The US has coal reserves for about 250 years at current consumption levels
Fair enough. I know China has significant coal reserves too. And of source there is also Canadian tar sands. And maybe methane clathrates...
I suspect 1000 years is a nice round number, but I won't fight very hard for it.
On the other hand, newer nuclear plants can extend the life of existing uranium reserves to a length of time longer than the entire history of humanity up until this point.
Out of curiosity, which design are you thinking of? I doubt that even breeders can do that, unless we find a way to extract Uranium from ocean water.
If you were thinking fusion, then I do agree with you. We just have to make that actually work. (As an aside, 87 $G would have gone a long way to making fusion a reality...)
I believe what Mr. Lovelock is saying is that in the next 50 years or so we're going to deplete our supply of fossil fuels to the point where they can't cover our power demands, and that nuclear fission is the only current method we have of replacing the huge gap that's going to be left.
I'm not sure if he's saying that or not, but it's not quite true. The fact of the matter is that while supplies of cheap oil are indeed limited and will likely run out in something like 50 years, there is ample coal available to sustain us for at least 1000 years. Now, the consequences of burning all that coal will be staggering. Think multiplying current CO2 levels by factors of 5; no reasonable scientist would argue that such extreme levels won't lead to serious warming and climate change. At that point you're talking shutdown of the Gulf Stream, 20 to 50-meter sea level change and the release of methane clathrates, among other things. Real fun stuff.
Mr. Lovelock is correct in that nuclear power will be needed in the near future if we are to avoid damaging our climate system. However, it won't be required because we run out of fossil fuel (coal).
The Saudis on the other hand are screwed - or at least their children are. Not that I'm all that sympatheitc to their plight, mind you. I'm sure they'll survive off of investments...
who's to say that such current changes dont occur every couple thousand years for various reasons? we just dont have enough data
Well, let's be careful here. We DO have data from ice cores, sediment beds, tree rings and other similar sources that indicate when these changes in ocean circulation have occurred. In the past, these events have happened at the end of Ice Ages, when large amounts of meltwater have entered the oceans .
They don't "just happen" for various reasons; there are pretty well-defined condistions for when the circulation changes.
But its no reason to start moving to the higher places on Earth anytime soon.
If the Gulf Stream shuts down you'll want to move SOUTH, not UP. At least if you live in Europe.
I haven't seen the movie, so I have no idea how badly they butchered the science. But I am concerned that "skeptics" are using this crappy movie as an excuse to belittle the very valid science that is being done in this area....
...were actually very common in the first half of the
last Century. Vannevar Bush was big in that area,
and many such computers were used as artillery computers in battleships. Google "Ford computer".
There were also machines that could be programmed to solve differential equations outside of the artillery problem.
The artist's illo clearly shows not a balloon, but a lifting body, an arrowhead shape.
Oh, that's just great. Now it's not just a balloon but also a lifting body? Why not throw in a space elevator section, too? A hallmark of crackpot ideas is that they keep changing so you can't pin them down on the physics.
Look, go dig out a basic text on airfoil theory and tell me what kind of lift you'll get with a large wing at 200,000 ft. Ever wonder why no-one has made one work before? Tell, me, what happens when the mean free path gets larger than the chord of the wing?
Actually, a hypersonic C_d is about 2, so that's an order of magnitude increase in drag. But who cares at this point?
The problem is fundamental misunderstanding of what buoyancy is doing. At float altitude, there is a buoyancey force that exactly equals the mass. It doesn't make the mass go away. Therefore, in order to go above float altitude, you have to counteract gravity working on all of your mass. In order to accelerate upward, you need m*g in thrust. Which only a conventional, inefficient rocket can provide.
You won't have some nice, balanced trajectory that increases in altitude unless you can provide that lifting force. If your engine provides 1 N of thrust, and your payload masses 100 kg, you won't accelerate upward at 0.01 m/s. You will rise to a new altitude where the loss of buoyancy due to the decreasing density is exactly equal to 1N. Which might be a few feet at most. Then you'll just sit there.
look - this isn't going to work. First of all, the hard part of getting to orbit is velocity, not altitude. See two posts ago for why. So the issue is how to stay above the atmosphere (and associated drag) long enough to build up orbital velocity. If you're above the atmosphere, you can't use a balloon. So you have to rely on a rocket of some kind. We've established that an ion engine doesn't provide the needed thrust.
