Gravity is not a defined term. Meaning it can't be used in science. Now if you are discussing density that can answer your question easily.

Think of how gold in water, compared to oxygen in water. Because of the surrounding volume we can observe difference in density.

Rain is more dense that nitrogen gas so there for we have rain.

LOL... two idiots arguing with each other and they're both wrong.

Kiwi prove me wrong. Just keep trying. I will applaud the day you have "gravity" more figured out than the rest of the class. People have not accepted that gravity was a stupid farce. I imagine you think there is a tangible form time and space. Which has never been proven, and will never be proven. It is a measurement of reality not a tangible force. Gravity was another trial for that concept, and it has since failed.

They are not more dense than the force created from a rotating planet. That is the kicker. On top of the fact that the "vacuum" of space implies a constant motion. This again is more powerful than a space shuttle or astronaut. So unless you using the force of another celestial body you will just keep moving in the direction of moving pressure. For example solar sails could work off solar flares.

How does density cause things to fall?

Well first it is good to remember that heat/energy is motion, and pressure is direction. So even on micro level we can see structures move in beats. Constriction, and expansion.

Secondly density will cause the object in question to fall if the volume occupied is less dense. Other wise like oxygen in water that bad boy rises fairly fast. UFO space craft use this same principle. Turning something into a photon from a solid, gas, plasma, or liquid state is a large burst of energy. A beach ball under water.

Imagine if that beach ball was full of water, but by using reverse polarization (or quickly safely heating the ball up) you separated the oxygen in it? Well boom that sucker moves. Which main stream science doesn't even consider when building vehicles. The reality is jet propulsion is straight up primitive. Nothing in nature uses that pattern.

Secondly density will cause the object in question to fall if the volume occupied is less dense.

Nope. Density has nothing to do with the direction of motion. There has to be some other force giving a direction to the motion. Dense objects fall toward the center of mass because of gravity. No gravity, no falling.

Consider this: In a lab we set up a sphere of water containing within it a small balloon of much less dense gas. What happens if the balloon is above the center of the sphere when it is released? It "floats" away from the center... right?

So that could be because the balloon is less dense than the water and the water is pushing it to the surface, trying to move it out of the water.

Now we do the same thing but release the balloon below the center of the sphere. This time it "floats" toward the center of the sphere of water, initially becoming deeper within the sphere.

How does this work? If the more dense water is pushing the balloon to the surface, it should push it away from the center... right? So why does the opposite happen?

It happens because in reality all the water in the sphere is trying to fall towards the center of mass, which on earth is the center of the earth. The water is "falling" towards the center because gravity is pulling on it with a strength relative to its density. The less dense balloon is also being pulled to the center of the earth, but less strongly. This causes the balloon to float to the top of the sphere, no matter where it is released.

The direction the balloon moves is solely governed by the direction of gravity, and has nothing to do with density.

If the gas in the balloon is less dense than water, but more dense than air, the balloon will rise until it reaches the less dense air, then will simply sit there, because gravity stops it from moving any higher. If the gas in the balloon is less dense than air then it will keep rising until it is high enough above the earth than the density of air is less than the density of the gas within it, and then it will just sit there.

At no point does gravity stop working on it, and the only reason it floated up to that altitude is because gravity was working more strongly on the air around it.

Put simply - no gravity, no buoyancy.

Your lab experiment doesn't work because the volume occupied has not changed. IF we were in the dead middle of space your point would be proven. However none of that really matters.

Humanity hasn't put this together, but a center point of density is why our planet is a sphere. More over pressure from heavy density adds the direction you are looking for in my science. Much like the formation of a planet the key factors are HEAT, and PRESSURE.

To add a little more on this cake, you should be aware that black matter has been disproved. Which means is "Space" is truly a translucent void. Most likely being pushed along side the galaxy, or large cosmic object moving. Ideally our very reality hinged on something becoming so dense that it broke threw a bottom layer funneling all of matter into this cosmic sink hole. Which creates the spiral effect all of this reality resembles.

