so you need a lot of high quality ore to get fuel in an expensive and energy intensive process (eg. heat a heavy metal all the way to a gas and centrifuge it).
Um, no. You only need to do that if you're planning on building bombs. (And anyway, gas centrifuges don't heat the uranium to a gas but chemically convert it to uranium hexafluoride before centrifuging.)
There are plenty of reactor designs that run on unenriched uranium, including most of the nuclear power plants in Canada (CANDU) and places to where Canada has sold reactors.
And what do you then say to the concept of maglev?
Show me a maglev wheelbarrow, or a maglev appliance dolly. Or even a maglev bicycle, or a maglev logging truck.
Also sleds have existed far longer than wheels with a similar purpose.
Indeed, and are still used on appropriate surfaces -- like snow or loose sand. They kind of suck on hard or high-friction surfaces though, and you can't apply motive power through them, they have to be pulled or pushed by something that's not a sled. So what?
So either I don't understand the "fundamental problem" wheels solve
No, apparently not. Try thinking about it some more. (Hint, see how many different kinds of "wheeled conveyance" you can come up with.)
The square wheel is just a special case of a four-toothed gear. In the real world, eventually both the square and the catenary surface it's "rolling" on will wear down toward a circle and a flat plane, respectively. A different size square wouldn't work worth a damn on that particular surface.
In the general case, round wheels work best.
Sure, one can always come up with exceptions -- and no doubt for exotic or special case hardware, you can find examples where a unix-like system isn't best.
Look at malware for one. Look at how many jokes revolve around software crashes of some sort, for another.
These are certainly problems that Windows has, but I don't see the relevance to modern unix-like operating systems. A modern alloy wheel with radial tires isn't the same as an old wooden chariot wheel, but they're both round; that's the essential "wheelness". Microsoft still hasn't figured out that an array of spokes works better if connected to a rim, they're too busy trying to figure out what color spokes work best.
As for the work you describe, it bears about as much relation to real-world operating systems as anti-gravity research does to wheels. Yeah, sounds wonderful, it'd be nice if it worked, but there are some fundamental reasons why it won't.
No, Rob Pike was not "part of the team that wrote the original Unix". Pike worked on 8th Edition Unix (an internal Bell Labs only successor to V7 while AT&T was commercializing Unix as System III), and later Plan 9 and others.
He also once delivered a talk at a Usenix while wearing harem pants, but that's as irrelevant as everything else you said.
There are certain ideas that are hard to improve upon beyond minor cosmetic and detail changes. There are a lot of things one can do to improve wheels -- materials, suspension, etc -- but changing the fundamental shape isn't one of them.
(And yes, one can invent radically new concepts for transportation -- e.g. wings -- but they don't solve the fundamental problems that wheels solve.)
Unix/linux, word processors, spreadsheets, etc solve certain fundamental problems. You want radically different software, look in radically different problem areas (as some other posters have noted).
There are certain shapes of non-round rollers that work fine, and even lumpy wheels work, but after continued use they'll both wear themselves to a circular wheel shape. Twenty years ago Henry Spencer's sig said "Those who do not understand Unix are condemned to reinvent it, poorly", and Microsoft (among others) has been proving him right.
Shrug. That probably doesn't begin to balance the number of sold-with-Windows computers (or for that matter, Macs) that have had Linux installed on them.
The office suite with 90% marketshare is moving to a documented, text-based format. And you can see NO technical good in it at all?
What in the world would lead you to believe that Microsoft Office will ever generate a document, except perhaps for the most trivial, that actually conforms to the spec they're pushing as MSOOXML? When has Microsoft software ever conformed to published specs, even those published by Microsoft (let alone some quasi third party)?
Oh, and it isn't all text-based, there's some binary crud in there too, as hex, neatly wrapped in appropriate equivalents to <TheFollowingIsABinaryChunkWithSomeDeepSignificanceToOffice> tags.
So no, there's no technical merit. It's just something Microsoft hopes will keep some of the competitors and OSS dupes (hi Miguel) distracted for a while, instead of producing software that might compete with MSFTs.
Anyone who thinks otherwise hasn't been paying attention to the history of the industry.
