Antimatter seems the boldest — and newest — of propulsion concepts, but in fact Eugen Sänger’s work on the uses of antimatter in rocketry goes back to the 1930s. The German scientist thought it would be possible to reflect gamma rays produced by the annihilation of electrons and positrons to produce thrust. His work wowed the Fourth International Astronautical Congress in 1952, but there was a catch: the gamma rays created by this reaction seemed too energetic to use the way Sänger hoped — they penetrated all known materials and could not be channeled effectively into a rocket exhaust.
Which is why most antimatter designs since have focused on antiprotons. When antiprotons and protons annihilate each other, they produce not only gamma rays but pi-mesons, short-lived particles also known as pions. Many of these are charged as they emerge from the proton/antiproton annihilation, and can therefore be controlled by sending them through a strong magnetic field. Early designs by Robert Forward and David Morgan (Lawrence Livermore National Laboratory) took advantage of these traits even though the technology to produce sufficient antimatter lagged far behind their visionary concepts.
But antimatter researcher Gerald Smith and colleagues have been working on a study for NASA’s Institute for Advanced Concepts that takes us back to positrons, one that could power a human mission to Mars with tens of milligrams of antimatter. Not only would such a design be far lighter than competing chemical and nuclear options, but it would be fast enough to dramatically shorten flight time to the Red Planet; advanced versions might make the trip in as little as 45 days.
Smith’s background in antimatter research needs little elaboration; he is a towering figure in the field. While at Pennsylvania State University, he oversaw two key hybrid designs called ICANN II and AIMStar that used antimatter as a catalyst to induce nuclear reactions. The author of hundreds of research papers, he is also the designer of both the Mark I portable antimatter trap and the current state of the art, the High Performance Antimatter Trap (HiPAT).
He is, in other words, a key figure when it comes to wedding powerful antimatter technologies to practical spacecraft designs. Now head of Positronics Research LLC in New Mexico, Smith has built on the lessons learned from these earlier concepts to promote a new design that seems to offer enormous benefits, if we can produce the antimatter needed to make it fly.
One advantage of positrons is that the gamma rays they generate are about 400 times less energetic than those created by antiprotons, making the spacecraft a far safer place for human crews. According to a description of Smith’s work posted on the NIAC Web site (PDF warning), the positron/electron annihilation “…results in the creation of two soft 511 keV gamma rays. These gamma rays can be easily absorbed to heat a working fluid in a closed, high-efficiency thermodynamic power system, or directly into a propellant.” The NIAC work is ongoing — Smith’s Phase I study was completed in March and he is now making the case for an advanced Phase II project that will examine design variants like the positron reactor shown below.
Image: A diagram of a rocket powered by a positron reactor. Positrons are directed from the storage unit to the attenuating matrix, where they interact with the material and release heat. Liquid hydrogen (H2) circulates through the attenuating matrix and picks up the heat. The hydrogen then flows to the nozzle exit (bell-shaped area in yellow and blue), where it expands into space, producing thrust. Credit: Positronics Research, LLC.
The high cost of antimatter is always an issue, but one that may become manageable. Smith is now estimating that the 10 milligrams of positrons a human Mars mission would require could be produced for roughly $250 million. It seems a reasonable assumption that antimatter production costs will continue to go down, just as it is also reasonable to question the wisdom of using staged chemical rockets with launch costs of $10,000 per pound when designs that could undertake far more sophisticated missions are waiting to be developed. Let’s talk more about these notions tomorrow and dig into antimatter’s advantages when it comes to deep space work.
Hi Paul
Just how do they proposed to store positrons against millions of Coulombs of mutual electrostatic repulsion? 50 milligrams is 91 moles of positrons, the equivalent of 8.8 MegaCoulombs of charge. How do they propose to neutralised all that charge?
Adam
Me again
Sanger tried very hard to get the gamma-rocket going as a viable design. Why are the new antimatter engineers so confident?
Another little puzzle is in Bob Zubrin’s discussion of photon rockets in his “Entering Space” – very reminiscent of the current proposal except the heating element’s photon emissions provide the thrust. He proposed heating a tungsten or carbon block to 2700 K, but the quoted thrust levels in his book are far too large for a 2700 K source.
So I dug up an older proposal – use a blazing hot, magnetically trapped plasma as the photon source. Heat it to 30,000 K and the thrust levels go way up. Only problem is a heavy enough element to use in the plasma – U238 or Th232 seemed the best options. Nice and heavy so the plasma ball wasn’t uncontrollable, and proton-proton annihilations wouldn’t smash it up in too great a hurry. Also the higher energy gammas would be better thermalised by such heavy nucleii.
What do you reckon?
Adam
Hi Adam,
The storage issue is crucial, as you say. We seem to be making good progress in that area, as the HiPAT trap has shown — I got to see HiPAT at Marshall Space Flight Center, and it’s a thing of beauty. But how we ramp up storage into the areas required here is a good question, and we don’t yet have Smith’s paper, which hasn’t been posted yet on the NIAC site. I’m going to see if I can get any comments from some of the people involved.
The older proposal you mention is intriguing — do you have the reference? Is it also Zubrin’s? I’d like to read through it and maybe write about it here, though that 30,000 K sure sounds daunting!
hmmm… amusing. “Robert L. Forward” was one of Isaac Asimov’s pseudonyms!
Forward as Asimov? Nope. Although that in itself would make a good SF tale. Having had good conversations with both his wife and his son, I can tell you that Robert Forward was no one but himself, though he would have appreciated the Asimov linkage.
If you get the chance, read his wonderful last memoir “Fast Forward Fifty Years”:
http://www.robertforward.com/Fast_Forward_Fifty_Years.htm
Re the storage problem Adam brought up above, this from Gerald Smith, who was kind enough to reply this afternoon: “We don’t store bare positrons for just the reason you state. We make neutral positronium atoms (bound positron and electron), and in the presence of electric and magnetic fields they are stabilized and stored in porous media.” Which ought to get around the problem; more on antimatter storage in the next week or so.
Smith is apparently exploiting a discovery from the late 1990s of long-lived excited states of positronium atoms. These states are greatly stretched along an electric field, with a perpendicular magnetic field inhibiting annihilation. They are much larger than ordinary positroniun atoms, but are not so weakly bound (as ordinary Rydberg states could be) so as to be dissociated by thermal background photons.
http://arxiv.org/abs/physics/9712028
http://prola.aps.org/abstract/PRA/v58/i2/p1129_1
http://www.freepatentsonline.com/6813330.html
BTW, positronium is also interesting for formation of neutral antihydrogen from antiprotons. The reaction pbar + (e-e+) –> Hbar(*) + e- can occur without the need for a photon to carry off energy and momentum, and should have a useful cross section.
Thanks for those links — very helpful!
See also these slides:
http://www.niac.usra.edu/files/library/meetings/fellows/mar04/Edwards_Kenneth.pdf
In the previous message ‘discovery from the late 1990s’ should read ‘theoretical discovery from the late 1990s’. I don’t know if that state has yet been experimentally confirmed, although the positronium system is simple enough that I don’t expect they made a mistake.
Hi All
My ‘reference’ for the plasma photon rocket isn’t a paper, but a discussion in ASTRA’s old book “Man and the Stars” (1973, ed. Duncan Lunan) of ‘foreseeable’ starship drives. Perhaps the design goes back to Krafft Ehricke himself? Alan Bond wrote up a discussion in “Spaceflight” (the BIS magazine) back in 1971, but as I have no access to a BIS archive going back that far I can’t check his sources. Apparently he suggested a uranium plasma radiator at 2 to 5 x 10^5 K ! Hence I think my more modest temperature is more likely – if we can make super-reflective surfaces for a UV peak thermal spectrum.
Of course, as already noted by one poster, the efficiency of antimatter production has a lot of room for improvement. Personally I’d put more stock in the possibility of macroscopic sphaleron fields and induced proton-decay as the mode of mass-energy conversion – but a fast positron rocket to Mars will do for now :-)
Adam
Of course, as already noted by one poster, the efficiency of antimatter production has a lot of room for improvement.
