https://phys.org/news/2018-12-universe-theory-percent-cosmos.html?utm_source=nwletter&utm_medium=email&utm_campaign=daily-nwletterScientists at the University of Oxford may have solved one of the biggest questions in modern physics, with a new paper unifying dark matter and dark energy into a single phenomenon: a fluid which possesses 'negative mass." If you were to push a negative mass, it would accelerate towards you. This astonishing new theory may also prove right a prediction that Einstein made 100 years ago.
Quote from: colbourne on 12/06/2018 05:16 amhttps://phys.org/news/2018-12-universe-theory-percent-cosmos.html?utm_source=nwletter&utm_medium=email&utm_campaign=daily-nwletterScientists at the University of Oxford may have solved one of the biggest questions in modern physics, with a new paper unifying dark matter and dark energy into a single phenomenon: a fluid which possesses 'negative mass." If you were to push a negative mass, it would accelerate towards you. This astonishing new theory may also prove right a prediction that Einstein made 100 years ago.Sonny White will be pleased to hear this. :>
Miguel Alcubierrre (1994) published a paper that showed that a warp drive is at least mathematically possible, although it would require huge amounts of negative energy. Pfenning and Ford (1997) showed that a warp bubble wall as proposed by Alcubierre would have to be impossibly thin in order to work. Low (1999) showed that a warp in spacetime could travel no faster than the speed of light and that such a warp would require exotic matter (negative energy). Natario (2002) had a little more positive result: he showed that warp drives could be possible in that they wouldn’t need to compress spacetime ahead of themselves and stretch it behind in order to move. Lobo and Visser (2004) most recently published on this and they showed that in order for a warp drive to work, a couple of things need to happen:1. The spaceship can’t travel faster than light2. The amount of negative energy must be a significant fraction of the mass of the ship.As I understand it, a spaceship using a warp drive can’t travel faster than light because gravity only travels at the speed of light, and such a ship would be relying on a negative gravitational force generated by the negative energy it is carrying along in its warp of spacetime.ReferencesThe warp drive: hyper-fast travel within general relativityMiguel AlcubierreClass. Quantum Grav. 11 No 5 (May 1994) L73-L77Fundamental limitations on 'warp drive' spacetimesFrancisco S N Lobo and Matt VisserClass. Quantum Grav. 21 No 24 (21 December 2004) 5871-5892Speed limits in general relativity Robert J LowClass. Quantum Grav. 16 No 2 (February 1999) 543-549Warp drive with zero expansionJ NatarioClass. Quantum Grav. 19 No 6 (21 March 2002) 1157-1165The unphysical nature of `warp drive' M J Pfenning and L H FordClass. Quantum Grav. 14 No 7 (July 1997) 1743-1751
This engineering model firmly establishes a viable solution to quantum gravity for engineers within the standard model of Quantum Electrodynamics.
It opens the door to new innovations that might permit artificial gravity or anti-gravity technologies to be invented. Through the use of stimulated emission, increased or reduced radiative damping, or by amplification of the resonant driving fields that inflate matter to higher ground state energies. Engineers now have a new set of old, familiar tools to work with when thinking about gravity and Metric Engineering [3].
What was presented herein puts gravity in the hands of engineers, who could potentially advance such technologies as; warp drive, artificial gravity and anti-gravity, from pure speculation, to achievable endeavors in our lifetime.
..."Also, to preempt a likely response to what I just said: As far as I can tell you just did a change of variables, without changing the underlying math. In this case (assuming no mistakes), your new formulation is automatically consistent with GR,..."
Quote from: meberbs on 01/12/2019 06:50 pm..."Also, to preempt a likely response to what I just said: As far as I can tell you just did a change of variables, without changing the underlying math. In this case (assuming no mistakes), your new formulation is automatically consistent with GR,..." No offense intended. I chalk it up to life experiences. I've only ever met a handful of engineers who even attempted to understand the mathematics and nuances of GR, and of them, I'm the best, which isn't saying much. So yeah, "most" engineers I've conversed with are not at that level in my experience, and simply find the topic an interesting curiosity. If you're an engineer, and given your understanding of GR, that makes "2", you and Hal Puthoff are unique in my experience....
I am really surprised that nobody is talking about this.This would seem to me (non engineer, lurker, medical professional) to move FTL into a less hand waveable contex.
"The energy required for this drive traveling at light speed encompassing a spacecraft of 100 meters in radius is on the order of hundreds of times of the mass of the planet Jupiter," Lentz says."The energy savings would need to be drastic, of approximately 30 orders of magnitude to be in range of modern nuclear fission reactors."
There is a fantastic difference between something that is probably impossible (or merely not proven possible) within the laws of physics and something that merely needs a jupiters-mass-worth of energy.
Quote from: KelvinZero on 04/18/2021 09:56 amThere is a fantastic difference between something that is probably impossible (or merely not proven possible) within the laws of physics and something that merely needs a jupiters-mass-worth of energy.No, not really. Unless you mean as in a "fantasy". And it's 100s of times the mass of Jupiter.Using up a Jupiter to send 1 bit would be quite useless, it is absurd to suggest otherwise. There are plenty of things we know for sure we can do, but still don't find it practical. e.g. supersonic passenger liners.Saying that something would revolutionize physicists understanding of the Universe is fantastically different to saying it would make any difference to the person on the street.
Looks like it has hit the (almost) the mainstream
Quote from: KelvinZero on 04/21/2021 09:23 pmLooks like it has hit the (almost) the mainstream I'm still not seeing how a warp drive is anything more than a fancy box that's particularly heavy (has high, black-hole like mass/energy density) in specific places.
Quote from: clippie on 04/15/2021 12:16 amI am really surprised that nobody is talking about this.This would seem to me (non engineer, lurker, medical professional) to move FTL into a less hand waveable contex.Because it would still require huge amounts of energyQuote"The energy required for this drive traveling at light speed encompassing a spacecraft of 100 meters in radius is on the order of hundreds of times of the mass of the planet Jupiter," Lentz says."The energy savings would need to be drastic, of approximately 30 orders of magnitude to be in range of modern nuclear fission reactors."Or, 10000000000000000000000000000 times more than a nuclear reactor. About a trillion trillion trillion Watts. When a scientist says 30 orders of magnitude, it is a practical impossibility.