There are a lot of misconceptions in popular culture about space, astrophysics, and what's possible versus what's probable. Not to ruin your love of space travel movies and graphic novels, but some of that stuff is straight-up impossible.
Space makes you float
Jupiter orbits the sun
Here's a stunner: Jupiter doesn't orbit around the sun. At least not if you go by the true definition of "orbit."
This is how National Geographic explains it: "When smaller objects orbit bigger objects, the smaller object doesn’t travel around the larger in a perfect circle — both objects orbit a meshed centre of gravity. In a way, they meet in the middle. This isn’t the case with Jupiter."
Instead, the center of gravity between the sun and Jupiter is just above the sun's surface, not inside of it. (So, Jupiter technically orbits around a space just above the sun.)
A space shuttle landed on the moon
US moon landings and NASA's space shuttle programs were separate accomplishments in space that do not overlap in time. So, no space shuttle has ever landed on the moon — no matter how fun that sounds. That's not what they were designed to do.
Space isn't that big
We often talk about travel to Mars as if it's just like a trip to the moon, itself a fairly distant place. But space is huge — way bigger than is easy for us to conceive of. Scientists think it's at least 7 trillion light years across. That quick trip to Mars? It takes about 7 months, depending on how close Mars is to Earth in its orbit.
Radiation belts are impossible to pass through
Probes launched in 2012 to study Van Allen Radiation Belts upended a long-held belief that radiation belts couldn't be traveled through. The study found that in certain parts of the belts, there is less radiation than previously thought. So, spacecrafts and humans would need much less radiation protection to travel through them.
Interstellar travel is possible
Space-travel movie fans look away: Interstellar travel is just not going to happen. Certainly not in our lifetimes and probably not ever. There is no conceivable technology that would permit it. And the logistics? The realities? Hardly playing on the strengths of humans. First, as Scientific American explains, there's the problem with damage caused when spacecraft collide with things — even really tiny things. Space shuttles took a beating over the course of their programs. Space isn't just a big emptiness, and running into things would thwart the mission. Also, the time frame required for space travel is problematic; we'd be traveling not for months or years but generations.
Bodies were made for zero gravity
With less gravity to work against, muscle and bone loss happen rapidly. So, say you don't mind becoming spindly, your body would still have to deal with the calcium buildup from the bone loss — which will give you kidney stones. Ouch! There's also the impact that decreased gravity has on our circulatory system. Turns out, we evolved to optimize bodies at the gravity we have here on Earth. Less gravity means more body problems.
