So Phong is "right" for the probe, because it incidentally matches what they're seeing better?
You should not treat this question as though it is a rhetorical. You should treat it as though it is an actual question to which you do not know the answer. And then go find out the answer, if it bothers you so much.
Not so. Since I heard about it, I've allowed the possibility that Newtonian/relativistic physics may have some inaccuracies at very large scales,
"Allowed" is what most physicists have done, though the most likely scenario was always considered to be that there was a mundane explanation. "Latched on to" is what crackpots have done, and will continue to do. Because they're trying to overturn all of physics, and "some inaccuracies" still means the existing theory is pretty good and predicts a great many things correctly. But they want to somehow undo all of that with one unexplained thing that the theory doesn't predict.
I'm not going to place any 300-year bets that our current understanding of physics is Correct(tm).
You and every scientist in existence, since they know it isn't Correct(tm) already. Why did you think that was even relevant to bring up? Do you think there is, or for some reason that I was creating, a false dichotomy between idiots trying to overturn physics without understanding it, and current theory being indubitably correct?
An ion engine needs a source of energy and reaction mass. It's a very efficient use of reaction mass, but nevertheless. So for the same energy source, you can thrust longer with a photon drive.
Massive thrust is not the point of a photonic drive because they suck at it. Ion drives aren't great at thrust either, but they do have more. So it depends on the particular application which one would be better, though I think for most things we're doing in the near term ion drives are better.
Yes, he said "at least it wasn't the Greeks", because of how often he finds out that something he thought was novel was discovered by them. Which would be 2000 years ago. Merely 300 years ago is better. Thus "at least it wasn't the Greeks".
Exactly. Photons have the worst case energy/momentum ratio. The advantage of photon drives is not energy efficiency (because they're completely the opposite), it's that you don't need reaction mass.
So if you only need minute amounts of thrust, and have some long-lasting but light-weight source of energy (like an RTG), you can thrust basically forever.
Well and every crackpot trying to overturn all of modern physics/cosmology without understanding it first. The number of times I've heard the Pioneer Anomaly brought up as evidence that modern physics was fundamentally broken and the Scientific Clergy refused to admit it is... very large. I think I've even heard EU morons claiming that their plasma cosmology explained the Pioneer Anomaly.
Of course nobody who latched on to the anomaly will be satisfied by this explanation. So it goes...
Or it could be they just had a good PR campaign...6 month designed operational life, I though I heard it was only 3? What does that even mean from a design standpoint? You can guess, but nobody knows for sure except them and the marketing dept. I say good job there, cause unfortunately in today's world NASA needs good PR.
Bullshit. Everyone paying attention knows.
The original 90 mission time frame was always about exactly one thing: The estimated amount of time before dust buildup on the solar panels would prevent them from receiving enough sunlight to power the rover.
What does that mean from a design standpoint? It means they had to decide whether to try to make some solar-panel-cleaning mechanism and pay the cost in money, weight, and chance of failure, or to just let the rovers die. They went with die.
Everything else on the rover was engineered as robustly as possible because it had to survive on another freaking planet with no possibility of maintenance, and the 90 day mission time frame was never intended to imply otherwise.
NASA was quite up-front about this from the beginning, and also quite up-front when their faulty assumption on dust build up turned out to be wrong and the hypothetical mission time frame was blown (get it? cus it was the Martian wind which cleaned the panels) wide open.
It's only people who don't know about this who assume the rovers were for some reason expected to break, yet survived anyway, who retroactively deduced this was some kind of deliberate marketing scheme to make NASA look good.
Of course it's going to be additional -- they're doing it to increase revenue, and protect revenue as more and more vehicles use less and less gas. It's still going to be a trivial factor in comparison to the rising price of gas for service industries.
You're in denial if you think otherwise. Searching for something to be scared of that's hypothetical and in the future, rather than the truly frightening price at the pump you're paying right now. No politician can get away with raising the tax as fast as the law of supply and demand, which is never up for election, is going to raise gas prices. And you know it.
without RTFA:-D, by interstellar space do you mean out of the solar system? that would seem to take more energy than sending it down a gravity well wouldn't it? (ignore the earth launch costs obviously for now)
Yeah, he means it's easier to achieve escape velocity for the solar system than to slow down enough to hit the sun.
If you could somehow place an object in space so that it was stationary with respect to the sun, then you would be correct and the object would naturally just fall into the sun.
