Oct 4, 2023 06:47 PM
(This post was last modified: Oct 4, 2023 06:49 PM by C C.)
https://bigthink.com/starts-with-a-bang/...hope-dies/
KEY POINTS: In order to make a working "warp drive," there must be some way to not only curve the fabric of space, but to curve it in fundamentally different directions ahead of and behind the spacecraft. By creating a positively curved region "contracting" the space in front of a spacecraft and a negatively curved region "rarefying" it behind, a "warp bubble" could be created. However, that would require negative mass/energy, and negatively-gravitating antimatter could have done it. Unfortunately, physics said otherwise: antimatter falls down.
EXCERPTS: ... Unfortunately, our hopes of visiting and exploring these worlds face a tremendous obstacle: the limitations of the speed of light. While it’s theoretically possible to accelerate objects, even macroscopic ones, close to the speed of light, the laws of physics not only prevent us from achieving or surpassing that speed, but they damn us to the severe experience of time dilation. Even if we were to get in a spaceship and travel at near-light speeds, everyone back at home would age spectacularly while we undertook our interstellar journey.
There was only one potential way out: warp drive, or taking a “short-cut” by severely curving the fabric of spacetime. Long thought impractical, the physics behind this possibility was worked out by Miguel Alcubierre in 1994, and the only requirement was something that anti-gravitated: something like “negative energy” or “negative mass.” With the recent measurement that antimatter falls down in a gravitational field, humanity’s greatest hope for practically achieving our warp drive dreams just suffered a massive blow. Here’s the science behind the amazing, but sobering, result.
The seeds of warp drive were planted even before Einstein’s general theory of relativity came along: back in the 19th century, when mathematicians began playing around with new types of geometry that went way beyond the imaginings of Euclid and his successors...
[...] f there were some type of negative energy in the Universe that could be harnessed and manipulated, then this type of warp-drive spacetime, now known as the Alcubierre metric, could be created in real life. The only problem, of course, is that all of the particles and fields known to exist, even in theory, only have one type of mass/energy: the positive type, and hence they all curve spacetime the same way. If warp drive is to be physically realized, some sort of “exotic matter” with negative mass/energy is required.
[...But...] antimatter doesn’t anti-gravitate, and with that, humanity’s best hope for achieving warp drive has just died.
[...] Although there are physicists who wonder “Why did we even need to do this experiment; we all knew that antimatter has positive mass,” that sentiment is absolutely foolish. We must remember — and I say this as a theoretical physicist myself — that physics is 100% an experimental science. We can be confident in our theory’s predictions only insofar as we can test and measure what it predicts; as soon as we step outside of the realm of what’s been validated by experiment, we run the risk of stepping outside the realm of where our theory is valid. We just learned that Einstein’s general relativity passed another test, the antimatter test, and with it, our greatest science-fiction hope for achieving warp drive has completely evaporated... (MORE - missing details)
KEY POINTS: In order to make a working "warp drive," there must be some way to not only curve the fabric of space, but to curve it in fundamentally different directions ahead of and behind the spacecraft. By creating a positively curved region "contracting" the space in front of a spacecraft and a negatively curved region "rarefying" it behind, a "warp bubble" could be created. However, that would require negative mass/energy, and negatively-gravitating antimatter could have done it. Unfortunately, physics said otherwise: antimatter falls down.
EXCERPTS: ... Unfortunately, our hopes of visiting and exploring these worlds face a tremendous obstacle: the limitations of the speed of light. While it’s theoretically possible to accelerate objects, even macroscopic ones, close to the speed of light, the laws of physics not only prevent us from achieving or surpassing that speed, but they damn us to the severe experience of time dilation. Even if we were to get in a spaceship and travel at near-light speeds, everyone back at home would age spectacularly while we undertook our interstellar journey.
There was only one potential way out: warp drive, or taking a “short-cut” by severely curving the fabric of spacetime. Long thought impractical, the physics behind this possibility was worked out by Miguel Alcubierre in 1994, and the only requirement was something that anti-gravitated: something like “negative energy” or “negative mass.” With the recent measurement that antimatter falls down in a gravitational field, humanity’s greatest hope for practically achieving our warp drive dreams just suffered a massive blow. Here’s the science behind the amazing, but sobering, result.
The seeds of warp drive were planted even before Einstein’s general theory of relativity came along: back in the 19th century, when mathematicians began playing around with new types of geometry that went way beyond the imaginings of Euclid and his successors...
[...] f there were some type of negative energy in the Universe that could be harnessed and manipulated, then this type of warp-drive spacetime, now known as the Alcubierre metric, could be created in real life. The only problem, of course, is that all of the particles and fields known to exist, even in theory, only have one type of mass/energy: the positive type, and hence they all curve spacetime the same way. If warp drive is to be physically realized, some sort of “exotic matter” with negative mass/energy is required.
[...But...] antimatter doesn’t anti-gravitate, and with that, humanity’s best hope for achieving warp drive has just died.
[...] Although there are physicists who wonder “Why did we even need to do this experiment; we all knew that antimatter has positive mass,” that sentiment is absolutely foolish. We must remember — and I say this as a theoretical physicist myself — that physics is 100% an experimental science. We can be confident in our theory’s predictions only insofar as we can test and measure what it predicts; as soon as we step outside of the realm of what’s been validated by experiment, we run the risk of stepping outside the realm of where our theory is valid. We just learned that Einstein’s general relativity passed another test, the antimatter test, and with it, our greatest science-fiction hope for achieving warp drive has completely evaporated... (MORE - missing details)