If your goal is to get a message to someone living at the bottom of the trench, why does it matter?To me it seems analogous to attaching a letter to a rock and dropping it in the ocean above the mariana trench: not really the same thing as sending a probe down.
How fast is NASA's prospective warp drive?
Moderator: NecronLord
Re: How fast is NASA's prospective warp drive?
You will be assimilated...bunghole!
-
Simon_Jester
- Emperor's Hand
- Posts: 30165
- Joined: 2009-05-23 07:29pm
Re: How fast is NASA's prospective warp drive?
Given that the probes are going to coast randomly through interstellar vacuum, the odds of anyone actually finding them are vanishingly small. We stuck records and plaques on as a matter of general principle, but really, we could fire off millions of the things without any alien ever learning about us from them...
This space dedicated to Vasily Arkhipov
-
Elheru Aran
- Emperor's Hand
- Posts: 13073
- Joined: 2004-03-04 01:15am
- Location: Georgia
Re: How fast is NASA's prospective warp drive?
Given basic physics of space travel, shouldn't it be possible to make an educated guess about the path they take once they leave the Solar System, using their last known trajectory and incorporating the various influences from gravitational sources, solar wind and all that?Simon_Jester wrote:Given that the probes are going to coast randomly through interstellar vacuum, the odds of anyone actually finding them are vanishingly small. We stuck records and plaques on as a matter of general principle, but really, we could fire off millions of the things without any alien ever learning about us from them...
It's a strange world. Let's keep it that way.
-
Eleventh Century Remnant
- Jedi Council Member
- Posts: 2361
- Joined: 2006-11-20 06:52am
- Location: Scotland
Re: How fast is NASA's prospective warp drive?
Oh, we (again human race, not me personally) know, close enough to point a telescope at anyway, where they're going to be for a very long, probably evolutionary- scale time ahead, longer than there is likely to be anyone to care. The thing is that they're not aimed anywhere in particular; after the last solar system flybys, Saturn and Neptune, they're out of delta- V and just roaming ballistically on into the cosmos. (They will achieve the same distance from the solar system as Proxima Centauri in 40,000 (?) years, but they're not actually heading that way.) The extra science they are delivering now is a bonus.
Once the RTGs finally crap out, the Voyagers and Pioneers are going to cool to cosmic background, at which point they will still be high albedo objects on a very unusual path; but they will no longer be radiating, and they will be very very small.
Oh, and testing hypotheses? http://en.wikipedia.org/wiki/White%E2%8 ... rferometer, http://ntrs.nasa.gov/archive/nasa/casi. ... 015936.pdf-
Once the RTGs finally crap out, the Voyagers and Pioneers are going to cool to cosmic background, at which point they will still be high albedo objects on a very unusual path; but they will no longer be radiating, and they will be very very small.
Oh, and testing hypotheses? http://en.wikipedia.org/wiki/White%E2%8 ... rferometer, http://ntrs.nasa.gov/archive/nasa/casi. ... 015936.pdf-
-
Simon_Jester
- Emperor's Hand
- Posts: 30165
- Joined: 2009-05-23 07:29pm
Re: How fast is NASA's prospective warp drive?
Yes- which is why we know that the probes aren't going anywhere near any star for a long, long time. Even if they did, they'd be relatively tiny masses of inert metal coasting through vacuum- easy to miss and troublesome to intercept.Elheru Aran wrote:Given basic physics of space travel, shouldn't it be possible to make an educated guess about the path they take once they leave the Solar System, using their last known trajectory and incorporating the various influences from gravitational sources, solar wind and all that?Simon_Jester wrote:Given that the probes are going to coast randomly through interstellar vacuum, the odds of anyone actually finding them are vanishingly small. We stuck records and plaques on as a matter of general principle, but really, we could fire off millions of the things without any alien ever learning about us from them...
It's sort of like sticking a message in a bottle and tossing it into the sea. There's a chance someone will read it but the odds are much better that it'll sink, or wash up somewhere on your own island, or end up in the middle of one of the great oceanic garbage patches.
This space dedicated to Vasily Arkhipov
Re: How fast is NASA's prospective warp drive?
For my Nova Mundi setting, I imagine that Warp drives have speeds of around about 3 light years per day. Fast enough to make interstellar FTL travel interesting, but slow enough that the greater galaxy is still a huge place full of mysteries.