Now you come up with a twist; somehow build up velocity so that you leave the atmosphere in a big arc that takes long enough that you can build up orbital velocity before you come back down. Well, if you think about it the time you stay above the atmosphere has to be less than 40 minutes, or you've just gone into orbit (i.e. it requires the associated velocity of 7.6 km/s which you were trying to get). Which means you have less than 40 minutes for your ion engine to do its thing. But we already know that it would take days to get to 8 km/s. So that won't work.
You're trying to get something for nothing - it ain't gonna happen.
You're a fucking ignoramus, same as everyone else. Lacking the vision.
Yes, the laws of physics are known to yield to obnoxious, foul-mouthed self-proclaimed visionaries like yourself.
Seriously though, if you are proposing to provide lift using ion engines, then they have to effectively provide 9.8 N of thrust for every kg of vehicle mass. In other words, the ion engine has to provide >1G of accelleration. That is far, far beyond what they can do - typically an ion engine will provide 0.0001 G or so.
You're trying a con - you want to use the atmosphere for lift (i.e. the balloon), but you don't want to pay the penalty of the associated drag. There is no "top" of the atmosphere - it falls off gradually; it's not like the ocean. As I calculated in a previous post, if there is enough atmosphere left to provide lift, there is enough to prevent orbital velocities. On the flip side of the coin, if you go outside the atmosphere to avoid drag, then you need >1 G of accelleration (remember, your NET acceleration is your thrust/mass - 1G from gravity) or you will start falling back to Earth. An ion engine simply does not have to thrust-to-weight ratio required to defeat gravity.
I suggest you not try a career as a rocket scientist.
I swear the moderators are on crack today, and I know I'll end up paying for this in karma, but someone needs to be the voice of sanity here. Does no-one know any physics? Lets break it down:
At this point, we'll say that the balloon is 'floating' on the very top of the Earth's atmosphere. It won't go down (buyoant[sp] force) and it won't go up (gravity). At this point, as long as the ion engines can beat the force of gravity, you have acceleration.
Wrong! As long as the ion engines can beat drag, you have acceleration. But they won't, and you can show that in a few lines - though I wish it were easier to write equations here...
At 50 km altitude the atmospheric denisty is something like 1 gram per cubic meter. So to lift 1 kg of mass with a balloon you need something like 1000 cubic meters of volume (actually more since you're using hydrogen and not vacuum, but whatever). That will mean a balloon with a radius of 6 meters. It will have a frontal area of 120 square meters. Now, the drag equation is: F_drag = Cd * Area * density * velocity^2, where Cd = 0.2, Area = 120 m2, denisty = 0.001 kg/m3, velocity = 8 km/s. So, F_d = 1.5 million Newton. The ion engine on DS-1 produced 0.09 N of thrust, and massed about 10 kg.
So this idea is cracked by a factor of 10 million or so. I'm sure I'll get lots of indignant, anonymous replies saying how it's actually at 60 km, not 50 etc etc. But the point remains, this is an idea anyone who passed high school physics should be able to see through. Sorry, but that's life. Don't moderate down the messenger....
I know I'm going to end up being modded a troll for this - it seems anyone who actually thinks critically about this stuff does. But seriously, I haven't lived under a bridge in years, and last time I went sunbathing I didn't turn to stone.
The problem with getting to orbit isn't altitude, it's velocity. From your handy-dandy high-school physics book: E_altitude = mgh (mass times gravity times altitude) = 1 kg * 9.8 m/s2 * 100 km = 9.8*10^5 J. Whereas kinetic energy is E_kinetic = 0.5*m*v^2 = 0.5 * 1kg *(7.6 km/s)^2 = 2.8*10^7 J.
So getting to altitude takes only 3% of the energy required to reach orbital velocity. This is again why all these schemes that have you starting on a balloon, or a tall tree or whatever just won't work. Saying I lack vision is idiotic; I just happen to know some physics.
