Buzz
Many individuals harbor some significant misunderstandings about space. To be honest, very few of us have actually been there, and there’s a lot left to explore before anyone can fully grasp the truth of what’s happening up there. On top of that, movies often paint a completely inaccurate picture. To help clear things up, here are 10 prevalent misconceptions about space, along with the facts that debunk them.
10. Humans Explode in Space
One of the most enduring and widespread myths is the belief that we would explode if exposed to the vacuum of space without protection. The logic behind this is that, with no atmospheric pressure, our bodies would inflate and burst, like an overinflated balloon. But you may be surprised to learn that humans are much tougher than balloons. Just like we don’t burst when pricked with a needle, we wouldn’t explode in space—our bodies are resilient enough to handle it. While we might swell up slightly, our bones, skin, and organs are durable enough to withstand the vacuum unless something actively damages them.
In reality, several individuals have already been exposed to extremely low-pressure environments during space missions. In 1966, one man was testing a space suit when it decompressed at an altitude of 120,000 feet. He lost consciousness, but surprisingly did not explode, and he made a full recovery.
9. Humans Freeze in Space
This myth is primarily fueled by movies. Many space-themed films feature scenes where a character is suddenly ejected into space without a suit. They quickly begin to freeze and, unless they can get back inside, turn into a solid ice block and float away. The truth is quite the opposite. You wouldn’t freeze if exposed to space; instead, you’d overheat.
You might recall the convection current diagrams from science class. In these diagrams, water heated by a source rises, cools down, and sinks again in a repeating cycle. This process happens because the heated water transfers its heat to the air, which cools it, making it denser and causing it to sink. In space, however, as the name suggests, there is nothing to transfer your heat to, meaning that cooling down enough to freeze is impossible. So, your body would keep generating heat as it always does. Naturally, before you could get uncomfortably hot, you’d be dead.
8. Your Blood Would Boil in Space
This misconception isn’t related to the fact that you would overheat if exposed to the vacuum of space. Instead, it comes from the understanding that the boiling point of any liquid is directly influenced by the pressure around it. The lower the pressure, the lower the boiling point. This means that, in theory, liquids could boil in space, including your blood.
The Armstrong line refers to the point where atmospheric pressure is so low that liquids can boil at the temperature of the human body. However, while exposed liquids would boil in space, your blood wouldn’t. Bodily fluids like the ones in your eyes and mouth, though, would. One man who decompressed at 120,000 feet reported that his saliva boiled off his tongue. But this “boiling” isn’t a searing heat—it’s more like the fluids are drying out. Since your blood is contained within your body, it remains pressurized within your veins and doesn’t boil into gas and float away, even in the vacuum of space.
7. The Sun
The Sun is one of the first things we learn about when studying space. It’s a massive, fiery sphere that all the planets orbit, positioned just far enough away to keep us warm without setting the Earth ablaze. Given that life as we know it would be impossible without the Sun’s light and heat, it’s surprising how many people still have a basic misconception about it: that the Sun is on fire. If you've ever burned yourself on a flame, then you've experienced more fire than the Sun ever has or will. In reality, the Sun is a massive ball of gas that emits light and heat through a process called nuclear fusion, where two hydrogen atoms combine to form helium. So while the Sun does provide light and warmth, there is no traditional fire involved. It’s simply a huge, radiant glow.
6. Black Holes Are Shaped Like Funnels
This is another widespread misconception fueled by the way black holes are depicted in movies and cartoons. While black holes are technically ‘invisible,’ filmmakers often turn them into ominous whirlpools of doom for dramatic effect. They’re typically shown as flat, funnel-like objects with only one side that pulls everything in. However, in reality, black holes are not funnel-shaped at all—they’re spherical. There’s no singular ‘entrance’ that will suck you in; it behaves more like a planet with an incredibly strong gravitational pull. If you venture too close on any side, you’ll get pulled in.
5. Re-Entry into Earth's Atmosphere
We’ve all seen footage of spacecraft re-entering Earth’s atmosphere. It’s a bumpy, intense ride, and the surface of the craft often gets extremely hot. Most of us have been told this heat is due to the friction between the spacecraft and the atmosphere, which makes sense at first glance: A spacecraft, which is in the vacuum of space, suddenly flies into an atmosphere at a mind-boggling speed, so of course it’s going to get hot.