I am optimistic positron production coulld be made very efficient. You make monoenergetic gammas with high efficiency by bouncing laser photons off oncoming relativistic electrons in a storage ring (this is well-demonstrated technology). Choose the photon energy correctly and you can get pair production in a target with efficiency somewhere in the 5-10% range (that is, 5-10% of the energy goes into positron rest mass). One could avoid thick target losses by passing the beam through several thin targets, each with its own particle extraction system afterwards.
The problem them is cooling the positrons, which will come out with energy on the order of a MeV. Right now they’re doing that with a cool moderator, losing a factor of 10^5 or so of the particles. I suspect you could do better by dumping the electrons and positrons into a magnetic bottle and cooling by cyclotron radiation. The e-folding time for energy loss to cyclotron radiation by a positron in a 10 T field is about 30 milliseconds, I think. This would fail if annihilation is too rapid, though; the question would be how low the density has to be to make the loss acceptable.
I think that it is useful to consider antimatter propulsion methods for interplanetary traval. However, these methods may become effective for manned interstellar missions if some of the following technologies can be developed.
1) Perhaps the use of beamed energy antimatter sails wherein microwave or laser light energy is beamed to a sail based spacecraft to achieve highly relativistic velocities. Once the craft leaves the effective range of the beam, the antimatter sail is gradually combined with matter extracted from the interstellar medium wherein the resultant reactions are utilized by a photon rocket for further highly relativistic kinetic energy gain. The light sails may be composed of metalic antihydrogen, anti carbon nanotubes, or highly reflective antimetals or antialloys and the like. Note that metalic states of hydrogen have been proposed wherein the metal would be extraordinarilly strong yet low in density compared to current alloys.
2) Perhaps the use of compound matter/antimatter beamed electromagnetic energy sails can be used to accellerate a spacecraft to highly relativistic velocites. The forward deployed matter component of the sail would be used to shield the backward antimatter sail component wherein the matter component would be electrically charged, contain nanoscale lasers, or use other means to divert, blunt, or otherwise block the damaging effects of the incident interstellar particulate matter from degrading the antimatter component of the sail. Once the beamed energy stage of accelleration has been completed, the matter/antimatter rocket propulsion system would take over in much the same manner as described in item 1) above except that the matter portion of the compound sail would also be used for matter/antimatter reactions.
3) Still another propulsion method utilizes either matter, antimatter, or compound matter/antimatter beamed electromagnetic energy sails and a stable volumetrically compactly stored form of antimatter. The craft would be accellerated to highly relativistic velocites by beamed energy after which the matter/antimatter rocket propulsion system would take over. The matter to antimatter mass ratios of the overall craft can be reduced to an arbitrarilly small fraction of unity as practicality permits.
4) Yet another propulsion method utilizes beamed charged and/or neutral massive particles to accellerate a matter, antimatter, or compound matter/antimatter sail based spacecraft that carries a volumetrically compactly stored stable form of antimatter. Upon reaching terminal beamed particle mode velocity, the matter/antimatter rocket propulsion system is activated in much the same way as described above.
5) Since positronium may be the easiest form of matter/antimatter fuel to produce, beamed energy sails may bring a craft up to highly relativistic velocites wherein upon completion of the beamed energy accelleration phase, the positronium is converted to pure electromagnetic energy to power a photon rocket or other reactionary propulsion system.
Note that sails composed of a highly conductive wire mesh or grating wherein the spacing between the mesh or grid elements is on the order of or smaller than the wavelength(s) of the beamed impinging electromagnetic energy and wherein the sail area therefor comprises mostly of vacant area allows that sails mass to be potentially greatly reduced for a given propulsive beamed power. This may also allow the sail to have much less drag while passing throught the interstellar medium. Also, certain types of nano technology such as self assembly and repair techniques may also be of use in maintaining the integrity of the sails, whatever from they may happen to take.
Given that it may be possible through medical advances to extend human life to well over 100 years according to certain medical researchers, manned travel thru-out the milky way galaxy during the onboard life span of a typical man or woman may be possible due to relativistic time dilation. One can see that a beamed energy system that would impart a relativistic kinetic energy of a spacecraft of say 20 to 30 times that of its rest mass followed by another 20 to 30 fold increase in spacecraft kinetic energy relative to its beamed energy mode terminal velocity may allow the craft to obtain a time dilation factor of up to roughly one thousand. This would enable a human able to live 200 years to reach just about any part of the Milkyway Galaxy when the need for decellaration is taken into account.
Because of the enourmous total output of solar energy, in excess of 10 EXP 26 Watts (equivalent to more than 1 million tons of matter being converted to energy per second via nuclear fusion), efficient spacebased photovoltaic, turboelectric , or other solar powered antimatter production facilities may be the best way to produce antimatter during the forseable future.
In the event that efficient cost effective quantities of antimatter are eventually produced, perhaps not only should we seek to use it for interplanetary propulsion, but we should also aim for the stars. It may one day be the case that antimatter, perhaps ultimately in a wide variety of stable elemental and isotopic forms, as well antimatter/matter fuel such as positronium, may well be listed in financial sections dailly newspapers under the commodities sections.
I am certain that I am not the first one to think of these propulsion concepts, but I stongly feel that they as well as other perhaps more exotic yet to be discovered propulsion methods are worthy of research and hopefully development. Were we as a race to start a global movement that is well funded and deliberative to reach the stars, the bickering and fighting among nations might be greatly mitigated if not ceased all together. Mankind might then meet any other civilizations among the stars and thus feel on par with them. We might then loose our insecurity over our own status and deal with any extraterrestrial races we find as mature equals. We saw how our landing on the moon galvanized the international community for a few days during each Apollo mission. When we go to Mars, and then perhaps onward to interstellar distinations unknown, I as well as many other humans I sure agree that the resulting good effect will become progressively greater.
james thank you for a well stated and thought out group of ideas about space flight propulsion.exactly the kind of thing i have been pushing for for a while now! but i still think that the best way to do this would be by means of warp drive or traversable worm holes…but… maybe i am getting ahead of myself. perhaps you sir are more to the point with the concept of sails and matter anti/matter propulsion,certainly more “doable” from our current position in history. just yesterday in fact i was looking for ideas about the potential use of matter/antimatter for interstellar flight,therefore it was a pleasure to read your posting.this too is indeed something to be seriously considered if “only” for unmanned missions. thank you very much,your friend george
These are fascinating ideas, James, and I second your notion on the possibility of drawing people together around the common theme of deep space exploration. Now if we really do get to the point where antimatter is listed on the financial pages, no doubt supported by an active futures market, we can definitely think about fast expenditions to the edges of the Solar System and start working on designs that could take us farther still. On that score (though without antimatter being listed as a commodity, to be sure), check out Steve Howe’s antimatter lightsail concept. Here’s a brief overview published in these pages a while back:
https://centauri-dreams.org/?p=28
It’s interesting, too, how sail maintenance ideas have developed. In Cordwainer Smith’s lovely story “The Lady Who Sailed the Soul,” a bevy of macro-scale robots did the work, more or less like the ‘wardens’ envisioned by Project Daedalus. If we can go to nanotechnological methods, our ability to keep an interstellar sail in good shape (and, for that matter, to maintain any other onboard systems) gets a powerful boost!
Hi George;
Thanks for your kind words regarding my blog posted on Jan 3 at 2:45 AM.
It is encouraging to correspond with folks like you and Paul Gilster who are willing to consider the strong possibility of real future space propulsion techniques that many today would consider as no more than purely science fiction at best. I too think that wormholes and spacewarps would be an outstanding method of long distance travel throughout the cosmos if and when they can be developed. In fact, I had made a half-heartedly humerous remark to some of my family members, but with some sincerity, that if we find a way to produce wormholes and hold them open from collapse with perhaps an exotic material with negative mass (as distinct from antimatter which has positive mass), the oil companies might try to have the insides of the wormholes paved with asfault so that we can drive SUVs powered by internal combustion engines that run on gasoline through the wormholes.
