Yes, I'm far more cognicent of potential energy than you can possibly know. What you're not thinking about is that when something goes wrong with explosives, there isn't time to compensadte. If your re-enty goes pear-shaped, you don't get smacked with ALL of the potential energy at once and you have some home of ajusting your plan.
Also, gravitational potential energy has to first turn into kinetic energy before it can kill you. It's easy dump kinetic energy as heat (parachute, drag on the craft, those little pinwheels held outside the spacecraft, etc.) and KE isn't, by itself, dangerous. (It's that stop at the end that you need to be thinking about.) With an explosion, a lot of the energy is inherently heating you and your craft. It's hard to harmlessly dissipate the energy of a fireball inside the craft or the energy of suddenly-expanding gases inside the craft. The inherent nature of both is to kill you, while KE is pretty indifferent to your survival.
No, the Chinese were quite adventurous during Europe's Middle Age. They were exploring the Indian Ocean as far as the Cape of Good Hope. But a change of leadership brought a change of policy. My understanding is that they exploration wasn't yeilding enough immediate benefits, so they basically cancelled it. Leaving the Europeans free to explore and profit later.
Yeah, but Apollo 13 kind of shows how much easier it is to recover from accidents once in space. All three astronauts survived *that* mishap. I can't think of any equivelently serious malfunction while launching or landing that didn't kill the crew.
(Also, note how many probes have had glitches while cruising in space and recovered versus how many have recovered from take-off or landing mistakes.)
Eh, not entirely. Like with aircraft, the most dangerous bit tends to be launch and landing. (Note that of the three cases of fatalities, one was on the launch pad (for a test, but I'd say it still is indicative), one was just after launch, and the final was on landing.) Landing tends to be most coasting/parachuting, which is relatively easy to do right. In fact, you can make it very safe by clever design of the module. (I believe that the Mercury and Apollo capsules were actually designed to always tend to re-enter in the correct orientation.)
Launch is more dangerous in some ways if only because you've got X tons of very flammable (dare I say explosive?) materials under your butt. A slip-up there will tend to be much harder to fix or escape from.
The following is a statement from NASA Administrator Sean O'Keefe about China's first successful human space flight.
"This launch is an important achievement in the history of human exploration. China, after Russia and the United States, is only the third nation to successfully launch humans into space.
"The Chinese people have a long and distinguished history of exploration. NASA wishes China a continued safe human space flight program.
What their real response (measure in actions, not press-relases) remains to be seen, of course.
I don't think Mileva had a lot of effect on GR. She and Albert divorced in 1914 (a year before GR was finally published) and their relationship was on the rocks for a while before that. It's possible that she had some effect, but I've never heard of any definate mention of it. (If she did provide input, Albert was likely the only one who knew. It's not very like him to not give due credit, but it's still possible that she helped.)
As to SR, Einstein was the first person to really cast off Newtonian physics. Poincare had stated a sort of primative version of the relativity principle, but he was still trying to be Newtonian with absolute space and time. So were Lorentz and Fitzgerald. In fact, the latter pretty much just assumed the length contraction equation to explain the Michelson-Morley experiment, rather than deriving it from first principles as near as I can tell.
Einstein abondoned absolute space and time, speculated that light's speed (in a vacuum) was constant for all observers (this was based on a Zeno-like argument, leveraging off of Maxwell's equations), and went to town from there. It isn't even clear that Einstein knew of the others' work, particular Poincare's, who published in 1904, just one year before Einsteins "Miracle Year". (It isn't even clear that Einstein knew about the Michaelson-Morley experiment. His motivation seems to have been more based on Maxwell's equations and the behavior of light.) Einstein later knew of the work of Lorentz, to be sure: he refers to the transformations that Lorentz postulated as "Lorentz Transformations" everywhere in his own books on relativity.
