Actually, you can bet that when NASA launches a rover designed to have a significantly longer lifespan, say, in 2009, there won't be solar panels on it to need cleaning.
Truth, but the original post was talking about a space station, which in my mind I was envisioning a BIG station (you know, the kind they said we'd be vacationing on in the year 2000), but you're absolutely right that a smaller object is under no threat whatsoever.
I was not being sufficiently clear in my explanation. Sorry for that.
I think my second point is still relevant, though.:-)
You cannot likely orbit something 10 miles above the lunar surface. Tidal stress on the orbiting body would likely render it apart, unless it was made of some really tough material.
Also, your margin of error is nonexistent if you pick up some unexpected impulse. It would be insane to live on something orbiting 10 miles over the moon.
The formula for escape velocity is Ev = sqrt((2*G*m)/r). Given the moon's mass and radius, we have to be certain your hypothetical rail gun has enough oomph to even achieve escape velocity.
In MKS, G is 6.67e-11 m^3/kg-s^2, the mass of the moon is 7.349e22 kg and the radius is 1.736e6 m. Plug and chug gives us about 2.4 km/sec from the moon's surface. So, it would be feasible as long as the direction of launch is within about 41 degrees of zenith (acos(theta) = (V/Ev)).
The problem of accurately striking the earth remains a three-body problem, though it's easier to approximate since the projectile mass is insignificant next to the mass of the earth and moon. There is no neat numerical answer to flight time, since there are a variety of paths that could be used to reach the earth, in addition to some trajectories that would never get you to earth. You could also put things into lunar orbit, earth orbit, or leave the earth-moon system entirely. The escape velocity of earth at the moon's perigee is about 1.4 km/s.
So, no matter how motivated one could be, the correct answer to your problem is "not enough information to answer".
Just to put the kinetic strike weapon concept to bed for now, accurate strikes would be a difficult problem to solve at best, especially since there's no mid-course correction available. Vagaries of the system's gravitation, perturbation by other celestial bodies, and atmospheric contact would all work together to increase the uncertainty of the problem.
Now, that railgun has some real potential to launch guided spacecraft cheaply (well, once the cost of construction has been amortized!), but as an unguided weapons platform, it's not too useful. Now, if you *could* accelerate something to.5c like the grandparent post suggested, you're onto something.
Not any kind of women I'd like to be around. My wife, bless her soul, can change oil, gap and replace spark plugs, flush and fill the radiator and even replaced a water pump on one car.
I wonder if when this car has a problem if a squeaky little voice comes out of the dash saying "cars are hard! Let's go shopping!" This just further backs my opinion that the worst discriminators against women are usually other women.
I'll bet my wife could kick these designers' asses, too.
The best part of that search is all the ads on the right for companies that promise to improve your search engine ranking, but yet do not appear in the first few pages of the search itself.
You see an event like this and wonder "why didn't my high school do this when I was there?" only to realize that the event didn't exist yet when you were in high school.
Those researching inertial electrostatic fusion hypothesize that IEF reactors could hypothetically create an electron flux using aneutronic fusion reactions. This electron flux could be tapped to produce current, without heating things with neutron bombardment.
I wish them luck, because for some reason it really disturbs my sense of aesthetics to create a power source that mimics the very stars and then take that power and run a good old 19th century steam turbine to get electrical power.
Also, let us not forget that working on one's own car is quite a hackish thing to do, and there's a bunch of personality overlap between car mechanics and computer geeks: the sheer joy of tinkering with something, obsessing and arguing over arcane details nobody else really cares about, Holy wars (Ford/Chevy or Windows/MacOS), and an independent streak that means we don't like to be pushed around by anyone, but especially by whimpering litigious nancy boys.
I wonder how many of us would have become full-time mechanics if computers had never been invented. Heaven knows I enjoy ripping into car engines on the weekends.
Answer: it shouldn't be diverted at all. By the time the asteroid arrives, the Earth has also moved in its orbit out of the way of the asteroid that was originally headed straight for its center.
