Wormholes - Revision history

Lwcamp at 19:07, 7 March 2026

2026-03-07T19:07:52Z

← Older revision		Revision as of 12:07, 7 March 2026
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	==References==		==References==

	[[Category:Physics]][[Category:Infrastructure]][[Category:Physics & Engineering‏‎]][[Category:Transportation & Infrastructure‏‎]][[Category:Metric Engineering]]		[[Category:Physics]][[Category:Infrastructure]][[Category:Physics & Engineering‏‎]][[Category:Physics & Math & Engineering]][[Category:Transportation & Infrastructure‏‎]][[Category:Metric Engineering]]

Lwcamp: /* Space-time: three space dimensions and one time dimension */

2026-03-07T18:51:10Z

Space-time: three space dimensions and one time dimension

← Older revision		Revision as of 11:51, 7 March 2026
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	</table>		</table>

	There is one distinction between space-time manifolds that will become important later. Some manifolds have an isolated region of high curvature (corresponding to a concentration of mass, or at least of stress-energy) but as you go farther away from the strongly curved region the space-time becomes increasingly flat. If you can always go out far enough away from a curved region that space-time becomes flatter than whatever flatness criterion you choose, no matter what direction you choose to leave the curved region, the manifold is called <i>asymptotically flat</i>. For our purposes, if you can go far enough away that the Newtonian approximation to general relativity is accurate, and gravity can be described as a force rather than requiring a geometric description, then the geometry can be considered asymptotically flat. You can also allow gravitational waves in your asymptotically flat space-time – their very small space-time curvature is not enough to cause problems and they can still be described by a linearized version of gravity. Both the Schwarzschild and the Minkowski geometries are asymptotically flat. Spherical or hyperbolic geometries are not asymptotically flat. Planets, stars, galaxies, neutron stars, black holes, and galactic clusters are all approximately asymptotically flat; but the universe as a whole is <i>not</i>. As long as we confine our attention to merely galactic clusters, we can make the approximation of asymptotic flatness.		There is one distinction between space-time manifolds that will become important later. Some manifolds have an isolated region of high curvature (corresponding to a concentration of mass, or at least of stress-energy) but as you go farther away from the strongly curved region the space-time becomes increasingly flat. If you can always go out far enough away from a curved region that space-time becomes flatter than whatever flatness criterion you choose, no matter what direction you choose to leave the curved region, the manifold is called <i>asymptotically flat</i>. For our purposes, if you can go far enough away that the Newtonian approximation to general relativity is accurate, and gravity can be described as a force rather than requiring a geometric description, then the geometry can be considered asymptotically flat. You can also allow gravitational waves in your asymptotically flat space-time – their very small space-time curvature is not enough to cause problems and they can still be described by a linearized version of gravity; linear deviations from Newtonian gravity such as gravito-magnetic effects can also fall into asymptitcally flat region of space-time. Both the Schwarzschild and the Minkowski geometries are asymptotically flat. Spherical or hyperbolic geometries are not asymptotically flat. Planets, stars, galaxies, neutron stars, black holes, and galactic clusters are all approximately asymptotically flat; but the universe as a whole is <i>not</i>. As long as we confine our attention to merely galactic clusters, we can make the approximation of asymptotic flatness.

	===Making a wormhole===		===Making a wormhole===

Oddturnip: /* Space-time: three space dimensions and one time dimension */

2026-02-18T03:14:21Z

Space-time: three space dimensions and one time dimension

← Older revision		Revision as of 20:14, 17 February 2026
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	</table>		</table>