Can somebody please explain to my why this isn't total crap? First of all, a typical balloon tops out at 140,000 ft (= 40 km) which is very different than
the 100-300 km for LEO. While you might be able to stay aloft from buoyancy at 140kft, since the pressure drops with increasing altitude, so does your buoyancy force. After all, space is a vacuum, and it's hard to be lighter-than-vacuum.
Second, to stay in orbit you need to be going at orbital velocities - i.e 7.6 km/s. That's fast, so doing it in the atmosphere creates lots of drag and spectacular fireworks. It takes energy to maintain orbital velocity in an atmosphere - much more than you can supply with a puny ion drive.
there is much evidence that shows that the so called "golden age of spain" was concocted in the early 1900s as propoganda so the British people would not mind allieing with the Turks.
What ignorant bullshit. Have you ever been to Spain? Have you ever seen the
al-Hambra? The fact is that during the 7th through 10th Centuries, while Europe was little more than a stinking barabaric backwater, Islamic civization
was very highly developed. They even had soap. During the Crusades, many Christian lords would try to get hold of Saracen physicians, because everyone knew that their medical methods were far superior to the European ones (which tended to consist of bleeding and wrapping the wound in dung).
It was Arab scholars who preserved much of the ancient Greek litterature. Without them we would have none of it. As for your statement about the library of Alexandria, you should read this.
In addition, who do you think invented algebra? (a hint: it should be al-gebra). Most of the stars visble to the naked eye have Arabic names (Aldebaran, Almitak, Algol, Betelgeuse, Achernar etc etc.), meaning that they had highly developed (for the time) mathematics and astronomy.
I understand you're pissed about terrorism; who wouldn't be? But don't make the mistake of letting current events color your view of the past. It's bad enough the other way around.
They've gotten over a hundred back, as far as I recall.
I could have sworn we only had five to begin with. Columbia, Discovery, Challenger, Atlantis, Endeavour and (if you count it) the Prototype Enterprise. Seeing as how we only had five to begin with (now three, unfortunataley) how could be have gotten over a hundred back?
Can someone please explain to me why this is an achievement? As I understand it they dropped a scaled-down glider from a helicopter and managed to have it land itself. BFD. The Russian Buran flew and landed (from orbit) autonomously back in the '80s. Now Europe comes along with a glider and we're supposed to be impressed?
Talk to me when they get the thing back from an orbital flight.
Actually, no. A scramjet - if it is ever made to work properly for more than 5 seconds - will accelereate you to something like Mach 12 and 100,000 feet. That is not space, nor orbital velocity. From there you have to use a rocket.
You can even go into space with a (really big) cannon.
But you can't go into orbit. Also, of you
were to start from the surface of the Earth with several times excape velocity you will a) be vaporized by the atmosphere, b) likely be slowed down such that you don't ever reached space, c) killed by the deceleration forces.
A while back this topic came up over a lunch discussion and I did some looking into it. Check this link for some interesting background. As best I can estimate the lid made it up to about 10 km altitude before it came back down.
So, what does all this mean? Simply that a jet engine will NEVER get you into space.
I have known too many couples with multiple PhDs where either one or both hates the job they have, just so they can both have jobs
Funny. The reason we both work is that we both love our jobs, both derive a sense of purpose from them, and would both be bored silly if we stayed home all day. (We don't have kids, mind you)
You said one thing that really made me question your devotion to acedemics: Maybe that education was wasted on you?
Ah, I lament the loss of the fine art of sarcasm... Both of the responses to my post neatly ignored the parenthesis that came after.
You know, you've been suggesting that one of us should give up a career and stay home with the children. I ask you, how often do you honestly think that will be the man in the family? In practice, such advice is simply a way to keep women at home. And you may or may not remember, but back in the good old days, one argument against letting women have acceess to places like Caltech and Harvard was "that education is wasted on them. They are just going to stay home and have babies."
1. restrict all non-productive distractions. This includes television, gameboys, and computer games. In my household there is ZERO broadcast television, ZERO non-public radio, ZERO gameboys, and about 2-4 hours of computer games a week. Some folks think this is hard it isn't - you especially realize this when you find that your children never beg for toys around christmas time - they just don't see the commercials.
