Please use this post for further comments in the above thread, which originally appeared under the title “A Practical Positron Rocket?”
Practical Positron Rocket Overflow Thread #2
by Paul Gilster | Oct 8, 2007 | Advanced Rocketry | 265 comments
by Paul Gilster | Oct 8, 2007 | Advanced Rocketry | 265 comments
Please use this post for further comments in the above thread, which originally appeared under the title “A Practical Positron Rocket?”
In Centauri Dreams, Paul Gilster looks at peer-reviewed research on deep space exploration, with an eye toward interstellar possibilities. For many years this site coordinated its efforts with the Tau Zero Foundation. It now serves as an independent forum for deep space news and ideas. In the logo above, the leftmost star is Alpha Centauri, a triple system closer than any other star, and a primary target for early interstellar probes. To its right is Beta Centauri (not a part of the Alpha Centauri system), with Beta, Gamma, Delta and Epsilon Crucis, stars in the Southern Cross, visible at the far right (image courtesy of Marco Lorenzi).
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Jim,
Theories are a dime a dozen. Don’t let my opinions restrict your imagination.
If my theories begin to be proven then think what you wish, until then restrict nothing/
yoiur friend forrest
Along those same lines which you discussed Jim,
My theories predict non-linear gravity currents both within and outside galaxies.
Perhaps some of these currents could be moving millions of miles per hour. These could be the highways of future space craft, but only in one direction, the direction of the dark matter (gravity) current. The most powerful of these currents accompany galactic jets which can extend from galaxy to galaxy in some cases. According to my theories a number of these jets are truly superliminous relative to the center of the galaxy that is emitting them. To ride the waves on the periphery of these jets mights by the fastest of these potential “highways”.
your friend forrest
Hi Forrest;
Thanks for the above postings.
The idea of superluminal gravity current highways is fascinating. I am a real fan of anything interstellar or intergalactic that uses the phrase highways and superluminal travel together. Part of this comes from my enjoyment of driving a car and the simplicity and independence of driving a car. This remains true even after having driven for close to 30 years. I love highway driving on cool temperate nights.
Whether such so-called cars drive thru wormholes, space time dimension transition zone boundaries as I implied above, or in superluminal gravity currents, I am all for it. Anything to advance the theory of interstellar or intergalactic transport is cool with me.
Thanks Again;
Your Friend Jim
Jim,
I feel certain that we’ll see a lot of great stuff in the next lets say 25 years, at least some of it will be very exciting and totally unexpected. Individual space travel (space cars, as you suggested) before the year 2200 would be awesome even though we wouldn’t see it. Just the idea is intriguing.
your friend forrest
Hi Forrest;
Thanks for the above posting.
The idea of unpredictable technological/scientific advances resonates deeply within me.
I remember as a 7th grader thinking that I would like to have my own computer oneday, but imagined that such a computer would be at least as big as a car and cost about 5 million dollars. I never would have imagined that I would own one with a purchase price 4 orders of magnitude less, even given the process of monetary inflation.
I remember reading an article about video phones in the mid 70s but I never would have imagined something as unbiquitous and powerful as the internet or emails. and cell phones that can text message, take pictures and transmit them as well as international phone calls for several minutes that would cost less then a typical single serving Hershey Bar.
We have not gone to Mars yet, but we have discovered water ice on Mars and rich Martian soil.
I look forward to the next 25 years with a sense of excitement and adventure, almost like a little kid in a candy shop, in anticipation of the knowns and unknowns that will come to past.
Thanks;
Your Friend Jim
I thought I would provide you the following URL for a Computer World article on a development of MIT regarding reduced size of computer chip circuit elements as follows:
http://www.computerworld.com/action/article.do?command=viewArticleBasic&articleId=9108318&intsrc=hm_list
The development of microchips with features on the scale of 25 nm is a great improvement. Not only can four times as many elements such as transistors and the like be produced for a given area relative to the 45 nm scale devices of prior art, but, since the pathways required for the electrons to carry information are greatly reduced, the travel time of not only the electrical current flowing through each circuit element is reduced, but so is the travel time of the individual electrons which is usually significantly less then the net charge drift based EMF or the electromotive force travel velocity within an electric circuit.
