If the earth is 8000 miles in diameter, the L2 point 930,000 miles from earth, the sun is 870,000 miles in diameter, and 93,000,000 miles from earth, then the sun will subtend about.53 degree in the sky from the L2 point, and the earth will subtend about.49 degree. So -- the sun will be eclipsed by the earth, but it will be an annular eclipse -- even if the Hershel and Planck were right in the middle of the shadow, they would see a rim of sun all around the earth.
Is my math wrong? Or are these telescopes still going to be in light, even if it's only 4% as bright as the full sun.
The THAAD system has never been deployed. It's always been a sore point for me -- typical headlines in Aviation Week are "THAAD fails tests for the third time in a row", or "THAAD deployment delayed yet again", or "THAAD does not live up to promises."
If you saw the movie Jarhead, it was all told from the perspective and point-of-view of a soldier -- you never saw the "big picture" of the war...there were no helicopter or crane shots, it was all shot from eye-level.
Forever War is told that same way, from one soldier's point of view...and it's clear that he has no idea what is going on in the war in general...although you also get the feeling that nobody else does, either. The way that the movie skips through time with each long near-lightspeed trip makes his adventure even harder for him to understand -- the whole world changes dramatically with each hop.
I think that unlike a lot of SF books, this one really could be made into a good movie, that would capture the richness of each of the episodes in imagery that takes Haldeman many many pages to describe. I just hope that they just let the audience be as confused and out-of-sorts as the narrator is.
Forever War seems to be one of those "writer's first books" [like Grisham's A Time for a Kill, Pirsig's Zen and the Art of Motorcycle Maintenance, Hofsteader's Godel Escher Bach] that was slaved over, re-editted, re-written, re-thought, and probably submitted to publishers a dozen times before it finally saw print, because it is as tight a book as I have read. There's nothing wasted, there's nothing overly described that is better left to the reader's imagination.
Mini has made a bunch of electric Mini's, that they're trying to get into the hands of drivers. After going through a long and actually pretty funny questionnaire, I didn't hear anything from them for six months.
Last week they called me to say the car was ready for me if I wanted it. Unfortunately, the terms were unchanged from the original offer -- they want $850/month for a one-year lease -- and there is no way to keep the car longer than that.
I suppose they'll get some people to sign up for it -- and an electric Mini is a lot more exotic a car than a production European Fiesta, but still...$850/month (they suggest that it's probably more like $1K/month after various fees and such)
Thanks...I suppose I was in GOCE rapture this morning when I read about it, and I was more harsh than I should have been. It's good to hear about the work that you're doing, and that you're possibly going to do a GRACE2. What are the other new features of GRACE2 over GRACE?
I love the apparent simplicity of GRACE -- I say apparent because I know there's a mountain of math between the distance measurements and the geoid data. Congratulations on your work, and keep it up!
GOCE is a gravity measuring satellite -- the spiritual successor to the amazing GRACE pair of satellites from a few years ago.
GRACE works by flying two satellites in the same orbit, one a few dozen miles ahead of the other. By monitoring the distance between the satellites with laser rangefinders, one can measure how strong gravity is -- the more gravity, the faster the satellite goes, so the distance between the satellites grows until the second one reaches the same area. This was the state-of-the-art, and GRACE made some amazing measurements. It was able, for instance, to measure the amount of extra groundwater during flooding along the Mississippi.
But GOCE does it all with one satellite. Where the baseline for GRACE was many miles, for GOCE it is just 50 cm.
Now, if you think about it, in any satellite, the amount of gravity you would feel is zero...or at least, very very close to zero, as you are orbiting inertially. But, really, gravity is only zero right at the center of mass of the satellite. You'd feel a tiny amount of acceleration the further you go. As you go toward the center of the earth, you would be in a lower orbit, and you would be pulled down with respect to the satellite.
GOCE measures this microgravity to rediculous precision. By measuring the difference in gravity affecting two test masses 50 cm apart, it can measure how strong gravity is at that point. It should have much better accuracy, and far better resolution, than GRACE.
GOCE is amazing in other ways, too. It flies very low, to get better resolution. So, it has fins! A satellite with fins, to keep it pointing along the direction of travel. Because there is some tiny amount of air drag at the altitude it is flying, GOCE has a tiny xenon ion engine pushing it along to keep it at the same altitude, and to keep the air drag on the satellite from overwhelming the gravity measurement.