The real solution is much more complicated, as it is a three body problem (Sun, Earth, asteroid) that must also take into account perturbations by other celestial bodies (Jupiter for sure, probably the inner planets and Earth's moon as well) for the kind of accuracy you would need for such a propulsion system. This solution requires a lot more ephemerides, and even a pre-Netwonian mechanics linear model would at a minimum require the magnitude of the velocity (speed) of the asteroid.
Personally, I think that the registered.* offenders lists, and DUI plates are a bad idea. If this person is still a danger to the community, that what the hell are they doing still free? Lock them up, or let them be.
You're less likely to see this these days
on
A Way to Save Hubble?
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· Score: 3, Insightful
because of the principle of unintended consequences. Now, there are laws that state that a publicly-traded company's board and executives must to their best to maximize shareholder revenue, which on the surface sounds like a nice anti-fraud idea.
The practice of it is corporations do relatively little basic scientific R&D anymore, and lay off masses of people at the first sign of financial difficulty.
I even remember the TV ads Bell Labs ran when that discovery was made (I'm telling my age a bit, I'm sure). Nowadays, if they crowed about it, the board would probably be up on charges of securities fraud because they were working on "pie-in-the-sky" abstractions and not figuring out how to integrate yet another toy function into a cell phone.
Erm, sure, let just use code I wrote for employer A and put in in employer B's code. I'm sure they won't mind. And of course, every data structure is identical, so there's no need to write this but once. And also of course, I've never had to develop a library that manipulates a linked list. I also have the luxury of only working on code that's perfectly designed.
Sorry, but if "p = head; while (p != NULL) { if (p->somevalue == looking_for) return p; p = p->next;} return NULL;" is a big mystery to you, then you've learned the concept of "abstraction" a little too well.
What's even funnier is this line is in a function br_get_port, which just traverses a linked list looking for a certain value. Even if the whole damn function was a duplicate, this sort of code is such an idiomatic C expression, it's like trying to claim ownership to any conversation that contains "How are you?" "Fine".
I've written functions like this myself dozens if not hundreds of times. I guess I owe SCO for every linked list I've ever written in C.
Yes, we could. Write your congressman and say you want future Mars lander and rover missions to have more ground systems funding and to fend off the eco-wackos and install RTGs on them.
And by the way, we could put together another MER mission for about 200 million per rover now, since a big chunk of theat 800 million was R&D for the two we have.
Also, I just watched "Hackers" with Angelina Jolie and Matthew Lillard and I finally have a clear idea what these hackers are about and how they break into mainframes.
The top picture, while very cool and very accurate, is not actually a picture taken directly by the orbiter. Since they take stereo pictures, it is a straightforward task to recompute a new picture from a different angle.
I've seen martian pictures done like this before, but always it was composites with different instruments, like MOC (Mars Orbital Camera) or THEMIS (Thermal Emission Imaging Spectrometer) to provide the visual component and MOLA (Mars Orbital Laser Altimeter) giving the third dimension data.
Still, it's impressive as hell, and from a science standpoint will have geometric effect on the knowledge we've gained from the MGS and Odyssey orbiters. I hope Express has many years of good observations, and I look forward to ESA and NASA continuing the exploration of Mars. It's definitely a step in the right direction.
My card is actually in the name of "Arthur Dent", who has a nonexistent address and phone number. I was at an SF con some years back and a group of us agreed to do this.
I'd dearly love to know what Arthur Dent's consumer profile looks like right now. Just trying to stock up on stuff before the Vogon Constructor Fleet arrives, I suppose.
Slashdot Mirror
Actually, you can bet that when NASA launches a rover designed to have a significantly longer lifespan, say, in 2009, there won't be solar panels on it to need cleaning.
Truth, but the original post was talking about a space station, which in my mind I was envisioning a BIG station (you know, the kind they said we'd be vacationing on in the year 2000), but you're absolutely right that a smaller object is under no threat whatsoever.