It sounds to me like you're doing a good job as a parent. But it also sounds like you are running the risk of being over-protective. Take TV commercials; they are very finely honed instruments for grabbing your attention and manipulating your thoughts. If you don't learn how to filter them out, you will be at a disadvantage in life. Maybe you should spend some time with the kids studying advertising techniques. Personally, I find that watching commercials on mute is very illuminating. My parents didn't let me watch TV as a kid, which has had all sorts of consequences. My wife thinks I was abducted by aliens in the 80's, since I miss all her references to various shows.
I also find that I am much more prone than others to be distracted by a commercial in the background.
Kids need to learn that the world is full of lying, manipulative a$$holes who will try to rip them off and hurt them. I'm not sure what the best way to teach them this is, but I suspect that a completely sheltered "Percival", when he finally enters the real world, will have a lot of painful learning to do.
I feel sick when I see people complaining about how they need two incomes while they are pumping gas for their luxury SUV that they use to drive 30 miles to work because they live on a 5 acre plot in the suburbs. Those aren't things you need, those are things you want!
There are two sides to that story. My wife and I both have science PhDs from one of the top-five research universities in the world, and the only cities where we could both find jobs commensurate with our degrees were Boston, LA and San Francisco. The median house price in Pasadena is $635,000 dollars, and it's higher in San Francisco. A newly-minted PhD in physics can expect around $70k. How the he!! are you supposed to afford a $600k house on one salary? Of couse, we could live out in the suburbs; in LA that's at least 50 miles.
Not all dual-income couples buy SUV's. But even a Prius is expensive. I drive a 10-year old Sentra and spend $150/month on gas, and another $90/month on road tolls.
It's nice for you to talk about priorities. But you've just admitted you gave up being a research engineer. Maybe that education was wasted on you? (actually, we need good high-school physics teachers, so good for you!)
My point (related to this topic) is that of course the U.S. is losing its scientific dominance when being a research scientist in this country ends up requiring the sacrificies it does. Specifically: salary (staying in academia was at least a factor of 3 cut compared to my other offers. Heck, the contractor doing my lawn makes $500/day - or he would've if I'd been that stupid.), flexibility (there are really only a very small number of places where you can find a science job, especially if your spouse is also a scientist - the "two-body problem"), family (it's very difficult to juggle having a family with working 10-12 hour days together with 2 hrs spent commuting. Not to mention getting daycare).
Getting back entirely on topic though; I'm not at all surprised that the U.S. science dominance is waning. I see it in my own field. We have never had a secondary-education system that produced enough sufficiently qualified students. For a long, long, time the U.S. has imported smart PhD's from all over the world, because they couldn't live as good a good life where they came from. Now that is beginning to change. Couple that with the recent spate of xenophobia (I know of several guys in my field who went home for vacations to places like China and Poland and either couldn't come back for months, or haven't been allowed back yet. You bet that sh$t like that is having an effect) and it is no surprise that we're losing speed. And then of course there is the area of bio-sciences, where the government is not only not supporting research, but actively outlawing it. Are you surprised that more progress in that area is being done in South Korea than here?
I have to laugh though. People talk about the knowledge ecomomy, and basically assume that Americans are somehow smarter than everyone else. That we have some sort of lock on innovation. That somehow we'll avoid becoming a second-rate economy. Personally I'm not so sure. I can easily see a world where China has the manufacturing middle-class, India has the software-engineering upper middle class, Europe is a big theme park, and the States is divided into a few ultra-rich investors, and a whole lot of minimum-wage service employees. What a cheerful thought.
I get so tired of this humans vs. robots debate. First of all, nobody ever changes their opinion one way or the other. Second, it's a stupid debate.
The truth is that you ultimately need both; they complement each other in many ways. A one-sided approach will never get very far.
Sure, humans are expensive and fragile. And sure, robots are improving, are cheaper, able to go p[laces humans can't, and they're of course expendible. But humans are much more adaptible and flexible, they can improvise, and they can think for themselves. Robots are DUMB. Take Mars as an example: cool as the robots are, they are lucky if they can move 100 meters in a day. And that's assuming they don't get confused by loose ground. Or have a flash formatting problem and just sit there for weeks...