If you think about it just a bit longer, you'd be surprised how much that car trip would cost. Your Jeep Liberty cost about $25,000, and let's be generous and say that you'll drive it 150,000 miles with no maintenance costs whatsoever. Then the 350 miles cost another $58 in wear and tear on the car. It probably makes sense to add in insurance costs as well, if you drive 15,000 miles per year and pay $500 in insurance, then the insurance costs were another $10. Oil changes every 5,000 miles at $30, then that's another $2 for your 350 mile trip.
When I realistically add up all the costs of driving my Prius, I get to something on the order of $0.67/mile (calculated from here.) So, your 350 mile trip would cost me something north of $200 in direct attributable costs.
Now, it is true that if you have multiple passengers, cars start to make a whole lot more sense. And yes, it's great to have the mobility when you get there. But looking at just gas costs are not a realistic way of measuring your own costs.
I had significant probelms with the science in it.
on
Anathem
·
· Score: 1
There are a number of extremely interesting bits of science in the book, that make it worth the read. They remind me of the Sumerian discourse at the heart of Snowcrash, and are just as stimulating -- Anathem will keep you thinking long after you read the final page.
But there are a few bits of orbital mechanics that are just wrong wrong wrong. And Stephenson would know that they are wrong. And any one of the scientifically literate reviewers would have known they were wrong. I just don't know why they were left in the book.
I do feel, too, that there was a bit of Harry Potter in Anathem too -- he would make up some completely ridiculous "technology" (at least in Harry Potter they call it magic) when it was necessary.
Nevertheless...these small flaws don't detract too much from the quality of the whole book. I would recommend it highly.
This is not a satellite photo -- it is an aerial photo. 1m resolution just wouldn't show the detail that we see here. The ballfield (100 m long) is about 135 pixels long, less than 1 m/pixel.
This telescope is amazing. The three-mirror configuration gives sharp focus, over a very wide field...the only problem is that the focus is on a spherical surface.
I am curious if they considered using a non-flat image sensor. It would be hard, but with e-beam or UV-laser lithography, I would think that you would be able to build a big sensor on a curved surface, and eliminate the inevitable light loss, distortion, chromatic abberations, and other problems with lenses.
This is something that could be added in the future, too, much as Hubble was modified after-the-fact. It just seems to this layman that it's too good an idea to pass up.
My daughter and I did this too with her college recruitment interviews. It's silly not to. Why not mention her years of jujitsu training if it turns out the interviewer is a martial arts freak?
It's my first non-standard shift car. Finally computers are better at it than a human can be. The continuously variable transmission in the Prius is truly the eighth wonder of the world.
But yeah, walking and biking are a far better idea than driving will ever be.
Yeah -- the statement my Prius makes is "engineering matters." It's why I bought mine. It's a damn good reason.
It turns out that it's a hell of a car.
Very few people understand the astonishing lengths Toyota has gone to with the Prius, to make it a low-emissions car. For some reason, Toyota doesn't talk about it too much. One example is that the car has a thermos bottle in the front, where all the radiator fluid is pumped after you shut off the car -- and is pumped from when you "start" the car. For the first 7 seconds, the radiator fluid is circulate through the engine to warm it up before the gas engine actually starts, to lower the emissions and wear associated with starting a stone-cold engine.
My wife dreamed of that wedding, it's true (the evidence is the picture she scribbled in my notebook to surprise me) On the other hand, when it was clear that it would be six months of torment to pay for three hours of fairy-tale, she suggested we elope. Been 24 years so far...
But it did come down, which means, some resource got drained... Which one? The batteries, which may have been only partially recharging during the day, is one possible explanation....
The first people to fly a solar-powered plane through the night, Tom Gage and his team at AC Propulsion, flew for 48 hours...and could have probably flown forever -- the resource that was drained was the on-ground pilots.
The plane was flown to use thermals as much as possible during the day, but it was tiring work.
Anyway, after two days, and with a battery charge higher than what they started at, they figured that they had made their point.
When I was in Japan shooting Fast and Furious 3: Tokyo Drift in December 2005, I had nothing to do one day, so I did some walking just to see what wonders there were to see -- and there were many.
