Re: [Vo]:Interstellar travel
Okay, to summarize this discussion: A radar would not be able to detect particles such as grains of sand or small rocks. Therefore I suppose you need a powerful laser in the front of the spacecraft to heat them and break them into molecules or plasma. It would have to be turned on at all times because you cannot detect these particles. Even atoms and molecules would be large enough to cause damage. So you need to push them out of the way. I suppose the only way to do this with known science is to ionize them and then use a magnetic field to push them out of the way. I do not know if you can ionize particles from a long distance away. It would have to be very long! Something like a science fiction "force field" would probably be the best solution. I have no idea whether such a thing is possible.
Re: [Vo]:Interstellar travel
> > > In such a galaxy, everyone would use similar FTL communications equipment, > effectively joined in a galaxy wide > "Internet", so the first thing an advanced civilization is going to try to > teach one that doesn't have it, is how to > build FTL comms gear. > Ever wondered what crop circles really are? FTL comms gear: Spaz.org/~magi They said it would help us have a "healthy civilization". They said the milky way is very old.
Re: [Vo]:Interstellar travel
Don't forget your towel. On Fri, Oct 9, 2020 at 3:55 PM H LV wrote: > https://www.youtube.com/watch?v=I8gu1p939a4 > Fritz Lang's 1929 vision of spaceflight. > > Wear a sweater! > > Harry > > > > On Fri, Oct 9, 2020 at 3:11 PM Terry Blanton wrote: > >> Oops. That was a different Robin. :) >> >> On Fri, Oct 9, 2020 at 3:06 PM Terry Blanton wrote: >> >>> Indeed, Robin. First we must overcome The Great Filter. >>> >>> On Fri, Oct 9, 2020 at 3:00 PM Robin >>> wrote: >>> In reply to Terry Blanton's message of Fri, 9 Oct 2020 14:11:08 -0400: Hi, [snip] >This is exactly why starships travel in subspace. >>> "sniff"> ...se we revert to SciFi to maintain the dream, rather than face reality? I think it's time we change the dream. We are not going to be leaving the Sol system any time soon, so we had better adapt to the fact and learn to live with one another here on Earth. OTOH there is still plenty of room for expansion within the Solar system. Lots of lovely planets and moons. Granted, the conditions are not ideal for life as we know it, but with the application of technology & energy some of them can be made habitable. If "subspace" ever becomes a reality, then we can reconsider the matter.
Re: [Vo]:Interstellar travel
Hi, At half the speed of light, the kinetic energy of a Hydrogen molecule is in excess of 200 MeV. At that energy it isn't going to bounce off. It's going to embed itself in the hull material and deposit all its energy, thereby ablating the hull material, irrespective of its composition. Note also that all this power needs to be supplied by the ship itself, since it's effectively required to overcome the "wind resistance". Even fusing the Hydrogen into Helium in a Bussard ramjet is only going to supply about 13 MeV / H2 molecule, which is far short of the 200 MeV needed. For a Bussard ramjet to break even it couldn't travel faster than c/7. Which implies a 28 year trip to the nearest star beyond the Sun. However complete conversion of matter to energy should do the trick.
Re: [Vo]:Interstellar travel
https://www.youtube.com/watch?v=I8gu1p939a4 Fritz Lang's 1929 vision of spaceflight. Wear a sweater! Harry On Fri, Oct 9, 2020 at 3:11 PM Terry Blanton wrote: > Oops. That was a different Robin. :) > > On Fri, Oct 9, 2020 at 3:06 PM Terry Blanton wrote: > >> Indeed, Robin. First we must overcome The Great Filter. >> >> On Fri, Oct 9, 2020 at 3:00 PM Robin >> wrote: >> >>> In reply to Terry Blanton's message of Fri, 9 Oct 2020 14:11:08 -0400: >>> Hi, >>> [snip] >>> >This is exactly why starships travel in subspace. >> "sniff"> >>> >>> ...se we revert to SciFi to maintain the dream, rather than face reality? >>> >>> I think it's time we change the dream. We are not going to be leaving >>> the Sol system any time soon, so we had better >>> adapt to the fact and learn to live with one another here on Earth. OTOH >>> there is still plenty of room for expansion >>> within the Solar system. Lots of lovely planets and moons. Granted, the >>> conditions are not ideal for life as we know it, >>> but with the application of technology & energy some of them can be made >>> habitable. >>> >>> If "subspace" ever becomes a reality, then we can reconsider the matter. >>> >>>
Re: [Vo]:Interstellar travel
In reply to Terry Blanton's message of Fri, 9 Oct 2020 15:06:27 -0400: Hi, [snip] >Indeed, Robin. First we must overcome The Great Filter. 1) I think I have just finished providing at least one reason why Interstellar travel is limited. 2) I think there is actually lots of evidence of technology beyond our currently acknowledged capabilities (UFO's), though it may not come from the stars.