And besides, digital audiotape? For movie archiving? I guess they mean magnetic tape, but the word "audio" should have been the first tip-off there, IMO.
They probably meant DAT and someone expanded the acronym. DAT and DDS tapes (4mm) are physically the same although DDS originally had higher specs (lower error rate). DDS-5 is also called DAT72, DDS-6 is also called DAT160 (160 GB compressed, 80 GB raw capacity).
It's a not-uncommon tape storage format, although LT has higher capacity and is more prevalent for larger backups.
It appears to have finally happened: the ever-shrinking distance between now and nostalgia has finally reached its zero-state. We are now nostalgic for our present.
Heck, I've been nostalgic for the future for a while now. It's almost 2008, where are our flying cars and cities on the Moon?
That's comparable to the first CD burners (the media may have been slightly cheaper, not much) and cheaper than the first DVD burners (Phillips had one for about $15,000), with about the same media price.
Best case: these things do produce at 100% output 12 hours a day. A one-watt panel would produce 4.38 kWh a year, for $0.226/kWh. To match coal at the $0.07/kWh someone else mentioned above (which may be low, and doesn't count environmental impact), the panels would have to last a bit over three years to match coal. If the panels last 10 years, they only need to produce full output for an average four hours per day, or half output for 8 hours a day.
I don't know what the performance degradation over the cell's lifetime is, but a 10-year lifespan is probably on the low side. It's not like there are moving parts, the principle reasons for wearing out would be degradation of the light-sensitive material and weather damage (hail, windstorm, surface erosion by dust, etc.) Yeah, I could see these things being cost-competitive with coal.
Then there's the advantages of being clean and able to provide power where the power lines don't go.
If an aircraft accidently happened to wander in to the path
If it was a plane it'd be flying at anywhere from 100 feet/second on up, so beam exposure would be sub-millisecond on any given part of the plane (or cockpit). Since helicopters can fly slowly or hover, it's less certain how long an accidental exposure might be -- although presumably the whole point of a green laser is that's it's bright enough to see the beam reflecting off dust in the air. The pilot might be a little surprised to see a beam materialize in front of him and move suddenly to avoid, but that's not the same as having the thing illuminating his cockpit. The latter seems to imply some deliberate aiming on the part of whoever is shining the laser.
First, he's lying to you (a bit) about the rocket equation. It tells you the mass ratio you need to achieve a given multiple of your exhaust velocity. Exhaust velocity depends on a number of things, fuel mix certainly being a significant one, but there are others.
While the second stage of Saturn V (the S-IIc) may (or may not, I haven't double checked) have had a dry mass fraction of 10%, what Bell omits is that it used five relatively low-performance (by today's standards) J-2 engines; replace those with a single SSME (Space Shuttle Main Engine) and the mass fraction improves considerably.
And then he hand-waves the weights for a full fledged vehicle, citing Venture-Star (which had serious design flaws which added weight, such as the landing mode and the fuel tank design) and DC-X, which was never designed as an orbital vehicle but as a subscale prototype to demonstrate operational concepts -- as long as the thing could get itself off the ground they didn't care (much) about weight.
As I understand it you want to land vertically and rocket assisted. Don't you think that in vacuum you would have to achieve the same weight ratio for going up as for going down with the engines being the same.
Land vertically and rocket assisted (just as DC-X demonstrated) yes. That doesn't mean using the rockets to decelerate to a dead stop in orbit and gently settle down from there, you use the atmosphere to slow you down to terminal velocity (which for a lightly loaded base-first decent won't be very high) and then brake with rockets for the last few hundred feet. DC-X did demonstrate this successfully and repeatedly. Aerobraking works, every spacecraft that has ever returned to Earth has used it.
Then you are still hoping for high turnaround times. Ok, you could pipeline the whole rebuilding effort which you will probably need as much as the shuttle
What rebuilding effort? It lands, you let it cool off, query the avionics on-board diagnostics for any issues, refuel and you're ready to go. DC-X demonstrated rapid turnaround -- launch, land, re-launch -- in less than 24 hours. The vehicle itself was actually ready for re-launch within 8 (yes, eight) hours after landing but the weather turned bad and they held until next day. The Shuttle requires a major overhaul (and of course, re-stacking) after every flight. It's 1970s technology, we've learned better.
