Tell that to Transmeta. They went the 100% outsourcing route with arguably one of the most innovative designs in the x86 space ever..and where are they now? Real men have fabs in the cpu biz...the rest fade away.
If they picked ONE foundry (like IBM), they'd have a chance, but chances are they will have to spread their orders across a number of them...all of them have their quirks, and they will all require tweaks and changes to their designs to match. This will slow down development...cause even longer delays to market, diminish market share, and kill them. You talk like sending your designs to a cutting-edge process size foundry is like emailing a jpeg and then chips pop off the line.
Yes, lots of companies already do this with their low end parts...THATS MY POINT!! If AMD wants to be relegated to a low-end part maker like the USED TO BE BEFORE THEY HAD FABS..then by all means..they should go fabless. If they want to keep up with Intel with cutting-edge parts, they need to have 100% control and accountability with the entire process...design to packaging. Intel does that, and it gives them a HUGE competitive advantage against anyone who doesn't. The AMD/IBM partnership is one that I could see working long term as an "outsourcing" scenario...as they have been working together for years and it is virtually in-house fab for all intents and purposes...but IBM simply doesn't have the fabs to provide the kind of volume-on-demand that AMD will require. Nor do they want to get into the foundry business wholesale. So AMD would need to forge new relationships, make even MORE changes/tweaks to their high-end parts like Barcelona to get them on a 3rd party fab..and lose even more marketshare. Great plan.
But I guess with less marketshare, volume becomes less of a problem, right?
I invite you to bookmark this page so in 2 years, if the rumors prove true, we can come back and issue a "I told you so" as appropriate.
Hmm, I suppose Intel knows nothing of the semiconductor business either. Yet they seem to be doing OK by running their own fabs...actually they're posed to bury AMD at the moment. This outsourcing move will just hasten it along.
Yes, it is expensive. But that's the cost of doing business. If you want to always be behind the curve...always modding your designs to fit someone else's fab quirks..then sure...this is the right path. It's also the path of delay-to-market...which leads to dwindling market share and the slow, painful death of a cpu company.
It works for Nvidia because their principal competitor also outsourced their fab stuff. So, they were on equal footing and took the same hit. The case is quite different in the cpu world where there is more pressure to use the latest process size (the video card industry was generally at least 1 and usually 2 generations behind "cutting edge" so costs were much lower). AMD will be at a distinct disadvantage on a margin basis if they outsource compared to Intel who keeps everything in-house. Their only hope is that the difference in margin will be made up by the elimination of capital costs. Personally, I don't think it will as it will take even *longer* to get new products out because of the additional coordination and cross-designing that will be needed to get a 100% outsource fab'd product out the door.
While I can see the case for reducing the short-term capital investment due to the perhaps-ill-advised aquisition of ATi...in the long run I think this would be a bad idea. Sure, dedicated fabs run by 3rd parties specializing in such things can probably be run more cheaply..but they also want to make a profit. Cost to AMD in the long run is at best probably break-even...and more realistically higher cost per chip (those 3rd parties are going to want a ROI on THEIR capital investment...PLUS make a profit) and that's assuming the same quality and yield can be met. If AMD feels that running fabs is just not a core competency that they want to keep due to expensive head-count or whatever..I wish them the best of luck. Intel's gonna have 'em for breakfast as they continue to reap the "keep all the money in the family" strategy of production..while AMD goes the outsourcing route and has to pay all the middlemen's cut. There's a reason that Wal-Mart kicks everyone's ass...high volume and as-direct-from-manufacturer-to-consumer as possible. Intel follows the Wal-Mart model. Currently, AMD is Target...same idea, just smaller scale. But they are moving to a botique model if they get out the fab business...and that's just not gonna cut it. But, I wish them well:) Competition has been great for the consumer!
How exactly do you propose to "map the reflections" when they are reflecting to places away from both the target and the firing platform? You planning on putting thousands of optical sensors throughout the battlefield for the purpose?