But above all, humans are essential not so much because of what they can do as because what they represent: the future. The whole idea of space exploration is that ultimately we want humanity to settle the stars. Not to relieve population pressure, and not because we want our vacations on Mars. But because that is what life itself does.
In the end, if space exploration is just a question of going a few places, taking some pictures, and maybe doing some science, then sooner or later it will die out. People won't keep spending $G for blue-sky science indefitiely. If you don't believe me, ask a particle physicist how much public support they're getting these days.
However, people do largely understand at a deep level that space is about the next frontier, and that is why NASA enjoys even the level of support it does.
My colleages (I'm a scientist) have a tendency to forget the human side of the equation. They get carried away by their science (that what it takes to BE a scientist), and forget just how reliant they are on public support. It's easy to think "imagine what we could do if we spent 5 $G on robots", when the truth is that there would never be the same level of resources available for robots. And for good reason - if space exploration is merely a science, then it should compete on a level playing field with other, equally important sciences, like biology. Or particle theory. Or agricultural sciences, or medicine. Or mathematics. But of course, NASA gets a disproportionately large share of the "science" budget.
That being said, I think that NASA's human spaceflight is a total clusterfsck. They need to actually accomplish something! Even something simple like figuring out how to -- or if it's possible -- to avoide bone loss in long-duration spaceflight.
Slashdot Mirror
Fair enough. I know China has significant coal reserves too. And of source there is also Canadian tar sands. And maybe methane clathrates... I suspect 1000 years is a nice round number, but I won't fight very hard for it.
On the other hand, newer nuclear plants can extend the life of existing uranium reserves to a length of time longer than the entire history of humanity up until this point.
Out of curiosity, which design are you thinking of? I doubt that even breeders can do that, unless we find a way to extract Uranium from ocean water. If you were thinking fusion, then I do agree with you. We just have to make that actually work. (As an aside, 87 $G would have gone a long way to making fusion a reality...)
I'm not sure if he's saying that or not, but it's not quite true. The fact of the matter is that while supplies of cheap oil are indeed limited and will likely run out in something like 50 years, there is ample coal available to sustain us for at least 1000 years. Now, the consequences of burning all that coal will be staggering. Think multiplying current CO2 levels by factors of 5; no reasonable scientist would argue that such extreme levels won't lead to serious warming and climate change. At that point you're talking shutdown of the Gulf Stream, 20 to 50-meter sea level change and the release of methane clathrates, among other things. Real fun stuff.
Mr. Lovelock is correct in that nuclear power will be needed in the near future if we are to avoid damaging our climate system. However, it won't be required because we run out of fossil fuel (coal). The Saudis on the other hand are screwed - or at least their children are. Not that I'm all that sympatheitc to their plight, mind you. I'm sure they'll survive off of investments...
Well, let's be careful here. We DO have data from ice cores, sediment beds, tree rings and other similar sources that indicate when these changes in ocean circulation have occurred. In the past, these events have happened at the end of Ice Ages, when large amounts of meltwater have entered the oceans . They don't "just happen" for various reasons; there are pretty well-defined condistions for when the circulation changes.
But its no reason to start moving to the higher places on Earth anytime soon.
If the Gulf Stream shuts down you'll want to move SOUTH, not UP. At least if you live in Europe.
I haven't seen the movie, so I have no idea how badly they butchered the science. But I am concerned that "skeptics" are using this crappy movie as an excuse to belittle the very valid science that is being done in this area....
Oh, that's just great. Now it's not just a balloon but also a lifting body? Why not throw in a space elevator section, too? A hallmark of crackpot ideas is that they keep changing so you can't pin them down on the physics.
Look, go dig out a basic text on airfoil theory and tell me what kind of lift you'll get with a large wing at 200,000 ft. Ever wonder why no-one has made one work before? Tell, me, what happens when the mean free path gets larger than the chord of the wing?
That being said, 73's to you too. W7FNE...
Actually, a hypersonic C_d is about 2, so that's an order of magnitude increase in drag. But who cares at this point?
