How come an orange inside the ISS just floats in the air? We know gravity keeps the Moon in orbit. Why is there no gravity on the ISS?

This is an image of Newton’s Canon. Given a high enough elevation, shooting a canon-ball at increasing velocity will cause it to travel further and further until it just goes into orbit, falling around the earth.

That is what’s happening inside the ISS. It’s called free-fall – the same as Newton’s canon-ball.

The ISS is falling toward the earth. The only reason it doesn’t crash to the ground as it falls is because it’s also moving horizontally so fast that as it falls, the earth curves away and they just keep missing, again and again, around and around. That’s called an orbit.

This is why we don’t say the astronauts on the ISS are weightless. We say they are in microgravity.

As an example, let’s say you get into an elevator at the top of the tallest building in the world, and the elevator drops in free fall. Fun! You would fall at the same speed as the elevator and to an observer you’d appear to be weightless. In fact, if you held an orange, it would appear to float out of your hand.

That would end tragically, however, when the elevator hit the ground. Not fun anymore!

That tragic end doesn’t happen to the ISS because the ground just curves away under them and they keep missing Earth! Inside, however, the oranges float around and the astronauts float because the ISS and everything inside it is falling at exactly the same rate.

Therefore there is gravity up there – almost the same gravity that we experience on the ground. If the spaceship could stop moving forward and just hover somehow (it can’t) then everybody would be able to walk around just like we do here on Earth. It’s only because the ISS is in free-fall around the earth that the people and things inside appear to float.

If you launched a satellite into low earth orbit and let it travel indefinitely without course corrections, how long would it take before it hits another object?

Okay, your question is how long until it hits another object also in low earth orbit, AKA space debris.

In low Earth orbit you are not completely above the atmosphere, though it’s pretty thin up there. Most objects we place in orbit don’t need course corrections and likely succumb to the ever so slight air resistance and over time de-orbit and come down in a ball of fire. The same happens for space debris at that altitude.

There’s a lot of debris at various altitudes, but really most satellites that are released into orbit don’t ever have course corrections. The problem isn’t crashing into something, but gradually slowing down and leaving orbit. It’s true the ISS sometimes has to move out of the way of space debris, but that stuff usually passes many football fields away, and the ISS is a big target. A small satellite is like a bullet. Getting hit by a piece of debris going the other direction is like two bullets hitting each other. Doesn’t happen. In fact, in over 50 years of space exploration, it’s only happened a couple of times.

Why is the International Space Station not in a circular orbit?

Why is the International Space Station not in a circular orbit? The International Space Station is in a circular orbit around a globe called Earth. But if you try to stretch the globe out to flat map it looks like a sine wave pattern. This flat earth map is probably why you’re thinking it’s not a circular orbit. Below the image here is an animation of what’s really happening.

Because of the inclination of the orbit, the space station never actually goes over either pole. So in the sine wave image above you’ll see it seems to curve away from the poles. Below you can see how the ISS travels around the globe to produce an orbit on a flat map like above.

Is it possible to mitigate the extreme gravity of a large planet with an appropriate orbiting space station?

Would it be possible to orbit at just the right altitude and speed to make Jupiter’s gravity ‘feel’ like earths?

 In any orbit, around any planet, you’re going to be in micro-gravity. You will “feel” weightless because essentially you are falling around the planet in an orbital trajectory.

Just like astronauts on the ISS float around their space station, an astronaut orbiting Jupiter would also float around his or her space craft. It matters not how far away from the surface the space craft is as long as it is orbiting above significant atmospheric drag.

In theory, by having a wheel shaped craft that spins slowly, just like in the movies, you could achieve 1G.

 

 

Would it be possible to put a person on the moon for a prolonged period of time?

We are too heavily influenced by science fiction writers, movies and XBox to see it for what it is.

Space. The final frontier.

One day in our futures humans will travel to other planets, terraform them and colonize them. We will spread out and our species will survive, even if our own sun blows up. We have to start somewhere. We’ve been to the moon once. Let’s go again. Let’s live on the moon.

That would be very difficult. We would need a way to supply our moon resident with food, water and food. Perhaps it could be as we do now with the International Space station (ISS), i.e. fly up supplies once in awhile.

The problem is that the ISS is in low Earth orbit at 249 miles above mean sea level. The moon, on the other hand is between 225,623 miles at it’s closest, and 248,855 miles at it’s farthest, and is moving away from Earth at a rate of 1.5 inches per year. The moon is more than 906 times further than the ISS.

Taken distances into consideration, I would say it is not practical to have a living human being on the Moon for an extended period of time unless he could somehow grow his own food, and get oxygen and water locally.

We are too heavily influenced by science fiction writers, movies and XBox to see it for what it is. Hopeless.

The answer to your question, sadly, is no.

Man-on-the-moon