With your larger number of launches to get the same mass into orbit you can easily cause higher costs for labor per mass in orbit which is going to kill your SSTO dreams.
Mass in orbit is a bogus figure of merit. Are we talking payload (there's a reason that word contains "pay") or total mass? In any case, compare labor costs against Shuttle which requires a full-time workforce of thousands for what, maybe five launches a year; vs a crew of about 15 (what DC-X had) for a potential 250+ launches a year (we'll give the guys weekends and holidays off;-) ). Just for the sake of argument assume Shuttle goes with 50,000 pounds of payload every time, that's 250,000 lb/year. SSTO only needs a payload of 1000 lb to match that with only 0.5% (or less) of the labor force.
Actual figures of course will vary but cutting your workforce by 99+% is definitely going to reduce your labor cost. A reasonable SSTO design will be scaled for an optimum payload weight, not a maximum payload weight as Shuttle was. Yeah, for special projects you'll need a heavy lift launcher -- but that shouldn't be doing double-duty as a delivery van or taxicab.
The "young" is yet to be demonstrated. (For that matter, so is whether or not this is really ice, but that seems a reasonable bet.) As for "active" -- if it's a glacier, it flows under the force of gravity, and either advances or (depending on temperature) the leading edge retreats; of course it's active.
TFA makes a big deal out of the exposed white areas, claiming that ice sublimates quickly on Mars. Well, some places it does, some places it doesn't. If it's exposed on the ridge peaks, that could be because a covering layer of dust was recently blown off -- or it could be that it was recently snowed (or frosted) upon. I'm not inflating their claims, perhaps the BBC is.
Well, 47.5 N is hardly equatorial, but it is further south (by about 8 degrees) than the typical maximum winter extent of the north polar cap, so I'll grant you "odd" but perhaps not "very odd". (We have equatorial glaciers here on Earth at sufficient altitude, although they're disappearing rapidly.)
I wouldn't be surprised if significant traces of water (ice) are found all over Vastitas Borealis; if it was once a sea bottom (and it bears characteristics of such) there could be a lot left just under the surface (which would help preserve it).
Scientists act surprised and excited at almost any discovery, partly because it either supports or disagrees with current theory, which in a relatively new field like planetology is interesting either way. But - and forgive me for being cynical - they also do it to encourage those who fund them to keep on funding them. If they'd said "ho hum, we expected that", how do you think the purse-string holders would react the next time the scientists went asking for money?
Yeah, it's an interesting find in the way any data about Mars is interesting. It's not - or shouldn't be - something that will shake the very foundations of planetology. Didn't anyone predict glaciers? If not, I hereby predict pingos, braided streams, and moraines -- although I think they've all already been observed.
We've known there was ice on Mars for a century or more. It is visible from Earth through any reasonably good telescope. You know, those white things at the poles?
Sure, in winter they get bigger from frozen out CO2, but there's a year-round permanent cap of water ice. Glaciers, permafrost, pingoes and other signs of ice should not be a surprise. Okay, a glacier on the Martian equator might be a surprise, except perhaps on one of the Tharsis Bulge volcanoes or Nix Olympica (er, Olympus Mons to you young whippersnappers; now get off my lawn).
Yet people seem to be surprised every time there's the merest hint, or act like it's of some cosmic significance. Sheesh.
But why and how would these things explode?! Well, they don't.
They do. The kinetic energy of something even at orbital velocity is roughly equivalent to the explosive energy of an equivalent mass of TNT. Energy goes up as the square of the velocity, and meteorites can come in at twice orbital velocity.
When they come to a more-or-less sudden stop (hitting dense atmosphere or the ground), that energy has to go somewhere.
Slashdot Mirror
At that rate, Linux will surpass the Mac's market share in 12 years, with 3161% of the market compared to Mac's 3132%. Oh, wait...
