losing dimensionsthis is something that has be a bit baffeled in space

[phat tony]

this is something that has me a bit baffled, i will say sorry because this is a long one.

if i am in a craft in space there is no true up/down/left /right or in and out correct, i do understand that there would be to me but not to the space around me. if i am upside down what can that be based on. to why i am asking that question. if you take a balloon under water and let it go it will rise to the top because of the difference in density but only because of the gravity. if in space there is no real gravity so if you then put a balloon in water where would it go???. my thinking is nowhere.

i was thinking of a pipe in deep space full with very high density gas, inside would be a craft filled with much lighter gas. where would the craft go, same answer would be nowhere am i right or is there enough small magnetic forces from planets or moons to allow the lighter to rise in some way.

i am thinking if the pipe was close enough to earth say 200,000km from earth there might be enough magnetic force to cause something to happen. yes/no?????

[acey]

You're quite right, our notion of "up" and "down" is based on gravity, i.e. "down" means towards the centre of the Earth (or any other gravitating body we might be standing on, e.g. Moon). This fact has been appreciated since at least 400BC.

If you were in zero gravity and had a fluid with a bubble in it, the bubble would not move (unless there was turbulence or motion in the fluid). Similarly, fire in zero gravity does not form rising flames, instead it becomes an expanding sphere of hot gas.

If you had a pipe filled with dense gas, containing a craft containing less dense gas, the craft would go nowhere. As to magnetic forces, consider the extent to which objects on Earth are moved by our planet's magnetic field: a compass needle needs a low-friction bearing in order to deflect at all. In space it's no different, except that the effect is weaker.

The most highly magnetised bodies are stars called magnetars. One of those at the distance of the Moon could be able to make small steel objects move on Earth. But there aren't many of those around, and they're spaced a long way apart. So "magnetar propulsion" would be a very slow and inefficient way to travel.

[phat tony]

Nasa are looking at creating gravity in space with spinning, this would be creating force in a spinning motion. it would not be gravity as we know it but it could create the feeling and some effect of gravity. but to me it would be like g in a car, when you accelerate fast from a standing position you feel massive g but as you continue you feel less and less until your body catches up with the speed. would that not be the same, what i mean is would they not have to keep accelerating and would they not then hit their max speed and lose that effect of gravity. as for the bubble in the water would the water and bubble if floating not just hit the back wall instead of feeling the gravity we are talking about that would cause the bubble to rise????.

[Ponoobersie]

Nice post! and an interesting one too.

Here is another thought for you....gravity is a force made by an object, the larger the object the greater the gravity yes? So lets say we could stand at the VERY centre of our planet.....where would gravity pull you?

[phat tony]

it could pull us in every direction. i do have my wife confused when i talk about this one, if you are standing on the true north pole you no longer have east west or north, everything is south from that point. drive her crazy, she just can understand.

[phat tony]

i don't understand what makes gravity, they say its based around mass but so many planets in our solar system have a larger mass but less gravity. i always believed that it is electric due to the shifting plates creating static electricity but i am no professor and i would believe them before i would believe me. static is crazy. a standard magnet does not effect organic material as much as static does why???? i do feel that it would explain why gravity has such and effect on everything.

[shellfish]

I just have a wife to pull me in every direction every time we go shopping...... Harumph lol

[phat tony]

hahaha mine is out at the moment and i can feel the money getting pulled out of my bank account as we speak hahahaha

[Ponoobersie]

Hahaha!!!! I think we are all in the same boat there!

Ye gravity is funny one, id love to know a profs thoughts on the standing at the centre of the earth though....its an interesting one for sure

[acey]

Newton proved that the gravitational field at the centre of any uniform spherical body (e.g. Earth, approximately) is zero. The force that's pulling you in every direction just cancels out: you'd be weightless.

[Ponoobersie]

But wouldnt the mass around you greate a gravitational pull?? because the shear mass around you would be great.

[Zakalwe]

But wouldnt the mass around you greate a gravitational pull?? because the shear mass around you would be great.

Yes it would, but as you are in the centre of that mass, it would pull you in all directions at the same time. Hence you would be weightless. Now , consider this. If you were in a spacesuit, in an evacuated (ie in a vacuum) hollow sphere at the centre of a planet, then unless you had something that you could throw away you would be trapped. There is nothing to push against so you would not be able to move......

