Momentum and space and gravity and stuff

[///d]

Sparked by the Existence thread and talk about light speed... and I'm bored waiting for 4:30pm...

Say you have a spaceship that generates its own gravity. Not by rotating, but "magically" like they do in Star Trek and the likes. This ship is your source of gravity. If the ship suddenly moves in any direction, do you feel the affects of that as if you would in a car?

I've read a lot on this and found a lot of yes answers, but none of them stated the ship as being the source of gravity.

I did find some things on proper acceleration vs coordinate acceleration, proper being acceleration that deviates from the local gravitational field, and coordinate being acceleration with respect to some fixed point. Humans feel proper acceleration, which would be like being on Earth and accelerating in a vehicle. The vehicle is deviating from the gravitational pull of the Earth. But humans would not feel coordinate acceleration, which is what I would think fits the scenario of a moving ship thats generating that gravitational pull.

[3.0L]

Originally Posted by ///d

Sparked by the Existence thread and talk about light speed... and I'm bored waiting for 4:30pm...

Say you have a spaceship that generates its own gravity. Not by rotating, but "magically" like they do in Star Trek and the likes. This ship is your source of gravity. If the ship suddenly moves in any direction, do you feel the affects of that as if you would in a car?

I've read a lot on this and found a lot of yes answers, but none of them stated the ship as being the source of gravity.

I did find some things on proper acceleration vs coordinate acceleration, proper being acceleration that deviates from the local gravitational field, and coordinate being acceleration with respect to some fixed point. Humans feel proper acceleration, which would be like being on Earth and accelerating in a vehicle. The vehicle is deviating from the gravitational pull of the Earth. But humans would not feel coordinate acceleration, which is what I would think fits the scenario of a moving ship thats generating that gravitational pull.

It's not about gravity, it's about acceleration.

[///d]

Originally Posted by 3.0L

It's not about gravity, it's about acceleration.

I dont really know how to explain this so I'll do my best.

In this case I when think about or or try to "view" the feeling of acceleration, its an object moving away from its point of center mass. Gravitational pull determines that point of center mass, so if that gravitational pull is moving as well, that point of center mass would move with it.

I don't know if thats the right way to try and explain where I'm coming from

[3.0L]

Originally Posted by ///d

I dont really know how to explain this so I'll do my best.

In this case I when think about or or try to "view" the feeling of acceleration, its an object moving away from its point of center mass. Gravitational pull determines that point of center mass, so if that gravitational pull is moving as well, that point of center mass would move with it.

I don't know if thats the right way to try and explain where I'm coming from

I think you're going to feel acceleration or deacceleration regardless of how you're glued to the floor. Or not. Weightless astronauts feel acceleration or deacceleration. And of course acceleration or deacceleration can be induced by hitting the throttle, the brakes or turning.

[tranquility]

I don't have anything to add but just to say that I somehow became an online influencer

[infinitekidM2C]

I don't know. My guess is it would depend on how strong the gravity is compared to the acceleration. Our planet is moving around but we don't feel anything but gravity.

I presume you're worried about getting space sick when the aliens take you away...

[leopard print]

Originally Posted by infinitekidM2C

I don't know. My guess is it would depend on how strong the gravity is compared to the acceleration. Our planet is moving around but we don't feel anything but gravity.

I presume you're worried about getting space sick when the aliens take you away...

My guess on why we don't feel anything is because the earth is already in motion and always has been. So we're acclimated to the movement. If the earth were to stop then accelerate again, we would feel that movement.

[Redd]

Originally Posted by leopard print

My guess on why we don't feel anything is because the earth is already in motion and always has been. So we're acclimated to the movement. If the earth were to stop then accelerate again, we would feel that movement.

Case in point - earthquakes.

[wtwo3]

The answer lies in the wind. Literally.

Look up the coriolis effect.

[kscarrol]

Originally Posted by leopard print

My guess on why we don't feel anything is because the earth is already in motion and always has been. So we're acclimated to the movement. If the earth were to stop then accelerate again, we would feel that movement.

This. We are moving at the same rotational speed as the earth. Slow or stop that rotation suddenly and we would most definitely feel it.

[tranquility]

Well, it's kinda like being on an airliner going what 900+kph?? Don't feel a thing.

[dreamingat30fps]

Originally Posted by tranquility

Well, it's kinda like being on an airliner going what 900+kph?? Don't feel a thing.

You do feel it, during take off. Once you and the plane are both moving at the same speed you stop feeling it. All you are feeling is the seat pushing against you because it's trying to move forward and you happen to be in the way.

[tranquility]

Originally Posted by dreamingat30fps

You do feel it, during take off. Once you and the plane are both moving at the same speed you stop feeling it. All you are feeling is the seat pushing against you because it's trying to move forward and you happen to be in the way.