Re: [Vo]:Interstellar travel
Oops. That was a different Robin. :) On Fri, Oct 9, 2020 at 3:06 PM Terry Blanton wrote: > Indeed, Robin. First we must overcome The Great Filter. > > On Fri, Oct 9, 2020 at 3:00 PM Robin > wrote: > >> In reply to Terry Blanton's message of Fri, 9 Oct 2020 14:11:08 -0400: >> Hi, >> [snip] >> >This is exactly why starships travel in subspace. > "sniff"> >> >> ...se we revert to SciFi to maintain the dream, rather than face reality? >> >> I think it's time we change the dream. We are not going to be leaving the >> Sol system any time soon, so we had better >> adapt to the fact and learn to live with one another here on Earth. OTOH >> there is still plenty of room for expansion >> within the Solar system. Lots of lovely planets and moons. Granted, the >> conditions are not ideal for life as we know it, >> but with the application of technology & energy some of them can be made >> habitable. >> >> If "subspace" ever becomes a reality, then we can reconsider the matter. >> >>
Re: [Vo]:Interstellar travel
Indeed, Robin. First we must overcome The Great Filter. On Fri, Oct 9, 2020 at 3:00 PM Robin wrote: > In reply to Terry Blanton's message of Fri, 9 Oct 2020 14:11:08 -0400: > Hi, > [snip] > >This is exactly why starships travel in subspace. > > ...se we revert to SciFi to maintain the dream, rather than face reality? > > I think it's time we change the dream. We are not going to be leaving the > Sol system any time soon, so we had better > adapt to the fact and learn to live with one another here on Earth. OTOH > there is still plenty of room for expansion > within the Solar system. Lots of lovely planets and moons. Granted, the > conditions are not ideal for life as we know it, > but with the application of technology & energy some of them can be made > habitable. > > If "subspace" ever becomes a reality, then we can reconsider the matter. > >
Re: [Vo]:Interstellar travel
In reply to Terry Blanton's message of Fri, 9 Oct 2020 14:11:08 -0400: Hi, [snip] >This is exactly why starships travel in subspace. ...se we revert to SciFi to maintain the dream, rather than face reality? I think it's time we change the dream. We are not going to be leaving the Sol system any time soon, so we had better adapt to the fact and learn to live with one another here on Earth. OTOH there is still plenty of room for expansion within the Solar system. Lots of lovely planets and moons. Granted, the conditions are not ideal for life as we know it, but with the application of technology & energy some of them can be made habitable. If "subspace" ever becomes a reality, then we can reconsider the matter.
Re: [Vo]:Interstellar travel
Pity the re-re-make of "Dune" release date has been delayed from December 2020 to October of 2021. We will probably encounter the TOET by then. On Fri, Oct 9, 2020 at 2:48 PM Terry Blanton wrote: > Ah, yes, the Stoned Ape Hypothesis. > > I have been studying the Novelty Time Wave Theory of late. Melange is > definitely required. :) > > On Fri, Oct 9, 2020 at 2:23 PM JonesBeene wrote: > >> Don’t you mean “folded space” ? >> >> >> >> That sniff has to do with the spice, IIRC >> >> >> >> *From: *Terry Blanton >> >> Robin wrote: >> > The real point I have been trying to make, is that space simply isn't >> empty at long distances, so high speeds become >> > very difficult. >> >> >> >> This is exactly why starships travel in subspace. >> >> >> >
Re: [Vo]:Interstellar travel
Ah, yes, the Stoned Ape Hypothesis. I have been studying the Novelty Time Wave Theory of late. Melange is definitely required. :) On Fri, Oct 9, 2020 at 2:23 PM JonesBeene wrote: > Don’t you mean “folded space” ? > > > > That sniff has to do with the spice, IIRC > > > > *From: *Terry Blanton > > Robin wrote: > > The real point I have been trying to make, is that space simply isn't > empty at long distances, so high speeds become > > very difficult. > > > > This is exactly why starships travel in subspace. > > >
RE: [Vo]:Interstellar travel
Don’t you mean “folded space” ? That sniff has to do with the spice, IIRC From: Terry Blanton Robin wrote: > The real point I have been trying to make, is that space simply isn't empty >at long distances, so high speeds become > very difficult. This is exactly why starships travel in subspace.
Re: [Vo]:Interstellar travel
On Thu, Oct 8, 2020 at 10:48 PM Robin wrote: > The real point I have been trying to make, is that space simply isn't empty at long distances, so high speeds become > very difficult. This is exactly why starships travel in subspace.