I'd guess non-zero, but very small via referencing the "Big Sky Theory". After all, the concentrated beam doesn't travel any further than the target if it is aimed properly. It's only about an inch wide...so even on a miss only an inch column along a single vector is subject to collateral damage..there's a whole lot of places for planes to *not* be by comparison to being in the way of the beam. But yeah, point taken..it's something that would have to be considered in the targeting/tracking system.
Good point...I didn't take the time to research it before your comment, but Nd:YAG retinal injuries are quite common and that laser operates at 1064nm. Either way...internal or external damage to the eye can be quite significant.
Maybe not retinal damage, but "not transparent" generally means "will absorb"...so you'd have have massive epithelial and corneal damage instead. Basically like having a LASIK device going randomly berserk on you. Not a happy thought, to say the least. In it's (apparently) intended use for shooting down missiles/mortars in the short-range theater...the ranges involved shouldn't allow for much in the way of intensity of the scatter. Use against nearby ground targets is, of course, might be a different story.
It's not Unreal 3..it's a *heavily* modified Unreal2 engine (some call it 2.5...semantics). Totally agree with you on the performance issue...I beta tested it since August and quite a number of us have been screaming about that for months. Only to be shouted down by the Vanbois in a chorus "It's only beta!". Well, it's now released..and it still sucks sweaty donkey balls. I wont' even go into the gameplay itself...suffice it to say that I haven't been impressed with the "Vision" that has been implemented in the death-march to release. I wouldn't play this piece of shit in it's current form if it was free (and I didn't for the last month leading up to release during beta...it was *that* bad). Gratz to Sigil for taking a great idea and completely destroying it.
Exactly. Since the young lad from the article is still alive (having not perished from the effects of neutron irradiation), I can only conclude that he didn't create a nuclear fusion device, but rather a very complicated neon light. Nice project for the science fair, but nothing to get excited about for our future energy supply.
Clearly spoken by someone who has never had to work until 3am cleaning up a network that has been infected by some idiot saleman who thought bringing his personal laptop in from home was a good idea. Obviously anti-virus software goes a long ways..but in sudden outbreaks like Nimda, SQL slammer, and friends...day-zero exploits have to be stopped at the access level and that is only possible when reasonable access control is present along with solid use policies that folks actually adhere to. Sorry if you consider that "inconvenient"..but until YOU actually are the one who has to clean up the messes, I'd keep your holier-than-IT attitudes to yourself. Just a random thought...
Yes, really. MPEG4 encoding is several orders of magnitude more computationally intensive. And it's MPEG4 that folks would be interested in for video iPods...the MPEG2 found on DVD's is just too big to be practical for loading on them (unless you plan to load only 3 or 4 movies at a time) Sure, you could have a specialized chip that could trancode MPEG2 to MPEG4 (or the various flavors..divx, h.264, etc) but as it stands now there's not much of a market for development of such a chip due to the aforementioned legal snags thanks to the DMCA and friends. So, that leaves us with general purpose cpu's doing those tasks...and it takes a lot of MHz to crank through a transcoding session at a reasonable pace.
I don't see how one method would be any more or less inherently robust than the other. Each is relying on the bandwidth of intermediate nodes, and by definition each is exposed to the same risks. By the time you add in the caching mechanism that would be needed for a bit torrent type application, you've added more things in the chain to go wrong by increasing the overall complexity. After all, each client would be required to cache the broadcast in exactly the same way, with exactly the same time intervals with exactly the same time references in order to break up the file into indexible pieces ala bit torrent. So, on that front I don't think either method has an advantage in "robustness"....if anything the skype method probably more robust due to its simplicity. In addition, the bit torrent approach necessarily introduces some finite programmatic latency based on tiers of connectivity (assuming you could solve the cache concurrency problem), but the skype approach does not.
And for a webcast where interactive elements are included (like many of Cisco's...where questions are entered via web, and then answered by the host on video), any kind of purpose-built latency on the order of minutes is unacceptable IMHO.