Does it follow that I reject all authority? Perish the thought. In the matter of boots, I defer to the authority of the boot-maker - Mikhail Bakunin
Capital is reckless of the health or length of life of the laborer, unless under compulsion from society - Karl Marx
Pollution is nothing but the resources we are not harvesting. We allow them to disperse because we've been ignorant of their value - R. Buckminster Fuller
The important thing is not to be human but to be humane - Eliezer S. Yudkowsky
Nova Mundi, my laughable attempt at an original worldbuilding/gameplay project
Capital is reckless of the health or length of life of the laborer, unless under compulsion from society - Karl Marx
Pollution is nothing but the resources we are not harvesting. We allow them to disperse because we've been ignorant of their value - R. Buckminster Fuller
The important thing is not to be human but to be humane - Eliezer S. Yudkowsky
Nova Mundi, my laughable attempt at an original worldbuilding/gameplay project
-
Eleventh Century Remnant
- Jedi Council Member
- Posts: 2361
- Joined: 2006-11-20 06:52am
- Location: Scotland
Re: How fast is NASA's prospective warp drive?
Which is actually a lot faster than most of the theories seem to suggest; the relevant numbers seem to be ten c, fifty- five c, a variable depending on how strongly exotic matter warps spacetime and whether how much of it actually matters (which it apparently does), ten thousand eight hundred c, and instantaneous provided you are prepared to wait the years required for a probability wave to reach the destination at the speed of light.
The past possibility is known as a Krasnikov tube- http://arxiv.org/abs/gr-qc/9511068 and may actually be physically self consistent, provided it is only one way. Hm.
The past possibility is known as a Krasnikov tube- http://arxiv.org/abs/gr-qc/9511068 and may actually be physically self consistent, provided it is only one way. Hm.
Re: How fast is NASA's prospective warp drive?
I'm not surprised, because I was thinking in worldbuilding terms from the start, rather than trying to be scientifically accurate and building from there.
One thing I don't think has been addressed yet is the issue of time travel. This page suggests that instantaneous FTL invokes time travel, and that the same applies for non-instantaneous superluminal paths:
FTL aside, I think the interstellar ramscoops Corvus 501 mentioned earlier are a good choice fiction-wise, but they are not without some real-life problems. For example, the volume of space within which the Solar system is located has a rather thin interstellar medium:
There are also apparently technical difficulties with channeling and fusing the interstellar medium. Proton-chain fusion is hard and a byproduct of funneling interstellar hydrogen will be lots of synchroton radiation, so I imagine radiation protection will be a major consideration in interstellar ramscoop design.
In Nova Mundi I opted for torch ships to carry the first STL colonists to nearby stars. I know that requires more handwaving but I like the idea and it seems to be more rare these days. Of course when colonists reach stars like Epsilon Bootis I suppose they could carry on into the greater galaxy via interstellar ramship since the ISM thickens up in those regions.
One thing I don't think has been addressed yet is the issue of time travel. This page suggests that instantaneous FTL invokes time travel, and that the same applies for non-instantaneous superluminal paths:
I wonder how complex those formulas are. Being able to plot a course into the past could give interstellar wars fought with FTL a new temporal dimension.Finally, FTL still can can bite you in non-instantaneous cases; where we're only going a "little bit" faster than light.
If you warp out, go to Tau Ceti, then with normal reaction engines accelerate away from earth, warp out again to go back to earth, you will indeed get back before you left. (Presuming that the real-space delta-v before the warp/hyperdrive/tachyon-watziz trips was "large enough"... there are formulas for such things in the textbooks)
FTL aside, I think the interstellar ramscoops Corvus 501 mentioned earlier are a good choice fiction-wise, but they are not without some real-life problems. For example, the volume of space within which the Solar system is located has a rather thin interstellar medium:
There are also apparently technical difficulties with channeling and fusing the interstellar medium. Proton-chain fusion is hard and a byproduct of funneling interstellar hydrogen will be lots of synchroton radiation, so I imagine radiation protection will be a major consideration in interstellar ramscoop design.
In Nova Mundi I opted for torch ships to carry the first STL colonists to nearby stars. I know that requires more handwaving but I like the idea and it seems to be more rare these days. Of course when colonists reach stars like Epsilon Bootis I suppose they could carry on into the greater galaxy via interstellar ramship since the ISM thickens up in those regions.