Space isn't zero gravity. It's microgravity

Meteor showers aren't objects being being pulled across space to earth. It's the Earth's orbit taking it through debris fields. The gravity from Earth (and other planets - Jupiter, for instance) can affect the trajectory and orbit of the debris fields, but I think you're just largely misunderstanding basic astrophysics.

how does it stop working on astronauts

It doesn't. The speed at which they are orbiting the Earth keeps them in a perpetual state of free fall. They are going around the Earth at 17k mph. Their orbital velocity essentially makes it so they are falling around the Earth rather than to it.

Same effect as the so-called "Vomit Comet," except they are able to sustain it for as long as they are in orbit.

Let's think about this rationally.

You really ought to take your own advice. As I mentioned in another post, the answers to your questions are literally a few seconds of searching away.

But let's be honest here: you're not asking these questions in good faith. You're not actually curious about the answers. You've made up your mind and think you're smart enough to play a game of "gotcha."

Unfortunately, you've chosen some pretty basic stuff to base your game on. Trying something a little more complex, something that even layman couldn't answer themselves with a four-second Google, and maybe you'll do better with your bait.

I can tell when people are clueless based on how they argue.

Yes. Yes, this is a very, very correct thing you've said.

Very, very correct.

(Hint: When you're in a car going 100mph, you're not being forced to the back of your seat, are you? But you are when you're accelerating hard to 100mph. Hmmmm. I wonder why that might be, and how they might relate to your totally honest, totally sincere question?)

In a turning car, friction with the road causes the car to turn, but the person inside it doesn't feel the friction from the road. All the person feels is the car turning while he continues in a straight line. If the car suddenly vanished the person would continue in the straight line.

In space the force that is turning the space craft is also directly turning the astronaut. If the spacecraft suddenly vanished the astronaut would continue to turn.

That's the difference.

They can't explain this to you due to the same reason I can't explain simple mathematics to a squirrel. The recipient doesn't have sufficient brain power to understand what is being presented to them.

Perhaps you would enjoy /r/eli5 or /r/politics. No thinking required.

Why does it have to be an argument? Did you really come into this with the assumption that you were 100% right and anyone who disagreed with you or pointed out the flaw in your logic was "arguing" with you?

I guess what I'm asking is, did you approach this willing to even accept the possibility that your hypothesis was incorrect? It seems like you didn't, and wouldn't that kinda defeat the purpose of a conversation?

I'm totally willing to be wrong

No, you're not. If you're not going to be honest, at least be honest about this and admit that you came here with your mind already set on one thing and no amount of information, proof, data, explaining, or teaching is going to sway you.

"I'm just questioning the status quo, man!" It's laughable. You're either purposely hoping to wind people up or you're broken.

Either or, it's not a good look.

You really ought not resort to ad hominem attacks. It's practically what they want you to do.

It's practically what they want you to do.

I'm okay with that. If this was someone asking sincere questions and truthfully looking for answers to them, no problem respecting that and trying to have a decent discussion with them.

They're not, though, and that is evident. Whether simply trolling or they're truly this out of it, it doesn't matter. After a certain point, neither scenario is worth a great deal of time or respect. They've gotten many, many good and factual answers throughout the thread. That's not what they want though. Nothing wrong with calling them out on it.

Besides, none of the above is an ad hominem attack. I didn't call him a delusional idiot or transparent troll, I accurately noted that he's not asking questions in good faith, the reasons why are obvious, and if he really wanted answers he could have them pretty quickly.

If I crossed a line I'd own it, but I'm pretty comfortable with my posts in this thread.

Their trajectory isn't changing, it's a constant turn around the earth. If they were to suddenly fire full boosters or whatever in the opposite direction, the astronauts would probably all hit the wall on whichever side the boosters is.

Why are boosters pointless in a vacuum?

It doesn't stop working on Astronauts, it just becomes very minimal because they are far enough away from an object of mass (the Earth) to see the noticeable effects. Stuff like Meteors have already been set in motion in their orbits eons ago and their motion is carrying them back and forth. As they get closer to the Sun they speed up and shoot back out but as they get farther away they slow down until the begin falling back into the Suns gravity well.

Like most things in science or really any specialized field you will find that there is the simplified layman's term that gets the point across to the average person, and then there is the technical definition of things which make the picture more complicated. This is the laymen vs. technical definition.