	There is one distinction between space-time manifolds that will become important later. Some manifolds have an isolated region of high curvature (corresponding to a concentration of mass, or at least of stress-energy) but as you go farther away from the strongly curved region the space-time becomes increasingly flat. If you can always go out far enough away from a curved region that space-time becomes flatter ~~that~~ whatever flatness criterion you choose, no matter what direction you choose to leave the curved region, the manifold is called <i>asymptotically flat</i>. For our purposes, if you can go far enough away that the Newtonian approximation to general relativity is accurate, and gravity can be described as a force rather than requiring a geometric description, then the geometry can be considered asymptotically flat. You can also allow gravitational waves in your asymptotically flat space-time – their very small space-time curvature is not enough to cause problems and they can still be described by a linearized version of gravity. Both the Schwarzschild and the Minkowski geometries are asymptotically flat. Spherical or hyperbolic geometries are not asymptotically flat. Planets, stars, galaxies, neutron stars, black holes, and galactic clusters are all approximately asymptotically flat; but the universe as a whole is <i>not</i>. As long as we confine our attention to merely galactic clusters, we can make the approximation of asymptotic flatness.		There is one distinction between space-time manifolds that will become important later. Some manifolds have an isolated region of high curvature (corresponding to a concentration of mass, or at least of stress-energy) but as you go farther away from the strongly curved region the space-time becomes increasingly flat. If you can always go out far enough away from a curved region that space-time becomes flatter than whatever flatness criterion you choose, no matter what direction you choose to leave the curved region, the manifold is called <i>asymptotically flat</i>. For our purposes, if you can go far enough away that the Newtonian approximation to general relativity is accurate, and gravity can be described as a force rather than requiring a geometric description, then the geometry can be considered asymptotically flat. You can also allow gravitational waves in your asymptotically flat space-time – their very small space-time curvature is not enough to cause problems and they can still be described by a linearized version of gravity. Both the Schwarzschild and the Minkowski geometries are asymptotically flat. Spherical or hyperbolic geometries are not asymptotically flat. Planets, stars, galaxies, neutron stars, black holes, and galactic clusters are all approximately asymptotically flat; but the universe as a whole is <i>not</i>. As long as we confine our attention to merely galactic clusters, we can make the approximation of asymptotic flatness.

	===Making a wormhole===		===Making a wormhole===

Lwcamp: /* Reducing or eliminating ANEC violating stuff */

2026-02-02T14:52:02Z

Reducing or eliminating ANEC violating stuff

← Older revision		Revision as of 07:52, 2 February 2026
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	<ref name="Blazquez-Salcedo_Knoll_Radu">Jose Luis Blázquez-Salcedo, Christian Knoll, and Eugen Radu, “Transversable wormholes in Einstein-Dirac-Maxwell theory”, Physical Review Letters <b>126</b>, 101102 (2021); ArXiv: 2010.07317v2 [gr-qc].</ref>		<ref name="Blazquez-Salcedo_Knoll_Radu">Jose Luis Blázquez-Salcedo, Christian Knoll, and Eugen Radu, “Transversable wormholes in Einstein-Dirac-Maxwell theory”, Physical Review Letters <b>126</b>, 101102 (2021); ArXiv: 2010.07317v2 [gr-qc].</ref>
	.		.
	However, an analysis<ref>Ben Kain, "Are Einstein-Dirac-Maxwell wormholes traversable", [https://arxiv.org/abs/2305.11217 arXiv:2305.11217 [gr-qc]], Phys. Rev. D 108, 044019 (2023) [https://doi.org/10.1103/PhysRevD.108.044019]</ref> was unable to find any solutions ~~of this class of wormholes~~ which did not collapse into a black hole before any signal could propagate through them and concluded that they were not traversable.		However, an analysis<ref>Ben Kain, "Are Einstein-Dirac-Maxwell wormholes traversable", [https://arxiv.org/abs/2305.11217 arXiv:2305.11217 [gr-qc]], Phys. Rev. D 108, 044019 (2023) https://doi.org/10.1103/PhysRevD.108.044019</ref> of this class of wormholes was unable to find any solutions which did not collapse into a black hole before any signal could propagate through them and concluded that they were not traversable.

	==Fields and conserved properties==		==Fields and conserved properties==

Lwcamp: /* Reducing or eliminating ANEC violating stuff */

2026-02-02T14:50:14Z

Reducing or eliminating ANEC violating stuff

← Older revision		Revision as of 07:50, 2 February 2026
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	Thin shell wormholes have also been the subject of investigation. One study <ref name="Mazharimousavi_Halilsoy">S. Habib Mazharimousavi, M. Halilsoy, "3 + 1-dimensional thin shell wormhole with deformed throat can be supported by normal matter", Eur. Phys. J. C (2015) 75:271 DOI 10.1140/epjc/s10052-015-3506-6</ref> found a number of thin shell wormholes with sharp-edged shapes could be supported entirely without any exotic energy. However, this only applies if the edges are infinitely sharp. A finite radius of curvature at the edges would require negative energy at those edges.		Thin shell wormholes have also been the subject of investigation. One study <ref name="Mazharimousavi_Halilsoy">S. Habib Mazharimousavi, M. Halilsoy, "3 + 1-dimensional thin shell wormhole with deformed throat can be supported by normal matter", Eur. Phys. J. C (2015) 75:271 DOI 10.1140/epjc/s10052-015-3506-6</ref> found a number of thin shell wormholes with sharp-edged shapes could be supported entirely without any exotic energy. However, this only applies if the edges are infinitely sharp. A finite radius of curvature at the edges would require negative energy at those edges.