But the earth is moving at 30 km/s perpendicular to the sun, so to get that object to be stationary, when launched from the earth, you need to add 30 km/s of delta-v.
Escape velocity for the solar system, on the other hand, is 42 km/s if you start at earth's distance from the sun. Which is only 12 kms/s faster than earth itself is already traveling. So that's actually easier.
If we can ever apply 30 km/s of delta-v to objects cheaply enough that we're considering doing it for our garbage, I'd like to think that we can 1) find better things to do with that delta-v and 2) find better things to do with our garbage, like recycle it since the energy cost is obviously no longer a concern.
You're concluding that he's more advanced in physics than math, because the physics described doesn't use advanced math.
I'd say it's exactly because the journalist doesn't know what they're writing about that no math more advanced than calculus is mentioned, and relativity and QM were name-dropped. However you don't need to know any math to correctly report that someone is taking graduate-level math, so that statement is likely to be correct.
I'm no astrophysicist, just a lowly programmer with a background in engineering physics, but I thought it was pretty much the standard (and understood by all) that carbon and anything heavier was produced by the stars? And I'm pretty sure I knew that by 12....
Um yes and he knows that too; he says so in another part of the quote. He's not saying the big bang predicts too much carbon too soon.
What he's saying is that it would take too long from the birth of the universe for sufficient carbon to be formed in stellar fusion for enough of it to be here in time to form earth. Thus "wouldn't there have to be some sort of carbon?" or "We'd have to be 21 billion years old . . . and that would just screw everything up."
I've heard observations like this before, along with cosmologists saying that there are theoretical explanations. I'm betting what others said is right -- he's not on to as much as he thinks, and not the first to think of this. But I'm willing to give him some credit.;)
There is a big gap between calculus-based physics and graduate level math--at least serious graduate level math.
Indeed there is, and for someone who is obviously taking a very non-traditional curriculum, there's nothing that odd about being at very different stages in two subjects, even related ones. For example I took college-level calculus when I was also taking HS freshman biology, for a not particularly noteworthy example.
My interpretation is the kid is more advanced at math than he is at physics. Nothing unusual about that.
I agree with previous posters that the subtext of the quotes of the letter from Prof. Tremaine is "I want to encourage you, but, aside from your age, your ideas are unremarkable at my level of physics."
Yes, it does sound that way. Heh, well, hopefully he stays interested.
Excluding the only disaster to ever occur at a reactor that did not have any kind of containment vessel is the only rational way to discuss the risks of reactors operating today.
It'd be like talking about the dangers of vehicles on the road today, which does include older cars with fewer safety features, but including a freakishly stupid car that was once built that had tanks filled with nitroglycerin attached to its exterior. Literally everyone recognizes that it was ridiculously retarded to ever build one that way, nobody would ever build another one, and there are no such cars remaining on the road. The relevance to real danger is zero.
Note that a Chernobyl-free discussion still includes a whole gamut of human error, flawed reactor designs, and other things we can rationally talk about. But all relevant reactors -- including TMI and Fukushima -- include containment vessels. It's the simplest, most brain-dead, obvious ultimate back-up plan for reactor safety. Even really old, outdated reactors are using them. And the benefits, when comparing Chernobyl to every other disaster, are obvious.
So yes. Excluding that disaster is the only reasonable way to talk about the dangers of nuclear power today.
I am not 100% sure how having a bigger particle accelerator peen is that much better
Okay, let me spell it out for you in terms having nothing to do with the size of America's wang (and how did Florida enter the conversation anyway?):
A particle accelerator 3 times as powerful as the design spec for the LHC, 15-20 years earlier.
It's not about pride, it's about physics. Physics that requires high energies to explore. We're still waiting for the LHC to answer questions that we could have answered over a decade ago, and there are other questions the LHC can't answer which the SSC could have.
Instead, here we are in 2011, still waiting to find out if a fundamental prediction of our current physics will be borne out or if we need to rework it entirely. Just like we have been for decades.
Dude, that's just the decoy ruin. The real SSC was built nearby, but far enough away that anyone looking for the known SSC site wouldn't see the people going in and out of the real site!
Do you have a clue as to how this will hurt service businesses such as plumbers and HVAC service people?
Yes. Vastly less than the rising price of gas is and will.