The truth, however, is that friction plays a minor role—less than one percent—in the searing heat we associate with re-entry. While it does contribute, the majority of the heat comes from compression. As the spacecraft speeds back toward Earth, the air in front of it gets compressed and surrounds the craft. This is called the bow shock. The compressed air gets trapped by the spacecraft, and the intense speed causes it to heat up quickly, leaving no time for cooling or decompression. Some of this heat is transferred to the spacecraft and absorbed by its heat shield, but the dramatic heat seen during re-entry is mostly due to the air around the spacecraft—and it’s exactly the kind of phenomenon scientists expect to see.
4. Comet Tails
Imagine a comet for a moment. Chances are, you picture a mass of ice speeding through space, with a trail of light or flame following it. However, the direction of the comet's tail has nothing to do with its movement. Unlike meteors, a comet's tail isn't formed by friction or breaking apart. Instead, it is shaped by heat and solar wind, which melt the ice and send dust particles flying away from the comet. Therefore, the tail always points away from the Sun, regardless of the comet's direction.
3. The Truth About Zero-Gravity
This idea seems so obvious that many people have a hard time believing it’s incorrect. Satellites, spacecraft, astronauts, and other objects in space do not experience true zero-gravity. Actual zero-gravity, or microgravity, is nearly nonexistent in space, and no human has ever truly experienced it. A common misconception is that astronauts float because they’re far enough from Earth to escape its gravitational pull, but it is in fact gravity that causes them to float.
When orbiting Earth, or any other large celestial body, an object is essentially in free fall. As the Earth is constantly in motion, spacecraft don’t crash into it. The planet’s gravity is constantly trying to pull the spacecraft down, but since the Earth is moving, the spacecraft keeps falling instead of hitting the surface. This ongoing fall creates the illusion of zero-gravity. The astronauts inside the craft are also falling, but since they’re falling at the same speed as the craft, they appear to be floating. This same sensation can be experienced in a falling elevator or airplane. In fact, the weightless scenes in the movie Apollo 13 were filmed in a plane designed to simulate zero-gravity. The plane ascends to 30,000 feet and then enters a near-freefall, creating 23 seconds of weightlessness. Although it lasts only a short time, this is the same experience astronauts have in space.
2. Probes
While the Curiosity rover on Mars is widely recognized for its groundbreaking scientific work, many other probes we’ve sent out over the years often go unnoticed. Take the Opportunity rover, which landed on Mars in 2003 with an expected lifespan of just 90 days. Almost a decade later, it’s still operational and roaming the Martian surface.
A common misconception is that we’ve only sent probes to Mars. While it’s true that landing on a planet is far more complex than launching a satellite into orbit, we’ve had more success than many realize. Between 1970 and 1984, the USSR managed to land eight probes on Venus. However, Venus’ extreme atmosphere makes it nearly impossible for rovers to survive for long, with the longest lasting about two hours—much longer than expected.
Looking further out, Jupiter presents an even bigger challenge for rovers than Mars or Venus, as the gas giant’s lack of solid surface makes landing impossible. Nonetheless, scientists sent a probe to Jupiter in 1989 with the Galileo spacecraft, which continued to study Jupiter and its moons for the next 14 years. Six years into its mission, Galileo released a probe that entered Jupiter’s atmosphere, sending back invaluable data about its composition. While another spacecraft is on its way to Jupiter, this remains the only probe to have entered its atmosphere, providing unexpected findings that caused scientists to rethink their understanding of planetary formation and dynamics.
1. Mercury
Since Pluto was reclassified, Mercury holds the title of our smallest planet. It's also the closest to the Sun, which leads many to assume that it must be the hottest. However, that’s not the case, and surprisingly, Mercury can get quite chilly. At its peak temperature, Mercury reaches about 801 degrees Fahrenheit (427 Celsius), which is hot, but still cooler than Venus, which has an average temperature of 860 degrees Fahrenheit (460 Celsius). The reason Venus is so much hotter, despite being further from the Sun, is because it has a thick atmosphere of CO2 that traps heat, while Mercury, lacking an atmosphere, cannot retain the warmth.
Mercury’s extreme temperature fluctuations are partly due to its unusual rotation and orbit. A full orbit around the Sun takes Mercury about 88 Earth days, while a complete rotation on its axis takes 58 Earth days. This means Mercury experiences nights that last 58 days, allowing the temperature to plummet to a frosty -279 degrees Fahrenheit (-173 Celsius) during the long period of darkness.