	If the wormhole is taken to have the properties of a class of subatomic particles called a fermion, then if the ratio of the electric charge to the mass is sufficiently large you can get a wormhole that can remain open without any negative energy regions at all		If the wormhole is taken to have the properties of a class of subatomic particles called a fermion, then if the ratio of the electric charge to the mass is sufficiently large you can get a wormhole that can remain open without any additional negative energy regions at all
	<ref name="Blazquez-Salcedo_Knoll_Radu">Jose Luis Blázquez-Salcedo, Christian Knoll, and Eugen Radu, “Transversable wormholes in Einstein-Dirac-Maxwell theory”, Physical Review Letters <b>126</b>, 101102 (2021); ArXiv: 2010.07317v2 [gr-qc].</ref>		<ref name="Blazquez-Salcedo_Knoll_Radu">Jose Luis Blázquez-Salcedo, Christian Knoll, and Eugen Radu, “Transversable wormholes in Einstein-Dirac-Maxwell theory”, Physical Review Letters <b>126</b>, 101102 (2021); ArXiv: 2010.07317v2 [gr-qc].</ref>
	.		.
			However, an analysis<ref>Ben Kain, "Are Einstein-Dirac-Maxwell wormholes traversable", [https://arxiv.org/abs/2305.11217 arXiv:2305.11217 [gr-qc]], Phys. Rev. D 108, 044019 (2023) [https://doi.org/10.1103/PhysRevD.108.044019]</ref> was unable to find any solutions of this class of wormholes which did not collapse into a black hole before any signal could propagate through them and concluded that they were not traversable.

	==Fields and conserved properties==		==Fields and conserved properties==

Lwcamp: /* Does gravity go through a wormhole? */

2025-10-06T04:03:09Z

Does gravity go through a wormhole?

← Older revision		Revision as of 21:03, 5 October 2025
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	The above diagrams of the electric field of a charge as it approaches a wormhole mouth also hold for the gravitational field of a mass that is near a wormhole mouth. In the same way that the electric field cannot enter the wormhole's interior or leak through to the other side unless the charge enters the wormhole or goes through to the other side, so to will the gravitational field of a nearby mass curve around the wormhole. The gravity of a nearby planet will fall to zero inside the wormhole throat and will not affect those near the opposite mouth.		The above diagrams of the electric field of a charge as it approaches a wormhole mouth also hold for the gravitational field of a mass that is near a wormhole mouth. In the same way that the electric field cannot enter the wormhole's interior or leak through to the other side unless the charge enters the wormhole or goes through to the other side, so to will the gravitational field of a nearby mass curve around the wormhole. The gravity of a nearby planet will fall to zero inside the wormhole throat and will not affect those near the opposite mouth.

	The caveat is that for a thin shell wormhole a small amount of field can bow out through the infinitesimally short throat to reach the immediate vicinity of the other side, corresponding to a field line that comes through and then loops back. These fringing fields leaking through may be noticeable when the throat is much shorter than the width of the mouths. When the throat is long compared to the size of the mouth, this will not be a concern.		The caveat is that for a thin shell wormhole a small amount of field can bow out through the infinitesimally short throat to reach the immediate vicinity of the other side, corresponding to a field line that comes through and then loops back. These fringing fields leaking through may be noticeable very close to the mouth when the throat is much shorter than the width of the mouths. When the throat is long compared to the size of the mouth, this will not be a concern.

