Negative masses in the simulator?

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robly18
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Negative masses in the simulator?

Post by robly18 »

The other day I was doing some random maths and I found myself with a small, yet obvious realization. It had to do with negative masses.
Basically I found out something pretty cool. Using Newton's formula for measuring gravity, I came to the following conclusions:

First of all, a negative mass experiences antigravity towards a positive mass. Not very surprising, now is this?

Secondly, and surprisingly, negative masses experience gravity towards negative masses!

Finally, I came to the conclusion that gravity is like the opposite of electromagnetism! What I mean by this is, while magnets attract opposite charge (opposite attracts negative and negative attracts positive), gravity attracts likewise "charges", taking polarity as an analogue to mass.
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A Random Player
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Re: Negative masses in the simulator?

Post by A Random Player »

We are actually unsure of the effects of gravity on matter/antimatter, and antimatter doesn't exactly have negative mass. But there might still be antigravity!

Though if antimatter does repel normal matter, then as you pointed out, it would be surprisingly similar to the opposite of electromagnetism.
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robly18
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Re: Negative masses in the simulator?

Post by robly18 »

I never mentioned antimatter. I was already aware that antimatter has positive mass. Still interesting though.
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Re: Negative masses in the simulator?

Post by A Random Player »

robly18 wrote:I never mentioned antimatter. I was already aware that antimatter has positive mass. Still interesting though.
Oh, oops :oops:
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robly18
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Re: Negative masses in the simulator?

Post by robly18 »

Heh, maybe seeing the words "matter" and "antigravity" in the same sentence makes you picture antimatter? Idunno.
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Re: Negative masses in the simulator?

Post by A Random Player »

robly18 wrote:Heh, maybe seeing the words "matter" and "antigravity" in the same sentence makes you picture antimatter? Idunno.
Probably something like "Negative", "Matter", and "Antigravity" :P
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Re: Negative masses in the simulator?

Post by testtubegames »

robly18 wrote:The other day I was doing some random maths and I found myself with a small, yet obvious realization. It had to do with negative masses.
Basically I found out something pretty cool. Using Newton's formula for measuring gravity, I came to the following conclusions:

First of all, a negative mass experiences antigravity towards a positive mass. Not very surprising, now is this?

Secondly, and surprisingly, negative masses experience gravity towards negative masses!

Finally, I came to the conclusion that gravity is like the opposite of electromagnetism! What I mean by this is, while magnets attract opposite charge (opposite attracts negative and negative attracts positive), gravity attracts likewise "charges", taking polarity as an analogue to mass.
Yeah, it is interesting to compare gravity and electricity like that. And it helps point out a key difference between the two. Gravity can just keep on attracting... more and more and more. Mass pulls on mass... and when they're combined they'll pull even more strongly on other mass... and when that comes over, they'll pull even stronger still... and so on until (and past) getting a black hole.

With Electricity, though, you'll never get anything like a 'black hole' with it. Since, if you've got a positive charge, it'll attract a negative charge. Then, when they're together... they'll balance out and won't really attract anything else.

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19683
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Re: Negative masses in the simulator?

Post by 19683 »

robly18 wrote:The other day I was doing some random maths and I found myself with a small, yet obvious realization. It had to do with negative masses.
Basically I found out something pretty cool. Using Newton's formula for measuring gravity, I came to the following conclusions:

First of all, a negative mass experiences antigravity towards a positive mass. Not very surprising, now is this?

Secondly, and surprisingly, negative masses experience gravity towards negative masses!

Finally, I came to the conclusion that gravity is like the opposite of electromagnetism! What I mean by this is, while magnets attract opposite charge (opposite attracts negative and negative attracts positive), gravity attracts likewise "charges", taking polarity as an analogue to mass.
I found a problem with this analysis.

While negative mass would experience a repulsive FORCE from positive, negative mass would ACCELERATE opposite to the force (TOWARD the mass). The mass however, would respond normally, accelerating away from the negative mass. Two negative masses would accelerate AWAY from each other (OPPOSITE the force). If you put mass and negative mass side by side, the mass would accelerate away, while the negative mass "chases" it. This "self propulsion" may seem to violate conservation of momentum and energy, put because the total mass is zero, this is not a problem.
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Re: Negative masses in the simulator?

Post by A Random Player »

19683 wrote:
robly18 wrote:The other day I was doing some random maths and I found myself with a small, yet obvious realization. It had to do with negative masses.
Basically I found out something pretty cool. Using Newton's formula for measuring gravity, I came to the following conclusions:

First of all, a negative mass experiences antigravity towards a positive mass. Not very surprising, now is this?

Secondly, and surprisingly, negative masses experience gravity towards negative masses!

Finally, I came to the conclusion that gravity is like the opposite of electromagnetism! What I mean by this is, while magnets attract opposite charge (opposite attracts negative and negative attracts positive), gravity attracts likewise "charges", taking polarity as an analogue to mass.
I found a problem with this analysis.

While negative mass would experience a repulsive FORCE from positive, negative mass would ACCELERATE opposite to the force (TOWARD the mass). The mass however, would respond normally, accelerating away from the negative mass. Two negative masses would accelerate AWAY from each other (OPPOSITE the force). If you put mass and negative mass side by side, the mass would accelerate away, while the negative mass "chases" it. This "self propulsion" may seem to violate conservation of momentum and energy, put because the total mass is zero, this is not a problem.
Well, the negative mass wouldn't chase the positive mass - They would both repel each other.
Normal matter--> <--Normal matter
Assume the masses are both 1, and they are 1 unit away from each other. The force would be G*m1*m2/r^2, or 1, toward each other. But if m2 is -1, the force on each particle would still be G*m1*m2/r^; but this is instead -1. This means the particles would each "attract" each other with a force of -1, or repel each other with a force of 1. This is indeed like an opposite of electromagnetism.
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robly18
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Re: Negative masses in the simulator?

Post by robly18 »

A Random Player wrote: Well, the negative mass wouldn't chase the positive mass - They would both repel each other.
Normal matter--> <--Normal matter
Assume the masses are both 1, and they are 1 unit away from each other. The force would be G*m1*m2/r^2, or 1, toward each other. But if m2 is -1, the force on each particle would still be G*m1*m2/r^; but this is instead -1. This means the particles would each "attract" each other with a force of -1, or repel each other with a force of 1. This is indeed like an opposite of electromagnetism.
No, I see where he's coming from. He has a point.

p = mv, therefor, v = p/m. Therefor, if we took G as 1, r as 1, m1 as 1 and m2 as -1, then p = G*m1*m2*r^-2. This means p = 1*1*-1*1^-2 which would equal -1. However, for the positive mass, as v = p/m, v = -1/1 which would be -1, or a speed of 1 going away from the other mass. However, for the negative mass, v = -1/-1 which equals 1. Therefor, it would chase the positive mass with a speed of one.

I suspect this is the basis of the alcubierre drive.

Anyways, in this case, it's... Wow, gravity is weird. This would have to mean, that if P was a positive mass and N was a negative mass:
P-> <-P
N-> P->
<-N N->

Good grief, this is weird.
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