Equation 3 implies that Mach effect thruster performance is heavily dependent on the velocity of the universe relative to the Mach effect thruster. In the SAIC proposal above 5 N/kWe was mooted. This implies a universal velocity of 200 m/s.
Quote from: Jim Davis on 10/03/2017 11:45 pmEquation 3 implies that Mach effect thruster performance is heavily dependent on the velocity of the universe relative to the Mach effect thruster. In the SAIC proposal above 5 N/kWe was mooted. This implies a universal velocity of 200 m/s.Some numbers you should be aware of when trying to figure out the relevant velocities:Speed due to Earth rotation at Equator: 640 m/sEarth's speed around the sun: 30 km/s (30000 m/s)Speed of sun around center of galaxy: about 200 km/s (200000 m/s)Earth's speed relative to the CMB: about 370 km/s (370000 m/s)I am not a particular proponent of the Mach effect due to questions related to instantaneous interactions and relativity as well as whether a "velocity of the universe relative to you" can even be defined.
If the universe gives you a little energy for a MEGA drive, eventually you could get up enough energy to pop a planet or star. We probably do not live in a universe where such self accelerating objects exist. If the Universe can give you a little energy why can't it give you a lot to warp spacetime? If the device only has KE= energy in but is gaining additional velocity by an effect that cannot be harvested to slam into a stellar object at reletavistic speeds, then once again we do not live in a universe where you can pop planets.
Anything that can propel a load at a significant fraction of c can be turned into a weapon just by not braking it and aiming it well.
here the link to the specific Space Show programhttp://thespaceshow.com/show/15-aug-2017/broadcast-2966-gary-hudsonthere is a description of the questions and arguments by Jim Davies, in the 4th paragraph.
Quote from: SteveD on 10/04/2017 05:25 amIf the universe gives you a little energy for a MEGA drive, eventually you could get up enough energy to pop a planet or star. We probably do not live in a universe where such self accelerating objects exist. If the Universe can give you a little energy why can't it give you a lot to warp spacetime? If the device only has KE= energy in but is gaining additional velocity by an effect that cannot be harvested to slam into a stellar object at reletavistic speeds, then once again we do not live in a universe where you can pop planets.Given there are talks about interstellar probes that can go to Proxima in 20 years with believed-to-be feasible improvements of the technology, then yes, we are talking about a technology capable of cracking planets.Anything that can propel a load at a significant fraction of c can be turned into a weapon just by not braking it and aiming it well.
Quote from: aceshigh on 10/04/2017 04:11 amhere the link to the specific Space Show programhttp://thespaceshow.com/show/15-aug-2017/broadcast-2966-gary-hudsonthere is a description of the questions and arguments by Jim Davies, in the 4th paragraph.Very interesting discussion and articles.Personally and given I'm no physicist, I have some trouble imagining why the intensive use of Mach Effect drives in the locality would result in universal acceleration.As per the talks elsewhere, the drives would be taking minute amounts of energy and momentum (probably quantum/Planck units of it) from the bodies all across the far reaches of the universe, balancing the energy equations and ensuring entropy always grows.Nevertheless, for me that means these far bodies would be increasing their entropy as a result, making their orbits slightly more chaotic or losing very small amounts of some other energy (e.g. heat/gravitational potential, etc.) through time in exchange. If we are alone using these drives, the effect on the cosmos may be negligible for a long while. But if there are other civilizations doing it and have been at it for millions of years, I can understand the difference could add up to produce significant cosmic changes.That means galaxies and bodies losing momentum and crashing into each other, that is, the universe probably losing impulse and contracting. Or is precisely the injection of additional energy in the local region the one somehow causing the acceleration at the expense of the rest?If it is, I fail to see how. I'd appreciate if anyone with more understanding could elaborate.
Quote from: tchernik on 10/04/2017 05:10 pmAnything that can propel a load at a significant fraction of c can be turned into a weapon just by not braking it and aiming it well.This will not make me sleep well tonight. Shades of Heinlein's "The Moon is a Harsh Mistress."
Thus my main objection to this (besides of realism of the phenomenon) is: do we really need to grow exponentially like roaches with an unlimited food supply?
Quote from: Bob Woods on 10/04/2017 06:22 pmQuote from: tchernik on 10/04/2017 05:10 pmAnything that can propel a load at a significant fraction of c can be turned into a weapon just by not braking it and aiming it well.This will not make me sleep well tonight. Shades of Heinlein's "The Moon is a Harsh Mistress."I wouldn't worry about that......worry about this instead. Effectively free energy + exponential growth + only cubic expansion of volume (linear expansion of radius).It doesn't matter if the energy is actually free or just effectively free. People would still exploit it. Ultimately it beats all other power sources because they are all limited by their mass. This can pull in energy and mass from somewhere else, forever.Never underestimate mere human exponential growth. The observable universe is unimaginably vast, but humans, doubling in population every 30 years or so, would crowd it in a mere handful of thousand years, if we were not limited by resource availability.Suppose we remain limited to light speed, but something like this provides effectively free energy. The maximum sphere of area we could possibly have populated would only expand at a crawl the mere speed of light, but he energy we pull into that sphere would expand exponentially, having dismantled all other available matter for exponential growth, we would also spin this effectively free energy into new matter.There is a problem here that many would immediately see.. but without FTL, how do you police the entire volume? some groups will choose to keep exponentially expanding and they will dominate.At some point the linearly increasing volume can not outrun the exponentially increasing density, and human civilisation along with several galaxies vanish, crushed behind an event horizon.If such a technology exists, it could explain Fermi's paradox.
Humans doubling in population every 30 years?If anything, we have seen that humans are tending to breed less and less. Even in some third world countries (like here in Brazil), fertility rates are below 2 children by woman already.In an advanced interstellar society, I guess couples would wait 100 years before having children...
Suppose we only double every thousand years. Where are we in a million years of unfettered growth? Have you got a calculator that can handle 21000?
I wouldn't worry about that......worry about this instead. Effectively free energy + exponential growth + only cubic expansion of volume (linear expansion of radius).It doesn't matter if the energy is actually free or just effectively free. People would still exploit it. Ultimately it beats all other power sources because they are all limited by their mass. This can pull in energy and mass from somewhere else, forever.Never underestimate mere human exponential growth. The observable universe is unimaginably vast, but humans, doubling in population every 30 years or so, would crowd it in a mere handful of thousand years, if we were not limited by resource availability.Suppose we remain limited to light speed, but something like this provides effectively free energy. The maximum sphere of area we could possibly have populated would only expand at a crawl the mere speed of light, but he energy we pull into that sphere would expand exponentially, having dismantled all other available matter for exponential growth, we would also spin this effectively free energy into new matter.There is a problem here that many would immediately see.. but without FTL, how do you police the entire volume? some groups will choose to keep exponentially expanding and they will dominate.At some point the linearly increasing volume can not outrun the exponentially increasing density, and human civilisation along with several galaxies vanish, crushed behind an event horizon.If such a technology exists, it could explain Fermi's paradox.