The problem is fundamental misunderstanding of what buoyancy is doing. At float altitude, there is a buoyancey force that exactly equals the mass. It doesn't make the mass go away. Therefore, in order to go above float altitude, you have to counteract gravity working on all of your mass. In order to accelerate upward, you need m*g in thrust. Which only a conventional, inefficient rocket can provide. You won't have some nice, balanced trajectory that increases in altitude unless you can provide that lifting force. If your engine provides 1 N of thrust, and your payload masses 100 kg, you won't accelerate upward at 0.01 m/s. You will rise to a new altitude where the loss of buoyancy due to the decreasing density is exactly equal to 1N. Which might be a few feet at most. Then you'll just sit there.
Now you come up with a twist; somehow build up velocity so that you leave the atmosphere in a big arc that takes long enough that you can build up orbital velocity before you come back down. Well, if you think about it the time you stay above the atmosphere has to be less than 40 minutes, or you've just gone into orbit (i.e. it requires the associated velocity of 7.6 km/s which you were trying to get). Which means you have less than 40 minutes for your ion engine to do its thing. But we already know that it would take days to get to 8 km/s. So that won't work.
You're trying to get something for nothing - it ain't gonna happen.
Yes, the laws of physics are known to yield to obnoxious, foul-mouthed self-proclaimed visionaries like yourself.
Seriously though, if you are proposing to provide lift using ion engines, then they have to effectively provide 9.8 N of thrust for every kg of vehicle mass. In other words, the ion engine has to provide >1G of accelleration. That is far, far beyond what they can do - typically an ion engine will provide 0.0001 G or so.
You're trying a con - you want to use the atmosphere for lift (i.e. the balloon), but you don't want to pay the penalty of the associated drag. There is no "top" of the atmosphere - it falls off gradually; it's not like the ocean. As I calculated in a previous post, if there is enough atmosphere left to provide lift, there is enough to prevent orbital velocities. On the flip side of the coin, if you go outside the atmosphere to avoid drag, then you need >1 G of accelleration (remember, your NET acceleration is your thrust/mass - 1G from gravity) or you will start falling back to Earth. An ion engine simply does not have to thrust-to-weight ratio required to defeat gravity.
I suggest you not try a career as a rocket scientist.
At this point, we'll say that the balloon is 'floating' on the very top of the Earth's atmosphere. It won't go down (buyoant[sp] force) and it won't go up (gravity). At this point, as long as the ion engines can beat the force of gravity, you have acceleration.
Wrong! As long as the ion engines can beat drag, you have acceleration. But they won't, and you can show that in a few lines - though I wish it were easier to write equations here...
At 50 km altitude the atmospheric denisty is something like 1 gram per cubic meter. So to lift 1 kg of mass with a balloon you need something like 1000 cubic meters of volume (actually more since you're using hydrogen and not vacuum, but whatever). That will mean a balloon with a radius of 6 meters. It will have a frontal area of 120 square meters. Now, the drag equation is: F_drag = Cd * Area * density * velocity^2, where Cd = 0.2, Area = 120 m2, denisty = 0.001 kg/m3, velocity = 8 km/s. So, F_d = 1.5 million Newton. The ion engine on DS-1 produced 0.09 N of thrust, and massed about 10 kg.
So this idea is cracked by a factor of 10 million or so. I'm sure I'll get lots of indignant, anonymous replies saying how it's actually at 60 km, not 50 etc etc. But the point remains, this is an idea anyone who passed high school physics should be able to see through. Sorry, but that's life. Don't moderate down the messenger....
The problem with getting to orbit isn't altitude, it's velocity. From your handy-dandy high-school physics book: E_altitude = mgh (mass times gravity times altitude) = 1 kg * 9.8 m/s2 * 100 km = 9.8*10^5 J. Whereas kinetic energy is E_kinetic = 0.5*m*v^2 = 0.5 * 1kg *(7.6 km/s)^2 = 2.8*10^7 J.
So getting to altitude takes only 3% of the energy required to reach orbital velocity. This is again why all these schemes that have you starting on a balloon, or a tall tree or whatever just won't work. Saying I lack vision is idiotic; I just happen to know some physics.