It would be interesting and perhaps ironic to possibly have an automobile highway system extending throughout the observable cosmos should macroscopic wormholes prove feasable to construct.
Once again, Many Thanks;
Your Friend Jim
jim roflol ! thank you for the kind words.i very much appreciate it.but… paved worm holes?? a highway that would stretch say,thousands of light years!! then… we would need hotels in there too.gas stations etc etc etc !!! there would be no end to what might eventually have to be included!! a very creative thought you had there to say the least!!!!! respectfully, your friend george
Three new papers on self-sustained traversable wormholes:
General Relativity and Quantum Cosmology, abstract
gr-qc/0501105
From: Remo Garattini [view email]
Date: Mon, 31 Jan 2005 15:31:23 GMT (13kb)
Self Sustained Traversable Wormholes?
Authors: Remo Garattini
Comments: RevTeX 4, 12 pages. Accepted for publication on Classical and Quantum Gravity
Journal-ref: Class.Quant.Grav. 22 (2005) 1105-1118
We compute the graviton one loop contribution to a classical energy in a traversable wormhole background. Such a contribution is evaluated by means of a variational approach with Gaussian trial wave functionals. A zeta function regularization is involved to handle with divergences. A renormalization procedure is introduced and the finite one loop energy is considered as a self-consistent source for the traversable wormhole.
http://arxiv.org/abs/gr-qc/0501105
General Relativity and Quantum Cosmology, abstract
gr-qc/0701019
From: Remo Garattini [view email]
Date: Tue, 2 Jan 2007 15:30:47 GMT (42kb)
Self sustained traversable wormholes and the equation of state
Authors: Remo Garattini
Comments: Uses RevTeX 4. 21 pages. Submitted to Classical and Quantum Gravity. Extended version of the talk given at ERE2006 (Palma de Mallorca, September 4-8, 2006) and of the talk given at MG11-GT5, Berlin, 23-29 July, 2006
We compute the graviton one loop contribution to a classical energy in a \textit{traversable} wormhole background. The form of the shape function considered is obtained by the equation of state $p=\omega\rho$. We investigate the size of the wormhole as a function of the parameter $\omega$. The investigation is evaluated by means of a variational approach with Gaussian trial wave functionals. A zeta function regularization is involved to handle with divergences. A renormalization procedure is introduced and the finite one loop energy is considered as a \textit{self-consistent} source for the traversable wormhole.The case of the phantom region is briefly discussed.
http://arxiv.org/abs/gr-qc/0701019
General Relativity and Quantum Cosmology, abstract
gr-qc/0701020
From: Remo Garattini [view email]
Date: Tue, 2 Jan 2007 16:57:51 GMT (59kb)
Self sustained phantom wormholes in semi-classical gravity
Authors: Remo Garattini, Francisco S. N. Lobo
Comments: Uses RevTeX 4. 10 pages
A possible candidate for the late time accelerated expanding Universe is phantom energy, which possesses rather bizarre properties, such as the prediction of a Big Rip singularity and the violation of the null energy condition. The latter is a fundamental ingredient of traversable wormholes, and it has been shown that phantom energy may indeed sustain these exotic geometries. Inspired by the evolving dark energy parameter crossing the phantom divide, we consider in this work a varying equation of state parameter dependent on the radial coordinate, i.e., $\omega(r)=p(r)/\rho(r)$. We shall impose that phantom energy is concentrated in the neighborhood of the throat, to ensure the flaring out condition, and several models are analyzed. We shall also consider the possibility that these phantom wormholes be sustained by their own quantum fluctuations. The energy density of the graviton one loop contribution to a classical energy in a phantom wormhole background and the finite one loop energy density are considered as a self-consistent source for these wormhole geometries. The latter semi-classical approach prohibits solutions with a constant equation of state parameter, which further motivates the imposition of a radial dependent parameter, $\omega(r)$, and only permits solutions with a steep positive slope proportional to the radial derivative of the equation of state parameter, evaluated at the throat. The size of the wormhole throat as a function of the relevant parameters is also explored.
http://arxiv.org/abs/gr-qc/0701020
ljk it was indeed a pleasure to see the above and know that this subject has recieved such serious consideration. thank you for the opportunitty to have had a look. your friend george ps i am not pretending to have understood every word but it is good to see such scholarly work has been done on the subject.
But even if the wormhole is traversable, wouldn’t you still get spaghettified going anywhere near it?
Regarding holding wormholes open against collapse, I am curious as to whether or not producing a self sustaining wormhole knit or fabric wherein one or more primary wormholes would be supported in a stably open position by additional wormholes that have mouths attached to or somehow fixed to either the “exterior” spacetime surrounding the external surface of the wormhole or atleast the outer boundary of the wormhole’s spacetime structure and/or the wormhole’s material and/or energy composition. Perhaps these additional (secondary) supporting wormholes could be held open by a tertiary level of supporting wormholes which are in turn held open by a fourth level and so on. In such a system (if the above concept is physically meaningful) the openings of the additional supporting wormholes would act either to hold the walls of the primary wormholes open by some sort of force, or to hold the primary wormholes open by the spacetime distortion that exists near the mouths of the secondary wormholes. The distinction that I make here between “some sort of force” and “spacetime distortion” involves the distinction between the concept of a force field as is commonly understood by say quantum field theory as opposed to the general relativistic concept of overall classical spacetime curvature. or distortion Obviously, the development of a successful long sought after theory that unifies general relativity with quantum mechanics might be of help here especially if such a theory can be applied to controlled highly quantified experiments in a laboratory setting to yield positive results.
One potential problem with the above concept is that the number of additional
wormholes required to hold a primary wormhole open and/or the number of levels of such additional wormholes might be very very large. However, in the cases where the wormhole is not stably self supported by any form of macroscopic quantity of exotic matter and/or energy for long time periods, perhaps the simultaneous production of a supporting fabric of wormholes along with the primary wormholes such as discribed above might hold the wormhole open long enough to allow save transit through the wormhole by macroscopic objects. Perhaps in cases where the wormhole is stably self supporting by exotic matter and/or exotic energy, it could be additionally reinforced by a fabric of additional wormholes whether or not the fabric is either continously generated or regenerated or is itself composed of stable self supporting wormholes.
Hi George, thanks for the valid points you made regarding the fanciful notion of wormhole highways made in my previous blog. However, it might make humorous fantasy comic strip material. I could just see Homer Simpson getting out of his car and complaining to a Wormhole Highway Patrol officer over a traffic jam caused by an overturned oil truck along Wormhole I-95.
Jim
so jim, a series of wormholes held open by a series of worm holes!?wow i would like to see the equipment that would generate that! imagination has always been in my opinion the motive force and on line i am luvky to know about a dozen people who have buckets of it ! thank you george ps yeah i’d love to see homer simpson in just such a situation!
Thanks George! I look forward to continued blogging/correspondance with you on this website and any comments you or others have regarding my blogs, or for that matter, regarding the blogs of others posted on this website.
Your Friend;
Jim
you bet jim,good to hear,it is i who thanks you! just started neil degrasse tysons new book “death by black hole” and have” lorentzian wormholes” by matt visser on order.so i guess i’ll be talking to everybody about a lot of things pretty soon.for example: a quote from a quote at the beginning of dr tysons book – in 1894 albert a. michelson said in a speech at the ryerson physics lab at the university of chicago – “the more important laws of physical science have all been discovered…”wow was that ever wrong in spite of how intelligent he was!there is now from our viewpoint 113 years later,so much to be explained discovered understood!!! i strongly suspect as does dr tyson that whole new branches of physics await discovery. i better stop there for now before i ramble on about more – i’ll leave that for another day. respectfully to all your friend george
Hi George;
There are some other additional concepts regarding interstellar propulsion methods that I find fascinating that utilize known laws of physics. Some are described below.