SR was definately in the air, so to speak, around 1905, and several people were nosing around the right idea, but Einstein was the first to really cast aside the old, Newtonian notions and seize the new idea for all that it was worth. If Einstein hadn't gotten there, someone else probably would have within another few years. (Similarly, the (probably) independent invention of the calculus by Newton and Leibinitz and the co-discovery of the theory of evolution by Darwin and Wallace. Very often, solutions to vexing problems are ripe for the plucking, and the person who gets there first was just particularly nimble-witted or lucky.) So in a sense, his contribution to SR wasn't *that* critical, but he definately did the work. As I said, GR is an entirely different matter. Einstein started with one "happy thought" and really went crazy with it.
If you know enough science history to know those names, you should know enough to know that your conclusion simply isn't true. Other had bandied about some of the ideas of SR before Einstein made his entry to the scene. (Hell, even Maxwell's equations implicitly include SR in them.) But Einstein was the first to really integrate it all together and get all of the necessary pieces in place. Einstein was never remotely shy about giving credit to those who proceeded him, but it's still agreed that the theory is as much his as anyone else's. If Einstein hadn't done it, someone else would have undoubtly would have. Unlike GR, which was entirely his baby. He had to get help with the mathematics, which was way beyond his own skills, but the theory itself was entirely due to him. It's unclear whether someone else would have proposed the same theory and, if so, when. But GR is most *definately* Einstein's brain-child, despite what you've been told.
No, I'm saying that you need to respect other people's opinions about what is right or wrong and not assume that you have the sole window on morality.
The folks in Sweden have been asked to award the Nobels each year. Someone not only invested them with the power to decide, but trusted them to decide wisely. Unfortunately, given the paucity of awards, it will always be unfair to many people who don't get Nobel Prizes. However, I'd cut them some slack and give them the benefit of the doubt. Start by assuming that they're doing the best that they can, and that perhaps you're personal opinions might not be the only ones worth holding.
I'm not. I'm saying you should consider that their point of view might be every bit as valid as yours and that you aren't the final arbiter of what is morally correct and what isn't.
Yeah, there's a limit to how far you want to go with it. But certainly when you give the prize to a team with a now-deceased member it seems fitting that that person still be recognized. And there is no reason why someone who died recently before s/he could be awarded shouldn't be allowed to be honored. It would be up to the committee to decide how far to go with it, just like it is up to them who they want to honor out of the many, many worth scientists/writers/activists/etc.
Yeah, my fault. I'd forgotten about that. Which absolves the academy for not awarding her. However, it raises another point: is it fair to ignore people who have had the misfortune to die (especially those that died young) before someone got around to nominating them for a Nobel? Granted, the money does them little good, but they could still be awarded. It would probably mean a lot to their families and collegues. (There are other cases of people dying before they should have gotten a Nobel. Henry Moseley, killed in action in the First World War, is a standard example.)
In any event, the point remains: the Nobel Prize isn't awarded based on popular view or even by vote amount the international scientific community. It's awarded by a small subsection based on criteria that they choose/were given. So, no, it isn't always what you or I would call fair, but them's the rules we were given and we don't get to change 'em.
And they evidently think that they're doing the right thing, morally speaking. Just because you disagree doesn't mean that they're necessarily wrong and that we should all listen to you.
So I ask you again, where do you get off telling them what to do with their prizes?
And yet many physicists have recieved Nobels for quantum mechanics or related areas (one of which was handed to Neils Bohr at the same ceremony where Albert got his for the photoelectric effect), which have even less application that relativity.
For that matter, the discovery of pulsars netted a Nobel for Hewish and Bell. Show me the application of *that* little beauty. And next, show me how detecting pulsar orbital decay (confirming general relativity) is applicable. And why *that* is more important than the original theory.
I'm not insulting the Nobel Prizes here. But one of the first things you figure out as a scientist is that the Nobel Prizes aren't really all that fair. For one thing, they only get awarded once a year, which severely limits how much that they can recognize. For another, they're being handed out by a small subsection of the community. It's something you just accept, and then move on with your life. Getting upset because you feel that you were cheated is unproductive and petty.
Why does someone have to keep their feet to the fire? It's private money bestowed upon people by a private organization. They can honor whomever they choose for any research they want to. If they want to leave someone out, well, that's their call. Why do you feel that you need to keep them on track?