This technology should allow us to produce much faster chips and corresponding computer speeds in both PC computers as well as in supercomputers utilizing many individual chips in parallel.
Even though there is much talk as of late about the potential of quantum computers, traditional digital computers will probably out perform quantum computers for many types of calculations.
I like to consider the possibility that in some far distant future date, if and when we have learned to manipulate the fabric of space time on the scale of the Planck Length of [(h bar)(G)/(C exp 3)] EXP (1/2) and the Planck time of [(h bar)(G)/(C exp 5)] EXP (1/2) or about 10 EXP -35 meters and 10 EXP – 43 seconds respectively, that we could some how produce circuit elements out of individual space time units or cells and somehow use them to carry information, who knows, perhaps by hypothetical quantum gravity field particles referred to as gravitons.
As a space head who dreams of applying known physics to interstellar travel, sooner rather than later, I am intrigued by every increase in computer power which can help us understand nuclear reactions in greater detail and perhaps elucidate observed anomalies in current particle accelerator research projects that hint of additional nuclear forces beyond the known strong and weak nuclear forces.
Thanks;
Jim
Hi George and Forrest;
I thought to mention a concept in a version that I have just this very day mentally elaborated on in terms of my first knowledge of the version.
The idea essentially involves producing a CMBR and starlight capturing planar membrane that would extend across the entire observable universe. The membrane would be on the order of 1 nm thick and would consist of only about 0.1 percent surface area material being that the membrane would be composed of highly conducting to superconducting thread on the scale of 1nm thick separated by roughly 0.5 microns to 1.0 microns to form an energy capturing fabric.
Thus a one trillion square meter portion of the extended fabric would have a mass of one metric ton assuming that the fabric was made of some low atomic mass number superconducting material such as metallic hydrogen or carbon nanotubes. The area of the sheet with the currently observable universe radius would be (pi)(R exp 2) = (pi){[2.75 x (10 EXP 26) meters] EXP 2} or about 2 x (10 EXP 53) square meters. Thus, the corresponding mass would be about 2 x (10 EXP 53)(10 EXP – 12) metric tons or 2 x (10 EXP 41) metric tons or about the mass of 100 large galaxies. Nanotech means might provided to maintain the membrane or perhaps nanobots or microbots could do the same.
Ideally, the membrane would have energy emission centers or stations where beamed energy could be transmitted in order to power intergalactic space faring craft. The membrane may optionally have super high area specific or super high volume specific charge capacitors or stations to convert generated electrical energy into fusion fuel or antimatter or matter/antimatter fuel. In 13.73 billion years, the membrane would effectively sweep a volume of space equal to that of the observable universe clean of star light and CMBR in terms of the total volume of such energy at any given point in our current epoch.
I wonder if the deployment of such a large membrane might have an impact on ordinary scale zero point fields, the curvature of space time within the region bifurcated, or any other such exotic effect(s) due to any coupling between the ultra small with the ultra large, and the possible general relativistic electrogravatic effects of such a large superconducting membrane on general space time geometry.
Thanks;
Your Friend Jim
Hi Folks;
I revisit a concept for which I posted comments at Tau Zero about a year or so ago and that involves the concept of a fusion wick that could be anywhere from a fraction of a light-year long to billions, if not in the far distance future, trillions or more light years long.
The idea is an extreme case involving a long white dwarf density wick that has about the cross-sectional diameter of a white dwarf. Thus a 10,000 kilometer segment would have a mass roughly equal to that of a white dwarf. A 27.46 billion light year long wick would have a mass of about 27.46 x (10 EXP 10)(10 EXP 13)/(10 EXP 4) solar masses or 2.746 x (10 EXP 20) solar masses or about 0.1 percent of the real mattergy content of the observable universe.