Re: [Vo]:Interstellar travel
In reply to Jed Rothwell's message of Thu, 8 Oct 2020 20:53:15 -0400: Hi, [snip] >Robin wrote: > > >> 5) Interstellar gas is not the only problem. A grain of sand or a pebble >> would spell disaster. >> > >You're gonna need a VERY high resolution radar and a laser. Radar waves are too long for grains of sand. Vaporizing them with a laser will be difficult because it has to happen before the ship arrives at that point, and it's going so fast that a long distance is implied. Also don't even try flying through an interstellar dust cloud. The real point I have been trying to make, is that space simply isn't empty at long distances, so high speeds become very difficult. Without high speeds, travel times are going to be very long. I short, I think we should give up going to the stars physically, at least directly. I suspect that highly advanced civilizations don't actually travel at all, but rather use FTL communications for "virtual" travel. IOW get a distant civilization to send you a movie of their world, rather than actually going there. In such a galaxy, everyone would use similar FTL communications equipment, effectively joined in a galaxy wide "Internet", so the first thing an advanced civilization is going to try to teach one that doesn't have it, is how to build FTL comms gear. Ever wondered what crop circles really are? (AI Robots traveling at low speed can take millennia to travel between the stars, programmed with the ability to reproduce the plans using whatever local "canvas" is available.)
Re: [Vo]:Interstellar travel
Robin wrote: > 5) Interstellar gas is not the only problem. A grain of sand or a pebble > would spell disaster. > You're gonna need a VERY high resolution radar and a laser.
Re: [Vo]:Interstellar travel
In reply to Jones Beene's message of Thu, 8 Oct 2020 15:25:39 + (UTC): Hi, [snip] > Looks like your angle is radiative cooling. At the melting point of Titanium it will radiate about 80 W/cm^2, compared to the calculated 500 kW/cm^2 kinetic energy. > >Plus, speaking of angles - the full kinetic energy of the particles would not >be transferred to the titanium. 1) A bow-wave may form that partially protects the hull, though the tip would still be problematic. 2) An extremely long pointed prow would have a much larger surface area than its cross section, making it possible to more equally balance the incoming and outgoing power, which would also make more particles bounce off. 3) As Harry says, forced cooling would be needed. 4) If might be possible to ionize the medium first so that it can be deflected by a magnetic field. 5) Interstellar gas is not the only problem. A grain of sand or a pebble would spell disaster.
Re: [Vo]:Interstellar travel
Robin wrote: > A space ship traveling at half the speed of light would encounter these > molecules traveling in the opposite direction at > that velocity. Assuming that the kinetic energy of these particles is > calculated using 1/2 m*v^2 (it's actually more at > that speed), then the power associated with the impact on the hull of the > ship is about 1/2 MW /cm^2. > If we further assume that the hull is made of 1/2 cm thick Titanium, then > it will reach it's melting point after an > exposure of 4 milliseconds. > Arthur Clarke and others who thought about interstellar spacecraft discussed this problem. In the 1970s, Clarke thought this could be fixed by putting a giant piece of ice in front of the spaceship, to absorb the particles. The ice would be gradually worn away. I guess the estimate of the total mass of particles was smaller. Or he did his arithmetic wrong. If these numbers are correct, I suppose the only way to overcome the particles is by moving them out of the way. I guess a gigantic cow-catcher would not work. A science-fiction "force field" would be ideal, but there is no such thing as far as I know. Can the particles be given a charge from a distance, and then moved out of the way with a magnetic field? Sort of like a flying tokamak.
Re: [Vo]:Interstellar travel
Looks like your angle is radiative cooling. Plus, speaking of angles - the full kinetic energy of the particles would not be transferred to the titanium. H LV wrote: The ship would need some way to stay to cool. Harry Robin wrote: According to wiki (https://en.wikipedia.org/wiki/Interstellar_medium) the density of matter in between stars in the galaxy is about 1E6 molecules / cm^3. We make the assumption that all of it is molecular Hydrogen. A space ship traveling at half the speed of light would encounter these molecules traveling in the opposite direction at that velocity. Assuming that the kinetic energy of these particles is calculated using 1/2 m*v^2 (it's actually more at that speed), then the power associated with the impact on the hull of the ship is about 1/2 MW /cm^2. If we further assume that the hull is made of 1/2 cm thick Titanium, then it will reach it's melting point after an exposure of 4 milliseconds. It's going to be very short trip. ;)
Re: [Vo]:Interstellar travel
The ship would need some way to stay to cool. Harry On Wed., Oct. 7, 2020, 9:58 p.m. Robin, wrote: > Hi, > > According to wiki (https://en.wikipedia.org/wiki/Interstellar_medium) the > density of matter in between stars in the > galaxy is about 1E6 molecules / cm^3. We make the assumption that all of > it is molecular Hydrogen. > > A space ship traveling at half the speed of light would encounter these > molecules traveling in the opposite direction at > that velocity. Assuming that the kinetic energy of these particles is > calculated using 1/2 m*v^2 (it's actually more at > that speed), then the power associated with the impact on the hull of the > ship is about 1/2 MW /cm^2. > If we further assume that the hull is made of 1/2 cm thick Titanium, then > it will reach it's melting point after an > exposure of 4 milliseconds. > > It's going to be very short trip. ;) > >