Second, to stay in orbit you need to be going at orbital velocities - i.e 7.6 km/s. That's fast, so doing it in the atmosphere creates lots of drag and spectacular fireworks. It takes energy to maintain orbital velocity in an atmosphere - much more than you can supply with a puny ion drive.
This just doesn't hold water.
How is this possible?
What ignorant bullshit. Have you ever been to Spain? Have you ever seen the al-Hambra? The fact is that during the 7th through 10th Centuries, while Europe was little more than a stinking barabaric backwater, Islamic civization was very highly developed. They even had soap. During the Crusades, many Christian lords would try to get hold of Saracen physicians, because everyone knew that their medical methods were far superior to the European ones (which tended to consist of bleeding and wrapping the wound in dung).
It was Arab scholars who preserved much of the ancient Greek litterature. Without them we would have none of it. As for your statement about the library of Alexandria, you should read this.
In addition, who do you think invented algebra? (a hint: it should be al-gebra). Most of the stars visble to the naked eye have Arabic names (Aldebaran, Almitak, Algol, Betelgeuse, Achernar etc etc.), meaning that they had highly developed (for the time) mathematics and astronomy.
I understand you're pissed about terrorism; who wouldn't be? But don't make the mistake of letting current events color your view of the past. It's bad enough the other way around.
I could have sworn we only had five to begin with. Columbia, Discovery, Challenger, Atlantis, Endeavour and (if you count it) the Prototype Enterprise. Seeing as how we only had five to begin with (now three, unfortunataley) how could be have gotten over a hundred back?
Becuase they each flew more than once is why.
Talk to me when Nasa gets a shuttle back from an orbital flight (in one piece).
They've gotten over a hundred back, as far as I recall.
Talk to me when they get the thing back from an orbital flight.
Actually, no. A scramjet - if it is ever made to work properly for more than 5 seconds - will accelereate you to something like Mach 12 and 100,000 feet. That is not space, nor orbital velocity. From there you have to use a rocket.
But you can't go into orbit. Also, of you were to start from the surface of the Earth with several times excape velocity you will a) be vaporized by the atmosphere, b) likely be slowed down such that you don't ever reached space, c) killed by the deceleration forces.
A while back this topic came up over a lunch discussion and I did some looking into it. Check this link for some interesting background. As best I can estimate the lid made it up to about 10 km altitude before it came back down.
So, what does all this mean? Simply that a jet engine will NEVER get you into space.
Funny. The reason we both work is that we both love our jobs, both derive a sense of purpose from them, and would both be bored silly if we stayed home all day. (We don't have kids, mind you)
You said one thing that really made me question your devotion to acedemics: Maybe that education was wasted on you?
Ah, I lament the loss of the fine art of sarcasm... Both of the responses to my post neatly ignored the parenthesis that came after. You know, you've been suggesting that one of us should give up a career and stay home with the children. I ask you, how often do you honestly think that will be the man in the family? In practice, such advice is simply a way to keep women at home. And you may or may not remember, but back in the good old days, one argument against letting women have acceess to places like Caltech and Harvard was "that education is wasted on them. They are just going to stay home and have babies."
It sounds to me like you're doing a good job as a parent. But it also sounds like you are running the risk of being over-protective. Take TV commercials; they are very finely honed instruments for grabbing your attention and manipulating your thoughts. If you don't learn how to filter them out, you will be at a disadvantage in life. Maybe you should spend some time with the kids studying advertising techniques. Personally, I find that watching commercials on mute is very illuminating. My parents didn't let me watch TV as a kid, which has had all sorts of consequences. My wife thinks I was abducted by aliens in the 80's, since I miss all her references to various shows. I also find that I am much more prone than others to be distracted by a commercial in the background.
Kids need to learn that the world is full of lying, manipulative a$$holes who will try to rip them off and hurt them. I'm not sure what the best way to teach them this is, but I suspect that a completely sheltered "Percival", when he finally enters the real world, will have a lot of painful learning to do.