Cool link..though from what I see it only works with pre-recorded stuff and wouldn't be useful for live webcasting as is the intention of the OP. After all, it's tough to get pieces of a broadcast from other clients when it hasn't been created yet:p Unless, of course, one is willing to have clients cache segments of the broadcast...and distribute that to other clients (with a noticeable latency to those further "downstream"). Going that way seems kinda kludgy to me. Something along the lines of skype would be better suited...where it builds a multi-cast-like tree of nodes and supernodes that could be used to distribute live content while providing a much greater scaling factor over the 1:1 that OP currently is getting (though not as good as a bit torrent type architecture would yield), and is suitable for distributing live content where everyone has similar latency, rather than "tiers" of latency. Just an idea...
Great idea in theory...not so good across the internet when you are trying to reach people who might be connected to any arbitrary Tier-1 provider. MBONE really isn't a solution, either, as it requires a lot of coordination in order to make use of it, and is more of a development tool than production-quality. The OP has a very interesting problem, for sure. I think a skype-like P2P architecture would probably be the best solution rather than multicast...where you effectively create a multi-cast-like network through establishment of application-level tree structures with nodes and supernodes. It's not quite the infinitely-scalable architecture that going with a bit torrent type system would yield...but it would be simpler for a latency-sensitive and order-of-arrival-senstive payload such as video...and still yield huge increases of "effective" bandwidth in the overall broadcast system. All that, and no special network voodoo needs to be arranged with the ISP like a multicast/MBONE application would require.
The "hub-bub" of the system is that, while SA hasn't been used in a while, the DoD still encrypts the P-code of the GPS system, thereby denying the high-precision capabilities to everyone except the U.S. military (and other government agencies, I assume). High-precision navigation with GPS for everyone else requires the use of differential GPS systems. The new European system will allow high-precision navigation to all who pony up the cash.
Well, I stand by my assertion that yvesdandoy used the wrong units...as he clearly pulled a number out of some reference and blindly attached a set of units to the end of it...clearly demonstrating a lack of knowledge of the physical system he/she was trying to comment on...and therefore using the wrong units attached to a (basically) correct number due to this lack of knowledge. ToMAYto, ToMAWto:p In any case...yvesdandoy's physics teacher should indeed be fired/shot/lynched as I earlier suggested.
And yes, I'm aware of the neutrino situation...and I appreciate the subtle jab at my rhetorical question I asked yvesdandoy. And as you pointed out, our probe isn't made of neutrinos...and thus would be stopped shortly after making contact with the surface of the earth, regardless of fraction of escape velocity it was traveling.
And by the way, "mph" is a perfectly acceptable term to use in measurements. Miles Per Hour describes the same mathematical quantities as miles/h. Likewise, Kilometers Per Hour (sometimes written kph) describes the same quantity as km/h. At least, it does to those who understand English beyond a 3rd grade level (becoming a rariety in our education system, I'll grant you). If you want to outlaw mph, you should also outlaw the legal terms Per Annum, Percent, and any number of such terms that describe quantitative relationships in some form other than what can be plugged directly into a unit analysis form of problem solving without a little interpretation. Wow...nice run-on sentence, huh? In any case, such nomenclature is widespread throughout most industries...so perhaps your students would be better served if you made them convert between various nomenclatures as well as unit systems, rather than pretending that only the "proper" nomenclature with SI units was the one-and-only way to describe things in the world.
As an engineer...I agree that the world would be a better place if we all used the same set of units across the world...SI or otherwise. I get tired of having to convert from one to the other...not to mention the potential for grievous errors from faulty conversions (smoking crater in Mars ring a bell to anyone? LOL). But also as an engineer, I recognize the reality of how the world works, and thus the necessity of being able to function in any/all unit systems and nomenclatures. It certainly beats hiding behind some utopian idea of measurements and nomenclature born in academia at the expense of being able to deal with anything that might be thrown your way. My 2 cents (sorry, I mean my 0.02 dollars).
Your physics teacher needs to be fired/lynched/shot (depending on local laws)
First of all, your units are wrong. Escape velocity is around 25,000 MILES per hour.