I was not being sufficiently clear in my explanation. Sorry for that.
I think my second point is still relevant, though. :-)
Jail probably isn't a stern enough punishment for that abomination.
What the old saw? An eye for an eye? Well, I just lost the use of two of them.
You cannot likely orbit something 10 miles above the lunar surface. Tidal stress on the orbiting body would likely render it apart, unless it was made of some really tough material.
Also, your margin of error is nonexistent if you pick up some unexpected impulse. It would be insane to live on something orbiting 10 miles over the moon.
The formula for escape velocity is Ev = sqrt((2*G*m)/r). Given the moon's mass and radius, we have to be certain your hypothetical rail gun has enough oomph to even achieve escape velocity.
In MKS, G is 6.67e-11 m^3/kg-s^2, the mass of the moon is 7.349e22 kg and the radius is 1.736e6 m. Plug and chug gives us about 2.4 km/sec from the moon's surface. So, it would be feasible as long as the direction of launch is within about 41 degrees of zenith (acos(theta) = (V/Ev)).
The problem of accurately striking the earth remains a three-body problem, though it's easier to approximate since the projectile mass is insignificant next to the mass of the earth and moon. There is no neat numerical answer to flight time, since there are a variety of paths that could be used to reach the earth, in addition to some trajectories that would never get you to earth. You could also put things into lunar orbit, earth orbit, or leave the earth-moon system entirely. The escape velocity of earth at the moon's perigee is about 1.4 km/s.
So, no matter how motivated one could be, the correct answer to your problem is "not enough information to answer".
Just to put the kinetic strike weapon concept to bed for now, accurate strikes would be a difficult problem to solve at best, especially since there's no mid-course correction available. Vagaries of the system's gravitation, perturbation by other celestial bodies, and atmospheric contact would all work together to increase the uncertainty of the problem.
Now, that railgun has some real potential to launch guided spacecraft cheaply (well, once the cost of construction has been amortized!), but as an unguided weapons platform, it's not too useful. Now, if you *could* accelerate something to .5c like the grandparent post suggested, you're onto something.
Oh, but he was creative. He just made that up!
Or watch an 11 month old baby walk in a similar fashion. They have to concentrate on it because it's new to them.
Give this guy more time to practice and the neurons will learn how to deal with it. The interface is there and is good, it just needs human practice.
Not any kind of women I'd like to be around. My wife, bless her soul, can change oil, gap and replace spark plugs, flush and fill the radiator and even replaced a water pump on one car.
I wonder if when this car has a problem if a squeaky little voice comes out of the dash saying "cars are hard! Let's go shopping!" This just further backs my opinion that the worst discriminators against women are usually other women.
I'll bet my wife could kick these designers' asses, too.
The best part of that search is all the ads on the right for companies that promise to improve your search engine ranking, but yet do not appear in the first few pages of the search itself.
Does this immediately disqualify them?
You see an event like this and wonder "why didn't my high school do this when I was there?" only to realize that the event didn't exist yet when you were in high school.
Those researching inertial electrostatic fusion hypothesize that IEF reactors could hypothetically create an electron flux using aneutronic fusion reactions. This electron flux could be tapped to produce current, without heating things with neutron bombardment.
I wish them luck, because for some reason it really disturbs my sense of aesthetics to create a power source that mimics the very stars and then take that power and run a good old 19th century steam turbine to get electrical power.
Precisely.
Also, let us not forget that working on one's own car is quite a hackish thing to do, and there's a bunch of personality overlap between car mechanics and computer geeks: the sheer joy of tinkering with something, obsessing and arguing over arcane details nobody else really cares about, Holy wars (Ford/Chevy or Windows/MacOS), and an independent streak that means we don't like to be pushed around by anyone, but especially by whimpering litigious nancy boys.
I wonder how many of us would have become full-time mechanics if computers had never been invented. Heaven knows I enjoy ripping into car engines on the weekends.