Such a wick, if when ignited and some sort of gradual burn rate mechanism was included such that the burning wick rate could propagate along side an accelerating space craft harnessing most of the wick fusion energy for KE gains, could in theory perhaps permit a stellar masses world civilization space craft to reach a gamma factor of about 10 EXP 18 after having propagated down the fusing wick for a distance equal to the radius of the observable universe. A space craft as such with the mass of the Earth could perhaps reach a gamma factor of 10 EXP 24 during the same interval. Obviously, some means of extraction friction energy from the interstellar and intergalactic medium and recycling it into to ship based KE would be required. If one wanted to go to even more extreme mathematical examples, a trillion metric ton ship might reach a gamma factor of 10 EXP 33.
The energy would be extracted from the fusion wick by some sort of electro-dynamic plasma energy capture mechanism and x ray and gamma ray energy capture mechanism and some way to cancel out the extreme acceleration of the above configurations would need to be provided. Currently impossibly strong, radiation, and heat resistant materials would be required in the construction of the craft. A much more realistic case would entail wick with a mass of 1 gram per kilometer length that would be a light year long and thus have a mass of 10 EXP 7 metric tons and be used to accelerate a 10,000 metric ton space craft to a gamma factor of about 1,000.
Thanks;
Jim
Hi Folks;
Regarding energy wicks for interstellar or intergalactic manned space craft propulsion, one might conjecture about such a wick made of neutron dense material that is somehow stabilized against decay. The wick might be activated by some sort of strong nuclear force interaction wherein the interaction would could initially propagate at a velocity below C but then increase to a propagation at C and perhaps even beyond C.
Now quantum-chromo-dynamics holds that the velocity of the strong nuclear force interaction proceeds at the velocity of light in vacuu, however, perhaps by construction of the wick out of just the right materials and/or of the right shape, superluminal reaction propagation rates might be achieved. Perhaps quantum tunneling of the process or thermodynamic energy states within the wick could result in superluminal burn rate. Another option might entail a nuclear force analogue of negative index of refraction electromagnetic materials wherein the actual energy associated with the reaction would propagate down the wick at superluminal velocities.
Note, that the electromagnetic energy transmission rates within negative refractive index materials remains at or below C in vacuu. Note that the refractive index is defined as n = c/v where c is the speed of light and v is the phase velocity of the wave. In some cases, v can be less than one. The signal or group wave velocity accordingly always remains at C or less and thus accordingly, relativity is not contradicted. However, perhaps unforeseen materials science will lead to materials with a group wave velocity greater then C in vacuu. The group index of refraction is Ng = C/Vg = n – (Lambda)[dn/d Lambda]. Thus if somehow the value of n – (Lambda)[dn/d Lambda] for optical materials could be increased to beyond C in vacuu, we might have superluminal EM energy transmission. As a result, there might be a corresponding analogue for nuclear force effects transmission. Perhaps nuclear matter electromagnetic Ng > C wicks would used gamma ray production to propagate the burn rate at > C by perturbative effects. Note that all known materials have a group wave velocity equal to C in vacuu or less. This include negative refractive index materials being developed also.
The point to all of the above is that if a burning effect within a wick can travel at V > C, perhaps this superluminal effect would some how drag the craft along with it by some casual coupling mechanism and perhaps even drag the craft in backward time travel.
Thanks;
Jim
Hi Folks;
I had some even more speculative concepts regarding interstellar space wicks.
The first concept involves the production of such wicks out of matter/antimatter composite fuel that is stable and heat and tear resistant. A 1 gram per kilometer length wick that would be a light year long and thus have a mass of 10 EXP 7 metric tons and be used to accelerate a 10,000 metric ton space craft to a gamma factor of about 1,000.