	===Can waves go through a wormhole?===		===Can waves go through a wormhole?===

Lwcamp: /* Matter with negative mass */

2025-08-14T02:41:14Z

Matter with negative mass

← Older revision		Revision as of 19:41, 13 August 2025
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	====Matter with negative mass====		====Matter with negative mass====

	It might be tempting to try to solve the negative energy density requirement for wormholes by introducing some sort of matter that naturally has negative mass. Negative mass would behave in unusual and non-intuitive ways. The force on an object is its acceleration times its mass. Most things accelerate in the direction you push them. But when the mass is negative, the acceleration will be in the opposite direction to the force on the object. If you try to push negative mass matter with your hand, then the negative matter is constrained to be accelerating in the direction of your hand ... so instead of pushing on it you must be pulling on it, and by Newton's third law of motion the negative mass will pull back on your hand. So as you try to push it it will tug you forward<ref name="ScienceMeetsFiction">[https://www.youtube.com/watch?v=zEGsq7H5egE\|Science Meets Fiction, "What Does Negative Mass Mean? Part 1"], [https://www.youtube.com/watch?v=1Xr4dTCZc7g\|Science Meets Fiction, "What Does Negative Mass Mean? Part 2"], [https://www.youtube.com/watch?v=2YFyvR7M_LI\|Science Meets Fiction, "Negative Mass Part 3: Energy, Friction, Gravity, and More"], [https://www.youtube.com/watch?v=Pr3j00DIrvM&t=1498s\|Science Meets Fiction, "Negative Mass Part 4: Life, the Universe, and Everything(-ish)"]</ref>.		It might be tempting to try to solve the negative energy density requirement for wormholes by introducing some sort of matter that naturally has negative mass. Negative mass would behave in unusual and non-intuitive ways. The force on an object is its acceleration times its mass. Most things accelerate in the direction you push them. But when the mass is negative, the acceleration will be in the opposite direction to the force on the object. If you try to push negative mass matter with your hand, then the negative matter is constrained to be accelerating in the direction of your hand ... so instead of pushing on it you must be pulling on it, and by Newton's third law of motion the negative mass will pull back on your hand. So as you try to push it it will tug you forward<ref name="ScienceMeetsFiction">[https://www.youtube.com/watch?v=zEGsq7H5egE\| Science Meets Fiction, "What Does Negative Mass Mean? Part 1"], [https://www.youtube.com/watch?v=1Xr4dTCZc7g\| Science Meets Fiction, "What Does Negative Mass Mean? Part 2"], [https://www.youtube.com/watch?v=2YFyvR7M_LI\| Science Meets Fiction, "Negative Mass Part 3: Energy, Friction, Gravity, and More"], [https://www.youtube.com/watch?v=Pr3j00DIrvM&t=1498s\| Science Meets Fiction, "Negative Mass Part 4: Life, the Universe, and Everything(-ish)"]</ref>.

	Gravitationally, the negative mass will exert a repulsive force on positive mass things around it, so large amounts of negative mass will push people away. Large nearby positive mass bodies normally extert attractive forces on things, but because the gravitational force is proportional to mass negative mass things will experience a force away from the positive mass … but remember that the acceleration of the negative mass is in the opposite direction to the force. The negative mass will still fall toward the positive mass object, and will be gravitationally repelled away from negative mass objects. This gets even weirder if a negative mass thing is next to a positive mass thing with the same magnitude to both their masses. The positive mass thing will accelerate away from the negative mass thing by gravity, but the negative mass thing also falls toward the positive mass thing. And because they have equal mass magnitudes, the acceleration will be the same. Both objects will continually accelerate, the negative mass chasing the positive mass, forever. The motion of the positive mass will give it positive kinetic energy and momentum in the direction it is going; the negative mass with the same motion will have negative kinetic energy to exactly balance the positive kinetic energy of the positive mass, and momentum opposite its direction of motion to exactly cancel the momentum of the positive mass in the other direction – conservation laws are still upheld, even if you have perpetual motion and reactionless acceleration. Unfortunately for this idea, however, you can't just hold the two objects apart with any sort of braces or connections. Any external force, no matter how small, will be amplified across the connections to infinity and break them. So that any slight imbalance in the initial masses will lead to them eventually drifting apart or colliding.		Gravitationally, the negative mass will exert a repulsive force on positive mass things around it, so large amounts of negative mass will push people away. Large nearby positive mass bodies normally extert attractive forces on things, but because the gravitational force is proportional to mass negative mass things will experience a force away from the positive mass … but remember that the acceleration of the negative mass is in the opposite direction to the force. The negative mass will still fall toward the positive mass object, and will be gravitationally repelled away from negative mass objects. This gets even weirder if a negative mass thing is next to a positive mass thing with the same magnitude to both their masses. The positive mass thing will accelerate away from the negative mass thing by gravity, but the negative mass thing also falls toward the positive mass thing. And because they have equal mass magnitudes, the acceleration will be the same. Both objects will continually accelerate, the negative mass chasing the positive mass, forever. The motion of the positive mass will give it positive kinetic energy and momentum in the direction it is going; the negative mass with the same motion will have negative kinetic energy to exactly balance the positive kinetic energy of the positive mass, and momentum opposite its direction of motion to exactly cancel the momentum of the positive mass in the other direction – conservation laws are still upheld, even if you have perpetual motion and reactionless acceleration. Unfortunately for this idea, however, you can't just hold the two objects apart with any sort of braces or connections. Any external force, no matter how small, will be amplified across the connections to infinity and break them. So that any slight imbalance in the initial masses will lead to them eventually drifting apart or colliding.