1) One can imaging using beamed energy, matter antimatter reactions, etc. to provide highly relativistic velocity to a manned spacecraft. Upon reaching a value of {1/[[1-(V exp 2)/(V exp 2)]exp1/2]} > 10,000, the incident cosmic background radiation photons on the front of the ship would be shifted to near optical light frequencies and the interstellar star light would be shifted to x ray frequencies. A large electomagnetic energy collection mechanism such as a photovoltaic system, photothermal system, and the like which may optionally include an energy concentrating reflector could be used to power an ion rocket, electron rocket, photon rocket, and the like. One would naturally have to provide a mechanism for diverting the interstellar particulate matter in the form of hydrogen, helium, other elemental species, and dust particles without inducing to much drag. Perhaps these particulate matter(s) could be ionized to the extent that they are not already and used as a reaction mass for the electron and/or ions rockets.
2) Instead of using the interstellar matter to provide a reaction mass for an electron or ion rocket, the matter might be diverted around the craft by a electroplasmahydrodynamic drive system, a magnetoplasmahydrodynamic drive system, or an electromagnetoplasmahydrodynaimic drive system. The energy provided by the incident blueshifted photons could be used to provide the reactive electric and/or magnetic fields required for propulsion.
3) Instead of relying on natural blue shifted photons, a beam of concentrated energy could be shinned onto an incomming craft but in substantially opposite direction of the crafts motion and accellaration. One can imaging a large series of beaming stations set up around our solar system, local interstellar space, and/or around other nearby stars. This would allow a greater power of incident blue dopplar shifted electromagnetic radiation to impinge upon the crafts energy collection systems. The greater the blue shift, the greater the relative energy between the spacecraft and the incident electromagnetic waves or photons.
To see why such a spacecraft might be able to accellerate even though the momentum of the incident photons is in substantially the reverse direction of the spacecraft’s would be motion and accellearation, consider a couple analogous examples. Imagine shinning a 10 watt flashlight beam onto a PV cell powered toy remote controlled car such as is commonly given to children as Christmas presents, birthday presents etc. If the PV cell was 15 percent efficient and the cars drive train was 66 percent efficient, then about 1 watt of power would be provided to the cars wheels and the car would more than easilly accelerate in a direction opposite of the beam of light. Note that 1 Watt is equal to one joule/sec. Ever drop a 11 oz can of soup on your hand while your hand was place on a rigid table, repeatedly? Surely 1 Watt of drive power is more than enough to make the toy car travel in any direction on a flat surface. Note that socalled multijunction PV cells that are 34 percent efficient under highly concentrated sun light have been developed in a laboratory environment. Researchers in the field of photovoltaic materials envision PV cells with still much higher effeciencies using PV materials having certain types of nanostructures and/or manufacturing principles that utilize nanotechnology.
Another example comes from design work on a photothermal heated gas or liquid effluent rocket. I once read a paper in which a scheme for using lightwieght solar energy concentrators to focus highly concentrated light onto a liquid or gas heating chamber wherein the effluent is heated to a few thousand Kelvin and ejected as a high pressure gas to produce a specific impulse of 1,000 compared to the maximum Isp value obtained in modern chemical rockets of only about 460. One can imagine that a square kilometer concentrating reflector would have more than enough capture area to provide 1 gigawatt of energy to the heating chamber. I have no doubt that such a spacebased craft could accellerate toward the Sun even if the Sun’s gravity field where somehow temperarilly suspended.
Regarding sources of interstellar antimatter, I remember reading about the productions of copious amounts of antimatter which appears to be ejected along the axis of rotation of accretion disks around some supermassive blackholes. Apparently, some process (be it antimatter forming reactions resulting from the collisions among atoms and/or other particles as a result of the superheated plasma in the accretion disk surrounding the blackhole or perhaps as the result of antimatter forming interaction among plasma ions ejected from the poles of the accretion disk around the black hole) is able to produce perhaps large multiples of solar masses of antimatter during the timeframe required for the matter/antimatter jet material traveling in excess of 0.9 C to diffuse into the intergalactic medium. Now, if we could only find a way to get there and fill up an earth size vessel with antimatter but have the antimatter stored in a stable form such as antithydrogen, positronium, or other electrically neutral form. Note that the concept of the ejected matter from the vacintiy of a supermassive blackhole does not violate the concept that once matter or energy has fallen past the blackholes event horizon, it cannot escape. The reason for such is that the ejected matter never gets close enough to the black hole to be pulled in. It is actually ejected as a result of outwardly directed thermodynamic pressures before it gets to close to the blackhole such that the blackholes gravity field overpowers the tendency of the matter to be pushed away from the blakhole by thermodynamic processes.
If the above propulsion techniques can actually work, then there just might not be any reason in theory why such a spacecraft cannot continue to accellerate forever. Obviously, dangerous interaction between the spacecraft and the incident ever more energtic photons and particles would have to be somehow avoided thus perhaps limiting the extent to which the craft could appraoch C. But perhaps the craft could obtain a velocity close enough to C such that any breakdown of special relativity for such extremely relativistic velocities would become manifest, assumming that special relativity might not be completely accurate at such high speeds. This and/or perhaps the relativistic geometric reference frame distoriton that theoretically results for relativistic objects, especially macroscopic object such as spaceships that are thus geometrically complex , might some how be used to further faciliate interstellar travel.
Anyhow, enough of my babble.
George, I look forward to hearing more from you regarding the contents of the book you ordered on Lorentzian Wormholes. I have recieved a few books interesting books myself over the past couple of months. I am a member of the Scientific American Bookclub. I joined simply by filling out an advertizement coupon that was included in an issue of Science News magazine. They give really good deals on science books.
Best Regards;
Jim
jim, it is certainly good to know that atleast in theory,large amounts of antimatter might be available to us for propulsion.but…to get out there to “harvest” it…therein lies the problem! we can now produve our own anti matter but unfortunately so far only in very small quantities indeed. might be more reasonable to find ways to “simply” (lol) increase production.wonder where all the antimatter starfleet uses on trek comes from?guess in that case we just have to suspend our disbelief and accept that they do indeed have it because for purposes of the star trek universe – they do.on the other hand we also need to develop the warp field to be a practical reality so that then we can put all that antimatter to good use.also traversable worm holes – a subject i seem to come back to time and again.with no doubt it will take “awhile” to develop them! but we should think about it or for sure it won’t be done.that is one of the things i am trying to do this year a good part of the reason i have the book by matt viser on its way.well,i guess it is about time to end my own “babble” for now its early in the week and there will be alot more chances. thank you very much one and all your friend george ps just reread that last and…i did not mean to imply lol that i am going to discover the means for traversable worm holes this year! just that i am going to give it some thought and invite others to join me.;) thanks g
Hi George;
I share your interest in wormholes but have not kept up with the latest developments on the subject. Your comments on wormholes have renewed my interest in the subject and I am looking forward to further discussions with you on the subject as well as continued reading of books and articles on wormholes.. Thanks for rekindling my interest in this really fascinating subject.
Best Regards;
Jim
jim this is exactly what i am driving at ,that is to say – getting others to have a serious look at subjects such as these.i only wish we had alot more talk back and forth between more of us.the administrator once explained to me that alot more people drop in to have a look at these comments than ever leave a comment of their own.so let me digress and ad a comment directly to them : alot of facinating subjects here – matter anti/matter drives,traversable worm holes,warp field technology… you could only help out with what you yourself think! why not just leave a comment today? respectfully to one and all your friend…now or future…george scaglione
read yesterday about how stars gain velocity by near misses with the super massive black holes at the center of galaxies.gave me an idea – what if it where possible to have a device which could project a black hole in front of your space craft? you get a gravity assist and then do it again and again to gain ever increasing speed ! but i have to admit something right now while my “black hole projector is switched off and i await my next boost. “maybe” and what does anybody think? – sometimes my ideas are a little too futuristic! which would tend to make them rather impossible for now. you know maybe this is done by an advanced race of aliens somewhere but us? soon? heck,we have all we can do for now to just return to the moon! i’d love to know what anybody thinks of any or all of this! thank you, your friend george
Regarding accelleration of a spacecraft using a blackhole, one can imagine the following scenareos among others.