The similar example I gave for the fusion wick in my above posting on July 13th, 2008 at 20:50 was inaccurate. The fusion wick version could only accellerate a 10,000 metric ton space craft to a gamma factor of 10 assumming a 1 gram/kilometer wick that is 1 light year long and thus has a mass of 10 EXP 7 metric tons. However, this fusion version as a continuos variable burn rate version of a fusion pellet runway beats taking all of the fuel aboard the space craft in effeciency by about 2 orders of magnitude. Note that the wick might be more stable then the geometical arrangement of discreet free floating fusion pellets.
What if new forms of mass are developed or new nuclear forces are discovered wherein the mass to energy conversion or nuclear reactions are much more exothermic that complete relativistic mass to energy conversion according to the relation: E = M(C EXP 2). Wicks based on any such exothermic mass transformation mechanisms could be much lower in mass to yield the same gamma factors that matter/antimatter wicks could which can yield relativistic kinetic craft energies about 100 times greater than ordinay fusion wicks could for the same fuel mass. Infact, the ratio of the gamma factors for the would be new forms of mass and/or novel nuclear reactions to matter antimatter reactions would be almost equal to the ratio of their energy yields. As the mass of the novel yet to be discovered fuels wick and the mass of the matter/antimatter wick increases wherein the mass of the two wicks remains constant, the equality of the two ratios grows more precise.
Thanks;
Jim
Hi Folks;
One more error to correct. In the final sentence of the above posting, I meant to state “… wherein the mass of the two wicks remains the same….” instead of “… wherein the mass of the two wicks remains constant… “.
Note that it is my policy to correct any grammar or other typos that can lead to strong misinterpretations of the points I am trying to convey.
Thanks;
Jim
Hi Folks;
I had a few other brief comments to make about energy wicks.
For a wick with a mass, M, of a times the mass, m, of a wick made of matter antimater fuel, the terminal gamma factor of a craft powered by the more mass specific exothermic fuel wick would be a times the ratio of the mass specific exothermic yields of the more exothermic exotic fuel over that of the matter/antimatter fuel. For wicks made of exotic super relativistic energy yield fuel that have the same linear mass density as that of a matter/antimatter fuel wick but which have a length of b times that of the matter/antimatter fuel wick, the terminal gamma factor of the craft powered by the exotic fuel wick would be b times the ratio of the mass specific exothermic yields of the more exothermic exotic fuel over that of the matter/antimatter fuel.
For wicks made of super-relativistic exothermic energy yield material that has a volumetric density of c times that of the matter antimater fuel, but otherwise having the same spatial dimensions, the terminal gamma factors of the the craft powered by the super-relativistic wick would be c times the ratio of the mass specific exothermic yields of the more exothermic exotic fuel over that of the matter/antimatter fuel.
If energy wicks could be assembled that have a length on the order of that of the radius of the observable universe, then some sort of wick material may be required that possesses good elastic properties in order to allow the wick to stretch as it is pulled on by the space time expansion of the universe. Thus, the wick material for wicks of such length would need to have a high strain capable characteristic.
Thanks;
Jim
Hi Folks;
I made an obvious set of repeated error above. The correct math is as follows.
For a wick with a mass, M, of a times the mass, m, of a wick made of matter antimater fuel, the terminal gamma factor of a craft powered by the more massive wick would be a times the ratio of the mass specific exothermic yields of the more exothermic exotic fuel over that of the matter/antimatter fuel times the terminal gamma factor of the matter/antimatter fuel wick powered craft. For wicks made of exotic super relativistic energy yield fuel that have the same linear mass density as that of a matter/antimatter fuel wick but which have a length of b times that of the matter/antimatter fuel wick, the terminal gamma factor of the craft powered by the exotic fuel wick would be b times the ratio of the mass specific exothermic yields of the more exothermic exotic fuel over that of the matter/antimatter fuel times the terminal gamma factor of the matter/antimatter fuel wick powered craft.