Lwcamp: /* Matter with negative mass */

2025-08-14T02:39:56Z

Matter with negative mass

← Older revision		Revision as of 19:39, 13 August 2025
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	====Matter with negative mass====		====Matter with negative mass====

	It might be tempting to try to solve the negative energy density requirement for wormholes by introducing some sort of matter that naturally has negative mass. Negative mass would behave in unusual and non-intuitive ways. The force on an object is its acceleration times its mass. Most things accelerate in the direction you push them. But when the mass is negative, the acceleration will be in the opposite direction to the force on the object. If you try to push negative mass matter with your hand, then the negative matter is constrained to be accelerating in the direction of your hand ... so instead of pushing on it you must be pulling on it, and by Newton's third law of motion the negative mass will pull back on your hand ~~– so~~ as you try to push it it will tug you forward<ref name="ScienceMeetsFiction">[https://www.youtube.com/watch?v=zEGsq7H5egE\|Science Meets Fiction, "What Does Negative Mass Mean? Part 1"], [https://www.youtube.com/watch?v=1Xr4dTCZc7g\|Science Meets Fiction, "What Does Negative Mass Mean? Part 2"], [https://www.youtube.com/watch?v=2YFyvR7M_LI\|Science Meets Fiction, "Negative Mass Part 3: Energy, Friction, Gravity, and More"], [https://www.youtube.com/watch?v=Pr3j00DIrvM&t=1498s\|Science Meets Fiction, "Negative Mass Part 4: Life, the Universe, and Everything(-ish)"]</ref>.		It might be tempting to try to solve the negative energy density requirement for wormholes by introducing some sort of matter that naturally has negative mass. Negative mass would behave in unusual and non-intuitive ways. The force on an object is its acceleration times its mass. Most things accelerate in the direction you push them. But when the mass is negative, the acceleration will be in the opposite direction to the force on the object. If you try to push negative mass matter with your hand, then the negative matter is constrained to be accelerating in the direction of your hand ... so instead of pushing on it you must be pulling on it, and by Newton's third law of motion the negative mass will pull back on your hand. So as you try to push it it will tug you forward<ref name="ScienceMeetsFiction">[https://www.youtube.com/watch?v=zEGsq7H5egE\|Science Meets Fiction, "What Does Negative Mass Mean? Part 1"], [https://www.youtube.com/watch?v=1Xr4dTCZc7g\|Science Meets Fiction, "What Does Negative Mass Mean? Part 2"], [https://www.youtube.com/watch?v=2YFyvR7M_LI\|Science Meets Fiction, "Negative Mass Part 3: Energy, Friction, Gravity, and More"], [https://www.youtube.com/watch?v=Pr3j00DIrvM&t=1498s\|Science Meets Fiction, "Negative Mass Part 4: Life, the Universe, and Everything(-ish)"]</ref>.