Imagine a very massive blackhole such as the multibillion solar mass blackholes that have been indirectly observed near the center of cetain galaxies. Imagine further that the blackhole is optionally spinning at its maximum possible rate of spin which is theoretically close to the speed of light. If a spaceship has a heading which will take it just outside the event horizon while under full powered antimatter/matter annihilation rocket mode, beamed energy powered rocket mode, and/or the same for electroplasmahydrodynamic, magnetoplasmahydrodynamic, electromagnetoplasmahydrodynamic mode, etc., the craft might be able to obtain a large additional relativistic increase in velocity as a result of a gravitational assist from the blackhole as well as additional velocity imparted to the craft as a result of the phenomenon commonly known as “reference frame dragging” whereby the spacetime in the vacinity of the blackhole is severely distorted and “dragged along” by the blackhole at a velocity of close to C (in the case of a blackhole spinning at its maximum rotational velocity almost equal to C). If multiple supermassive blackholes can be positively identified and precisely located and they are located close enough to each other, perhaps they can be used to “throw” a spacecraft back and forth using one or both of the effects described above to obtain an ever increasing velocity closing in on C.
One way a society might be to able to prolong the lifespan of its citizens so that meaningful millions or billions of lightyear trips away from the society’s home base might be feasible is to have the citizens dwell in an orbit close to the event horizon of the blackhole but not dangerously close. For blackholes of extreme size, the tidal forces acting on these dwellings might be low enough to permit longterm habitation without undue discomfort to these citizens. The time dilation effects that might greatly expand the relative life span within the orbiting habitats would result from both gravitational time dilation and the extremely relativistic velocities of the habitats orbiting the blackhole. Obviously, care must be taken so that the orbiting habitats do not fall into the blackhole. Also, a way of providing propulsive motion to vehicles entering and leaving the inhabited zone around the blackhole must be provided without adding so much mass to the blackhole such that its event horizon grows to envelope the orbiting inhabitants.
George, thanks again for your remarks regarding blackhole based propulsion concepts. I am curious as always in what you have to say regarding interstellar travel.
Best Regards;
Jim
Building a civilization around a black hole would be a good idea,
just in terms of getting rid of their trash and generating power
for themselves. Dumping their waste onto a black hole will give
them back energy they can use to power their facilities.
And when the Universe starts dying out eons from now, we will
likely find most remaining societies huddled around black holes,
one of the few celestial objects remaining in our Universe.
jim and ljk,thank you both for interesting comments that reflect great intelligence and imagination,i appreciate talking with you,respectfully your friend george
Regarding the distant future construction of huge accellerators to accellerate spacecraft, manned or unmanned, I would like to summarize a few concepts that have intrigued me over the past several years.
1) If a spacecraft accellerator could be constructed with the diameter of the Milky Way Galaxy (on the order of 10 EXP 18 kilometers) wherein the centripital accellerations on the spacecraft are equivalent to those experienced by subatomic particles in today’s most powerful accellerators (currently, protons can be accellerated to energies over 1 TeV or about 1,000 times their rest mass), the terminal relativistic kinetic energy increase and thus the relativistic time dilation factor could become equal to 10 EXP 20 assumming that today’s accellerators are about 10 Kilometers in diameter which is about the size of the CERN accellerator. For a 10 metric ton “manned space truck”, the terminal relativistic energy increase would roughly equal to the mass of the Earth. Perhaps the accellerator could be powered by numerous discreetly positioned nuclear fusion electrical energy generation stations, photovoltaic generator stations, cosmic microwave background radiation powered electrical generators, and/or galactic magnetic field energy extraction based electrical power generators, etc.. Such a system would allow the spacecraft inhabitants to travel distances many orders of magnitude greater than the radius of the currently observable universe in one year ship time.
The draw backs of the daunting process of constructing such a system would be the required strength of the accellerator’s material of composition in order to resist; more than anything else, the centripital forces acting on the accellerators structure as the path of the continuosly accellerating spacecraft is changed during the accelleration process. Even if some exotic super strong material could be created to build such an accellerator to specification, the potential need for vibration damping systems would need to be considered. But if we are willing to consider that perhaps wormholes can be held open by exotic materials with negative mass, and even the possibility of the existence of materials with imaginary mass (in the imaginary and/or complex number sense), then perhaps the development of materials for and the resulting huge construction project of the accellerator looks a little less daunting
The supply of energy to the accellerator is less of a challenge since it would require only the equivalent of roughly the Earth’s mass be converted into energy if it where over 20 percent efficient. Note that the energy output of the Sun over the last 1 billion years is about the equivalent of roughly 100 times the mass of the Earth converted into energy. The energy emmitted by the craft in terms of synchlotron radiation as a result of its accelleration might be mostly if not entirely absorbed by the accellerator’s walls and recycled back into the driving electromagnetic force fields to further facilitate the crafts accelleration.
The forces acting on the spacecraft and the passengers would be stupendous, but might be effectively reduced by continously and varyingly electrically charging the space craft and its passengers, and/or somehow magnetizing the craft and passengers wherein the force fields thus generated could be made to react against magnetic and/or electric force fields produced by the accellerator to effectively cancel the forces of centripital and curvilinear accelleration experienced by the craft and its occupants.
Now all of the above seems hard to accomplish. Perhaps in a few billion years, it may be feasible to the point of possibility. Perhaps limiting the accellerations to 1 G would be much more wise to consider. Item 2) below may be a more sensible approach.
2) Perhaps a linear accellerator can be constructed with a length ranging from .0001 lightyear (about a billion kilometers) to millions if not billions of light years long. The accellerator could be powered by Sun and/or other starlight, CMBR, fusion reactor powered electrical energy generating stations, interstellar, galactic, or cosmic magnetic field energy extraction mechanisms, and/or the like. For a billion km long accellerator and an accelleration of 10,000 Gs, a manned craft would be able to reach terminal relativistic velocities great enough to permit the craft to travel to the nearest stars during a generation within a human lifetime. Linear accellerators of sizes toward the extreme end of the conjectured length range given above might be built over thousands, millions, if not billions of years of future human existence, perhaps with the cooperation of any extraterrestrial races if they exist. One can imagine that accelleration values many orders of magnitude greater than 10,000 Gs might be possible given technological developments that might occur in the comming millenia, or perhaps eons.
For linear accellerators as such, distortion of the accellerators as a result of transiting craft, gravitational perturbations resulting from the interaction of the accellerator with planetary, stellar, and /or galactic gravitational fields, planetary, interstellar, and/or galactic electrostatic, magnetostatic, and/or electromagetic fields, hydrodynamic interaction with interstellar and/or intergalactic gas and/or dust clouds, etc., would need to be addressed in the design and maintenance of the accellerators.
3) Another option is to deploy very long, high power capable closed circuited electrical cables, energized by any of the energy supplies mentioned above. The craft would obtain electrical power from the cable system in order to power an onboard electron, ion, or photon rocket propulsion system. This sytem is simmilar to the fuel pellot runway system that has been suggested to power interstellar missions wherein a trail of nuclear fusion fuel and/or matter and antimatter pellots would be deployed along the future route of the spacecraft out to a distance of up to a light year or so. The pellots could be sequentially launched by an accellerator and collected by the accellerating spacecraft as it travelled down the “runway”. In the case of the electrical cables, considerably more time would be required to deploy the respective system, and instead of extracting energy in bit mode as is the case for the runway pellot method, the energy for onboard propulsion systems could, optionally, be continously extracted from the electrical cable system. Cables made from superconducting materials could be used to minimize electroresistive power losses.
I must admit that the above systems would involve huge construction efforts that would be extremely long in duration, but in the event that other potentially much more effiecient types of propulsion techniques such as wormholes, spacewarps, faster than light inertial travel through space, macroscopic scale induced quantum mechanical tunnelling, teleportation, etc., do not come to fruition, we may still have ways to travel cosmic distances within one generation of a human lifetime in the ship’s reference frame; and in the shorter timeframe, perhaps even this century, land men and woman on any terrestrial like planets orbiting nearby stars. In the most extreme cases of sublightspeed technology such as the example I gave under item 1) above, time travel into the cosmically remote future may be possible along with travel in space of cosmically remote destinations. Such a craft could travel so far in space from Earth, such that even though it might be limited to sub-light speed travel “through space”, it may actually travel far enough from Earth such that, eventially, its recessional speed from Earth could be much greater than C as a result of the velocity of the craft through space superposed on the expansion of space resulting from the ongoing cosmic expansion as a result of the Big Bang. Perhaps in one way or another, we will eventually travel much faster than light from our Earthly crib and boldly go where no man has gone before.