Literally from NASA itself:

"Microgravity is the condition in which people or objects appear to be weightless. The effects of microgravity can be seen when astronauts and objects float in space. Microgravity can be experienced in other ways, as well. "Micro-" means "very small," so microgravity refers to the condition where gravity seems to be very small. In microgravity, astronauts can float in their spacecraft - or outside, on a spacewalk. Heavy objects move around easily. For example, astronauts can move equipment weighing hundreds of pounds with their fingertips. Microgravity is sometimes called "zero gravity," but this is misleading."

This is incorrect. The gravity they feel from the earth isn't that much weaker than what we feel at the surface. They are being accelerated toward the earth at about 9-ish meters per second per second (it's 9.8 here on the surface).

It's the orbit that makes them appear to be weightless.

Thanks for the correction! Always been more of a history person, just trying to explain what I remember from my Astronomy class lmao.

Isn't it the fact that they are under the same gravity as the spaceship? You don't even need to be orbiting, just jump off a cliff and you feel weightless. Push a box off a cliff and put a camera inside and then everything inside looks weightless too.

Yup! As long as gravity is the only force acting on them (they're in free fall) they will appear to be weightless. They're not weightless (gravity is still pulling them down, being pulled down by gravity is how we define weight) but they appear to be weightless next to all the other stuff that's falling right along with them.

But, in order orbit in the first place, you need the force of gravity acting on you. So it's important that they still feel gravity pulling on them, otherwise they'd just fly into space. What's more, it doesn't really matter how strong the gravity is. It could be 100 times greater than earth's gravity, and as long as they're in free fall, they'll still feel weightless.

The answer is that gravity doesn't "stop working" at all. Zero gravity doesn't exist. And you'd know that if you took all of five minutes to educate yourself.

Again, it's microgravity. The force of gravity is literally lessened because they are far enough from a planetary mass. Gravity reduces with distance from mass.

This is true, but it isn't the reason they appear weightless. The force of gravity on them is still about 9 meters per second per second (it's 9.8 here on the surface). The astronauts appear to be weightless because they're in free fall, not because the force of gravity has significantly reduces.

You've walked into a logical minefield repeating things either not understood or purpose misinformation.

Gravity and mass do not appear to be related [cannot be logically correlated without additional variables].

The moon is 1.2% the Earths mass and said to be 1/6th of the gravity. Mars and Mercury are both claimed to be 3.7m/s2 gravity, but the mass of Mars is Mercury's doubled.

Gravity has also never been experimentally proven (by objective physical evidence) on another celestial body. Besides the silly hammer drop video on the moon, which is not a proper experiment.

It works on the astronauts just like it works on their space ship. The reason you feel it on earth when you're standing on something is that you can't be pulled any further in, because the ground stops you.

But imagine you're in a box being held up by a cable and the cable snaps, then you'll feel "weightless" inside the box until you hit the ground.

You can literally pay to fly on a plane and feel zero gravity for a few seconds. I think they climb up high and then dive down.

Am I, because as I understand gravity is part of astrophysics.

Yes, and you misunderstand gravity, so vanitypridelust's point stands.

Meteors aren't pulled to Earth by gravity. They are already traveling at a high rate of speed. Earth's gravity might speed them up a minute amount but that's it. Think of gravity like magnetism.. when a magnet is close to a metal object the force is strong but then as you move it away the force disappears quickly.

Which magnetism are you talking about? In orbit they are traveling at an immense speed.. which overcomes the force of gravity. Think of it like firing a bullet.. the bullet overcomes the force of gravity. But the spacecraft is traveling at a speed much faster than a bullet even. And it takes an immense amount of energy to get a heavy weight to that speed. So it is inertia that overcomes the forve of gravity - the same would be true of magnetism too.

If they were in the atmosphere it would effect their bodies. You also have to accelerate slowly.

It takes a massive amount of energy to overcome gravity enough to get in orbit. This is why they call orbit endless falling... you haven't overcome the earth's gravity forever.. eventually you slow down and fall to earth again. But it's the speed and distance from earth that allow it.

It still wouldn't affect their bodies, would it? The hull of the ship would be affected, but to the people inside it wouldn't make much difference whether the ship was in the atmosphere or not.