You are essentially saying that the cost of transportation is relevant to these service industries (no duh), but acting like a mileage tax is the only thing affecting it. This is ridiculous especially when talking about contractors, who are some of the few people who basically need fuel-inefficient trucks to haul their equipment.
All the soccer Moms can trade in their Excursions and Escalades for electric vehicles, and then their mileage tax may be a big portion of their transportation cost.
But for the contractor with an AC unit in the bed of their pickup, which do you think is going to matter more: The mileage tax, or the price of gas doubling? And for freaking semi trucks? Forget about it!
All these industries have already been affected by rising gas prices more than a mileage tax will. And the price of gas is only going to go up. That is what is going to put a large hit on the economy.
Which, to my mind, is exactly why everyone who doesn't need a fuel-inefficient vehicle needs to stop fucking using them so as much of the remaining fuel will be available for those who do need it. It's not very realistic to think the demand could be reduced to make the price of gas go down, but hopefully it can at least keep the increase in check.
One of the bits that really struck that home to me was the first episode (I think) where Serenity drops from space into a planet's atmosphere, and suddenly you can hear the roar of the engines. It's possibly a little too sudden, but I think we can handwave that by saying the ship was dropping pretty quickly.
Or handwave it by saying it's still basically right yet dramatically effective. I mean, I don't know how fair you'd have to be in an atmosphere before you could hear sound, nor how fast the ship was falling, so yeah, plus-or-minus my ignorance it works.:)
Heck if we did decide we were going to nitpick the accuracy, there's also a scene in that episode where Serenity and the Reaver ship slooooooowly pass each. Wedon himself admitted it didn't really make any sense .:)
Slashdot Mirror
Of course he's the real Randal Stallman!
So Phong is "right" for the probe, because it incidentally matches what they're seeing better?
You should not treat this question as though it is a rhetorical. You should treat it as though it is an actual question to which you do not know the answer. And then go find out the answer, if it bothers you so much.
From your response, I think your usage meant, "this proves all of physics is wrong."
My response, and the very first sentence of my first post. :P
But I'm glad we understand each other now.
Not so. Since I heard about it, I've allowed the possibility that Newtonian/relativistic physics may have some inaccuracies at very large scales,
"Allowed" is what most physicists have done, though the most likely scenario was always considered to be that there was a mundane explanation. "Latched on to" is what crackpots have done, and will continue to do. Because they're trying to overturn all of physics, and "some inaccuracies" still means the existing theory is pretty good and predicts a great many things correctly. But they want to somehow undo all of that with one unexplained thing that the theory doesn't predict.
I'm not going to place any 300-year bets that our current understanding of physics is Correct(tm).
You and every scientist in existence, since they know it isn't Correct(tm) already. Why did you think that was even relevant to bring up? Do you think there is, or for some reason that I was creating, a false dichotomy between idiots trying to overturn physics without understanding it, and current theory being indubitably correct?
An ion engine needs a source of energy and reaction mass. It's a very efficient use of reaction mass, but nevertheless. So for the same energy source, you can thrust longer with a photon drive.
Massive thrust is not the point of a photonic drive because they suck at it. Ion drives aren't great at thrust either, but they do have more. So it depends on the particular application which one would be better, though I think for most things we're doing in the near term ion drives are better.
Yes, he said "at least it wasn't the Greeks", because of how often he finds out that something he thought was novel was discovered by them. Which would be 2000 years ago. Merely 300 years ago is better. Thus "at least it wasn't the Greeks".
Got it now?
Exactly. Photons have the worst case energy/momentum ratio. The advantage of photon drives is not energy efficiency (because they're completely the opposite), it's that you don't need reaction mass.
So if you only need minute amounts of thrust, and have some long-lasting but light-weight source of energy (like an RTG), you can thrust basically forever.
Notice how in that sentence he was talking about the Greeks.
Well and every crackpot trying to overturn all of modern physics/cosmology without understanding it first. The number of times I've heard the Pioneer Anomaly brought up as evidence that modern physics was fundamentally broken and the Scientific Clergy refused to admit it is... very large. I think I've even heard EU morons claiming that their plasma cosmology explained the Pioneer Anomaly.
Of course nobody who latched on to the anomaly will be satisfied by this explanation. So it goes...
Or it could be they just had a good PR campaign...6 month designed operational life, I though I heard it was only 3? What does that even mean from a design standpoint? You can guess, but nobody knows for sure except them and the marketing dept. I say good job there, cause unfortunately in today's world NASA needs good PR.