Donate enough money to endow your own prize, then you can give it out in your own way. And you can get all the lovely complaints by loudmouts who feel that they are entitled to your money.
Not a crime, just pathetic. He doesn't want recognition, he's gotten that. He wants a specific prize and a money, evidently. Neither of which he has any claim on, beyond feeling that he's earned it.
History is full of examples of people who were overlooked for the Nobel Prize. (Rosalind Franklin, anyone? Heck, Einstein was never recognized with that award for his really major works: special and general relativity.) The prize isn't something people "earn" and it's not something that you're entitled to. It's something that one particular group of people decide to bestow upon you because you've done significant work in their view.
I personally know at least one person fairly well who was overlooked for a Nobel. (This in the view of most of his collegues. Having read the work in question, I tend to agree.) He's very mellow about it, rather praising his friends who did win the prize. To take out ads to bitch makes me suspect that this guy is stuck in the 4-year-old emotional stage. (Or he's greedy and he wants a cut of the $1 million. Either way, pathetic.)
Because if you open the criteria up too much, you end up having no clue what to look for and whether you've found it when you see it. We know how things work on Earth, so that's where we begin. Note that it isn't the *end* of the search, but just the start.
Very well put. However (and this is trivia, not a correction), I'm betting that they'll look not for molecular oxygen (O2), but ozone (O3). The latter has a much better spectroscopic signature since the former is a homonuclear diatomic (2 atoms of the same species) and therefore doesn't absorb a lot of light. And ozone is almost certainly around if any significant amount of molecular oxygen is present.
Given that GR has been more precisely tested (passing all tests) than any other theory, including QM, I'm not sure that "iffy" is really a good way to describe it. Especially since the incompatability could point to flaws in either theory (or both). Frankly, and I admit to being something of a heratic here, I'm more expecting QM to fall down before GR.
But that's what you are asserting: that they need to take GR into account. You'd better believe that you can show that that is the case (or not the case, either way). All *you* have to do (or them, to prove that they don't need GR) is to work out the GR correction from the Newtonian ephemeris for Cassini. You would have to show that it affects the position enough to significantly affect the measurement in question. They just need to show that the affect is too small to be important at their level of precision.
Actually, I doubt you need to factor in GR for that kind of accuracy. GR rapidly goes to Netowian mechanics as you move away from the Sun. Look at Mercury: the anomalous perihelion shift is 43 seconds of arc per *century*. Mercury itself will have orbited though more than 10 million times that angle in only one century. The GR correct, even there, is minute. Out between Jupiter and Saturn it isn't worth taking into account. NASA has guided several spacecraft out to that part of the solar system with very high accuracy without using GR.
Given all of that, I think it's up to you to show that they need to use GR to get this position. You're welcomed to show me the math and convince me that it matters. But until you do, you're just guessing, and guessing against the evidence at that.
Cassini is never near the Sun. The signal sometimes passes near the Sun, but Cassini never does.
Cassini is on a well-measured orbit far from the Sun. As I said, in this limit, Newtonian gravity is all you need to get the trajectory. (Newton agrees with GR, and no one doubts the validity of either in this regime)
Nice measurement, no doubt. But the article is a bit misleading. This isn't the most precise measurement of GR, just the most precise mesurement of this prediction. It sounds like they got this measurement to an error of one part per fifty thousand. If memeory serves, the measurements of the orbit on pulsar 1933+16 (the one that netted Taylor and Hulse the Nobel Prize about a decade ago) are precise to one part in something lik ten to the eleventh. And they agree with GR.
One some level it amazes me that GR passes every test we throw at it with such flying colors. On another level, I agree with Albert: the theory is too beautiful *not* to be true.
Presumably they did measure the distance: you can get the round-trip signal when the path to Cassini is far from the Sun. That, along with the fact that Cassini is itself far from any significant gravitational source means that it's easy to know exactly where Cassini is right now. (In this limit, Newton and Einstein are pretty much identical. You can argue that this theory is incorrect, but that's a pretty difficult argument to make, given how often it has worked quite well.)
So, no, they don't really need to use GR to get the distance.