The most impressive, though, was a large van...with a one-inch thick sheet of aluminum bolted to the top, on which were mounted four hi-def cameras, four laser scanners, a GPS, and some other gear I didn't recognize. After walking by, walking back, walking away, and walking back again I couldn't help but ask (in English, of course) what they were doing.
You see, for Fast and Furious through 4, we built various camera rigs to film streets, to use as backgrounds for greenscreen work. This was clearly a similar rig, but on steroids. Radioactive mutant steroids.
The best english-speaking person on the crew came up to me and said "Ah, are you engineer?" I wish:) No, I am a filmmaker, but I have to know what you are doing!
He gave me a tour of the whole rig. There were enough computers inside the van to put my computer animation facility to shame. The were driving up and down all the streets of Tokyo, building a 3D, textured model of every building, for use in car navigation units. The geometry information from the laser scanners was merged with the photographic information from the hi-def cameras, and registered with the GPS.
So -- I find the protestations recorded in the article a bit suspect.
You know -- sadly what you are referring to was the Apollo-Soyuz mission of the mid 80's. The Russian KURS automated docking system is used all the time on the space station now, and it has worked flawlessly every time.
It also worked perfectly on the Mir. They did have a docking mishap on the Mir, but that as when they tried to do a manual docking.
In the Good Old Days of photochemical process work, say on Star Wars, it was not uncommon to shoot the visual effects shots on VistaVision and the rest of the movie at normal film resolution. The idea was that the process work at the time added significant grain, blurriness, and reduced contrast to the image, so starting from a larger format with less grain helped make the visual effects shots blend in somewhat more seamlessly.
Doing the process shots on IMAX is a bit of a step up from VistaVision (ok, maybe two steps up!) but it makes some sense. Modern film stocks are much better than what was used on Star Wars, but there will always be something to be said for having more film acreage to work with.
That said -- there is a bit of "because we can" here as well. When they made The Dark Knight, they apparently didn't want to compromise in any way.
[disclaimer: I'm VFX supervisor for a film in production right now, with some 1000 shots...none of which we are doing at 8K]
What you do is you take their comments, and edit them, to make them say exactly the opposite of what they are saying. So, if they say
Rob Sucks!
You can edit it to say
Rob did a great job.
Or something like that. It's really frustrating for trolls to find that their comments become benign.
Or, just ignore them. That works too!
Finally, what some people do is a little tricky. You ban their IPs, so that nobody *but them* can see their post. They think they are posting some vicious flames, and it shows up when they view the site, but nobody else (not even you, if you want) see it.
Yes, you can compare the 230mpg with all of the other plug-in hybrids out there.
Oh, right, there aren't any.
Seriously, I don't believe that Aptera has even built a hybrid version of the car yet, all the prototyping has been done on a relatively-easy-to-build pure electric car. The 230mpg is a projection based on that data.
At 70mph, even with a.11 drag coefficient, tiny hard tires, and very light weight, it's hard to believe they could get anywhere near 230mpg under gasoline power. Maybe 120 mpg would be possible. Even at that, though, it would be a revolutionary car. [I say "would" instead of "will" because while I would dearly love the company to succeed, there are thousands of failed car companies for every one that succeeds, and Aptera is trying something harder than most of them]
Well, this is pretty much what the Prius does. I never had an automatic transmission car until now, because finally there is a computer that can do a much better job of it than I can.
The various modes that the Prius drivetrain executes to maximize efficiency and minimize pollutants will blow your mind. Feature this -- for tooling around town when the engine is already warm, one of the electric motors actually adds a load to the engine just to keep the RPMs down to the most efficient mode, and stores the resulting energy so that the car can be pure electric at low speeds -- exactly the burn/coast feature that the grandparent article is referring to.
Slashdot Mirror
Wow. Just wow.
> No you idiot, it's to upgrade. It isn't crippled because you're perfectly aware of what you're going to buy in the first place.
If the earth is 8000 miles in diameter, the L2 point 930,000 miles from earth, the sun is 870,000 miles in diameter, and 93,000,000 miles from earth, then the sun will subtend about .53 degree in the sky from the L2 point, and the earth will subtend about .49 degree. So -- the sun will be eclipsed by the earth, but it will be an annular eclipse -- even if the Hershel and Planck were right in the middle of the shadow, they would see a rim of sun all around the earth.