Second, if the object is actually headed *towards* earth, it's own trajectory will preclude it from "escaping". Do you think anything traveling faster than escape velocity will simply quantum-tunnel through the earth?
Third, lots of meteors enter the earth's atmosphere every day with velocities on the order of, or exceeding, the "escape velocity" of earth. Yet, somehow they magically manage to burn up in the atmosphere and/or strike the earth anyway. Wow. Do ya think that maybe, just maybe, the probe might use a similar technique/trajectory to return to earth?
Ignorance can be cured. Stupidity is permanent. I'm not sure what camp you fall into yet.
At the 1967 Wistar Institute Symposium, top-level evolutionary biologists and mathematicians met to mathematically test the idea of evolution by mutation/selection. When the super-computers finished crunching their numbers, it was obvious that the answer was 'impossible'. It was reported that when someone very cautiously (maybe even rhetorically) asked whether this meant that perhaps one should look at special creation as an option, there were loud cries of 'No!' 'No!' from the floor.
Modern attempts at computational investigation of evolution have proven just the opposite. While the results are of course restricted to microevolution...evolution by mutation/adaption is computationally model-able, as well observable. Even distantly related bacteria have been observed exchanging dna fragments...thus undergoing a type of mutation. Viruses routinely mutate through random processes as well as exchanges of RNA. If we can observe such radical changes in the behavior and structure of such organisms within the lifespan of a human...how can creationists seriously challenge the idea of what might have been accomplished over billions of years?
I'll be the first to say that science can't discount that something or someone ultimately created the rules by which things that we observe behave. Well, others have said it before me...so I'll be the next. Even Stephen Hawking has commented that because we, and anything we create (including ideas) are contained within this universe, that by mathematical consequence of self-referencing systems we are incapable of completely describing the universe and all of its rules and behavior. However, we *can* see and describe discrete chunks of it, and to discount such behavior after we see it (as the creationist zealots do) is stupidity at its finest.
I'll just touch on the question about DE's. That's the realm of Numerical Analysis...solving DE's through step-wise calculations using discrete intervals. That's how the "pros" plan real missions, as the real equations of motion are not solvable analytically for interplantary missions.
At the end of the day, it depends on how close you need to get...how much maneuvering fuel you have budgeted...which determines how many factors you need to leave in the equations.
In theory yeah...but relativity really only comes into play at very high velocities (think particle accelerators) or in the presence of very strong gravity fields (like one would experience inside Mercury's orbit). There is virtually zero pay-off for using relativistic modeling for a mission to mars, though it might prove useful for a probe destined to orbit exceptionally close to the sun.
At the end of the day, at the scales that are involved, you might have improved the accuracy by a foot or two but it's hardly worth the effort.
Believe me, getting ultra-accurate trajectories via standard Newtonian physics *is* possible...just really computationally intensive (has to be solved numerically).
1) Cut taxes by $1 trillion/year 2) Declare that deficits are actually good for the economy so the sheep in this country think it's a good idea to both increase spending and cut taxes at the same time. 3) Go to Mars (previously known as the 'Profit!' step)
With a decent mathematical background, the book could be followed fairly well to get an idea of what it takes to calculate the trajectory for a Martian mission. There are other books out there too...but I am familiar with this one since I used it in college. Dr. Szebehely was an awesome prof, by the way...everyone should have the privilege of learning from someone like him at least once in their lives.
Of course, in the "real Solar System", the gravity of Jupiter can be a real factor, in addition to the other planets (depending on how close you need your calculations to be)...and unfortunately only the 2-body problem can be easily solved in a general closed form. For other scenarios, numerical methods that calculate the trajectory "step-by-step" must be employed.
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Tell that to Transmeta. They went the 100% outsourcing route with arguably one of the most innovative designs in the x86 space ever..and where are they now? Real men have fabs in the cpu biz...the rest fade away.