George and ljk, good to hear from you. Keep thinking about wormholes. Hopefully someone will come up with a much more effective and practical way to travel throughout the galaxy and beyond then the conjectured methods I outlined in items 1) thru 3) above.
jim thank you.many of us here think big and that is cool. but you know what the problem is,repectfully my friend!? congress does not want to fully fund the cev project,let alone IDEAS LIKE OURS!!!!! heck buddy maybe just maybe they are within a couple of light years of being right.you know how much MONEY all of this would cost!!!!!!!! all the best to all your friend george
To literally illustrate what I said earlier about an advanced
civilization using a black hole to solve both its waste and
energy issues, here is a diagram of just such a process from
the sixth issue of Cosmic Search, the first magazine devoted
to SETI:
http://www.bigear.org/CSMO/Images/CS06/cs06p33l.gif
BTW, every issue of this pioneering and historic magazine
(all 13 issues) are now online.
http://www.bigear.org/CSMO/HTML/CSIntro.htm
all of that sounds good and makes sense ljk hope it will someday show up “at a news stand near me” as they used to say! thank you george
ljk;
Thanks for posting the diagram of the blackhole powered city. As you stated earlier, eventually as the cosmos cools as it expands, we may have to live in the vacinity of blackholes as the final stars burn out.
George;
Thanks for your comments about the potential cost of some of the expansive cosmic construction projects I outlined above. I can well imagine that the cost of such projects could be greater in real dollars than the number of atoms that make up the Earth. Given that the dollar value of the current U.S. Gross Domestic Product is only about 10 or 20 trillion, which is about the number of atoms in small bacterium, future engineers and construction organizations would have a hard time convincing Congress or other organizations to come up with the necessary money for the construction costs. Wormholes and spacewarps are starting to seem, all the more, like better techniques for getting around the cosmos.
Very Respectfully;
Jim
yes jim these projects will be very very expensive indeed and i like the concepts of travel by wormholes and spacewarps very much. i think alot of thought should go into both subjects.something which is apparently happening too. strange you many times see both subjects discussed side by side.right now i am finishing up on the book lorentzian wormholes by matt visser.have to tell everybody that it is one of the most difficult volumes i have ever encountered.especially since i have no real expierience at all with higher mathematics. but none the less i have taken afew pages of interesting (to me) notes. the fact that so much thought has already gone into these subjects means that someday they will be done. if…they can be done.but even if they could not,take heart! another cool method is always just around the corner or so it would seem.ljk is right too power furnished by black hole is a good way too just will take some developing! or errr aaah maybe – ALOT of developing! again thank you one and all george
ok i finished up on lorentzian wormholes by matt visser and i will admit putting ego aside for the moment that it was perhaps the most difficult book i have ever read.even when i went ahead and googled certain definitions. i think that you would be best served to have a phd in physics when you first pick the book up! still i admit that i took afew pages of cool notes that will eventually serve well in discussion. respectfully to all your friend george
Have you read this book:
Thorne, Kip S. (1994). Black Holes and Time Warps. Norton, W. W. & Company, Inc. ISBN 0-393-31276-3
Regarding concepts of interstellar travel, I would like to describe below some more ideas for which I am definately not the originator but which interest me none-the-less.
1) The first concept involves somehow inducing macroscopic quantum mechanical tunneling of spaceship sized objects. Ordinarilly, tunneling has only been observed on atomic distance scales, or at most, over small molecular scales. Note that the probability of a particle tunneling across an energy barrier very rapidly increases with a particles mass as well as with distance to be tunnelled such that macroscopic objects are in practice, never observed to tunnel.
Now what if the socalled quantum mechanical wavefunction that defines a space craft could be altered such that the great majority of the probability amplitude for the location of the spacecraft is suddenly tailored to exist at a great distance (say at a cosmic distance) away from the previous location of the craft. Given enough time, perhaps ideally only a very short period of time, maybe the craft can somehow be induced to tunnel through the spatial barrier of cosmic distance scales.
It is anyone’s guess as to how such a tunneling event can be induced in practice. One way might be to set of some elaborate physical mechanical structure in front of the spacecraft that alters the leading edge of the probability amplitude of the spacecraft such that the spatial and temporal probability amplitude suddenly evolves to be essentially very locally located at a point of cosmic distance from the spacecraft’s original position. Another way to induce macroscopic tunneling as such might include setting up some kind of elaborate force field pattern such as a gravitational field, a magnetic field, an electric field, or an electromagnetic field or combinations of fields thereof in the vacinity of the spacecraft.
If the above method of tailoring the location of the wavefunction of the space craft cannot be made to work, then perhaps the structure of the socalled vacuum energy state associated with zeropoint vacuum energy fluctuations can be minipulated to shift the location of the bulk of the probability amplitude of the spacecraft to cosmically distant locations. Perhaps the apparatus and/or forcefields described above can be minipulated to achieve this end. Another method of altering the structure of the vacuum energy state might be to locate assemblages of electrically conducting plates or other electromagnetic energy reflecting mechanisms in proximity to the spacecraft wherein the space enclosed within these plates restricts the wavelenths of the standing electromagnetic zero point energy fluctuation waves to a maximum equal to distances between the electromagnetic energy reflecting plates. If the structure of the vacuum state can not be practically altered by the above method for the above purpose, then perhaps the judicious use of arrangements of an exotic yet to be discovered material with a negative mass can do such. If this does not work, than perhaps some form of dark energy, simmillar to the conjectured energy field that supposedly is causing the rate of the expansion of the universe to increase with time may be of use.
If the string theorists are correct in their theories that our universe or big bang resulted in the formation of a total of 10 or 11 dimensions, one of these dimensions being time and the remaining being spatial, then perhaps a craft can be induced to travel through these additional dimensions to a location that is cosmically distant from Earth in the ordinary 4 spacetime dimensions of special and general relativity. Recall that the additional 6 or 7 spatial dimensions in many versions of string theory are compactified so that they are only made manifest on an extremely small distance scale of approximately 10 EXP -35 meter, although newer versions of string theory suggest that the scale of the additional spatial dimensions may be as large as a substantial fraction of a millimeter. If the craft can be induced to tunnel in a direction through some or all of these additional dimensions, then perhaps the craft would not have to tunnel so far as it would otherwise thus making the process of tunneling more easilly accomplished.
2) The second concept I will mention involves tunneling of macroscopic spacecraft but only in short hops. Here, the spacecraft would be induced to sequentially jump or tunnel from one location to another wherein the quantum tunneling events would occur in the ordinary 4 dimensional spacetime and would occur over much smaller distance scales-perhaps only on microscopic scales. After a large number of jumps, the space craft would finally arrive at its destination. Perhaps the methods of tunnelling I outlined in section 1) above can be used to induce the short distance sequential tunneling events outlined in this paragraph.
3) Another method of interstellar travel includes the concept of wormholes wherein the mouths of the wormholes are produced in ordinary 4 dimensional spacetime but wherein the throats of the wormholes extent through the extra 6 or 7 spatial dimensions proposed by string theory and/or those extra spatial dimensions proposed by other theories involving more than 3 dimensions of space. The “length” of the wormhole required for travel might somehow be greatly reduced thus possibly facilitating the future production of practical wormoles for interstellar travel.
4) Yet another method of wormhole travel might include the production of nested wormholes wherein one or more wormholes would be enclosed by one or more additional wormholes. Thus, if an outer wormhole would connect two points in ordinary spacetime located at cosmic distances, but wherein the distance between these two points through the outer wormhole is still very large (perhaps many lightyears). perhaps one or more secondary wormholes can be set up within the outermost or primary wormhole such that the required distance of travel through the primary wormhole is greatly reduced over what it would be otherwise. A series of inwardly sequential wormholes would repeatedly reduce the required distance of travel between the two external points located at the mouths of the primary wormhole.
ljk, I could be wrong, but I think I may have read that book. If I am not mistaken, I found it very fascinating and would recommend any wormhole and spacetime warp enthusiast read it.