If you accelerate too fast it will crush you against the inside of this ship. This is why acceleration has to be gradual. It is the same idea as coming to a stop very quickly but in reverse. Inertia creates this issue again. A resting mass has has its own kind of inertia.

Inertia is the resistance of any physical object to any change in its state of motion. This includes changes to the object's speed, direction, or state of rest. Inertia is also defined as the tendency of objects to keep moving in a straight line at a constant velocity.

I think you might have replied to the wrong comment. I was talking about acceleration in a couple others, but here I was referring to the fact that it would make no difference to an astronaut in a spaceship whether the ship was flying through atmosphere or not.

The ship is sealed, so they could be in space or in the air or even under water, and the inside of the ship wouldn't care. Either way it's sealed.

I might have been referring to the atmosphere slowing the craft down more quickly. Not sure... In space there is no atmosphere so a bullet or anything else will travel longer than a bullet close to the Earth's surface.

Yep

All rockets overcome the force of gravity.

Airplanes overcome the force of gravity with thrust from engines and lift from wings.

You personally overcome gravity on a daily basis by merely standing and walking with your muscles.

This is true... the thing is at 30 times the speed of a bullet you travel so far sideways you miss the ground when you fall, and have to do it all over again.

And unlike a bullet, in space there is very little friction to slow you down.

It's called "orbit".

Think of it like firing a bullet.. the bullet overcomes the force of gravity.

Actually, it doesn't. If you fired a bullet sideways and dropped an identical bullet at the same time from the same height, they'd both hit the ground at the same time.

The difference is one would have moved hundreds of yards away away before it hit the ground.

True.. but traveling hundreds of yards through the atmosphere at a high rate of speed is a big deal... gravity is what makes it a big deal..

which the bullet overcame to do it.

Nope. At no time does the bullet "overcome" gravity. It simply travels sideways at the same time as it falls.

That's overcoming gravity.. otherwise the trajectory wouldn't change.. If you aim the bullet up it is overcoming gravity by the delay when it hits the earth.

If you aim the bullet up it is overcoming gravity by the delay when it hits the earth.

Nope. Even if you aim the bullet directly upwards, the bullet isn't overcoming gravity. The instant it leaves the barrel it begins to slow down, because gravity is acting on it.

Gravity is always acting on it, and gravity always wins.

Even when you escape earth's gravitational well, you're still in the sun's gravitational well. Even when you escape the sun's gravitational well, you're still in the galaxy's gravitational well. Even if everything else in the universe except you and your spaceship disappeared... you'd be affected by the gravitational attraction between you and the ship itself (although it would be extremely weak).

We know of no way to "overcome gravity". All we know how to do is to move fast enough so that we can move from one gravitational well to another.

I didn't say gravity wasn't there... you don't seem to know what "over come" means...

I can overcome the control of another person.. that's doesn't mean they aren't there acting on me..

I also said it was temporary. The point is that you are modifying the effects of gravity by overcoming their normal effects.

why is there no gravity in space?

There is gravity in space.

So how is it that gravity just stops when they travel to space?

It doesn't.

how does a space shuttle enter space and then they start floating around in No gravity. Good luck explaining this.

The shuttle is in a perpetual state of free fall. The astronauts inside are not actually weightless.

The answers to your questions are literally a few seconds of searching away.

Free fall? Then they would be plastered to the roof. Not in a suspended state they can freely move up and down in.

Not true. Imagine being in an accelerating car. You'd be pushed against your seat. Now imagine a really fast car that's at a constant speed. You wouldn't feel it at all.

The ship is heavier and more dense . As soon as the propulsion stopped it would revert to earth and take them down hard.

Not if it's flying sideways so fast that it's in orbit.

They are trying to get away from the center. But the centripetal force of gravity counters that tendency. It's not a coincidence, they did a whole bunch of math first to make sure it lined up like that. But the force of gravity and their tendency to move away from earth balance each other. We call this an orbit.

They would have to constantly be forcing themselves away from the attraction...

This is where you're incorrect. Let's look at you, right now. You maintain your altitude by standing on the ground. The ground is providing the force necessary to keep you up. But, obviously, you're not weightless. But, there's another way to maintain your altitude.