	Gravitationally, the negative mass will exert a repulsive force on positive mass things around it, so large amounts of negative mass will push people away. Large nearby positive mass bodies normally extert attractive forces on things, but because the gravitational force is proportional to mass negative mass things will experience a force away from the positive mass … but remember that the acceleration of the negative mass is in the opposite direction to the force. The negative mass will still fall toward the positive mass object, and will be gravitationally repelled away from negative mass objects. This gets even weirder if a negative mass thing is next to a positive mass thing with the same magnitude to both their masses. The positive mass thing will accelerate away from the negative mass thing by gravity, but the negative mass thing also falls toward the positive mass thing. And because they have equal mass magnitudes, the acceleration will be the same. Both objects will continually accelerate, the negative mass chasing the positive mass, forever. The motion of the positive mass will give it positive kinetic energy and momentum in the direction it is going; the negative mass with the same motion will have negative kinetic energy to exactly balance the positive kinetic energy of the positive mass, and momentum opposite its direction of motion to exactly cancel the momentum of the positive mass in the other direction – conservation laws are still upheld, even if you have perpetual motion and reactionless acceleration. Unfortunately for this idea, however, you can't just hold the two objects apart with any sort of braces or connections. Any external force, no matter how small, will be amplified across the connections to infinity and break them. So that any slight imbalance in the initial masses will lead to them eventually drifting apart or colliding.		Gravitationally, the negative mass will exert a repulsive force on positive mass things around it, so large amounts of negative mass will push people away. Large nearby positive mass bodies normally extert attractive forces on things, but because the gravitational force is proportional to mass negative mass things will experience a force away from the positive mass … but remember that the acceleration of the negative mass is in the opposite direction to the force. The negative mass will still fall toward the positive mass object, and will be gravitationally repelled away from negative mass objects. This gets even weirder if a negative mass thing is next to a positive mass thing with the same magnitude to both their masses. The positive mass thing will accelerate away from the negative mass thing by gravity, but the negative mass thing also falls toward the positive mass thing. And because they have equal mass magnitudes, the acceleration will be the same. Both objects will continually accelerate, the negative mass chasing the positive mass, forever. The motion of the positive mass will give it positive kinetic energy and momentum in the direction it is going; the negative mass with the same motion will have negative kinetic energy to exactly balance the positive kinetic energy of the positive mass, and momentum opposite its direction of motion to exactly cancel the momentum of the positive mass in the other direction – conservation laws are still upheld, even if you have perpetual motion and reactionless acceleration. Unfortunately for this idea, however, you can't just hold the two objects apart with any sort of braces or connections. Any external force, no matter how small, will be amplified across the connections to infinity and break them. So that any slight imbalance in the initial masses will lead to them eventually drifting apart or colliding.

Lwcamp: /* Matter with negative mass */

2025-08-14T02:38:58Z

Matter with negative mass

← Older revision		Revision as of 19:38, 13 August 2025
Line 282:		Line 282:
	====Matter with negative mass====		====Matter with negative mass====

	It might be tempting to try to solve the negative energy density requirement for wormholes by introducing some sort of matter that naturally has negative mass. Negative mass would behave in unusual and non-intuitive ways. The force on an object is its acceleration times its mass. Most things accelerate in the direction you push them. But when the mass is negative, the acceleration will be in the opposite direction to the force on the object. If you try to push negative mass matter with your hand, then the negative matter is constrained to be accelerating in the direction of your hand ... so instead of pushing on it you must be pulling on it, and by Newton's third law of motion the negative mass will pull back on your hand – so as you try to push it it will tug you forward.		It might be tempting to try to solve the negative energy density requirement for wormholes by introducing some sort of matter that naturally has negative mass. Negative mass would behave in unusual and non-intuitive ways. The force on an object is its acceleration times its mass. Most things accelerate in the direction you push them. But when the mass is negative, the acceleration will be in the opposite direction to the force on the object. If you try to push negative mass matter with your hand, then the negative matter is constrained to be accelerating in the direction of your hand ... so instead of pushing on it you must be pulling on it, and by Newton's third law of motion the negative mass will pull back on your hand – so as you try to push it it will tug you forward<ref name="ScienceMeetsFiction">[https://www.youtube.com/watch?v=zEGsq7H5egE\|Science Meets Fiction, "What Does Negative Mass Mean? Part 1"], [https://www.youtube.com/watch?v=1Xr4dTCZc7g\|Science Meets Fiction, "What Does Negative Mass Mean? Part 2"], [https://www.youtube.com/watch?v=2YFyvR7M_LI\|Science Meets Fiction, "Negative Mass Part 3: Energy, Friction, Gravity, and More"], [https://www.youtube.com/watch?v=Pr3j00DIrvM&t=1498s\|Science Meets Fiction, "Negative Mass Part 4: Life, the Universe, and Everything(-ish)"]</ref>.

