is there a possibility to send some nuclear generator, like submarine one or this famous russian lighthouse? Or maybe 5 of them, it might solve some problems
It's gotten a lot of thought. I regard it as pretty likely.
L1 might be between the two bodies but it's gravitationally unstable. The only Lagrange points suitable for stationing a refueling base are L4 and L5, since those points wouldn't require continual adjustments to maintain a stable orbit..
This is misleading. All the Earth-Moon Lagrange points are perturbed by the Sun and the planets, and all will in practice need station-keeping. And, yes, the L1 and L2 Lagrange points are unstable (as is L3), but a Lissajous orbit about them requires about the same amount of station-keeping as would L4 and L5.
Note, BTW, that there are a number of spacecraft at the Earth-Sun L1 and L2 Lagrange points, which are also unstable and also subject to planetary perturbations.
Also, there is no gravitationally neutral spot, as every planet in the solar system is constantly moving.
Lagrange Points are what they are talking about. And, yes, they are neutral, particularly L1, L2, L4 and L5. They are talking about Earth-Moon L1 or L2.
If you could find one in or near a Mars cycler orbit, this might make a lot of sense.
Remember, astronauts in long duration deep space flights should get a fair amount of shielding, and a big rock should be able to provide the few meters of rock that would be best.
By "it" in my last sentence, I meant Voyager I. You can get to the stars faster if you spend more delta V doing so.
An interesting tidbit is that 1 year at 1 g thrust gets you to just about the speed of light. After 1 year at one g, you don't really go much faster (from the standpoint of someone left behind) but, boy does the relativistic time dilation kick in. Factoring in time dilation, you can get to almost anywhere in a fairly reasonably subjective time (i.e., the relativistic proper time for the traveler), assuming you can accelerate and deaccelerate continuously at 1 g. , Thrusting at 1 g also has the comfort advantage that we are totally used to it.
Of course, if you go very far, humans, or even the Earth, may not be there when you get back. And, how to achieve a constant 1 g thrust has to left as an exercise for the reader...
Could you get more by slingshotting around the sun?
Only if you are coming in from the outside the solar system. These gravitational slingshots exchange orbital momentum between the planet and the spacecraft. You could use the Sun to do that with the Sun and the Galaxy, but only if you were coming in on a galactic orbit.
(Now, you could get close to the Sun and unfurl a big solar sail and use that as a source of thrust, but that is different.)
Gravity is GM / R**2. Mass is proportional to R**3, which means that Gravity is proportional to R, if the density is the same. Inverting that, Gravity is proportional is M**(1/3), so 4 times the mass is 1.587 times the gravity (for a constant density).
With Weak Stability Boundary theory trajectories you can basically get from a lunar transfer orbit (or either ES or EM L1/2) to anywhere else around without spending any fuel, if you are willing to wait long enough. This pdf presentation should give you the idea.
Now, in practice you can't do it with no fuel, but if you are willing to be patient, you can do amazing things with a piddling expenditure of delta-V.
Note that there are a few craters, but not many (asteroid Itokawa has no craters in Hayabusa images), so as usual something is resurfacing the surface.
There is a big dose of FUD here. There are thousands of defunct satellites, and pieces thereof, up there. The chances of something out of control hitting something is very small. Now, it would be bad if it blew up, turning into thousands of pieces, but just by itself it is no big deal.
Rock and minerals are mosly recycled by our active planet. The oldest rock is 4.03 billion years old (gniess from NW Canada), and oldest mineral is 4.3 billion years (zircon crystals from west australia). But neither tells us the age of the Earth.
Well, they do tell us for sure that the Earth is > 4.3 billion years old, which is 95%+ of the way there. If you want to argue at the few per cent level, I'll be glad to listen.
If we really seriously want to move from the expensive launch vehicle, expensive hardware optimization we are currently in, we probably need to do something like this.
NASA doesn't like to commit to really long missions. Get it up there, get good results, and they will then commit to extensions. (See, for example, the "3 month mission" of the MER rover Opportunity.)
Kepler is not looking at particularly close stars, so it not likely to find any real flyby candidates, even for the century star ship time frame. The recent find at Alpha Centauri is much more encouraging in that regard.
Well, more exactly, they think that their expected return is positive. So, if they think that the chance of a full payout was 10%, their premiums are presumably going to total something more than $ 2 million (minus a little bit for the present value of future money, which is always 1). Insurance works by making many such bets, and getting right on a large enough aggregate.
My understanding is that the first X Prize was funded on the cheap, as the Insurance company really didn't think they would ever have to pay out. That is not likely to happen again.
It can be thought of as an attempt to do probabilistic type arguments, when you don't have any data to do probability with.