Answer: it shouldn't be diverted at all. By the time the asteroid arrives, the Earth has also moved in its orbit out of the way of the asteroid that was originally headed straight for its center.
The real solution is much more complicated, as it is a three body problem (Sun, Earth, asteroid) that must also take into account perturbations by other celestial bodies (Jupiter for sure, probably the inner planets and Earth's moon as well) for the kind of accuracy you would need for such a propulsion system. This solution requires a lot more ephemerides, and even a pre-Netwonian mechanics linear model would at a minimum require the magnitude of the velocity (speed) of the asteroid.
333, the mark of the semiantichrist.
Because it takes 2000 years of work to make one, and nobody's started on it yet.
Personally, I think that the registered .* offenders lists, and DUI plates are a bad idea. If this person is still a danger to the community, that what the hell are they doing still free? Lock them up, or let them be.
because of the principle of unintended consequences. Now, there are laws that state that a publicly-traded company's board and executives must to their best to maximize shareholder revenue, which on the surface sounds like a nice anti-fraud idea.
The practice of it is corporations do relatively little basic scientific R&D anymore, and lay off masses of people at the first sign of financial difficulty.
I even remember the TV ads Bell Labs ran when that discovery was made (I'm telling my age a bit, I'm sure). Nowadays, if they crowed about it, the board would probably be up on charges of securities fraud because they were working on "pie-in-the-sky" abstractions and not figuring out how to integrate yet another toy function into a cell phone.
Erm, sure, let just use code I wrote for employer A and put in in employer B's code. I'm sure they won't mind. And of course, every data structure is identical, so there's no need to write this but once. And also of course, I've never had to develop a library that manipulates a linked list. I also have the luxury of only working on code that's perfectly designed.
Sorry, but if "p = head; while (p != NULL) { if (p->somevalue == looking_for) return p; p = p->next;} return NULL;" is a big mystery to you, then you've learned the concept of "abstraction" a little too well.
What's even funnier is this line is in a function br_get_port, which just traverses a linked list looking for a certain value. Even if the whole damn function was a duplicate, this sort of code is such an idiomatic C expression, it's like trying to claim ownership to any conversation that contains "How are you?" "Fine".
I've written functions like this myself dozens if not hundreds of times. I guess I owe SCO for every linked list I've ever written in C.
Yes, we could. Write your congressman and say you want future Mars lander and rover missions to have more ground systems funding and to fend off the eco-wackos and install RTGs on them.
And by the way, we could put together another MER mission for about 200 million per rover now, since a big chunk of theat 800 million was R&D for the two we have.
Also, I just watched "Hackers" with Angelina Jolie and Matthew Lillard and I finally have a clear idea what these hackers are about and how they break into mainframes.
But I've got a deal for you. For just 49.95 you can name that diamond after your significant other!
You wil receive an official seal and I will register my documents stating that the rock is named after your sweetie at the US Copyright office!
Dear Lord, we are doomed.
The top picture, while very cool and very accurate, is not actually a picture taken directly by the orbiter. Since they take stereo pictures, it is a straightforward task to recompute a new picture from a different angle.
I've seen martian pictures done like this before, but always it was composites with different instruments, like MOC (Mars Orbital Camera) or THEMIS (Thermal Emission Imaging Spectrometer) to provide the visual component and MOLA (Mars Orbital Laser Altimeter) giving the third dimension data.
Still, it's impressive as hell, and from a science standpoint will have geometric effect on the knowledge we've gained from the MGS and Odyssey orbiters. I hope Express has many years of good observations, and I look forward to ESA and NASA continuing the exploration of Mars. It's definitely a step in the right direction.
My card is actually in the name of "Arthur Dent", who has a nonexistent address and phone number. I was at an SF con some years back and a group of us agreed to do this.
I'd dearly love to know what Arthur Dent's consumer profile looks like right now. Just trying to stock up on stuff before the Vogon Constructor Fleet arrives, I suppose.