Isn't that about as much an oxymoron as "reality TV"?
and requires the heavier isotope
Oh, and actually it's the lighter isotope (235 vs 238) that's the one of interest.
so you need a lot of high quality ore to get fuel in an expensive and energy intensive process (eg. heat a heavy metal all the way to a gas and centrifuge it).
Um, no. You only need to do that if you're planning on building bombs. (And anyway, gas centrifuges don't heat the uranium to a gas but chemically convert it to uranium hexafluoride before centrifuging.)
There are plenty of reactor designs that run on unenriched uranium, including most of the nuclear power plants in Canada (CANDU) and places to where Canada has sold reactors.
And what do you then say to the concept of maglev?
Show me a maglev wheelbarrow, or a maglev appliance dolly. Or even a maglev bicycle, or a maglev logging truck.
Also sleds have existed far longer than wheels with a similar purpose.
Indeed, and are still used on appropriate surfaces -- like snow or loose sand. They kind of suck on hard or high-friction surfaces though, and you can't apply motive power through them, they have to be pulled or pushed by something that's not a sled. So what?
So either I don't understand the "fundamental problem" wheels solve
No, apparently not. Try thinking about it some more. (Hint, see how many different kinds of "wheeled conveyance" you can come up with.)
The square wheel is just a special case of a four-toothed gear. In the real world, eventually both the square and the catenary surface it's "rolling" on will wear down toward a circle and a flat plane, respectively. A different size square wouldn't work worth a damn on that particular surface.
In the general case, round wheels work best.
Sure, one can always come up with exceptions -- and no doubt for exotic or special case hardware, you can find examples where a unix-like system isn't best.
So what?
Look at malware for one. Look at how many jokes revolve around software crashes of some sort, for another.
These are certainly problems that Windows has, but I don't see the relevance to modern unix-like operating systems. A modern alloy wheel with radial tires isn't the same as an old wooden chariot wheel, but they're both round; that's the essential "wheelness". Microsoft still hasn't figured out that an array of spokes works better if connected to a rim, they're too busy trying to figure out what color spokes work best.
As for the work you describe, it bears about as much relation to real-world operating systems as anti-gravity research does to wheels. Yeah, sounds wonderful, it'd be nice if it worked, but there are some fundamental reasons why it won't.
No, Rob Pike was not "part of the team that wrote the original Unix". Pike worked on 8th Edition Unix (an internal Bell Labs only successor to V7 while AT&T was commercializing Unix as System III), and later Plan 9 and others.
He also once delivered a talk at a Usenix while wearing harem pants, but that's as irrelevant as everything else you said.
Best word
wheel
There are certain ideas that are hard to improve upon beyond minor cosmetic and detail changes. There are a lot of things one can do to improve wheels -- materials, suspension, etc -- but changing the fundamental shape isn't one of them.
(And yes, one can invent radically new concepts for transportation -- e.g. wings -- but they don't solve the fundamental problems that wheels solve.)
Unix/linux, word processors, spreadsheets, etc solve certain fundamental problems. You want radically different software, look in radically different problem areas (as some other posters have noted).
There are certain shapes of non-round rollers that work fine, and even lumpy wheels work, but after continued use they'll both wear themselves to a circular wheel shape. Twenty years ago Henry Spencer's sig said "Those who do not understand Unix are condemned to reinvent it, poorly", and Microsoft (among others) has been proving him right.
Shrug. That probably doesn't begin to balance the number of sold-with-Windows computers (or for that matter, Macs) that have had Linux installed on them.
Dang, I already posted to this thread or I'd mod you +1 insightful.
The office suite with 90% marketshare is moving to a documented, text-based format. And you can see NO technical good in it at all?
What in the world would lead you to believe that Microsoft Office will ever generate a document, except perhaps for the most trivial, that actually conforms to the spec they're pushing as MSOOXML? When has Microsoft software ever conformed to published specs, even those published by Microsoft (let alone some quasi third party)?
Oh, and it isn't all text-based, there's some binary crud in there too, as hex, neatly wrapped in appropriate equivalents to <TheFollowingIsABinaryChunkWithSomeDeepSignificanceToOffice> tags.
So no, there's no technical merit. It's just something Microsoft hopes will keep some of the competitors and OSS dupes (hi Miguel) distracted for a while, instead of producing software that might compete with MSFTs.