[freeflyjay]

Nasa are looking at creating gravity in space with spinning, this would be creating force in a spinning motion. it would not be gravity as we know it but it could create the feeling and some effect of gravity. but to me it would be like g in a car, when you accelerate fast from a standing position you feel massive g but as you continue you feel less and less until your body catches up with the speed. would that not be the same, what i mean is would they not have to keep accelerating and would they not then hit their max speed and lose that effect of gravity. as for the bubble in the water would the water and bubble if floating not just hit the back wall instead of feeling the gravity we are talking about that would cause the bubble to rise????.

that is centrifugal force to create an illusion of gravity, any object will continue in the same direction unless acted upon by another force, imagine a wheel but each atom of the wheel as a single part each part wants to go in a straight line but cann`t as it is joined at a tether at the middle, if you were inside the wheel your body would want to be going in a straight line too but could not as the inside of the wheel is in the way, the faster the spin the more force is needed to stop you from going in a straight line and the higher the illusion of gravity.

[Ponoobersie]

Yes it would, but as you are in the centre of that mass, it would pull you in all directions at the same time. Hence you would be weightless. Now , consider this. If you were in a spacesuit, in an evacuated (ie in a vacuum) hollow sphere at the centre of a planet, then unless you had something that you could throw away you would be trapped. There is nothing to push against so you would not be able to move......

My brain hurts :eek: but I do see your point, that would be ever so slightly frustratiing now wouldnt it haha

[phat tony]

freeflyjay i understand centrifugal force, the way i always explain it is a conker on a string or water in a bucket. the point i was making was not if the body would keep spinning but if it would still feel the force as it did in the beginning without increasing the speed. like in a car. it would be the same feeling to the body but as in a car you need to keep accelerating to keep feeling the g. this is what i was saying about the centrifugal force, you would need to keep accelerating for the body to feel the g.

Ponoobersie life in a vacuum would be very boring without my pc, the idea of no force but only force is a strange one. you cant go in any direction without feeling like your getting pulled back and would you not get ripped apart by the force trying top pull you in every direction because the only part of you that would feel true 0 g would be a very small part of your inside, did you ever see a slow-mo of a wet tennis ball in mid air spinning. the water flies off but as acey said there should be 0 g in the center so no water would fly off if in the middle. my brain is hurting a bit with that one.

we have drifted from the thread topic but in a good direction. back to my first question mixed with my other ones. could we not create a small static energy that would act as a fake gravity so the balloon would rise from the water?????, the static energy would pull the water back but the balloon would get pulled back less due to its density compared to water. or would the balloon get pulled back just slower than the water????

[Zakalwe]

Why would you get ripped apart? The difference between the gravity at the tips of your fingers and at the centre of mass of your body would be tiny....in fact, you are experiencing it all the time. There is a slight difference in the gravity felt at your feet compared to the gravity at your head. The "strength" of gravity declines with the square of the distance, so the distance from your feet to the centre of the Earth is slightly different from the top of your head to the centre of Earth. Hence your body already "feels" the difference in gravity.

Now this raises some interesting effects. As time runs at different speeds in different gravitational fields, this means that your hair is ageing at a slightly different rate from your toenails!

This difference in gravity is described as a tidal force

In a small gravity field the effect is pretty weak, but in strong gravitational fields the effects can be devastating. In the presence of a massive field (approaching a black hole, for instance) the tidal force would rip you apart.

[Zakalwe]

we have drifted from the thread topic but in a good direction. back to my first question mixed with my other ones. could we not create a small static energy that would act as a fake gravity so the balloon would rise from the water?????, the static energy would pull the water back but the balloon would get pulled back less due to its density compared to water. or would the balloon get pulled back just slower than the water????

Just move the container of water. Inertia still applies, so the balloon (having less inertia than the surrounding water) will move. The same effect happens if you hold a helium-filled balloon by its string whilst sitting in a moving car. If the driver brakes hard, the balloon moves backward, as the air (having more inertia) moves forward.

[freeflyjay]

freeflyjay i understand centrifugal force, the way i always explain it is a conker on a string or water in a bucket. the point i was making was not if the body would keep spinning but if it would still feel the force as it did in the beginning without increasing the speed. like in a car. it would be the same feeling to the body but as in a car you need to keep accelerating to keep feeling the g. this is what i was saying about the centrifugal force, you would need to keep accelerating for the body to feel the g.