If they picked ONE foundry (like IBM), they'd have a chance, but chances are they will have to spread their orders across a number of them...all of them have their quirks, and they will all require tweaks and changes to their designs to match. This will slow down development...cause even longer delays to market, diminish market share, and kill them. You talk like sending your designs to a cutting-edge process size foundry is like emailing a jpeg and then chips pop off the line.
Yes, lots of companies already do this with their low end parts...THATS MY POINT!! If AMD wants to be relegated to a low-end part maker like the USED TO BE BEFORE THEY HAD FABS..then by all means..they should go fabless. If they want to keep up with Intel with cutting-edge parts, they need to have 100% control and accountability with the entire process...design to packaging. Intel does that, and it gives them a HUGE competitive advantage against anyone who doesn't. The AMD/IBM partnership is one that I could see working long term as an "outsourcing" scenario...as they have been working together for years and it is virtually in-house fab for all intents and purposes...but IBM simply doesn't have the fabs to provide the kind of volume-on-demand that AMD will require. Nor do they want to get into the foundry business wholesale. So AMD would need to forge new relationships, make even MORE changes/tweaks to their high-end parts like Barcelona to get them on a 3rd party fab..and lose even more marketshare. Great plan.
But I guess with less marketshare, volume becomes less of a problem, right?
I invite you to bookmark this page so in 2 years, if the rumors prove true, we can come back and issue a "I told you so" as appropriate.
Hmm, I suppose Intel knows nothing of the semiconductor business either. Yet they seem to be doing OK by running their own fabs...actually they're posed to bury AMD at the moment. This outsourcing move will just hasten it along.
Yes, it is expensive. But that's the cost of doing business. If you want to always be behind the curve...always modding your designs to fit someone else's fab quirks..then sure...this is the right path. It's also the path of delay-to-market...which leads to dwindling market share and the slow, painful death of a cpu company.
It works for Nvidia because their principal competitor also outsourced their fab stuff. So, they were on equal footing and took the same hit. The case is quite different in the cpu world where there is more pressure to use the latest process size (the video card industry was generally at least 1 and usually 2 generations behind "cutting edge" so costs were much lower). AMD will be at a distinct disadvantage on a margin basis if they outsource compared to Intel who keeps everything in-house. Their only hope is that the difference in margin will be made up by the elimination of capital costs. Personally, I don't think it will as it will take even *longer* to get new products out because of the additional coordination and cross-designing that will be needed to get a 100% outsource fab'd product out the door.
While I can see the case for reducing the short-term capital investment due to the perhaps-ill-advised aquisition of ATi...in the long run I think this would be a bad idea. Sure, dedicated fabs run by 3rd parties specializing in such things can probably be run more cheaply..but they also want to make a profit. Cost to AMD in the long run is at best probably break-even...and more realistically higher cost per chip (those 3rd parties are going to want a ROI on THEIR capital investment...PLUS make a profit) and that's assuming the same quality and yield can be met. If AMD feels that running fabs is just not a core competency that they want to keep due to expensive head-count or whatever..I wish them the best of luck. Intel's gonna have 'em for breakfast as they continue to reap the "keep all the money in the family" strategy of production..while AMD goes the outsourcing route and has to pay all the middlemen's cut. There's a reason that Wal-Mart kicks everyone's ass...high volume and as-direct-from-manufacturer-to-consumer as possible. Intel follows the Wal-Mart model. Currently, AMD is Target...same idea, just smaller scale. But they are moving to a botique model if they get out the fab business...and that's just not gonna cut it. But, I wish them well :) Competition has been great for the consumer!
Uverse has been live since 2006 (while admittedly in a small geographic area). This is hardly news. http://www.uverseusers.com/
How exactly do you propose to "map the reflections" when they are reflecting to places away from both the target and the firing platform? You planning on putting thousands of optical sensors throughout the battlefield for the purpose?
I'd guess non-zero, but very small via referencing the "Big Sky Theory". After all, the concentrated beam doesn't travel any further than the target if it is aimed properly. It's only about an inch wide...so even on a miss only an inch column along a single vector is subject to collateral damage..there's a whole lot of places for planes to *not* be by comparison to being in the way of the beam. But yeah, point taken..it's something that would have to be considered in the targeting/tracking system.