Anyone who thinks otherwise hasn't been paying attention to the history of the industry.
Mmmm, Apple pi!
And besides, digital audiotape? For movie archiving? I guess they mean magnetic tape, but the word "audio" should have been the first tip-off there, IMO.
They probably meant DAT and someone expanded the acronym. DAT and DDS tapes (4mm) are physically the same although DDS originally had higher specs (lower error rate). DDS-5 is also called DAT72, DDS-6 is also called DAT160 (160 GB compressed, 80 GB raw capacity).
It's a not-uncommon tape storage format, although LT has higher capacity and is more prevalent for larger backups.
It appears to have finally happened: the ever-shrinking distance between now and nostalgia has finally reached its zero-state. We are now nostalgic for our present.
Heck, I've been nostalgic for the future for a while now. It's almost 2008, where are our flying cars and cities on the Moon?
That's comparable to the first CD burners (the media may have been slightly cheaper, not much) and cheaper than the first DVD burners (Phillips had one for about $15,000), with about the same media price.
All true, but we can estimate.
Best case: these things do produce at 100% output 12 hours a day. A one-watt panel would produce 4.38 kWh a year, for $0.226/kWh. To match coal at the $0.07/kWh someone else mentioned above (which may be low, and doesn't count environmental impact), the panels would have to last a bit over three years to match coal. If the panels last 10 years, they only need to produce full output for an average four hours per day, or half output for 8 hours a day.
I don't know what the performance degradation over the cell's lifetime is, but a 10-year lifespan is probably on the low side. It's not like there are moving parts, the principle reasons for wearing out would be degradation of the light-sensitive material and weather damage (hail, windstorm, surface erosion by dust, etc.) Yeah, I could see these things being cost-competitive with coal.
Then there's the advantages of being clean and able to provide power where the power lines don't go.
If an aircraft accidently happened to wander in to the path
If it was a plane it'd be flying at anywhere from 100 feet/second on up, so beam exposure would be sub-millisecond on any given part of the plane (or cockpit). Since helicopters can fly slowly or hover, it's less certain how long an accidental exposure might be -- although presumably the whole point of a green laser is that's it's bright enough to see the beam reflecting off dust in the air. The pilot might be a little surprised to see a beam materialize in front of him and move suddenly to avoid, but that's not the same as having the thing illuminating his cockpit. The latter seems to imply some deliberate aiming on the part of whoever is shining the laser.
First, he's lying to you (a bit) about the rocket equation. It tells you the mass ratio you need to achieve a given multiple of your exhaust velocity. Exhaust velocity depends on a number of things, fuel mix certainly being a significant one, but there are others.
;-) ). Just for the sake of argument assume Shuttle goes with 50,000 pounds of payload every time, that's 250,000 lb/year. SSTO only needs a payload of 1000 lb to match that with only 0.5% (or less) of the labor force.
While the second stage of Saturn V (the S-IIc) may (or may not, I haven't double checked) have had a dry mass fraction of 10%, what Bell omits is that it used five relatively low-performance (by today's standards) J-2 engines; replace those with a single SSME (Space Shuttle Main Engine) and the mass fraction improves considerably.
And then he hand-waves the weights for a full fledged vehicle, citing Venture-Star (which had serious design flaws which added weight, such as the landing mode and the fuel tank design) and DC-X, which was never designed as an orbital vehicle but as a subscale prototype to demonstrate operational concepts -- as long as the thing could get itself off the ground they didn't care (much) about weight.
As I understand it you want to land vertically and rocket assisted. Don't you think that in vacuum you would have to achieve the same weight ratio for going up as for going down with the engines being the same.
Land vertically and rocket assisted (just as DC-X demonstrated) yes. That doesn't mean using the rockets to decelerate to a dead stop in orbit and gently settle down from there, you use the atmosphere to slow you down to terminal velocity (which for a lightly loaded base-first decent won't be very high) and then brake with rockets for the last few hundred feet. DC-X did demonstrate this successfully and repeatedly. Aerobraking works, every spacecraft that has ever returned to Earth has used it.