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Yes, I'm far more cognicent of potential energy than you can possibly know. What you're not thinking about is that when something goes wrong with explosives, there isn't time to compensadte. If your re-enty goes pear-shaped, you don't get smacked with ALL of the potential energy at once and you have some home of ajusting your plan.
Also, gravitational potential energy has to first turn into kinetic energy before it can kill you. It's easy dump kinetic energy as heat (parachute, drag on the craft, those little pinwheels held outside the spacecraft, etc.) and KE isn't, by itself, dangerous. (It's that stop at the end that you need to be thinking about.) With an explosion, a lot of the energy is inherently heating you and your craft. It's hard to harmlessly dissipate the energy of a fireball inside the craft or the energy of suddenly-expanding gases inside the craft. The inherent nature of both is to kill you, while KE is pretty indifferent to your survival.
No, the Chinese were quite adventurous during Europe's Middle Age. They were exploring the Indian Ocean as far as the Cape of Good Hope. But a change of leadership brought a change of policy. My understanding is that they exploration wasn't yeilding enough immediate benefits, so they basically cancelled it. Leaving the Europeans free to explore and profit later.
Yeah, but Apollo 13 kind of shows how much easier it is to recover from accidents once in space. All three astronauts survived *that* mishap. I can't think of any equivelently serious malfunction while launching or landing that didn't kill the crew.
(Also, note how many probes have had glitches while cruising in space and recovered versus how many have recovered from take-off or landing mistakes.)
Eh, not entirely. Like with aircraft, the most dangerous bit tends to be launch and landing. (Note that of the three cases of fatalities, one was on the launch pad (for a test, but I'd say it still is indicative), one was just after launch, and the final was on landing.) Landing tends to be most coasting/parachuting, which is relatively easy to do right. In fact, you can make it very safe by clever design of the module. (I believe that the Mercury and Apollo capsules were actually designed to always tend to re-enter in the correct orientation.)
Launch is more dangerous in some ways if only because you've got X tons of very flammable (dare I say explosive?) materials under your butt. A slip-up there will tend to be much harder to fix or escape from.
NASA's offical response:
What their real response (measure in actions, not press-relases) remains to be seen, of course.
I don't think Mileva had a lot of effect on GR. She and Albert divorced in 1914 (a year before GR was finally published) and their relationship was on the rocks for a while before that. It's possible that she had some effect, but I've never heard of any definate mention of it. (If she did provide input, Albert was likely the only one who knew. It's not very like him to not give due credit, but it's still possible that she helped.)
As to SR, Einstein was the first person to really cast off Newtonian physics. Poincare had stated a sort of primative version of the relativity principle, but he was still trying to be Newtonian with absolute space and time. So were Lorentz and Fitzgerald. In fact, the latter pretty much just assumed the length contraction equation to explain the Michelson-Morley experiment, rather than deriving it from first principles as near as I can tell.
Einstein abondoned absolute space and time, speculated that light's speed (in a vacuum) was constant for all observers (this was based on a Zeno-like argument, leveraging off of Maxwell's equations), and went to town from there.
It isn't even clear that Einstein knew of the others' work, particular Poincare's, who published in 1904, just one year before Einsteins "Miracle Year". (It isn't even clear that Einstein knew about the Michaelson-Morley experiment. His motivation seems to have been more based on Maxwell's equations and the behavior of light.) Einstein later knew of the work of Lorentz, to be sure: he refers to the transformations that Lorentz postulated as "Lorentz Transformations" everywhere in his own books on relativity.
SR was definately in the air, so to speak, around 1905, and several people were nosing around the right idea, but Einstein was the first to really cast aside the old, Newtonian notions and seize the new idea for all that it was worth. If Einstein hadn't gotten there, someone else probably would have within another few years. (Similarly, the (probably) independent invention of the calculus by Newton and Leibinitz and the co-discovery of the theory of evolution by Darwin and Wallace. Very often, solutions to vexing problems are ripe for the plucking, and the person who gets there first was just particularly nimble-witted or lucky.) So in a sense, his contribution to SR wasn't *that* critical, but he definately did the work. As I said, GR is an entirely different matter. Einstein started with one "happy thought" and really went crazy with it.
