-years away, which means this won't happen for 4 billion years.
Jupiter could almost fit the whole solar system inside
It's well-known that Jupiter is the largest planet in the Solar System, but it's easy to underestimate just how much bigger it is than all the other planets. If the Sun weren't larger than the gas giant, there would be nothing stopping the entire Solar System from fitting inside it.
According to NASA, Jupiter is not only larger than all the other planets combined, but it's more than twice as large. So, it's definitely fair to say all the other planets could fit inside of it, and it sounds like it wouldn't even be a tight squeeze.
A day on Mercury lasts longer than a year
Since it's the closest planet to the Sun, it's natural that Mercury would have the shortest years, with each one lasting only 88 days. However, that doesn't mean that its days also run shorter. Thanks to its elliptical orbit and its proximity to the Sun's gravity, the Sun appears to move in the Mercurial sky like it's glitching. In other words, it'll go in one direction, stop entirely, and then move backward a little.
According to the European Southern Observatory, Mercury turns on its axis so slowly that a day actually takes about twice as long as a year there. To be exact, about 176 Earth days pass between sunrises on Mercury.
Comets are 4.6 billion-year-old leftovers
Comets are commonly understood to be largely composed of ice but have a lair of dust and other organic material coating it. According to NASA, that means they tend to be characterized as "dirty snowballs." But that doesn't really express how important they may have been to life on Earth.
That's because the agency also explained that they are composed of leftover materials from the creation of the Solar System about 4.6 billion years ago. And while some, like Haley's Comet, hurtle through space in orbits that can take hundreds of years to complete, others end up colliding with planets or evaporating as they approach the Sun. As such, it's possible that comets were responsible for the water and organic material that gave Earth the foundation for its many life forms.
It would only take 15 seconds to pass out in space
When fiction writers explore what happens to a person who ends up in space without a space suit, the nightmarish consequences tend to vary from imagination to imagination. However, one doesn't need to embellish what would be a pretty grim reality.
Although a person doesn't instantly die when they end up in space unprotected, it only takes about 15 seconds to fall unconscious from a lack of oxygen. From there, it takes only minutes before the point of no possible return is reached. According to Space.com, holding one's breath actually makes this process less survivable because the oxygen expands in the lungs when a body is exposed to space, which causes it to rupture.
Ceres is a big dwarf planet in a small belt
According to NASA, Ceres is the largest object in the asteroid belt dividing Mars and Jupiter. Compared to the other rocky forms in there, it's so large that scientists decided it wasn't an asteroid at all but rather a dwarf planet. As such, it's the first body in the Solar System with that classification to receive a visit from a spacecraft.
But as impressive as Ceres is in the asteroid planet, it's actually very small when compared to other dwarf planets. For instance, Pluto is about 14 times bigger. And while Pluto was large enough to straddle the line between dwarf planets and full-fledged planets, this diagram also shows that even Earth's Moon is bigger than Ceres.
There are more stars in the universe than people can count
According to the European Space Agency, there are an estimated billion stars in the Milky Way Galaxy alone. But naturally, that isn't the only galaxy humanity is aware of. But since even the closest galaxies are difficult to observe and impossible to reach at present, it's hard to realistically know how many stars are in them and the galaxies beyond them.
The agency's website described the process of estimating star numbers as akin to counting individual grains of sand on a beach, which means that the best possible estimate comes from multiplying the stars known to exist in the Milky Way. This leads them to arrive at the ballpark estimate of between a sextillion and a septillion stars, but this is admittedly a rough figure encompassing a huge potential range.
Everest is nowhere near the Solar System's tallest mountain
According to the Smithsonian Magazine, Rheasilvea Mons on the asteroid Vesta is about three times as tall as Mount Everest, with a peak standing at an estimated 13.2 miles high. However, there's some debate as to whether this is even the tallest mountain in the Solar System.
That's because its main competition is the Olympus Mons volcano on Mars (pictured), which the magazine reports as having a 15.5-mile peak. That may sound like it doesn't leave much room for debate, but researchers tend to disagree on these height estimates, which makes it unclear whether the Asteroid Belt or Mars holds the tallest peak. After all, it's tough to get a precise estimate from worlds away.