Is my math wrong? Or are these telescopes still going to be in light, even if it's only 4% as bright as the full sun.
The THAAD system has never been deployed. It's always been a sore point for me -- typical headlines in Aviation Week are "THAAD fails tests for the third time in a row", or "THAAD deployment delayed yet again", or "THAAD does not live up to promises."
Kinda pisses me off.
Thad [just one A!] Beier
If you saw the movie Jarhead, it was all told from the perspective and point-of-view of a soldier -- you never saw the "big picture" of the war...there were no helicopter or crane shots, it was all shot from eye-level.
Forever War is told that same way, from one soldier's point of view...and it's clear that he has no idea what is going on in the war in general...although you also get the feeling that nobody else does, either. The way that the movie skips through time with each long near-lightspeed trip makes his adventure even harder for him to understand -- the whole world changes dramatically with each hop.
I think that unlike a lot of SF books, this one really could be made into a good movie, that would capture the richness of each of the episodes in imagery that takes Haldeman many many pages to describe. I just hope that they just let the audience be as confused and out-of-sorts as the narrator is.
Forever War seems to be one of those "writer's first books" [like Grisham's A Time for a Kill, Pirsig's Zen and the Art of Motorcycle Maintenance, Hofsteader's Godel Escher Bach] that was slaved over, re-editted, re-written, re-thought, and probably submitted to publishers a dozen times before it finally saw print, because it is as tight a book as I have read. There's nothing wasted, there's nothing overly described that is better left to the reader's imagination.
Great choice, Ridley.
Mini has made a bunch of electric Mini's, that they're trying to get into the hands of drivers. After going through a long and actually pretty funny questionnaire, I didn't hear anything from them for six months.
Last week they called me to say the car was ready for me if I wanted it. Unfortunately, the terms were unchanged from the original offer -- they want $850/month for a one-year lease -- and there is no way to keep the car longer than that.
I suppose they'll get some people to sign up for it -- and an electric Mini is a lot more exotic a car than a production European Fiesta, but still...$850/month (they suggest that it's probably more like $1K/month after various fees and such)
Haven't seen one on the road yet.
Thanks...I suppose I was in GOCE rapture this morning when I read about it, and I was more harsh than I should have been. It's good to hear about the work that you're doing, and that you're possibly going to do a GRACE2. What are the other new features of GRACE2 over GRACE?
I love the apparent simplicity of GRACE -- I say apparent because I know there's a mountain of math between the distance measurements and the geoid data. Congratulations on your work, and keep it up!
GOCE is a gravity measuring satellite -- the spiritual successor to the amazing GRACE pair of satellites from a few years ago.
GRACE works by flying two satellites in the same orbit, one a few dozen miles ahead of the other. By monitoring the distance between the satellites with laser rangefinders, one can measure how strong gravity is -- the more gravity, the faster the satellite goes, so the distance between the satellites grows until the second one reaches the same area. This was the state-of-the-art, and GRACE made some amazing measurements. It was able, for instance, to measure the amount of extra groundwater during flooding along the Mississippi.
But GOCE does it all with one satellite. Where the baseline for GRACE was many miles, for GOCE it is just 50 cm.
Now, if you think about it, in any satellite, the amount of gravity you would feel is zero...or at least, very very close to zero, as you are orbiting inertially. But, really, gravity is only zero right at the center of mass of the satellite. You'd feel a tiny amount of acceleration the further you go. As you go toward the center of the earth, you would be in a lower orbit, and you would be pulled down with respect to the satellite.
GOCE measures this microgravity to rediculous precision. By measuring the difference in gravity affecting two test masses 50 cm apart, it can measure how strong gravity is at that point. It should have much better accuracy, and far better resolution, than GRACE.
GOCE is amazing in other ways, too. It flies very low, to get better resolution. So, it has fins! A satellite with fins, to keep it pointing along the direction of travel. Because there is some tiny amount of air drag at the altitude it is flying, GOCE has a tiny xenon ion engine pushing it along to keep it at the same altitude, and to keep the air drag on the satellite from overwhelming the gravity measurement.
Hats off to ESA, this is an amazing machine!