Ya, once everything is stable is when I meant. I don't think the seat is pushing against you when that happens since you're both at the same speed.

[dreamingat30fps]

Originally Posted by tranquility

Ya, once everything is stable is when I meant. I don't think the seat is pushing against you when that happens since you're both at the same speed.

Yes, except your ass is always being pushed into the seat by gravity. So while I have no idea how the effects of magic gravity on a ship would differentiate from earths gravity on a plane... I would imagine the effects are similar.

[///d]

Last night I was thinking about this more and I think I've kind of cleared it up in my head a little.

This explanation is very unscientific lol

I started comparing it to g-forces and how g-force starts to equal out as you stop accelerating. Even though its not technically correct the way I explain g-forces, I find it easier to make sense and visualize.

When we accelerate in a jet and experience g's, I visualize it as you suddenly leaving your gravitational center of mass. You are accelerating away from the initial point at which the Earths gravitational pull was pulling you down. As long as you are accelerating that gravitational center of mass never catches up, once you stop accelerating and become consistent that point catches up and equalizes and you no longer feel the g's. I visualize this like the cartoons when someone takes off running and their body/shadow stretches out and needs to catch up

Now lets flip that, instead of you being the thing thats accelerating, instead the source of gravitational pull is accelerating away. Your center of gravitational mass accelerates away from you, which is going to cause you to experience negative g's pulling you towards that source.

So, yes, now I do think you would feel it.

[///d]

Next question, does anything think we will ever be able to create artificial gravity?

And I don't mean through centrifugal force.

Gravity comes from mass. A ship will never have the mass of a planet, especially not one the size of Earth, so I would think you'd have to create artificial mass or a miniature contained black hole and keep it smack dab in the middle of your ship.

[freakystyly]

Yeah if you think of the earth as the space ship.. As mentioned earlier.. gravity is acceleration and Earth's is 9.81 m/s^2. The earth is rotating at 460 m/s (1000 mph). The outward force pulling up is actually really negligible vs gravity pulling down.

If the Earth stopped spinning though, you would pancake against the thing beside you going 1000 mph.

I don't think we can "fake" gravity, which is why the "realistic space shows" use magnet boots

Types of forces:
Gravitational force.
Electric force.
Magnetic force.
Nuclear force.
Frictional force.

[wtwo3]

A freshly baked pizza has a stronger gravitational pull than anything in this universe.

[NYG]

Originally Posted by ///d

Say you have a spaceship that generates its own gravity. Not by rotating, but "magically" like they do in Star Trek and the likes. This ship is your source of gravity. If the ship suddenly moves in any direction, do you feel the affects of that as if you would in a car?

This is impossible to answer just given by the fact that gravity is "magically" created and also because you're labeling it as "gravity." Gravity can be described as an attraction vector between two masses but in actuality it's the curvature of space-time. A spaceship wouldn't have anywhere near the mass to create gravity, at least the magnitude we're talking about, so it would be a theoretical artificial acceleration. It wouldn't be outrageous to assume that it can "magically" generate acceleration in any direction of free space including the ones you're talking about.

If there is a change in velocity, then a mass will always experience a force. The mass within the mass will experience relative acceleration given whatever boundary conditions exist. If that boundary is "magic" then anything goes.

[BMWILUVU]

Originally Posted by ///d

Sparked by the Existence thread and talk about light speed... and I'm bored waiting for 4:30pm...

Say you have a spaceship that generates its own gravity. Not by rotating, but "magically" like they do in Star Trek and the likes. This ship is your source of gravity. If the ship suddenly moves in any direction, do you feel the affects of that as if you would in a car?

I've read a lot on this and found a lot of yes answers, but none of them stated the ship as being the source of gravity.

I did find some things on proper acceleration vs coordinate acceleration, proper being acceleration that deviates from the local gravitational field, and coordinate being acceleration with respect to some fixed point. Humans feel proper acceleration, which would be like being on Earth and accelerating in a vehicle. The vehicle is deviating from the gravitational pull of the Earth. But humans would not feel coordinate acceleration, which is what I would think fits the scenario of a moving ship thats generating that gravitational pull.

The short answer is yes if the ship replicates the gravitation of the earth only.

[3.0L]

Originally Posted by ///d

Next question, does anything think we will ever be able to create artificial gravity?

And I don't mean through centrifugal force.

Gravity comes from mass. A ship will never have the mass of a planet, especially not one the size of Earth, so I would think you'd have to create artificial mass or a miniature contained black hole and keep it smack dab in the middle of your ship.

There is no gravity. The earth sucks.

[owenscj21]

If you were on a train travelling at the speed of light and walked from the back to the front of the train, are you travelling faster than the speed of light?