There are two sides to that story. My wife and I both have science PhDs from one of the top-five research universities in the world, and the only cities where we could both find jobs commensurate with our degrees were Boston, LA and San Francisco. The median house price in Pasadena is $635,000 dollars, and it's higher in San Francisco. A newly-minted PhD in physics can expect around $70k. How the he!! are you supposed to afford a $600k house on one salary? Of couse, we could live out in the suburbs; in LA that's at least 50 miles.
Not all dual-income couples buy SUV's. But even a Prius is expensive. I drive a 10-year old Sentra and spend $150/month on gas, and another $90/month on road tolls.
It's nice for you to talk about priorities. But you've just admitted you gave up being a research engineer. Maybe that education was wasted on you? (actually, we need good high-school physics teachers, so good for you!)
My point (related to this topic) is that of course the U.S. is losing its scientific dominance when being a research scientist in this country ends up requiring the sacrificies it does. Specifically: salary (staying in academia was at least a factor of 3 cut compared to my other offers. Heck, the contractor doing my lawn makes $500/day - or he would've if I'd been that stupid.), flexibility (there are really only a very small number of places where you can find a science job, especially if your spouse is also a scientist - the "two-body problem"), family (it's very difficult to juggle having a family with working 10-12 hour days together with 2 hrs spent commuting. Not to mention getting daycare).
Getting back entirely on topic though; I'm not at all surprised that the U.S. science dominance is waning. I see it in my own field. We have never had a secondary-education system that produced enough sufficiently qualified students. For a long, long, time the U.S. has imported smart PhD's from all over the world, because they couldn't live as good a good life where they came from. Now that is beginning to change. Couple that with the recent spate of xenophobia (I know of several guys in my field who went home for vacations to places like China and Poland and either couldn't come back for months, or haven't been allowed back yet. You bet that sh$t like that is having an effect) and it is no surprise that we're losing speed. And then of course there is the area of bio-sciences, where the government is not only not supporting research, but actively outlawing it. Are you surprised that more progress in that area is being done in South Korea than here?
I have to laugh though. People talk about the knowledge ecomomy, and basically assume that Americans are somehow smarter than everyone else. That we have some sort of lock on innovation. That somehow we'll avoid becoming a second-rate economy. Personally I'm not so sure. I can easily see a world where China has the manufacturing middle-class, India has the software-engineering upper middle class, Europe is a big theme park, and the States is divided into a few ultra-rich investors, and a whole lot of minimum-wage service employees. What a cheerful thought.
I don't think we'll be settling stars anytime soon.
Thus the word ultimately.
Sure, humans are expensive and fragile. And sure, robots are improving, are cheaper, able to go p[laces humans can't, and they're of course expendible. But humans are much more adaptible and flexible, they can improvise, and they can think for themselves. Robots are DUMB. Take Mars as an example: cool as the robots are, they are lucky if they can move 100 meters in a day. And that's assuming they don't get confused by loose ground. Or have a flash formatting problem and just sit there for weeks...
But above all, humans are essential not so much because of what they can do as because what they represent: the future. The whole idea of space exploration is that ultimately we want humanity to settle the stars. Not to relieve population pressure, and not because we want our vacations on Mars. But because that is what life itself does. In the end, if space exploration is just a question of going a few places, taking some pictures, and maybe doing some science, then sooner or later it will die out. People won't keep spending $G for blue-sky science indefitiely. If you don't believe me, ask a particle physicist how much public support they're getting these days. However, people do largely understand at a deep level that space is about the next frontier, and that is why NASA enjoys even the level of support it does.
My colleages (I'm a scientist) have a tendency to forget the human side of the equation. They get carried away by their science (that what it takes to BE a scientist), and forget just how reliant they are on public support. It's easy to think "imagine what we could do if we spent 5 $G on robots", when the truth is that there would never be the same level of resources available for robots. And for good reason - if space exploration is merely a science, then it should compete on a level playing field with other, equally important sciences, like biology. Or particle theory. Or agricultural sciences, or medicine. Or mathematics. But of course, NASA gets a disproportionately large share of the "science" budget.
That being said, I think that NASA's human spaceflight is a total clusterfsck. They need to actually accomplish something! Even something simple like figuring out how to -- or if it's possible -- to avoide bone loss in long-duration spaceflight.