Sunking2,
If you think about it just a bit longer, you'd be surprised how much that car trip would cost. Your Jeep Liberty cost about $25,000, and let's be generous and say that you'll drive it 150,000 miles with no maintenance costs whatsoever. Then the 350 miles cost another $58 in wear and tear on the car. It probably makes sense to add in insurance costs as well, if you drive 15,000 miles per year and pay $500 in insurance, then the insurance costs were another $10. Oil changes every 5,000 miles at $30, then that's another $2 for your 350 mile trip.
When I realistically add up all the costs of driving my Prius, I get to something on the order of $0.67/mile (calculated from here.)
So, your 350 mile trip would cost me something north of $200 in direct attributable costs.
Now, it is true that if you have multiple passengers, cars start to make a whole lot more sense. And yes, it's great to have the mobility when you get there. But looking at just gas costs are not a realistic way of measuring your own costs.
There are a number of extremely interesting bits of science in the book, that make it worth the read. They remind me of the Sumerian discourse at the heart of Snowcrash, and are just as stimulating -- Anathem will keep you thinking long after you read the final page.
But there are a few bits of orbital mechanics that are just wrong wrong wrong. And Stephenson would know that they are wrong. And any one of the scientifically literate reviewers would have known they were wrong. I just don't know why they were left in the book.
I do feel, too, that there was a bit of Harry Potter in Anathem too -- he would make up some completely ridiculous "technology" (at least in Harry Potter they call it magic) when it was necessary.
Nevertheless...these small flaws don't detract too much from the quality of the whole book. I would recommend it highly.
It's already being done, and very successfully.
Unfortunately, it's all being done by criminal gangs using botnets. But, it is a proof of concept!
This is not a satellite photo -- it is an aerial photo. 1m resolution just wouldn't show the detail that we see here. The ballfield (100 m long) is about 135 pixels long, less than 1 m/pixel.
How can this be a satellite photo?
Thad
This telescope is amazing. The three-mirror configuration gives sharp focus, over a very wide field...the only problem is that the focus is on a spherical surface.
The LSST fixes this by having three relatively small (small compared to the mirrors) lenses to flatten the field, and they use a very large image sensor.
I am curious if they considered using a non-flat image sensor. It would be hard, but with e-beam or UV-laser lithography, I would think that you would be able to build a big sensor on a curved surface, and eliminate the inevitable light loss, distortion, chromatic abberations, and other problems with lenses.
This is something that could be added in the future, too, much as Hubble was modified after-the-fact. It just seems to this layman that it's too good an idea to pass up.
My daughter and I did this too with her college recruitment interviews. It's silly not to. Why not mention her years of jujitsu training if it turns out the interviewer is a martial arts freak?
Ok, she still didn't get into Brown...
Thad
Really -- can we sue the other 80% for malpractice?
Thad
No cadmium in a Prius -- it's NiMH.
It's my first non-standard shift car. Finally computers are better at it than a human can be. The continuously variable transmission in the Prius is truly the eighth wonder of the world.
But yeah, walking and biking are a far better idea than driving will ever be.
Yeah -- the statement my Prius makes is "engineering matters." It's why I bought mine. It's a damn good reason.
It turns out that it's a hell of a car.
Very few people understand the astonishing lengths Toyota has gone to with the Prius, to make it a low-emissions car. For some reason, Toyota doesn't talk about it too much. One example is that the car has a thermos bottle in the front, where all the radiator fluid is pumped after you shut off the car -- and is pumped from when you "start" the car. For the first 7 seconds, the radiator fluid is circulate through the engine to warm it up before the gas engine actually starts, to lower the emissions and wear associated with starting a stone-cold engine.
My wife dreamed of that wedding, it's true (the evidence is the picture she scribbled in my notebook to surprise me) On the other hand, when it was clear that it would be six months of torment to pay for three hours of fairy-tale, she suggested we elope. Been 24 years so far...
But it did come down, which means, some resource got drained... Which one? The batteries, which may have been only partially recharging during the day, is one possible explanation....
The first people to fly a solar-powered plane through the night, Tom Gage and his team at AC Propulsion, flew for 48 hours...and could have probably flown forever -- the resource that was drained was the on-ground pilots.
The plane was flown to use thermals as much as possible during the day, but it was tiring work.