	Gravitationally, the negative mass will exert a repulsive force on positive mass things around it, so large amounts of negative mass will push people away. Large nearby positive mass bodies normally extert attractive forces on things, but because the gravitational force is proportional to mass negative mass things will experience a force away from the positive mass … but remember that the acceleration of the negative mass is in the opposite direction to the force. The negative mass will still fall toward the positive mass object, and will be gravitationally repelled away from negative mass objects. This gets even weirder if a negative mass thing is next to a positive mass thing with the same magnitude to both their masses. The positive mass thing will accelerate away from the negative mass thing by gravity, but the negative mass thing also falls toward the positive mass thing. And because they have equal mass magnitudes, the acceleration will be the same. Both objects will continually accelerate, the negative mass chasing the positive mass, forever. The motion of the positive mass will give it positive kinetic energy and momentum in the direction it is going; the negative mass with the same motion will have negative kinetic energy to exactly balance the positive kinetic energy of the positive mass, and momentum opposite its direction of motion to exactly cancel the momentum of the positive mass in the other direction – conservation laws are still upheld, even if you have perpetual motion and reactionless acceleration. Unfortunately for this idea, however, you can't just hold the two objects apart with any sort of braces or connections. Any external force, no matter how small, will be amplified across the connections to infinity and break them. So that any slight imbalance in the initial masses will lead to them eventually drifting apart or colliding.		Gravitationally, the negative mass will exert a repulsive force on positive mass things around it, so large amounts of negative mass will push people away. Large nearby positive mass bodies normally extert attractive forces on things, but because the gravitational force is proportional to mass negative mass things will experience a force away from the positive mass … but remember that the acceleration of the negative mass is in the opposite direction to the force. The negative mass will still fall toward the positive mass object, and will be gravitationally repelled away from negative mass objects. This gets even weirder if a negative mass thing is next to a positive mass thing with the same magnitude to both their masses. The positive mass thing will accelerate away from the negative mass thing by gravity, but the negative mass thing also falls toward the positive mass thing. And because they have equal mass magnitudes, the acceleration will be the same. Both objects will continually accelerate, the negative mass chasing the positive mass, forever. The motion of the positive mass will give it positive kinetic energy and momentum in the direction it is going; the negative mass with the same motion will have negative kinetic energy to exactly balance the positive kinetic energy of the positive mass, and momentum opposite its direction of motion to exactly cancel the momentum of the positive mass in the other direction – conservation laws are still upheld, even if you have perpetual motion and reactionless acceleration. Unfortunately for this idea, however, you can't just hold the two objects apart with any sort of braces or connections. Any external force, no matter how small, will be amplified across the connections to infinity and break them. So that any slight imbalance in the initial masses will lead to them eventually drifting apart or colliding.

Lwcamp: /* Matter with negative mass */

2025-08-14T02:25:50Z

Matter with negative mass

← Older revision		Revision as of 19:25, 13 August 2025
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	It might be tempting to try to solve the negative energy density requirement for wormholes by introducing some sort of matter that naturally has negative mass. Negative mass would behave in unusual and non-intuitive ways. The force on an object is its acceleration times its mass. Most things accelerate in the direction you push them. But when the mass is negative, the acceleration will be in the opposite direction to the force on the object. If you try to push negative mass matter with your hand, then the negative matter is constrained to be accelerating in the direction of your hand ... so instead of pushing on it you must be pulling on it, and by Newton's third law of motion the negative mass will pull back on your hand – so as you try to push it it will tug you forward.		It might be tempting to try to solve the negative energy density requirement for wormholes by introducing some sort of matter that naturally has negative mass. Negative mass would behave in unusual and non-intuitive ways. The force on an object is its acceleration times its mass. Most things accelerate in the direction you push them. But when the mass is negative, the acceleration will be in the opposite direction to the force on the object. If you try to push negative mass matter with your hand, then the negative matter is constrained to be accelerating in the direction of your hand ... so instead of pushing on it you must be pulling on it, and by Newton's third law of motion the negative mass will pull back on your hand – so as you try to push it it will tug you forward.