Good point...I didn't take the time to research it before your comment, but Nd:YAG retinal injuries are quite common and that laser operates at 1064nm. Either way...internal or external damage to the eye can be quite significant.
Maybe not retinal damage, but "not transparent" generally means "will absorb"...so you'd have have massive epithelial and corneal damage instead. Basically like having a LASIK device going randomly berserk on you. Not a happy thought, to say the least. In it's (apparently) intended use for shooting down missiles/mortars in the short-range theater...the ranges involved shouldn't allow for much in the way of intensity of the scatter. Use against nearby ground targets is, of course, might be a different story.
It's not Unreal 3..it's a *heavily* modified Unreal2 engine (some call it 2.5...semantics). Totally agree with you on the performance issue...I beta tested it since August and quite a number of us have been screaming about that for months. Only to be shouted down by the Vanbois in a chorus "It's only beta!". Well, it's now released..and it still sucks sweaty donkey balls. I wont' even go into the gameplay itself...suffice it to say that I haven't been impressed with the "Vision" that has been implemented in the death-march to release. I wouldn't play this piece of shit in it's current form if it was free (and I didn't for the last month leading up to release during beta...it was *that* bad). Gratz to Sigil for taking a great idea and completely destroying it.
Exactly. Since the young lad from the article is still alive (having not perished from the effects of neutron irradiation), I can only conclude that he didn't create a nuclear fusion device, but rather a very complicated neon light. Nice project for the science fair, but nothing to get excited about for our future energy supply.
Clearly spoken by someone who has never had to work until 3am cleaning up a network that has been infected by some idiot saleman who thought bringing his personal laptop in from home was a good idea. Obviously anti-virus software goes a long ways..but in sudden outbreaks like Nimda, SQL slammer, and friends...day-zero exploits have to be stopped at the access level and that is only possible when reasonable access control is present along with solid use policies that folks actually adhere to. Sorry if you consider that "inconvenient"..but until YOU actually are the one who has to clean up the messes, I'd keep your holier-than-IT attitudes to yourself. Just a random thought...
Yes, really. MPEG4 encoding is several orders of magnitude more computationally intensive. And it's MPEG4 that folks would be interested in for video iPods...the MPEG2 found on DVD's is just too big to be practical for loading on them (unless you plan to load only 3 or 4 movies at a time) Sure, you could have a specialized chip that could trancode MPEG2 to MPEG4 (or the various flavors..divx, h.264, etc) but as it stands now there's not much of a market for development of such a chip due to the aforementioned legal snags thanks to the DMCA and friends. So, that leaves us with general purpose cpu's doing those tasks...and it takes a lot of MHz to crank through a transcoding session at a reasonable pace.
I don't see how one method would be any more or less inherently robust than the other. Each is relying on the bandwidth of intermediate nodes, and by definition each is exposed to the same risks. By the time you add in the caching mechanism that would be needed for a bit torrent type application, you've added more things in the chain to go wrong by increasing the overall complexity. After all, each client would be required to cache the broadcast in exactly the same way, with exactly the same time intervals with exactly the same time references in order to break up the file into indexible pieces ala bit torrent. So, on that front I don't think either method has an advantage in "robustness"....if anything the skype method probably more robust due to its simplicity. In addition, the bit torrent approach necessarily introduces some finite programmatic latency based on tiers of connectivity (assuming you could solve the cache concurrency problem), but the skype approach does not.
And for a webcast where interactive elements are included (like many of Cisco's...where questions are entered via web, and then answered by the host on video), any kind of purpose-built latency on the order of minutes is unacceptable IMHO.
Cool link..though from what I see it only works with pre-recorded stuff and wouldn't be useful for live webcasting as is the intention of the OP. After all, it's tough to get pieces of a broadcast from other clients when it hasn't been created yet :p Unless, of course, one is willing to have clients cache segments of the broadcast...and distribute that to other clients (with a noticeable latency to those further "downstream"). Going that way seems kinda kludgy to me. Something along the lines of skype would be better suited...where it builds a multi-cast-like tree of nodes and supernodes that could be used to distribute live content while providing a much greater scaling factor over the 1:1 that OP currently is getting (though not as good as a bit torrent type architecture would yield), and is suitable for distributing live content where everyone has similar latency, rather than "tiers" of latency. Just an idea...