If you know enough science history to know those names, you should know enough to know that your conclusion simply isn't true. Other had bandied about some of the ideas of SR before Einstein made his entry to the scene. (Hell, even Maxwell's equations implicitly include SR in them.) But Einstein was the first to really integrate it all together and get all of the necessary pieces in place. Einstein was never remotely shy about giving credit to those who proceeded him, but it's still agreed that the theory is as much his as anyone else's. If Einstein hadn't done it, someone else would have undoubtly would have. Unlike GR, which was entirely his baby. He had to get help with the mathematics, which was way beyond his own skills, but the theory itself was entirely due to him. It's unclear whether someone else would have proposed the same theory and, if so, when. But GR is most *definately* Einstein's brain-child, despite what you've been told.
Wow, you're argumentative. Cool off.
No, I'm saying that you need to respect other people's opinions about what is right or wrong and not assume that you have the sole window on morality.
The folks in Sweden have been asked to award the Nobels each year. Someone not only invested them with the power to decide, but trusted them to decide wisely. Unfortunately, given the paucity of awards, it will always be unfair to many people who don't get Nobel Prizes. However, I'd cut them some slack and give them the benefit of the doubt. Start by assuming that they're doing the best that they can, and that perhaps you're personal opinions might not be the only ones worth holding.
I'm not. I'm saying you should consider that their point of view might be every bit as valid as yours and that you aren't the final arbiter of what is morally correct and what isn't.
Yeah, there's a limit to how far you want to go with it. But certainly when you give the prize to a team with a now-deceased member it seems fitting that that person still be recognized. And there is no reason why someone who died recently before s/he could be awarded shouldn't be allowed to be honored. It would be up to the committee to decide how far to go with it, just like it is up to them who they want to honor out of the many, many worth scientists/writers/activists/etc.
Yeah, my fault. I'd forgotten about that. Which absolves the academy for not awarding her. However, it raises another point: is it fair to ignore people who have had the misfortune to die (especially those that died young) before someone got around to nominating them for a Nobel? Granted, the money does them little good, but they could still be awarded. It would probably mean a lot to their families and collegues. (There are other cases of people dying before they should have gotten a Nobel. Henry Moseley, killed in action in the First World War, is a standard example.)
In any event, the point remains: the Nobel Prize isn't awarded based on popular view or even by vote amount the international scientific community. It's awarded by a small subsection based on criteria that they choose/were given. So, no, it isn't always what you or I would call fair, but them's the rules we were given and we don't get to change 'em.
And they evidently think that they're doing the right thing, morally speaking. Just because you disagree doesn't mean that they're necessarily wrong and that we should all listen to you.
So I ask you again, where do you get off telling them what to do with their prizes?
And yet many physicists have recieved Nobels for quantum mechanics or related areas (one of which was handed to Neils Bohr at the same ceremony where Albert got his for the photoelectric effect), which have even less application that relativity.
For that matter, the discovery of pulsars netted a Nobel for Hewish and Bell. Show me the application of *that* little beauty. And next, show me how detecting pulsar orbital decay (confirming general relativity) is applicable. And why *that* is more important than the original theory.
I'm not insulting the Nobel Prizes here. But one of the first things you figure out as a scientist is that the Nobel Prizes aren't really all that fair. For one thing, they only get awarded once a year, which severely limits how much that they can recognize. For another, they're being handed out by a small subsection of the community. It's something you just accept, and then move on with your life. Getting upset because you feel that you were cheated is unproductive and petty.
Why does someone have to keep their feet to the fire? It's private money bestowed upon people by a private organization. They can honor whomever they choose for any research they want to. If they want to leave someone out, well, that's their call. Why do you feel that you need to keep them on track?
Donate enough money to endow your own prize, then you can give it out in your own way. And you can get all the lovely complaints by loudmouts who feel that they are entitled to your money.
Not a crime, just pathetic. He doesn't want recognition, he's gotten that. He wants a specific prize and a money, evidently. Neither of which he has any claim on, beyond feeling that he's earned it.