For wicks made of super-relativistic exothermic energy yield material that has a volumetric density of c times that of the matter antimater fuel wick, but otherwise having the same spatial dimensions, the terminal gamma factors of the the craft powered by the super-relativistic wick would be c times the ratio of the mass specific exothermic yields of the more exothermic exotic fuel over that of the matter/antimatter fuel times the terminal gamma factor of the matter/antimatter wick powered craft. For such wicks having the same relative volumetric density ratio of c, but wherein the length of the super relativistic exothermic yield wick is b times that of the matter/antimatter wick wherein the cross sectional area of the two wicks are the same, then the terminal gamma factors of the the craft powered by the super-relativistic wick would be (c)(b) times the ratio of the mass specific exothermic yields of the more exothermic exotic fuel over that of the matter/antimatter fuel times the terminal gamma factor of the matter/antimatter wick powered craft.
For such wicks having the same relative volumetric density ratio of c, but wherein the length of the super relativistic exothermic yield wick is b times that of the matter/antimatter wick wherein the cross sectional area of the super-relativistic energy wick is d times that of the matter/antimatter wick, then the terminal gamma factors of the the craft powered by the super-relativistic wick would be (c)(b)(d) times the ratio of the mass specific exothermic yields of the more exothermic exotic fuel over that of the matter/antimatter fuel times the terminal gamma factor of the matter/antimatter wick powered craft.
Thanks for your patients.
Jim
Hi Folks;
Reading an article summary regarding the Facility for Rare Isotope Beams (FRIB), made my day yesterday.
Producing never before observed isotopes of not only known elements, but also of never before observed super-heavy elements can help us obtain a better understanding of the strong and weak nuclear forces, and may even help us better interpret anomalies that hint at existence of additional nuclear forces.
If we were to find such additional nuclear forces, it is possible that nuclear reactions involving such additional nuclear forces may involve exothermic energy releases with considerably greater rest mass specific energy conversion than the currently highest known single reaction pathway involving hydrogen fusion which involves the conversion of about 0.7 percent of the rest mass of the reactants into energy.
It might even be possible that exothermic reactions may be discovered that are of higher apparent efficiency of mass-energy conversion than complete mass conversion into energy such as that which occurs in the electron and positron annihilation reaction. Perhaps any such super-relativistic reactions might involve hidden forms of mass associated with what we refer to as inertial mass or new forms of mass that do not quite follow the rules of the relation E = M(C EXP 2).
The real point I am trying to convey is that for every new advance in particle physics accelerator apparatus, there remains the chance for the observation of exotic new behavior for which we can only speculate as to it useful applications to technology. For one, where all the more exothermic fuels are developed, rockets with ever higher gamma factors become possible in theory.
An ironic situation would entail the possibility of the best manned interstellar space propulsion methods actually using rockets. If there is any breakdown of special relativity for super high gamma factors, perhaps rockets could be used to accellerate space craft beyond the speed of light.
Thanks;
Jim
Jim,
Jim, George, glad to be back on site.
I agree that pellet fuel of some type seems quite possible for future aircraft to go from earth to space. The closest we’ve come so far is solid rocket fuel which is a problem because their rate of burn cannot be throttled. Present fuels that are compressed into heavy tanks using cryogenics might become obsolete if encapsulated fuel components and combustible containers were invented.
The idea is that two or more chemically different BB sized encapsulated chemical composite pellet material could be injected into an exhaust chamber where heat would enable continuous combustion. Each element of the fuel separately could not burn or explode. Even the very light fuel containers themselves might be made from combustible solid materials and also used for fuel as the container empties. Composite exterior materials could be used for the fuselage and exterior skin making the craft relatively light enabling a bigger payload and hopefully an earth to orbit capability. It could refuel with a different kind of fuel tank and fuel at a space station after reaching orbit enabling it to go out and about in the solar system.
your friend forrest