George, thanks for the update on the book on Lorentzian Wormholes. I look forward to hearing from both you and ljk in the days ahead.
thank you jim for some really good ideas you have put out there and ljk thanks for the tip in the future i will keep an eye out for that book.correct me if i’m wrong jim but part of what you just said seems to remind me of the series of wormholes,the subway system if you will that carl sagan speaks of in contact.would not i fear my friend be so simple to build. respectfully to one and all george scaglione
i have already mentioned this to everybody else today,or it seems like it,so i am going to post it here too for consideration by any and all as they may choose. first of all i have come to believe that the cev is an unnesssary intermediate step that will just cost us time and money making what we should do occur only all the later. what i think is this: we should begin to build a new fleet of shuttles and then use them to capitalize on our lessons learned about building things in space by constucting large space ships in orbit.sort of like the one we all saw in the movie 2001 a space oddyssey. then those ships could be used for the moon mars and beyond.would take alot of work and probably research but seems to be a more logical way to go after our goals than the rather piece meal way i’ll bet you fifty cents that we think we are going to do it now. (!) funny thing gang but i would bet that back when i was a kid and just beginning my strong interest in space,every body was sure that by excuse me !!! 2007 !!! we would already have a manned base on the “planet” pluto! glad for any feedback anybody would like to send along. again, your friend george
Hi George;
Good Comments!! The spaceshuttle is true and tried technology. It would make sense to build a whole new fleet of them with improved safety features, more advanced materials, and perhaps greater payload capacity. Given that the CEV is based on improvements to the Apollo Program era spacecraft, it seems like NASA is trying new ways to skin an old cat. If we are able to obtain quick, easy, relatively low cost, and safe access to Earth Orbit, then indeed many things become much more feasible early on. I could see that if we obtain such low cost access to space, we would be able to construct really large spacecraft in low to medium Earth orbit. I would think that a manned fusion rocket powered spacecraft, even one that carries all of its fuel with it, could be designed and assembled in low Earth orbit and ready for launch to one of the nearest stars on a 40 to 60 year journey, and arrive at say the Alpha Centuri system or Barnard’s star before the end of the 21st century. Even though such a fusion rocket craft would not yet be an exotic spacewarp or wormhole driven craft, simply to plan to travel to another star system during the lifetime of those just being born today would seem to be enough to excite great enthusiasm for the wonder of manned space flight, something that the general public seems to have lost after the termination of the Apollo Program. Heck, if I were reasonably sure that I could live another 80 or 90 years past my current age of 44 due to medical advancements, I would love to go on such a mission provided I could pass all of the medical requirements at the age of say 74 during the year 2037. A successful manned interstellar mission would unit all of humanity in awe, and spark further wonderlust to go even further out into space beyond our immeadiate stellar neigborhood.
Very Respectfully;
Jim
jim maybe you have put your finger on a big part of the truth people very much need to get fired up again about the space program and want more and better from it.being able to reach another star system before the end of this century would be a great thing i would be very interested in such a mission and so would you…would alot of people?probably. but enough? maybe not. :( still we can do more and better,in my opinion anyhow,for space exploration and i hope we begin soon. just read today that the war in iraq will cost something like 8.4 billion dollars a month in 2007! while congress does not give nasa an increase! a real shame quite literally.anyhow thanks for your ideas too.my only critisism of this site is that not enough people take part. although the moderator once told me that alot more people stop by to read than to type in their own opinions! so maybe the few of us do do some good even if only indirectly by posting some ideas.the audience might just be bigger than we suppose. let me say again something in that vein that i have already said afew days ago right here – if you are reading this now and are one of the persons i just mentioned. then please post i am sure that everyone would be interested in whatever it was that you might have to say. thanks jim and respectfully to one and all,your friend george
Hi George. Thanks for the encouragement!
Below are some additional interstellar propulsion concepts that may be of interest to the viewers of this website.
1) It may one day be possible to produce blackholes that are large enough to be stable against premature detonation as a result of Hawking Radiation (named after Stephen Hawking who is well known for his theoretical work on blackhole physics and other fields within the science of cosmology). If such blackholes can be produced and safety stored for their latent energy content, then perhaps some how they can be used as a fantastically powerful energy source upon detonation to propel large spacecraft, manned or unmanned, to extremely relativistic velocities almost instantly. Now this assumes that materials can be developed to absorb the energy and/or momentum of the massive Hawking Radiation release without being destroyed as well as a means for keeping the contents within the spacecraft from being destroyed as a result of extraordinarilly high accellerations. Perhaps magnetizing the contents within the craft and using additional magnetic fields to react against these contents and/or a simmillar process utilizing electric fields can result in the cancellation of the tremendous forces due to accelleration that would result.
Perhaps the blackholes could be induced to detonate by artificially effecting the vacuum energy state of the region of space in which they are located since according to blackhole thermodynamic principles, the Hawking Radiation results from the zero point vacuum energy fluctuations that occur in the surrounding space just outside the event horizon. Perhaps enclosing the blackhole with highly conductive, if not superconductive, plates to restrict the standing waves of the electromagnetic vacuum energy fluctuations to those whose nodes are located on the inner surfaces of the plates may be of help in preventing premature detonation and for timing controlled detonation. Other factors such as the minipulation of the geometric shape of the enclosure, the use of reflective materials of predetermined and/or changable spectral reflectivity, etc. perhaps may be of use for this purpose also. Other methods that alter the permittivity and/or the permeability of the free space surrounding the black hole perhaps may be useful as well. Perhaps selectively feeding the blackhole to keep its mass above the critical limit for a predetermined period of time can be of help here also.
One can imagine that a whole series of such blackholes distributed like a run way in interstellar space could be sequentially detonated and used to propel a spacecraft to unheard of relativistic kinetic energies.
I am not sure what the effective critical mass limit of a small blackhole is and I think that I remember reading that it was not precisely known, however, I also remember reading that it was theoretically somewhere in the range of one thousand metric tons to 1 quadrillion metric tons, the uncertainty being due to sensitivities of the Hawking Radiation process with respect to various aspects of the constants of nature that govern such and/or other aspects of the laws of physics that govern the radiation release, some of which apparently are not known accurately enough to give a us precise value of the critical mass limit.
Assuming that such a system can be used to propel a spacecraft with a mass of 5,000 metric tons; that the effeciency for capturing the Hawking Radiation is 50%, and the effective critical blackhole mass limit is 1 billion metric tons; the craft should theoretically be able to have an almost instantaneous increase in relativistic kenetic energy of a factor of 100,000. Obviously, if such a system can be made to work, successive detonations could be used to increase the velocity of the spacecraft. Alternatively, detonating multiple blackholes simultaneously can provide an even greater kinetic energy increase for each step in the accelleration process. Now if we can only figure out how to produce blackholes having a large enough mass to be stable as well as materials able to absorb, reflect, and/or otherwise reradiate the tremendous power surge resulting from blackhole detonations!
Note that great care would need to be exercised such that the blackhole would not be detonated near the Earth, let alone fall into the Earth, both of which would have disasterous consequences.
2) The second concept that comes to mind involves utilizing the intense electromagnetic solar radiation in the vacinity of a star such as the Sun as well as the highly ionized plasma that exist within the suns coronasphere and/or magnetosphere. I once heard of a concept wherein a spacecraft would utilize intense solar electromagnetic radiation in close proximity to the sun, supplemented by the collection and nuclear fusion of solar atmospheric hydrogen and/or helium to power a fusion rocket or ramjet wherein the craft would accellerate around the sun or other star for months. The thrust from the rocket or jet propulsion system would be directed such that the craft would be propelled in a circular motion instead of prematurely flying away from the sun on a tangential trajectory. Additionally, electroplasmahydrodynamic, magnetoplasmahydrodynamic, and/or electromagnetoplasmahydrodynamic propulsion sytem(s) would utilize the ever more energetic interaction of the stellar atmosphere, coronaesphere, and/or magnetosphere with the craft to enhance the ships accelleration and direction of travel until the point of departure at which time the ship would, optionally, be travelling at a highly relativstic velocity.