.... sad.
History is full of examples of people who were overlooked for the Nobel Prize. (Rosalind Franklin, anyone? Heck, Einstein was never recognized with that award for his really major works: special and general relativity.) The prize isn't something people "earn" and it's not something that you're entitled to. It's something that one particular group of people decide to bestow upon you because you've done significant work in their view.
I personally know at least one person fairly well who was overlooked for a Nobel. (This in the view of most of his collegues. Having read the work in question, I tend to agree.) He's very mellow about it, rather praising his friends who did win the prize. To take out ads to bitch makes me suspect that this guy is stuck in the 4-year-old emotional stage. (Or he's greedy and he wants a cut of the $1 million. Either way, pathetic.)
Because if you open the criteria up too much, you end up having no clue what to look for and whether you've found it when you see it. We know how things work on Earth, so that's where we begin. Note that it isn't the *end* of the search, but just the start.
Very well put.
However (and this is trivia, not a correction), I'm betting that they'll look not for molecular oxygen (O2), but ozone (O3). The latter has a much better spectroscopic signature since the former is a homonuclear diatomic (2 atoms of the same species) and therefore doesn't absorb a lot of light. And ozone is almost certainly around if any significant amount of molecular oxygen is present.
"General relativity remains iffy,"
Given that GR has been more precisely tested (passing all tests) than any other theory, including QM, I'm not sure that "iffy" is really a good way to describe it. Especially since the incompatability could point to flaws in either theory (or both). Frankly, and I admit to being something of a heratic here, I'm more expecting QM to fall down before GR.
"You must also precisely measure the distance, and you can't measure that without using Einstein's equations."
Sounds like you are asserting that to me.
In any event, this has become futile. You either don't understand, don't want to understand, or are simply trolling. In any case, I'm out of here.
But that's what you are asserting: that they need to take GR into account. You'd better believe that you can show that that is the case (or not the case, either way).
All *you* have to do (or them, to prove that they don't need GR) is to work out the GR correction from the Newtonian ephemeris for Cassini. You would have to show that it affects the position enough to significantly affect the measurement in question. They just need to show that the affect is too small to be important at their level of precision.
Actually, I doubt you need to factor in GR for that kind of accuracy. GR rapidly goes to Netowian mechanics as you move away from the Sun. Look at Mercury: the anomalous perihelion shift is 43 seconds of arc per *century*. Mercury itself will have orbited though more than 10 million times that angle in only one century. The GR correct, even there, is minute. Out between Jupiter and Saturn it isn't worth taking into account. NASA has guided several spacecraft out to that part of the solar system with very high accuracy without using GR.
Given all of that, I think it's up to you to show that they need to use GR to get this position. You're welcomed to show me the math and convince me that it matters. But until you do, you're just guessing, and guessing against the evidence at that.
Cassini is never near the Sun. The signal sometimes passes near the Sun, but Cassini never does.
Cassini is on a well-measured orbit far from the Sun. As I said, in this limit, Newtonian gravity is all you need to get the trajectory. (Newton agrees with GR, and no one doubts the validity of either in this regime)
Nice measurement, no doubt. But the article is a bit misleading. This isn't the most precise measurement of GR, just the most precise mesurement of this prediction. It sounds like they got this measurement to an error of one part per fifty thousand. If memeory serves, the measurements of the orbit on pulsar 1933+16 (the one that netted Taylor and Hulse the Nobel Prize about a decade ago) are precise to one part in something lik ten to the eleventh. And they agree with GR.
One some level it amazes me that GR passes every test we throw at it with such flying colors. On another level, I agree with Albert: the theory is too beautiful *not* to be true.
Presumably they did measure the distance: you can get the round-trip signal when the path to Cassini is far from the Sun. That, along with the fact that Cassini is itself far from any significant gravitational source means that it's easy to know exactly where Cassini is right now. (In this limit, Newton and Einstein are pretty much identical. You can argue that this theory is incorrect, but that's a pretty difficult argument to make, given how often it has worked quite well.)
So, no, they don't really need to use GR to get the distance.