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Gravity Generators

That site is pure bogus, only the gnomes in the center of the Earth can generate gravity. And they'll stop it if we don't keep giving them gold. Little buggers are worse than the North Koreans.
 
That page is pure gibberish.

The first part on gravity generation amounts to nothing more than taking a common analogy for General Relativity, and saying "we can do this in the analogy, so we must be able to do it for real". There is no actual explanation of what they are claiming to be able to do within the context of the actual theory of GR.

The second part, on antimatter creation, is just plain silly. While it is probably true that the decay from element 116 to 115 releases a positron, which is technically anti-matter, the total energy released by that decay (including the rest mass of the positron) is exactly the same as the energy required to convert 115 to 116 in the first place.

Basically it is all pseudo-scientific BS, designed by somebody who knows a lot of physics terminology, but either knows very little actual physics, or is just plain lying.


Dr. Stupid
 
Is what they are talking about even possible?
 
But really...

If gravity is mass-related, then what if we go down to the center of earth? We would have half of the surface mass under our feet, and the other half over our heads... would we weight half? And which side would be up, if we came down there walking?

Deep mining should be a completely odd issue.

Wondering...
 
Tony said:
http://www.fortunecity.com/greenfield/bp/16/lazargg.htm

What's the science behind this? Is this b.s.?

Is it possible to generate artificial gravity?
Click to expand...
There is no science behind it. It is B.S. As near as anyone has been able to tell, gravitational mass = inertial mass.

Centrifugal force could be used to generate 'artificlal graivty', but this is in no way like real gravity. It would just generate a force on the body for the comfort of people who are used to planetary gravity fields.

If you went to the very center of the earth, your mass would be unchanged (actually it's really hot there, so maybe you would sweat off a lot of water) but your weight would be near zero. Weight is the accleration on your body due to gravity. This is why your weight varies from planet to planet, although your mass may be the same.
 
Chupacabras said:
If gravity is mass-related, then what if we go down to the center of earth? We would have half of the surface mass under our feet, and the other half over our heads... would we weight half? And which side would be up, if we came down there walking?

Deep mining should be a completely odd issue.
Click to expand...

At the center of the earth, assuming you could create a space there at the intense heat and pressure, the net force of gravity (1) would be zero; you'd effectively be weightless.

As a matter of fact, any spherical shell effectively generates no gravity from it's own mass within the shell, all the forces cancel out to zero.(2) The force of gravity decreases with the square of distance; while you might be closer to one side of the sphere and therefore the mass on that side generates more attraction, there is more mass on the OTHER side to cancel it all out. I don't think I'm explaining this well.



(1) At least, the net force of the gravity from earth's mass would be zero.

(2) Obviously, the inside of a sphere on the earth's surface isn't a zero-gravity chamber because the gravitational effect of the sphere's mass it inconsequential to the effect of Earth's mass.
 
What if we assume that we can pass through a solid sphere, not an empty shell?

I assume the gravitational force will gradually go down as we near the centre as the forces on either side balance. Is this decrease linear?

David
 
davidhorman,

What if we assume that we can pass through a solid sphere, not an empty shell?

I assume the gravitational force will gradually go down as we near the centre as the forces on either side balance. Is this decrease linear?
Click to expand...

If the density is uniform, yes.

You can think of the solid sphere as a solid sphere of radius r, where r is your distance to the center, and a hollow shell.

Since you are inside the hollow shell, it exerts no net force. The solid sphere exerts a force proportional to its mass, and inversely proportional to the r^2. But its mass is proportional to its volume, which is proportional to r^3. So the total force will be proportional to r, linearly going to zero as you move towards the center.


Dr. Stupid
 
davidhorman said:
What if we assume that we can pass through a solid sphere, not an empty shell?

I assume the gravitational force will gradually go down as we near the centre as the forces on either side balance. Is this decrease linear?

David
Click to expand...
You may treat a solid ball (the correct term) as a series of spheres, one inside another. You are on the inside of the spheres having a radius greater than your distance from the center, therefore the remaining gravitational force on you is equivalent to a ball with a radius just smaller than your distance from the center.
 
Chupacabras said:
But really...

If gravity is mass-related, then what if we go down to the center of earth? We would have half of the surface mass under our feet, and the other half over our heads... would we weight half? And which side would be up, if we came down there walking?

Deep mining should be a completely odd issue.

Wondering...
Click to expand...

This is actually a standard first semester Physics question. The answer is yes, the deeper you go, the less you weigh.

The demonstration is a shaft through the center of the earth. Given a perfect tunnel (No leaking magma allowed!) and no friction (No atmosphere allowed!) If you put on a space suit and stepped off the the edge you would accelerate toward the center of the earth.

As you got closer and closer to the center, your rate of acceleration would decrease until it reached zero at the center of the earth. Your velocity, however, would steadily increase until it reached maximum at the center of the earth.

Once you passed the midpoint (Doing a quick 'turn over' so you are now facing heads up) you would start to experience greater and greater deceleration as you increased your distance from the center. Your velocity would decrease until you finally reached a point where your velocity would equal zero.

At that point you could step back over the edge of the shaft, and onto the surface of the opposite side of the planet!

A more interesting (to me) question is what would happen inside a non-rotating Dyson Sphere. The answer is 'no gravity at all!' which I find quite cool.


(edited to add) Oops - shoulda read the whole thread first - I should have known the writers at the forum are on the ball! (or - IN it?)
 
Does this means that all those SF films where people walk around in spaceships are bogus?! :eek: Darth Vader would not be able to stand up with his lightsaber? :eek: Kirk and Spock floating at the Enterprise bridge?:eek:

Nooo...

Chupacabras, heat and pressure would also provide additional problems to your mining project...
 
Correa Neto said:
Does this means that all those SF films where people walk around in spaceships are bogus?! :eek: Darth Vader would not be able to stand up with his lightsaber? :eek: Kirk and Spock floating at the Enterprise bridge?:eek:

Nooo...
Click to expand...

i'm under the assumption that gravitons have been ignored in this thread, since they have never been physically measured and are theoretical.
 
Correa Neto said:
Does this means that all those SF films where people walk around in spaceships are bogus?! :eek: Darth Vader would not be able to stand up with his lightsaber? :eek: Kirk and Spock floating at the Enterprise bridge?:eek:

Nooo...

Chupacabras, heat and pressure would also provide additional problems to your mining project...
Click to expand...

I just want the starships to stop making whooshing noises as they fly by.
:rolleyes:
 
Is it possible to generate artificial gravity?
Click to expand...
Sure - first get a large artificial mass. Something like a bazillion tons of Cheezits. There you go - all the artificial gravity you want, and less fattening too.
 
calladus said:


I just want the starships to stop making whooshing noises as they fly by.
:rolleyes:
Click to expand...

even Mr Bad Astronomer admits that space movies feel weird when the ships don't make sounds, so cut sci-fi directors some slack.
 
calladus said:
I just want the starships to stop making whooshing noises as they fly by.
:rolleyes:
Click to expand...
Next thing you know you're gonna tell me that you dont like the way all the aliens species speak fluent English (and usually with American accents)...
 
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