Suppose that astronauts find a long abandoned alien base on the Moon. All equipment was carefully removed, but we know that the doors and corridors are all 4 meters wide and 3 meters high. It would be "natural" to assume that the aliens (or their machinery) were typically less, but not much less, than 3 meters tall. That could be wrong - maybe they are 1 meter birds who like room to fly in. Or maybe they are 4 meter giants who don't mind stooping. But, in the absence of any other evidence, it is a "natural" assumption. Such assumptions are very common in places like cosmology and quantum gravity.
One argument from naturalness is that dimensionless constants should "naturally" be near one, without a good reason to have some specific value. (The other "natural" is of course zero.).
Take the axion and CP violation. You can add a term to the QCD Lagrangian which violates Charge+Parity (or CP), which means that this term allows for particles and their antiparticles to behave differently. This term is multiplied by a constant denoted by theta, with theta = 0 meaning no CP violation. It turns out you can restrict theta to be 10^-10 experimentally. So, presumably, theta IS zero (as zero is a much more "natural" number than the really tiny 10^-10). The axion came from assuming that theta really described a new field (with a new particle, the axion), and was driven towards zero in the evolution of the universe. It seemed much more "natural" to say that "after about the first microsecond of the big bang theta is driven to be zero" than just saying "this constant is really tiny."
The reason I said that about the cosmological constant (lambda) is that it is about 0.7 and (in the same units) the standard model value for it is about 10^122. (Or, in natural units, its current value is about 10^-122.) That is an extraordinary result. Many people were sure that lambda was exactly zero (as that could also be "natural,") but it isn't. Note that the value for the axion's theta is by contrast almost routine. If theta is like winning the lottery, lambda is like having every atom in the universe winning the lottery simultaneously for every nanosecond that the universe has existed. So, I regard these arguments as less persuasive than I did 20 years ago,
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is there a possibility to send some nuclear generator, like submarine one or this famous russian lighthouse? Or maybe 5 of them, it might solve some problems
It's gotten a lot of thought. I regard it as pretty likely.
But, you are still likely to be power limited.
L1 might be between the two bodies but it's gravitationally unstable. The only Lagrange points suitable for stationing a refueling base are L4 and L5, since those points wouldn't require continual adjustments to maintain a stable orbit..
This is misleading. All the Earth-Moon Lagrange points are perturbed by the Sun and the planets, and all will in practice need station-keeping. And, yes, the L1 and L2 Lagrange points are unstable (as is L3), but a Lissajous orbit about them requires about the same amount of station-keeping as would L4 and L5.
Note, BTW, that there are a number of spacecraft at the Earth-Sun L1 and L2 Lagrange points, which are also unstable and also subject to planetary perturbations.
Also, there is no gravitationally neutral spot, as every planet in the solar system is constantly moving.
Lagrange Points are what they are talking about. And, yes, they are neutral, particularly L1, L2, L4 and L5. They are talking about Earth-Moon L1 or L2.
If you could find one in or near a Mars cycler orbit, this might make a lot of sense.
Remember, astronauts in long duration deep space flights should get a fair amount of shielding, and a big rock should be able to provide the few meters of rock
that would be best.
Testing is simple - plug it in, and run it till it fails. Might as well use it in the mean-time.
By "it" in my last sentence, I meant Voyager I. You can get to the stars faster if you spend more delta V doing so.
An interesting tidbit is that 1 year at 1 g thrust gets you to just about the speed of light. After 1 year at one g, you don't really go much faster (from the standpoint of someone left behind) but, boy does the relativistic time dilation kick in. Factoring in time dilation, you can get to almost anywhere in a fairly reasonably subjective time (i.e., the relativistic proper time for the traveler), assuming you can accelerate and deaccelerate continuously at 1 g. , Thrusting at 1 g also has the comfort advantage that we are totally used to it.
Of course, if you go very far, humans, or even the Earth, may not be there when you get back. And, how to achieve a constant 1 g thrust has to left as an exercise for the reader...
Could you get more by slingshotting around the sun?
Only if you are coming in from the outside the solar system. These gravitational slingshots exchange orbital momentum between the planet and the spacecraft. You could use the Sun to do that with the Sun and the Galaxy, but only if you were coming in on a galactic orbit.
(Now, you could get close to the Sun and unfurl a big solar sail and use that as a source of thrust, but that is different.)
Gravity is GM / R**2. Mass is proportional to R**3, which means that Gravity is proportional to R, if the density is the same. Inverting that, Gravity is proportional is M**(1/3), so 4 times the mass is 1.587 times the gravity (for a constant density).
So, I wouldn't rule it out.
The math is wrong - Voyager I is 0.71 light days away, or 0.0019 light years away. It will take a lot longer than 840 years to get to another star.