Bullshit. Everyone paying attention knows.
The original 90 mission time frame was always about exactly one thing: The estimated amount of time before dust buildup on the solar panels would prevent them from receiving enough sunlight to power the rover.
What does that mean from a design standpoint? It means they had to decide whether to try to make some solar-panel-cleaning mechanism and pay the cost in money, weight, and chance of failure, or to just let the rovers die. They went with die.
Everything else on the rover was engineered as robustly as possible because it had to survive on another freaking planet with no possibility of maintenance, and the 90 day mission time frame was never intended to imply otherwise.
NASA was quite up-front about this from the beginning, and also quite up-front when their faulty assumption on dust build up turned out to be wrong and the hypothetical mission time frame was blown (get it? cus it was the Martian wind which cleaned the panels) wide open.
It's only people who don't know about this who assume the rovers were for some reason expected to break, yet survived anyway, who retroactively deduced this was some kind of deliberate marketing scheme to make NASA look good.
Here's a link with more info about the rover's lifespan, panels being cleaned by dust devils, and mechanical problems
Here's a link from before the rovers were launched clearly discussing the significance of the 90 day mission time.
And here's one from cornell from not long after the mission was extended: http://www.news.cornell.edu/releases/rover/Rover.ops.to.html
Of course it's going to be additional -- they're doing it to increase revenue, and protect revenue as more and more vehicles use less and less gas. It's still going to be a trivial factor in comparison to the rising price of gas for service industries.
You're in denial if you think otherwise. Searching for something to be scared of that's hypothetical and in the future, rather than the truly frightening price at the pump you're paying right now. No politician can get away with raising the tax as fast as the law of supply and demand, which is never up for election, is going to raise gas prices. And you know it.
without RTFA :-D, by interstellar space do you mean out of the solar system? that would seem to take more energy than sending it down a gravity well wouldn't it? (ignore the earth launch costs obviously for now)
Yeah, he means it's easier to achieve escape velocity for the solar system than to slow down enough to hit the sun.
If you could somehow place an object in space so that it was stationary with respect to the sun, then you would be correct and the object would naturally just fall into the sun.
But the earth is moving at 30 km/s perpendicular to the sun, so to get that object to be stationary, when launched from the earth, you need to add 30 km/s of delta-v.
Escape velocity for the solar system, on the other hand, is 42 km/s if you start at earth's distance from the sun. Which is only 12 kms/s faster than earth itself is already traveling. So that's actually easier.
Counter-intuitive, no? But so it goes.
If we can ever apply 30 km/s of delta-v to objects cheaply enough that we're considering doing it for our garbage, I'd like to think that we can 1) find better things to do with that delta-v and 2) find better things to do with our garbage, like recycle it since the energy cost is obviously no longer a concern.
Yeah. The people predicting that plants could fail like this are called nuclear advocates.
"Cynical jaded type"? Come on! All you have to do is to keep your eyes open for a while to see that this is indeed typical behavior.
Cynicism is just realism plus experience.
You're concluding that he's more advanced in physics than math, because the physics described doesn't use advanced math.
I'd say it's exactly because the journalist doesn't know what they're writing about that no math more advanced than calculus is mentioned, and relativity and QM were name-dropped. However you don't need to know any math to correctly report that someone is taking graduate-level math, so that statement is likely to be correct.
I'm no astrophysicist, just a lowly programmer with a background in engineering physics, but I thought it was pretty much the standard (and understood by all) that carbon and anything heavier was produced by the stars? And I'm pretty sure I knew that by 12....
Um yes and he knows that too; he says so in another part of the quote. He's not saying the big bang predicts too much carbon too soon.
What he's saying is that it would take too long from the birth of the universe for sufficient carbon to be formed in stellar fusion for enough of it to be here in time to form earth. Thus "wouldn't there have to be some sort of carbon?" or "We'd have to be 21 billion years old . . . and that would just screw everything up."
I've heard observations like this before, along with cosmologists saying that there are theoretical explanations. I'm betting what others said is right -- he's not on to as much as he thinks, and not the first to think of this. But I'm willing to give him some credit. ;)
There is a big gap between calculus-based physics and graduate level math--at least serious graduate level math.
