Mar 12, 2024 06:28 PM
(This post was last modified: Mar 12, 2024 06:34 PM by C C.)
https://theness.com/neurologicablog/mach...ters-fail/
EXCERPTS: . . . In recent years NASA has tested two speculative technologies that claim to be able to produce thrust without propellant – the EM drive and the Mach Effect thruster (MET). For some reason the EM drive received more media attention (including from me), but the MET was actually the more interesting claim.
All existing forms of internal thrust involve throwing something out the back end of the ship. The conservation of momentum means that there will be an equal and opposite reaction, and the ship will be thrust in the opposite direction. This is your basic rocket. We can get more efficient by accelerating the propellant to higher and higher velocity, so that you get maximal thrust from each atom or propellant your ship carries, but there is no escape from the basic physics.
Ion drives are perhaps the most efficient thrusters we have, because they accelerate charged particles to relativistic speeds, but they produce very little thrust. So they are good for moving ships around in space but cannot get a ship off the surface of the Earth.
[....] The problem with propellantless drives is that they probably violate the laws of physics, specifically the conservation of momentum. Again, the real question is – how confident are we that such a drive is impossible? Saying we don’t know how it could work is not the same as saying we know it can’t work. The EM drive is alleged to work using microwaves in a specially designed cone so that as they bounce around they push slightly more against one side than the other, generating a small amount of net thrust (yes, this is a simplification, but that’s the basic idea). It was never a very compelling idea, but early tests did show some possible net thrust, although very tiny.
[...] And in fact when NASA tested the EM drive under rigorous testing conditions, they could not detect any anomalous thrust. With new technology there are two basic types of studies we can do to explore them. One is to explore the potential underlying physics or phenomena – how could such technology work. The other is to simply test whether or not the technology works, regardless of how. Ideally both of these types of evidence will align. There is often debate about which type of evidence is more important, with many proponents arguing that the only thing that matters is if the technology works. But the problem here is that often the evidence is low-grade or ambiguous, and we need the mechanistic research to put it into context.
But I do agree, at the end of the day, if you have sufficiently high level rigorous evidence that the phenomenon either exists or doesn’t exist, that would trump whether or not we currently know the mechanism or the underlying physics. That is what NASA was trying to do – a highly rigorous experiment to simply answer the question – is there anomalous thrust. Their answer was no.
The same is true of the MET.... (MORE - missing details)
EXCERPTS: . . . In recent years NASA has tested two speculative technologies that claim to be able to produce thrust without propellant – the EM drive and the Mach Effect thruster (MET). For some reason the EM drive received more media attention (including from me), but the MET was actually the more interesting claim.
All existing forms of internal thrust involve throwing something out the back end of the ship. The conservation of momentum means that there will be an equal and opposite reaction, and the ship will be thrust in the opposite direction. This is your basic rocket. We can get more efficient by accelerating the propellant to higher and higher velocity, so that you get maximal thrust from each atom or propellant your ship carries, but there is no escape from the basic physics.
Ion drives are perhaps the most efficient thrusters we have, because they accelerate charged particles to relativistic speeds, but they produce very little thrust. So they are good for moving ships around in space but cannot get a ship off the surface of the Earth.
[....] The problem with propellantless drives is that they probably violate the laws of physics, specifically the conservation of momentum. Again, the real question is – how confident are we that such a drive is impossible? Saying we don’t know how it could work is not the same as saying we know it can’t work. The EM drive is alleged to work using microwaves in a specially designed cone so that as they bounce around they push slightly more against one side than the other, generating a small amount of net thrust (yes, this is a simplification, but that’s the basic idea). It was never a very compelling idea, but early tests did show some possible net thrust, although very tiny.
[...] And in fact when NASA tested the EM drive under rigorous testing conditions, they could not detect any anomalous thrust. With new technology there are two basic types of studies we can do to explore them. One is to explore the potential underlying physics or phenomena – how could such technology work. The other is to simply test whether or not the technology works, regardless of how. Ideally both of these types of evidence will align. There is often debate about which type of evidence is more important, with many proponents arguing that the only thing that matters is if the technology works. But the problem here is that often the evidence is low-grade or ambiguous, and we need the mechanistic research to put it into context.
But I do agree, at the end of the day, if you have sufficiently high level rigorous evidence that the phenomenon either exists or doesn’t exist, that would trump whether or not we currently know the mechanism or the underlying physics. That is what NASA was trying to do – a highly rigorous experiment to simply answer the question – is there anomalous thrust. Their answer was no.
The same is true of the MET.... (MORE - missing details)