I generally find it safe to assume that State of South Carolina does not show the way on how to do anything.
With Weak Stability Boundary theory trajectories you can basically get from a lunar transfer orbit (or either ES or EM L1/2) to anywhere else around without spending any fuel, if you are willing to wait long enough. This pdf presentation should give you the idea.
Now, in practice you can't do it with no fuel, but if you are willing to be patient, you can do amazing things with a piddling expenditure of delta-V.
If you compare this image with the Goldstone image of Toutatis by Earth-based radar - see Figure 1 in Hudson et al - you can see that the Earth radar does OK, but actually going there is better. Toutatis's rotation period is 176 hours, so we won't get to see the other side in the flyby.
Note that there are a few craters, but not many (asteroid Itokawa has no craters in Hayabusa images), so as usual something is resurfacing the surface.
There is a big dose of FUD here. There are thousands of defunct satellites, and pieces thereof, up there. The chances of something out of control hitting something is very small. Now, it would be bad if it blew up, turning into thousands of pieces, but just by itself it is no big deal.
Yes. I, for one, just can't wait until he marries Pocahontas in the next Star Wars movie.
The sad thing is that I might have bought this before the three prequels came out.
There was a huge stink about this when the RHIC was brought on line (stranglets will eat Long Island !!!). This report covers the basics.
There is no science here. Please don't pretend otherwise.
Rock and minerals are mosly recycled by our active planet. The oldest rock is 4.03 billion years old (gniess from NW Canada), and oldest mineral is 4.3 billion years (zircon crystals from west australia). But neither tells us the age of the Earth.
Well, they do tell us for sure that the Earth is > 4.3 billion years old, which is 95%+ of the way there. If you want to argue at the few per cent level, I'll be glad to listen.
It is a pity when insane people are allowed to embarrass themselves in public so.
If we really seriously want to move from the expensive launch vehicle, expensive hardware optimization we are currently in, we probably need to do something like this.
What more needs to be said.
NASA doesn't like to commit to really long missions. Get it up there, get good results, and they will then commit to extensions. (See, for example, the "3 month mission" of the MER rover Opportunity.)
Kepler is not looking at particularly close stars, so it not likely to find any real flyby candidates, even for the century star ship time frame. The recent find at Alpha Centauri is much more encouraging in that regard.
Well, more exactly, they think that their expected return is positive. So, if they think that the chance of a full payout was 10%, their premiums are presumably going to total something more than $ 2 million (minus a little bit for the present value of future money, which is always 1). Insurance works by making many such bets, and getting right on a large enough aggregate.
My understanding is that the first X Prize was funded on the cheap, as the Insurance company really didn't think they would ever have to pay out. That is not likely to happen again.
It can be thought of as an attempt to do probabilistic type arguments, when you don't have any data to do probability with.
Suppose that astronauts find a long abandoned alien base on the Moon. All equipment was carefully removed, but we know that the doors and corridors are all 4 meters wide and 3 meters high. It would be "natural" to assume that the aliens (or their machinery) were typically less, but not much less, than 3 meters tall. That could be wrong - maybe they are 1 meter birds who like room to fly in. Or maybe they are 4 meter giants who don't mind stooping. But, in the absence of any other evidence, it is a "natural" assumption. Such assumptions are very common in places like cosmology and quantum gravity.
One argument from naturalness is that dimensionless constants should "naturally" be near one, without a good reason to have some specific value. (The other "natural" is of course zero.).
Take the axion and CP violation. You can add a term to the QCD Lagrangian which violates Charge+Parity (or CP), which means that this term allows for particles and their antiparticles to behave differently. This term is multiplied by a constant denoted by theta, with theta = 0 meaning no CP violation. It turns out you can restrict theta to be 10^-10 experimentally. So, presumably, theta IS zero (as zero is a much more "natural" number than the really tiny 10^-10). The axion came from assuming that theta really described a new field (with a new particle, the axion), and was driven towards zero in the evolution of the universe. It seemed much more "natural" to say that "after about the first microsecond of the big bang theta is driven to be zero" than just saying "this constant is really tiny."
The reason I said that about the cosmological constant (lambda) is that it is about 0.7 and (in the same units) the standard model value for it is about 10^122. (Or,
in natural units, its current value is about 10^-122.) That is an extraordinary result. Many people were sure that lambda was exactly zero (as that could also be "natural,") but it isn't. Note that the value for the axion's theta is by contrast almost routine. If theta is like winning the lottery, lambda is like having every atom in the universe winning the lottery simultaneously for every nanosecond that the universe has existed. So, I regard these arguments as less persuasive than I did 20 years ago,