The larger and/or more luminous stars would provide a greater source of energy and reaction mass to accellerate the craft. Blue supergiant stars would provide a much higher level of electromagnetic energy power to the craft because of the T EXP 4 dependancy of total radiative power output for a blackbody by which a stellar surface is well approximated. Red supergiants, because of their extreme diameter would allow terminal craft velocities with angular accelleration values to be much less than that for stars like the sun, although for relativistic terminal velocities, the G force loading on the craft would be several orders of magnitude higher than the 1 G we experience on Earth. Therefore, whatever the position of the utilized star on the main sequence, great effort would be needed to counteract the extreme angular accellerations acting upon the craft and its occupants.
3) The final method that I will describe tonight involves a system simmilar to that just described in item 2) except that the accretion disks around super massive blackholes are utilized to provide the electromagnetic radiation power input, the fusion material for fusion rockets or jets, and the reaction mass for the various forms of electrodynamic propulsion methods that might be utilized. Since blackhole accretion disks can apparently be many light years in diamter, extremely relativistic velocities might be attainable for very large craft, with relatively very minimal angular accelleration.
Very Respectfully;
Your Friend Jim
jim thank you very much for the interesting and…VERY ADVANCED concepts i suppose theory however always outdistances technology. that is to say that one gets an idea then puts it out there,then… hopefully,as i have said many times before,somebody reads it and comes up with a concept for making it work and you are off to the races as they say.all i really shoot for is that my friend.putting forth a concept that might then advance us in space unimaginably…when worked on by finer minds than my own! i see that you too are right in there pitching in this respect. thank you very much again and have a great week end your friend george
i like this site very much but or rather so… with all respect to the members…how is it that no matter how i “bang the drum” to try to encourage participation or post ideas or ask for opinions. still… days or more can go by between comments back and forth ! know what its like? the sf conversations we’ve all read about that because they are limited by the speed of light take months! or better put years.no offense meant to anybody at all but it becomes boring. (!) i think i have made my point as best i can lol end of tirade. but still as i insist,respectfully to all your friend george
Hi George. You bring up several valid points. Thanks for the critique. If interstellar travel is ever going to occur for mankind in any of its variety of forms, it will do so because people like you and other bloggers on websites like this have the vision and courage to speak out openly on the subject.
To that end, below, I have outlined several more concepts for interstellar propulsion that are available within the open literature.
1) The first concept that I mention involves the concept of using faster than light media to transport a spacecraft and/or persons much the way that the concept of beaming someone from one location to another is accomplished in the sci-fi series Star Trek. In this scheme, the object to be transported would be converted into hypothetical particles known as tachyons that always travel faster than light, but also back in time. According to leading theorists within this field, special relativity suggests that faster than light inertial travel through space also results in backward time travel. Upon being reassembled at a distant location of space-time in the past, the craft could accelerate to near the speed of light and “catch up to the present” using relativistic time dilation with the result being effectively instantaneous or near instantaneous travel over interstellar if not cosmic distances. Note that one of my undergraduate physics professors participated in theoretical work on the possibility of certain types of neutrinos being tachyons that travel a small but non-trivial velocity of 3 millimeters per second faster than the speed of light in a vacuum. Also note that neutrinos might be an otherwise ideal medium in which to transport some macroscopic object because they interact with ordinary matter and energy through only the weak nuclear force and gravity. In fact, a beam of neutrinos could travel through light years of solid lead while remaining largely unattenuated.. Perhaps other low interaction particles can be used as a transmission medium for beamed energy teleportation such as the currently yet to be detected Weakly Interacting Massive Particles or WIMPS proposed to exist according to certain theories known as supersymmetry
2) The second concept that I will mention involves the teleportation of the quantum mechanical information that defines an object as apposed to the matter and/or energy that compose the object. In this concept, an object may be effectively teleported by transferring the information that defines its energy state through the process known as quantum entanglement. In this scheme, the quantum information requires a carrier mass or energy “body” in which the quantum information is transferred to and imprinted on wherein the quantum information of the mass or energy of origin is linked by quantum entanglement to the remote mass or energy “body” to which the information is imprinted. Note that quantum teleportation has apparently been achieved in a laboratory setting by using a tiny but macroscopic group of atoms of a single element over a distance of about 0.5 meters although without perfect fidelity. Here fidelity is a measure of the quality or clarity of the quantum information signal teleported. If the fidelity of quantum teleportation can be made essentially perfect for large macroscopic objects over large distances (perhaps interstellar distances), then maybe we can be beamed to remote locations within the universe some day. Perhaps if the carrier mass or energy can take the form of tachyons, perhaps neutrinos, and be beamed to a distant location in space-time, then perhaps we can develop an even better transporter than the one envisioned by Star Trek.
3) The third concept I wish to discuss involves either of the transport methods described in items 1) or 2) above but wherein the transportation happens in a piecewise manner. Here, the object would be transported over numerous short hops in rapid succession to interstellar locations. This might actually be more doable in the case of quantum teleportation especially if the fidelity of quantum signal transport happens to degrade over interstellar distances.
4) In the event that teleportation does not prove viable, then perhaps tachyons can be used for providing thrust to tachyon rockets wherein the specific impulse associated with tachyon thrust would be higher than that associated with photons as in the case of the photon rocket. I assume here that the relativistic rocket equation (delta V) = C{tanh[(Isp/C)ln(M0/M1)]} would hold up in at least some forms of tachyon rocket propulsion methods and/or within certain limits to an at least reasonably good approximation. As such, tachyon rockets might eventually allow us to approach the speed of light from below more efficiently and thus more closely.
5) In some newer versions of special relativity referred to as Double Special Relativity, the velocity in a free vacuum of a photon increases with energy. Accordingly, as the photon energy approaches the Planck energy or about 10 EXP 29 electron volts, the velocity of the photon in a vacuum increases dramatically. In some theories of the Big Bang, during the very earliest instances of the universe, the photons in the universe were so energetic due to the incredibly high temperatures early on that these photons traveled at infinite velocities for all practical purposes. Note that this effect would not be measurable with the photon energies we commonly observe in a laboratory or observational setting, because at ordinary energies, even those involving nuclear reactions, the effect is theoretically too small to be measured by current laboratory equipment.. Perhaps, some time in the future, ultra fast photons can be utilized in photon rockets for a similar effect as described above for the so called tachyon rockets.
Once again, many thanks to you George as well as others have the courage to speak out on this website. I look forward to further correspondence with you in the days ahead.
Most Respectfully;
Jim
Hi James
A few problems arise.
(1) Neutrinos have positive rest mass, as has been shown over the past few years. John Cramer used to advocate for a possibly imaginary mass for the neutrino, but he has noted recently this has been disproven. However if tachyons exist then they will work as per his article on just this topic…
http://www.npl.washington.edu/av/altvw61.html
…thus a tachyon rocket will allow a non-rocket drive, but it will use energy. If that energy is generated on-board then the vehicle will face inherent limits of energy density and efficiency. If it uses beamed power above about 0.2 c red-shift effects will cause its efficiency to rapidly decline versus other drive systems. For ultra-relativistic speeds the current best options are still versions of ramjets and mass-beam drives.
2) Teleportation involves the destructive scanning of whatever object is having its quantum characteristics sent across interstellar distances, then reconstruction of that object at the other end. Thus a receiver is involved at the other end and it still has to get to the stars via some other means – until a beam network is set up there’s no great advantage. Stephen Baxter’s teleport network in “Manifold: Space” uses exchange particles stored in a dense ring, and also uses the gravitational focus of the stars as the means of amplifying the signals required.
3) Doubly special relativity will doubtless have to be taken into account, but the Planck energy scale is a bit high for technological manipulation. I’m hoping for breakthroughs from multi-dimensional physics too, but there’s not a lot of data yet.
Adam