Indeed there is, and for someone who is obviously taking a very non-traditional curriculum, there's nothing that odd about being at very different stages in two subjects, even related ones. For example I took college-level calculus when I was also taking HS freshman biology, for a not particularly noteworthy example.
My interpretation is the kid is more advanced at math than he is at physics. Nothing unusual about that.
I agree with previous posters that the subtext of the quotes of the letter from Prof. Tremaine is "I want to encourage you, but, aside from your age, your ideas are unremarkable at my level of physics."
Yes, it does sound that way. Heh, well, hopefully he stays interested.
Excluding the only disaster to ever occur at a reactor that did not have any kind of containment vessel is the only rational way to discuss the risks of reactors operating today.
It'd be like talking about the dangers of vehicles on the road today, which does include older cars with fewer safety features, but including a freakishly stupid car that was once built that had tanks filled with nitroglycerin attached to its exterior. Literally everyone recognizes that it was ridiculously retarded to ever build one that way, nobody would ever build another one, and there are no such cars remaining on the road. The relevance to real danger is zero.
Note that a Chernobyl-free discussion still includes a whole gamut of human error, flawed reactor designs, and other things we can rationally talk about. But all relevant reactors -- including TMI and Fukushima -- include containment vessels. It's the simplest, most brain-dead, obvious ultimate back-up plan for reactor safety. Even really old, outdated reactors are using them. And the benefits, when comparing Chernobyl to every other disaster, are obvious.
So yes. Excluding that disaster is the only reasonable way to talk about the dangers of nuclear power today.
What will President Schwarzenegger be blamed for?
Well, terminators is the obvious answer, but I'm blaming him for his predecessor, President DeVito.
That's why I always blame future presidents.
And our current economic crisis, not to mention the loss of the SSC, are clearly the fault of President Bieber!
I am not 100% sure how having a bigger particle accelerator peen is that much better
Okay, let me spell it out for you in terms having nothing to do with the size of America's wang (and how did Florida enter the conversation anyway?):
A particle accelerator 3 times as powerful as the design spec for the LHC, 15-20 years earlier.
It's not about pride, it's about physics. Physics that requires high energies to explore. We're still waiting for the LHC to answer questions that we could have answered over a decade ago, and there are other questions the LHC can't answer which the SSC could have.
Instead, here we are in 2011, still waiting to find out if a fundamental prediction of our current physics will be borne out or if we need to rework it entirely. Just like we have been for decades.
Dude, that's just the decoy ruin. The real SSC was built nearby, but far enough away that anyone looking for the known SSC site wouldn't see the people going in and out of the real site!
Do you have a clue as to how this will hurt service businesses such as plumbers and HVAC service people?
Yes. Vastly less than the rising price of gas is and will.
You are essentially saying that the cost of transportation is relevant to these service industries (no duh), but acting like a mileage tax is the only thing affecting it. This is ridiculous especially when talking about contractors, who are some of the few people who basically need fuel-inefficient trucks to haul their equipment.
All the soccer Moms can trade in their Excursions and Escalades for electric vehicles, and then their mileage tax may be a big portion of their transportation cost.
But for the contractor with an AC unit in the bed of their pickup, which do you think is going to matter more: The mileage tax, or the price of gas doubling? And for freaking semi trucks? Forget about it!
All these industries have already been affected by rising gas prices more than a mileage tax will. And the price of gas is only going to go up. That is what is going to put a large hit on the economy.
Which, to my mind, is exactly why everyone who doesn't need a fuel-inefficient vehicle needs to stop fucking using them so as much of the remaining fuel will be available for those who do need it. It's not very realistic to think the demand could be reduced to make the price of gas go down, but hopefully it can at least keep the increase in check.
One of the bits that really struck that home to me was the first episode (I think) where Serenity drops from space into a planet's atmosphere, and suddenly you can hear the roar of the engines. It's possibly a little too sudden, but I think we can handwave that by saying the ship was dropping pretty quickly.
Or handwave it by saying it's still basically right yet dramatically effective. I mean, I don't know how fair you'd have to be in an atmosphere before you could hear sound, nor how fast the ship was falling, so yeah, plus-or-minus my ignorance it works. :)
Heck if we did decide we were going to nitpick the accuracy, there's also a scene in that episode where Serenity and the Reaver ship slooooooowly pass each. Wedon himself admitted it didn't really make any sense . :)
I think you're right about the engine hum thing.