Humanity has left about 12,676 tons of junk in space
According to the European Space Agency, about 6,500 rockets and 16,990 satellites have been launched into space since 1957. And while about 9,000 of the 11,500 of these objects that remain in space still work, that leaves about 2,500 that don't. That's a potential problem for life on Earth and a serious hazard for future launches.
That's because there have been over 640 incidents that have seen this space debris break up, explode, or collide with other things, which makes the potentially dangerous fragments that could cause further accidents spread out even further. With 12,676 tons of this debris in space and 36,500 of the resulting objects measuring larger than a softball, the odds of this stuff getting in the way increase the more humanity leaves debris up there.
"Sphaghettification" is not as delicious as it sounds
According to the Royal Museums Greenwich, "spaghettification" is a real term in astrophysics that describes how the tidal effect of a particularly strong gravitational field can stretch things towards the source of that pull as it reels them in. This is often used to explain what happens to things that get sucked in by black holes.
Unfortunately, astronomers have every reason to believe that the same thing would happen to a human body that got too close to a black hole. Before that person is pulled in, they'd be stretched beyond the limits of their body by the power of the black hole's light-absorbing gravity. However, the museum website also noted that this depends on the size of the black hole, as a supermassive one may not injure the person at all. That's one risky "may," though.
Stars don't twinkle in space
When people watch the night sky, they can typically differentiate stars from planets by whether they appear to twinkle. While planets stay solidly bright from an earthbound person's perspective, there's a shimmering effect that can be seen with stars. However, that twinkling has more to do with the view from Earth than the stars themselves.
According to the BBC's Sky At Night Magazine, Earth's atmosphere extends about 6214 miles up from its surface, and in that expanse, warm and cold air has a lot of room to shift and mix together at various densities. When light passes through these different air conditions, it bends and distorts, which means that a star's twinkling is really the result of its light passing through the atmosphere.
Neutron stars are among the densest things in the universe
If a star compresses into a neutron star after its energy collapses on itself, that means that all of the mass that the star used to have gets packed into an area that's typically only about 12 miles in diameter. According to the U.S. Department of Energy, that makes them denser than the Sun, despite the fact that the Sun is 72,000 times bigger.
As such, this makes these tightly bound balls of leftover heat and energy some of the densest objects in the known universe. To put it in perspective, if someone were to take enough of a neutron star's material to fit it in a teaspoon, that small sample would weigh about 10 million tons.
The temperatures on Mars are all over the place
Like many desert environments, the temperatures on Mars can fluctuate wildly depending on an area's position relative to the Sun. So, while some times of day and year can feel like a balmy 70 degrees Fahrenheit, temperatures during colder periods on Mars can plummet as low as an unlivable -225 degrees.
However, NASA explained that because Mars has such a thin atmosphere, the Sun's heat can leave the planet just as rapidly as it arrives, and that can make a massive temperature difference even across just a few feet of distance. For instance, a person standing at the Martian equator at noon can easily feel temperatures of 75 degrees at their feet at the same time as feeling 34 degrees at their head. Essentially, they can experience winter and spring temperatures at the same time.
Nothing in the universe is stronger than Gamma Ray Bursts
Although Space.com noted that the Milky Way hadn't experienced gamma ray bursts for 2 billion to 3 billion years, they're so bright and powerful that they can easily be spotted from other galaxies. Gamma ray bursts are overwhelmingly powerful explosions that can last between a few milliseconds and several minutes, and which end of this spectrum they fall under depends on what caused them.
If they last less than two seconds, a neutron star either collided with a black hole or another neutron star. If they last longer, they're a sign that a black hole was just created. When they go off, they're known to be hundreds of times brighter than a supernova, making them shine like a quadrillion suns.
The coldest place in the Solar System isn't Pluto
Although Pluto's great distance from the Sun certainly makes it cold, even its most blistering potential surface temperature of -400 degrees Fahrenheit doesn't quite make it the coldest part of the Solar System. It's a close race, but the amazing fact is that the competitor that just beats it out for this honor is closer to home than many people realize.