Let's take you a little bit higher (so it's easier to visualize) and release you from a few hundred thousand kilometers away. Obviously, there's still gravity out here, so you'd plummet toward the earth.

However, rather than just dropping you, launch you side ways, really fast!

Well, you'd still plummet toward the earth (gavity's gravity after all). But, the gravity would be trying to over come your initial speed. As you feel toward the earth, you'd continue to move sideways. If I threw you fast enough, gravity wouldn't be able to pull you in, and you'd miss the earth entirely.

If I threw you just hard enough, though, you'd miss the earth, but gravity would have also deflected your path quite a bit (a whole 90 degrees!). Gravity canceled out that initial push I started you with, but all that falling you've done has given you a new speed, in a new direction. But gravity is now pulling sideways to that new speed (because you moved around to the side of the planet). So the whole thing repeats again... and again... and again! You're actually using the planet's own gravity to stay up there! We call this effect an orbit!

r/shittyaskscience

The centrifugal motion of orbit counteracts the centripetal force of gravity. If they were going too slow, they'd fall to the earth. If they were going faster, they'd escape earth's orbit go off into space.

And they are being forced away from the center, which is what orbit is. It's just that the ship they're inside is also being forced away from the center.

Yet another thing that has bee explained to you multiple times in this thread, but that you've chosen to ignore.

Why do you pretend to be curious for knowledge when you're really not? Do you just need attention that badly or are you legitimately having difficulty processing this information?

It is pretty fast, but it doesn't instantly accelerate to that speed. While it's accelerating the astronauts definitely feel the force of the rocket pulling against the force of gravity, pushing them into the back of their chairs as gravity pulls them down but the rocket pushes them up.

It isn't that much of a jolt if you accelerate slowly enough though, which is why it doesn't kill them. And once they are in orbit and at a constant speed, there's no more inertia.

The whole earth is traveling through space at 67,000 miles per hour, but we don't feel that since we are all moving at the same speed and so our velocity relative to the earth is 0.

Gravity is “produced” by large objects. Think of it like a force field sucking you closer to itself. Further you get away from it, the less of an effect gravity has. Go a smaller object like the moon and gravity has a smaller pull. Go further away from any big objects and you can get close to a state of zero gravity, but never total lack of gravity.

Enormous, how does it's gravitation attract the moon, yet here are the astronauts floating freely between them?

Multiple people in this thread have explained it to you.

Your refusal to listen shows that your questions aren't honest and that you have an agenda.

Unfortunately, it's an agenda driven by sheer stupidity, and you can't help the stupid.

The truth is gravity is proportional to the mass of both objects.

The mutual attraction between the moon and the earth is much higher than the mutual attraction between the ISS and the earth because the moon itself is much more massive than the ISS.

https://en.wikipedia.org/wiki/Lagrangian_point

TL;DR: The ISS is under the effect of gravity, about 90% of surface gravity. However, as they fall, they keep missing the earth.

Astronauts are under the effect of gravity, and it's about 90% the strength we feel here at the surface (gravity gets weaker the farther away you are from an object). That means if you suddenly teleported to the altitude of the ISS, you'd start falling at about 9 meters per second per second. In fact, this is about how fast the ISS is falling toward the Earth as we speak. So, why hasn't it crashed, and why do the astronauts seem to float?

If you've ever been in free fall (like on a roller coaster, or one of those reduced gravity planes) you'll know you can get the feeling of being without gravity quite easily. Let's take a look at those planes. The basically fly up really high, then allow themselves to free fall back to earth for a little while, before flying back up to do it again.

If we look more closely at their flight path, however, we'll see something odd. The part were you stop feeling gravity actually starts while the plane is still going upward!

Think about it this way: we know you're in free fall if you only have the force of gravity acting on you. No engines from a ship, no ground holding you up, etc. If the plane is heading upward, then shuts off their engines, they still have their upward momentum that has to be canceled out first, before they start falling downward. But, the moment they cut off their engines, they are in free fall; the plane is only under the effect of gravity.

So how does this apply to the astronauts? Well, the ISS doesn't have any engines holding up there, so they are free falling too. Why haven't they crashed yet? The ISS is also moving sideways very fast as well. As it falls, it is moving sideways. It's moving sideways so fast (7 kilometers per second), the earth actually curves away before it would hit the ground.