Ponoobersie life in a vacuum would be very boring without my pc, the idea of no force but only force is a strange one. you cant go in any direction without feeling like your getting pulled back and would you not get ripped apart by the force trying top pull you in every direction because the only part of you that would feel true 0 g would be a very small part of your inside, did you ever see a slow-mo of a wet tennis ball in mid air spinning. the water flies off but as acey said there should be 0 g in the center so no water would fly off if in the middle. my brain is hurting a bit with that one.

we have drifted from the thread topic but in a good direction. back to my first question mixed with my other ones. could we not create a small static energy that would act as a fake gravity so the balloon would rise from the water?????, the static energy would pull the water back but the balloon would get pulled back less due to its density compared to water. or would the balloon get pulled back just slower than the water????

tony you clearly do not understand centrifugal force then, you do not need to keep accelerating , get in your car go to a roundabout and drive around it at a fast constant speed and you`ll soon see that, the g force experienced in acceleration is a different thing entirely.

[Islander]

Erm actually any object in a closed circular path is constantly accellerating towards the axis of rotation - this is centripetal force. What you experience as a g force is the reactive centrifugal force that opposes the centripetal force.

If you weren't accellerating, you'd be travelling in a straight line (Newton's first law).

[phat tony]

freeflyjay your right and i am wrong, the roundabout is a great example, thank you for putting me right . the silly thing is when i was younger i went in the wall of death on my bike and once i hit my target speed i hit a toggle switch to keep that speed so i was thinking i knew the force but i was not thinking right at all. did you ever go on the Mexican hat ride. you get a mixture of both forces or g if you like. the centrifugal and straight line g. would that be the same for the astronauts in a spinning craft.

[Thirdway]

I still can't quite get my head around newtons experiment with the spinning bucket of water. Yes it forms a dish in the water, while the static bucket exhibits no dish effect, so how does the water know to do that ? It's almost like the experiment is another quantum double slit experiment.

I say, gravity has nothing to do with mass at all, it just happens to occupy an area of corrupted space because that's how the universe is balanced. Mass just effects other mass through electro weak forces. When insufficient mass occupies one of these previously balanced areas it tries to rebalance and insufficient local mass is available, inevitably the corrupt space is revealed as a black hole.

All the time there are masses in motion with respect to time ( universal time not earth time), they travel ever expanding curved space because the velocity is relevant only to the expanding field. Sometimes they get captured and form galaxies and solar systems. Although from oneoint of view they are in static orbit he universe isn't, they are just a local, stable region of mass.

It's impossible to stand at the centre of a planetary mass, even hypothetically, the pressure would be too extreme. If you could shift the mass somewhere else by a massive explosion then the prime centre would no longer be neutral, it would be the heart of a small black hole.

Do I have any scientific evidence for that.....not one iota :-/ but still, a mate of mine absently worked out string theory in a chemistry lesson before it was ever considered ( we just laughed ) he also proposed the idea of a three wheel vehicle that could lean around corners ( we just laughed again, but one is now a common site on many roads ). I worked out that 1 and zero were the same, during a night on the beer, only to have it confirmed as something long known to mathematicians. so, cooky as it might be, somehow it just seems right so I'm going with it :-)

[JamesF]

Think of fairground rides. There's one where you stand against the walls of a cylinder that starts spinning until it's going around fast enough to "stick" you to the wall. It then tips until the base of the cylinder vertical and you spin over the top, facing the ground. It doesn't need to go faster and faster to keep you there. Once it's turning fast enough, that's it. And in theory at least, you could take off the safety harness and walk around the walls without falling.

James

[phat tony]

Janesf, that ride is called the Mexican hat over here. when you are on it you feel like you are stuck as you said but you also feel as if you are getting slightly pulled to one side, the opposite of the spinning direction . would that not be the same for astronauts in a craft that would be spinning. a better way to look at it is if you where in a hamster wheel that was on its side spinning the same way as that ride and facing in the direction the wheel was spinning would you not need to step back or would you not fall back with that second force or g.?????

[phat tony]

[phat tony]

would this picture above not be right about the forces and how to solve this problem if it is a problem, by the way excuse the bad graphics i normally do better work but this was a rush job