That's because the coldest known place in the Solar System is actually on the Moon. Specifically, it's the Hermite Crater near the north pole of Earth's natural satellite. According to NASA's webpage dedicated to its Lunar Orbiter Laser Altimeter, the Hermite Crater's temperature is typically about -416.2 Fahrenheit. As for how it can get that cold, it's because the crater features regions that never experience any sunlight at all. Again, that's not even true of Pluto.
A massive trench on Mars puts the Grand Canyon to shame
For those who have seen the Grand Canyon, it's likely hard to imagine a deeper hole than the 500-mile long and one-mile deep recess that stretches across the deserts of the American Southwest. However, NASA explained that the Valles Marineris canyon system on Mars makes even the vast Grand Canyon look positively puny by comparison.
Measuring 2,500 miles long and four miles deep, Valles Marineris not only dwarfs the Grand Canyon five times over but is about as long as the entirety of the United States. With that in mind, it's not exactly surprising to learn that it stretches across 20% of Mars's surface.
The Sun is heavier than everything else in the Solar System
In terms of mass, all of the eight planets combined don't account for even a single percentage of the weight in the totality of the Solar System. And if someone were to add the weight of Pluto, Ceres, all the planets' moons, and every asteroid, comet, and meteor in that same neighborhood together, it would still amount to less than 1%.
According to NASA, that's because the Sun accounts for more than 99% of the Solar System's total mass all on its own. At least, that's an easier way to picture how utterly gargantuan the Sun is than describing it as weighing well over a nonillion pounds.
The International Space Station is the size of a football field
Considering how cramped conditions tend to be for astronauts aboard the International Space Station, it's easy to forget just how large the whole unit is. NASA describes the station's living space as being larger than a six-bedroom house, but that house would have to sit on a lot of real estate to take up comparable space.
That's because the whole station is about 356 feet wide, which is just one yard shy of the full playing space in a regulation American football stadium. That width also dwarfs the 262-foot wingspan of the Airbus A380, the largest passenger aircraft in the world.
Supernovas are hundreds of years old when they're seen
Although people commonly confuse light-years as a measurement of time rather than distance, there is an underlying aspect of time involved in measuring that distance. In other words, when an astronomer spots a supernova occurring through a telescope, that supernova didn't just happen before they were born but before their great-great-great grandfather was born.
After all, when something is 650 light-years away, that means it took light 650 years to make it to Earth from there. As Space.com explained this phenomenon, if the Betelgeuse star appeared to die out and become a supernova tomorrow, that would mean that supernova would have actually happened 650 years ago.
Jupiter's Great Red Spot is a centuries-old storm
According to Space.com, Jupiter's Great Red Spot is an anticyclone, which refers to a high-pressure area of intense storming that has persisted for well over 100 years on end. However, depending on whether Robert Hooke was right in 1664 or Giovanni Cassini was right a year later, that storm could have been raging for over 350 years by now. At the latest, it's 150 years old.
Unlike when anticyclones appear on Earth, it's unclear how exactly the Great Red Spot formed in the first place and just as unclear how it's lasted so long. However, what scientists have observed is that the spot has shown an overall shrinking trend since it was officially discovered in the 19th Century. If this isn't part of a wider fluctuation, this could suggest that the storms will eventually die down, and the Great Red Spot could disappear. Still, that could very easily take decades to happen.
Neptune has only orbited the Sun once since its discovery
According to NASA, Neptune is far enough from Earth that it can't be seen with the naked eye, and since Pluto's demotion, it's been considered the furthest planet from the Sun in the Solar System. As such, it's not necessarily a surprise that it would take 165 years to complete a revolution around the Sun.
However, it's still easy to underestimate how long that is in terms of human civilization. That's especially true when the fact that Neptune was discovered in 1846 is considered. Indeed, humanity has only observed one full orbit in the entire time they've been aware of Neptune's existence, which was completed sometime in 2011.