Great idea in theory...not so good across the internet when you are trying to reach people who might be connected to any arbitrary Tier-1 provider. MBONE really isn't a solution, either, as it requires a lot of coordination in order to make use of it, and is more of a development tool than production-quality. The OP has a very interesting problem, for sure. I think a skype-like P2P architecture would probably be the best solution rather than multicast...where you effectively create a multi-cast-like network through establishment of application-level tree structures with nodes and supernodes. It's not quite the infinitely-scalable architecture that going with a bit torrent type system would yield...but it would be simpler for a latency-sensitive and order-of-arrival-senstive payload such as video...and still yield huge increases of "effective" bandwidth in the overall broadcast system. All that, and no special network voodoo needs to be arranged with the ISP like a multicast/MBONE application would require.
The "hub-bub" of the system is that, while SA hasn't been used in a while, the DoD still encrypts the P-code of the GPS system, thereby denying the high-precision capabilities to everyone except the U.S. military (and other government agencies, I assume). High-precision navigation with GPS for everyone else requires the use of differential GPS systems. The new European system will allow high-precision navigation to all who pony up the cash.
Well, I stand by my assertion that yvesdandoy used the wrong units...as he clearly pulled a number out of some reference and blindly attached a set of units to the end of it...clearly demonstrating a lack of knowledge of the physical system he/she was trying to comment on...and therefore using the wrong units attached to a (basically) correct number due to this lack of knowledge. ToMAYto, ToMAWto :p In any case...yvesdandoy's physics teacher should indeed be fired/shot/lynched as I earlier suggested.
And yes, I'm aware of the neutrino situation...and I appreciate the subtle jab at my rhetorical question I asked yvesdandoy. And as you pointed out, our probe isn't made of neutrinos...and thus would be stopped shortly after making contact with the surface of the earth, regardless of fraction of escape velocity it was traveling.
And by the way, "mph" is a perfectly acceptable term to use in measurements. Miles Per Hour describes the same mathematical quantities as miles/h. Likewise, Kilometers Per Hour (sometimes written kph) describes the same quantity as km/h. At least, it does to those who understand English beyond a 3rd grade level (becoming a rariety in our education system, I'll grant you). If you want to outlaw mph, you should also outlaw the legal terms Per Annum, Percent, and any number of such terms that describe quantitative relationships in some form other than what can be plugged directly into a unit analysis form of problem solving without a little interpretation. Wow...nice run-on sentence, huh? In any case, such nomenclature is widespread throughout most industries...so perhaps your students would be better served if you made them convert between various nomenclatures as well as unit systems, rather than pretending that only the "proper" nomenclature with SI units was the one-and-only way to describe things in the world.
As an engineer...I agree that the world would be a better place if we all used the same set of units across the world...SI or otherwise. I get tired of having to convert from one to the other...not to mention the potential for grievous errors from faulty conversions (smoking crater in Mars ring a bell to anyone? LOL). But also as an engineer, I recognize the reality of how the world works, and thus the necessity of being able to function in any/all unit systems and nomenclatures. It certainly beats hiding behind some utopian idea of measurements and nomenclature born in academia at the expense of being able to deal with anything that might be thrown your way. My 2 cents (sorry, I mean my 0.02 dollars).
Your physics teacher needs to be fired/lynched/shot (depending on local laws)
First of all, your units are wrong. Escape velocity is around 25,000 MILES per hour.
Second, if the object is actually headed *towards* earth, it's own trajectory will preclude it from "escaping". Do you think anything traveling faster than escape velocity will simply quantum-tunnel through the earth?