Does it follow that I reject all authority? Perish the thought. In the matter of boots, I defer to the authority of the boot-maker - Mikhail Bakunin
Capital is reckless of the health or length of life of the laborer, unless under compulsion from society - Karl Marx
Pollution is nothing but the resources we are not harvesting. We allow them to disperse because we've been ignorant of their value - R. Buckminster Fuller
The important thing is not to be human but to be humane - Eliezer S. Yudkowsky
Nova Mundi, my laughable attempt at an original worldbuilding/gameplay project
Capital is reckless of the health or length of life of the laborer, unless under compulsion from society - Karl Marx
Pollution is nothing but the resources we are not harvesting. We allow them to disperse because we've been ignorant of their value - R. Buckminster Fuller
The important thing is not to be human but to be humane - Eliezer S. Yudkowsky
Nova Mundi, my laughable attempt at an original worldbuilding/gameplay project
-
Eleventh Century Remnant
- Jedi Council Member
- Posts: 2361
- Joined: 2006-11-20 06:52am
- Location: Scotland
Re: How fast is NASA's prospective warp drive?
The problem is implicit in the current approach- Alcubierre (et al, see; Woodward Effect, Mach- Lorentz) attempt to avoid travelling in time by distorting spacetime so that you are, in effect, moving slower than light in a universe the shape of which you are altering to your convenience. It is not really going from place to place; it is making a new place, a corridor of distorted spacetime, that happens to be much more the shape you want the universe to be. Avoiding time travel by resorting to cosmic engineering.
The excerpt from Stephen Baxter on the same page as the link leads to gives some of the flavour of it- the human consequences are vastly easier to plot out than the physical, for most of us.
Actual outright into the past, change history style time travel seems to be flat out impossible. But that is one of the reasons it is science fiction...
Oh, and ramscoops; there were several novels written around a society made possible by them by the same guy who presented the Kzinti Lesson- and ramscoops have a really, really nasty take on that principle. The magnetic field of the scoops he described was going to have to be immense, easily hundreds of teslas; far beyond Carrington Event, probably enough to completely EMP- blast the infrastructure of a computerised world, if not as he depicted it turn organic creatures' nervous systems into fried putty. (Current hypothetical designs are a bit kinder- UV beams ionise the gas in the path ahead, making a much less intense scoop field equally effective.)
I mention ten thousand eight hundred because- and I am going to have to look for this because it is annoying me now- there was an experiment that measured that as the phase velocity of quantum entanglement. Which, if you can entangle with the leading edge of the warp bubble, does give you some slight possibility of actually steering. And very, very big if.
Intermediate speeds, like your nice round number thousand or so, may be possible depending on how much the exotic matter warps space; I like the Woodward effect, which with some other stuff suggests the creation of exotic matter on the fly, basically by Casimir effects in the drive field- which means you may have a lot more manoeuvrability and operational control than with a straightforward Alcubierre model.
The excerpt from Stephen Baxter on the same page as the link leads to gives some of the flavour of it- the human consequences are vastly easier to plot out than the physical, for most of us.
Actual outright into the past, change history style time travel seems to be flat out impossible. But that is one of the reasons it is science fiction...
Oh, and ramscoops; there were several novels written around a society made possible by them by the same guy who presented the Kzinti Lesson- and ramscoops have a really, really nasty take on that principle. The magnetic field of the scoops he described was going to have to be immense, easily hundreds of teslas; far beyond Carrington Event, probably enough to completely EMP- blast the infrastructure of a computerised world, if not as he depicted it turn organic creatures' nervous systems into fried putty. (Current hypothetical designs are a bit kinder- UV beams ionise the gas in the path ahead, making a much less intense scoop field equally effective.)
I mention ten thousand eight hundred because- and I am going to have to look for this because it is annoying me now- there was an experiment that measured that as the phase velocity of quantum entanglement. Which, if you can entangle with the leading edge of the warp bubble, does give you some slight possibility of actually steering. And very, very big if.
Intermediate speeds, like your nice round number thousand or so, may be possible depending on how much the exotic matter warps space; I like the Woodward effect, which with some other stuff suggests the creation of exotic matter on the fly, basically by Casimir effects in the drive field- which means you may have a lot more manoeuvrability and operational control than with a straightforward Alcubierre model.