So, the astronauts are under the effect of gravity, but everything around them is too. It looks like they aren't because all the stuff around them is plummeting toward the earth as well.

You're right! Everything is attracted to the sun.

When you orbit the earth, you're also orbiting the sun. You, right now, sitting in your chair on the computer, are currently orbiting the sun. If the earth vanished out from under you, and you were floating in space, you'd still be orbiting the sun. What're more, if the sun then disappeared, you'd still have your orbit around the galactic core!

As we speak, you are being pulled directly toward the center of the sun! You're in free fall toward the sun! However, just like the ISS here on earth, we're also moving sideways very quickly. As we fall toward the sun, we're also moving sideways at the same time. By the time we would have reached the sun (about 3 months), we've moved sideways to far that we're actually basically the same distance away as when we started! We call this effect an orbit.

http://www.dictionary.com/browse/proximity

Hope that helps (even though it clearly won't).

So at least the astronauts should be being pulled towards the sun.

They are being pulled towards the sun - the astronauts, their spacecraft, the earth and the moon are all in orbit around the sun. That's because all of them are being attracted to the sun.

The difference is, they are much closer to the earth so it is the dominant force they feel.

"worst troll ever" - comic book guy

You are a troll because you don't even consider the answers people give you. You repeat the same lines no matter the replies you receive to your questions, putting the conversation in an perpetual loop.

Well, you are either trolling or clinicaly stupid to the point of not being able to hold a conversation. Which one is it?

Gravity doesn't stop in space. If you are asking why they don't fall to Earth it is because they are traveling forward fast enough that they stay at the same elevation even though they fall at a constant rate.

Vsauce has a good video on this called "Which direction is down". On mobile at the moment, will update later if need be.

But, gravity doesn't stop, ever. We are being pulled by galaxies and stars from all over. It's just that our planet and our sub are closer and this stronger than those other forces.

It's not exactly outward, but "perpendicular" to the Earth in the direction of their orbit. So while they're falling, they stay at the same height because their speed keeps them going. Thus, they are being pulled down to earth, but because of their forward motion the Earth"falls" away from them. If they were to travel faster thru would start to gain elevation. So, by traveling a specific speed they maintain their elevation.

Second, how is propulsion useless on a vacuum? How else would they move?

They would be have to be traveling outward, not forward.

The earth is a sphere. Traveling forward above it is the same as traveling outward because the surface is dropping away from them.

Astronots :)

So how is it that gravity just stops when they travel to space?

It doesn't. Satellites, the ISS and the Moon stay in orbit around the earth because gravity doesn't stop when you travel into space.

Your ignorance is pretty astounding.

Good luck explaining this.

It's called orbit. Put simply objects in orbit are moving perpendicular to the direction of gravity at a speed that essentially means the by the time they have "fallen" far enough to have hit the planet, they have moved sideways enough to actually miss it.

the state of today's education system folks.

The same way the moon rotates around the earth because , in lieu of a better term: IT is "falling" and earth's gravity is pulling her, thus, creating an orbit.

The same thing happends with the space shuttle. They don't float around in "no gravity" they just fall. continuously.

Here is the lovely Kate Upton to show this to you in a tiny video.

Yet another thing that has bee explained to you multiple times in this thread, but that you've chosen to ignore.

Why do you pretend to be curious for knowledge when you're really not? Do you just need attention that badly or are you legitimately having difficulty processing this information?

It is pretty fast, but it doesn't instantly accelerate to that speed. While it's accelerating the astronauts definitely feel the force of the rocket pulling against the force of gravity, pushing them into the back of their chairs as gravity pulls them down but the rocket pushes them up.

It isn't that much of a jolt if you accelerate slowly enough though, which is why it doesn't kill them. And once they are in orbit and at a constant speed, there's no more inertia.

The whole earth is traveling through space at 67,000 miles per hour, but we don't feel that since we are all moving at the same speed and so our velocity relative to the earth is 0.

True.. but traveling hundreds of yards through the atmosphere at a high rate of speed is a big deal... gravity is what makes it a big deal..