Third, lots of meteors enter the earth's atmosphere every day with velocities on the order of, or exceeding, the "escape velocity" of earth. Yet, somehow they magically manage to burn up in the atmosphere and/or strike the earth anyway. Wow. Do ya think that maybe, just maybe, the probe might use a similar technique/trajectory to return to earth?
Ignorance can be cured. Stupidity is permanent. I'm not sure what camp you fall into yet.
At the 1967 Wistar Institute Symposium, top-level evolutionary biologists and mathematicians met to mathematically test the idea of evolution by mutation/selection. When the super-computers finished crunching their numbers, it was obvious that the answer was 'impossible'. It was reported that when someone very cautiously (maybe even rhetorically) asked whether this meant that perhaps one should look at special creation as an option, there were loud cries of 'No!' 'No!' from the floor.
Modern attempts at computational investigation of evolution have proven just the opposite. While the results are of course restricted to microevolution...evolution by mutation/adaption is computationally model-able, as well observable. Even distantly related bacteria have been observed exchanging dna fragments...thus undergoing a type of mutation. Viruses routinely mutate through random processes as well as exchanges of RNA. If we can observe such radical changes in the behavior and structure of such organisms within the lifespan of a human...how can creationists seriously challenge the idea of what might have been accomplished over billions of years?
I'll be the first to say that science can't discount that something or someone ultimately created the rules by which things that we observe behave. Well, others have said it before me...so I'll be the next. Even Stephen Hawking has commented that because we, and anything we create (including ideas) are contained within this universe, that by mathematical consequence of self-referencing systems we are incapable of completely describing the universe and all of its rules and behavior. However, we *can* see and describe discrete chunks of it, and to discount such behavior after we see it (as the creationist zealots do) is stupidity at its finest.
Yeah, that's one method for integration of ordinary DE's. You got it :)
I'll just touch on the question about DE's. That's the realm of Numerical Analysis...solving DE's through step-wise calculations using discrete intervals. That's how the "pros" plan real missions, as the real equations of motion are not solvable analytically for interplantary missions.
At the end of the day, it depends on how close you need to get...how much maneuvering fuel you have budgeted...which determines how many factors you need to leave in the equations.
In theory yeah...but relativity really only comes into play at very high velocities (think particle accelerators) or in the presence of very strong gravity fields (like one would experience inside Mercury's orbit). There is virtually zero pay-off for using relativistic modeling for a mission to mars, though it might prove useful for a probe destined to orbit exceptionally close to the sun.
At the end of the day, at the scales that are involved, you might have improved the accuracy by a foot or two but it's hardly worth the effort.
Believe me, getting ultra-accurate trajectories via standard Newtonian physics *is* possible...just really computationally intensive (has to be solved numerically).
Nah, that's easy.
1) Cut taxes by $1 trillion/year
2) Declare that deficits are actually good for the economy so the sheep in this country think it's a good idea to both increase spending and cut taxes at the same time.
3) Go to Mars (previously known as the 'Profit!' step)
The web page the OP found looks pretty cool..though I agree it's a little too condensed to be useful for a complete beginner. While I don't want to imply that orbital mechanics is out of the reach of intelligent, math-oriented folks without some sort of formal instruction....a course in the subject matter can definitely help. I took a class with the author of this book http://www.amazon.com/exec/obidos/tg/detail/-/0292 751052/qid=1124147579/sr=8-2/ref=sr_8_xs_ap_i1_xgl 14/102-9094747-8542529?v=glance&s=books&n=507846
With a decent mathematical background, the book could be followed fairly well to get an idea of what it takes to calculate the trajectory for a Martian mission. There are other books out there too...but I am familiar with this one since I used it in college. Dr. Szebehely was an awesome prof, by the way...everyone should have the privilege of learning from someone like him at least once in their lives.
Of course, in the "real Solar System", the gravity of Jupiter can be a real factor, in addition to the other planets (depending on how close you need your calculations to be)...and unfortunately only the 2-body problem can be easily solved in a general closed form. For other scenarios, numerical methods that calculate the trajectory "step-by-step" must be employed.
Good Luck!