Then you are still hoping for high turnaround times. Ok, you could pipeline the whole rebuilding effort which you will probably need as much as the shuttle
What rebuilding effort? It lands, you let it cool off, query the avionics on-board diagnostics for any issues, refuel and you're ready to go. DC-X demonstrated rapid turnaround -- launch, land, re-launch -- in less than 24 hours. The vehicle itself was actually ready for re-launch within 8 (yes, eight) hours after landing but the weather turned bad and they held until next day. The Shuttle requires a major overhaul (and of course, re-stacking) after every flight. It's 1970s technology, we've learned better.
With your larger number of launches to get the same mass into orbit you can easily cause higher costs for labor per mass in orbit which is going to kill your SSTO dreams.
Mass in orbit is a bogus figure of merit. Are we talking payload (there's a reason that word contains "pay") or total mass? In any case, compare labor costs against Shuttle which requires a full-time workforce of thousands for what, maybe five launches a year; vs a crew of about 15 (what DC-X had) for a potential 250+ launches a year (we'll give the guys weekends and holidays off
Actual figures of course will vary but cutting your workforce by 99+% is definitely going to reduce your labor cost. A reasonable SSTO design will be scaled for an optimum payload weight, not a maximum payload weight as Shuttle was. Yeah, for special projects you'll need a heavy lift launcher -- but that shouldn't be doing double-duty as a delivery van or taxicab.
The "young" is yet to be demonstrated. (For that matter, so is whether or not this is really ice, but that seems a reasonable bet.) As for "active" -- if it's a glacier, it flows under the force of gravity, and either advances or (depending on temperature) the leading edge retreats; of course it's active.
TFA makes a big deal out of the exposed white areas, claiming that ice sublimates quickly on Mars. Well, some places it does, some places it doesn't. If it's exposed on the ridge peaks, that could be because a covering layer of dust was recently blown off -- or it could be that it was recently snowed (or frosted) upon. I'm not inflating their claims, perhaps the BBC is.
You misunderstand (or somebody did).
It's not Duke Neukem, it's Doc Neukem.
Well, 47.5 N is hardly equatorial, but it is further south (by about 8 degrees) than the typical maximum winter extent of the north polar cap, so I'll grant you "odd" but perhaps not "very odd". (We have equatorial glaciers here on Earth at sufficient altitude, although they're disappearing rapidly.)
;-)
I wouldn't be surprised if significant traces of water (ice) are found all over Vastitas Borealis; if it was once a sea bottom (and it bears characteristics of such) there could be a lot left just under the surface (which would help preserve it).
The real question is whether they find sodium
Scientists act surprised and excited at almost any discovery, partly because it either supports or disagrees with current theory, which in a relatively new field like planetology is interesting either way. But - and forgive me for being cynical - they also do it to encourage those who fund them to keep on funding them. If they'd said "ho hum, we expected that", how do you think the purse-string holders would react the next time the scientists went asking for money?
Yeah, it's an interesting find in the way any data about Mars is interesting. It's not - or shouldn't be - something that will shake the very foundations of planetology. Didn't anyone predict glaciers? If not, I hereby predict pingos, braided streams, and moraines -- although I think they've all already been observed.
We've known there was ice on Mars for a century or more. It is visible from Earth through any reasonably good telescope. You know, those white things at the poles?
Sure, in winter they get bigger from frozen out CO2, but there's a year-round permanent cap of water ice. Glaciers, permafrost, pingoes and other signs of ice should not be a surprise. Okay, a glacier on the Martian equator might be a surprise, except perhaps on one of the Tharsis Bulge volcanoes or Nix Olympica (er, Olympus Mons to you young whippersnappers; now get off my lawn).
Yet people seem to be surprised every time there's the merest hint, or act like it's of some cosmic significance. Sheesh.
But why and how would these things explode?! Well, they don't.
They do. The kinetic energy of something even at orbital velocity is roughly equivalent to the explosive energy of an equivalent mass of TNT. Energy goes up as the square of the velocity, and meteorites can come in at twice orbital velocity.
When they come to a more-or-less sudden stop (hitting dense atmosphere or the ground), that energy has to go somewhere.