	Gravitationally, the negative mass will exert a repulsive force on positive mass things around it, so large amounts of negative mass will push people away. Large nearby positive mass bodies normally extert attractive forces on things, but because the gravitational force is proportional to mass negative mass things will experience a force away from the positive mass … but remember that the acceleration of the negative mass is in the opposite direction to the force. The negative mass will still fall toward the positive mass object, and will be gravitationally repelled away from negative mass objects. This gets even weirder if a negative mass thing is next to a positive mass thing with the same magnitude to both their masses. The positive mass thing will accelerate away from the negative mass thing by gravity, but the negative mass thing also falls toward the positive mass thing. And because they have equal mass magnitudes, the acceleration will be the same. Both objects will continually accelerate, the negative mass chasing the positive mass, forever. The motion of the positive mass will give it positive kinetic energy and momentum in the direction it is going; the negative mass with the same motion will have negative kinetic energy to exactly balance the positive kinetic energy of the positive mass, and momentum opposite its direction of motion to exactly cancel the momentum of the positive mass in the other direction – conservation laws are still upheld, even if you have perpetual motion and reactionless acceleration.		Gravitationally, the negative mass will exert a repulsive force on positive mass things around it, so large amounts of negative mass will push people away. Large nearby positive mass bodies normally extert attractive forces on things, but because the gravitational force is proportional to mass negative mass things will experience a force away from the positive mass … but remember that the acceleration of the negative mass is in the opposite direction to the force. The negative mass will still fall toward the positive mass object, and will be gravitationally repelled away from negative mass objects. This gets even weirder if a negative mass thing is next to a positive mass thing with the same magnitude to both their masses. The positive mass thing will accelerate away from the negative mass thing by gravity, but the negative mass thing also falls toward the positive mass thing. And because they have equal mass magnitudes, the acceleration will be the same. Both objects will continually accelerate, the negative mass chasing the positive mass, forever. The motion of the positive mass will give it positive kinetic energy and momentum in the direction it is going; the negative mass with the same motion will have negative kinetic energy to exactly balance the positive kinetic energy of the positive mass, and momentum opposite its direction of motion to exactly cancel the momentum of the positive mass in the other direction – conservation laws are still upheld, even if you have perpetual motion and reactionless acceleration. Unfortunately for this idea, however, you can't just hold the two objects apart with any sort of braces or connections. Any external force, no matter how small, will be amplified across the connections to infinity and break them. So that any slight imbalance in the initial masses will lead to them eventually drifting apart or colliding.

	However, negative mass would introduce all kinds of problems to the smooth operation of how the world works. For one thing, if negative mass (or equivalently energy) can exist, why doesn't it just spontaneously pop out of empty space accompanied by an equal magnitude of positive mass (or energy)? For another, negative masses lead to all kinds of runaway instabilities. For example, consider a negative mass thing in air. If it moves through the air, the drag force is in the opposite direction to its motion. But the negative mass accelerates opposite the force, so it accelerates in the direction of its motion. Unlike positive mass things that slow down from drag, negative mass things go faster! And the faster they go the more drag they experience, leading to a runaway exponential increase in their speed. Eventually they will be going so fast that they will be heating up the air, driving shock waves, and even producing radiant fireballs. All the energy for those phenomena come from the negative mass gaining negative energy the faster it goes. Any initial motion, no matter how small, will get amplified without bound. And because on the molecular scale the forces from atoms colliding with the negative mass will be subject to statistical fluctuations, even if initially exactly at rest the negative mass will soon start accelerating and run away off to infinity.		However, negative mass would introduce all kinds of problems to the smooth operation of how the world works. For one thing, if negative mass (or equivalently energy) can exist, why doesn't it just spontaneously pop out of empty space accompanied by an equal magnitude of positive mass (or energy)? For another, negative masses lead to all kinds of runaway instabilities. For example, consider a negative mass thing in air. If it moves through the air, the drag force is in the opposite direction to its motion. But the negative mass accelerates opposite the force, so it accelerates in the direction of its motion. Unlike positive mass things that slow down from drag, negative mass things go faster! And the faster they go the more drag they experience, leading to a runaway exponential increase in their speed. Eventually they will be going so fast that they will be heating up the air, driving shock waves, and even producing radiant fireballs. All the energy for those phenomena come from the negative mass gaining negative energy the faster it goes. Any initial motion, no matter how small, will get amplified without bound. And because on the molecular scale the forces from atoms colliding with the negative mass will be subject to statistical fluctuations, even if initially exactly at rest the negative mass will soon start accelerating and run away off to infinity.