Anyway, after two days, and with a battery charge higher than what they started at, they figured that they had made their point.
When I was in Japan shooting Fast and Furious 3: Tokyo Drift in December 2005, I had nothing to do one day, so I did some walking just to see what wonders there were to see -- and there were many.
The most impressive, though, was a large van...with a one-inch thick sheet of aluminum bolted to the top, on which were mounted four hi-def cameras, four laser scanners, a GPS, and some other gear I didn't recognize. After walking by, walking back, walking away, and walking back again I couldn't help but ask (in English, of course) what they were doing.
You see, for Fast and Furious through 4, we built various camera rigs to film streets, to use as backgrounds for greenscreen work. This was clearly a similar rig, but on steroids. Radioactive mutant steroids.
The best english-speaking person on the crew came up to me and said "Ah, are you engineer?" I wish :) No, I am a filmmaker, but I have to know what you are doing!
He gave me a tour of the whole rig. There were enough computers inside the van to put my computer animation facility to shame. The were driving up and down all the streets of Tokyo, building a 3D, textured model of every building, for use in car navigation units. The geometry information from the laser scanners was merged with the photographic information from the hi-def cameras, and registered with the GPS.
So -- I find the protestations recorded in the article a bit suspect.
You know -- sadly what you are referring to was the Apollo-Soyuz mission of the mid 80's. The Russian KURS automated docking system is used all the time on the space station now, and it has worked flawlessly every time.
It also worked perfectly on the Mir. They did have a docking mishap on the Mir, but that as when they tried to do a manual docking.
Thad
Darren,
In the Good Old Days of photochemical process work, say on Star Wars, it was not uncommon to shoot the visual effects shots on VistaVision and the rest of the movie at normal film resolution. The idea was that the process work at the time added significant grain, blurriness, and reduced contrast to the image, so starting from a larger format with less grain helped make the visual effects shots blend in somewhat more seamlessly.
Doing the process shots on IMAX is a bit of a step up from VistaVision (ok, maybe two steps up!) but it makes some sense. Modern film stocks are much better than what was used on Star Wars, but there will always be something to be said for having more film acreage to work with.
That said -- there is a bit of "because we can" here as well. When they made The Dark Knight, they apparently didn't want to compromise in any way.
[disclaimer: I'm VFX supervisor for a film in production right now, with some 1000 shots...none of which we are doing at 8K]
What you do is you take their comments, and edit them, to make them say exactly the opposite of what they are saying. So, if they say
Rob Sucks!
You can edit it to say
Rob did a great job.
Or something like that. It's really frustrating for trolls to find that their comments become benign.
Or, just ignore them. That works too!
Finally, what some people do is a little tricky. You ban their IPs, so that nobody *but them* can see their post. They think they are posting some vicious flames, and it shows up when they view the site, but nobody else (not even you, if you want) see it.
Yes, you can compare the 230mpg with all of the other plug-in hybrids out there.
Oh, right, there aren't any.
Seriously, I don't believe that Aptera has even built a hybrid version of the car yet, all the prototyping has been done on a relatively-easy-to-build pure electric car. The 230mpg is a projection based on that data.
At 70mph, even with a .11 drag coefficient, tiny hard tires, and very light weight, it's hard to believe they could get anywhere near 230mpg under gasoline power. Maybe 120 mpg would be possible. Even at that, though, it would be a revolutionary car. [I say "would" instead of "will" because while I would dearly love the company to succeed, there are thousands of failed car companies for every one that succeeds, and Aptera is trying something harder than most of them]
Well, the Toyota Highlander and the Lexus RX300, for a time, were basically the same car with the Lexus a little curvier and $5,000 more expensive.
I think Toyota sold a bunch of both of them. My wife bought the Lexus, to my dismay...
Thad
Well, this is pretty much what the Prius does. I never had an automatic transmission car until now, because finally there is a computer that can do a much better job of it than I can.
The various modes that the Prius drivetrain executes to maximize efficiency and minimize pollutants will blow your mind. Feature this -- for tooling around town when the engine is already warm, one of the electric motors actually adds a load to the engine just to keep the RPMs down to the most efficient mode, and stores the resulting energy so that the car can be pure electric at low speeds -- exactly the burn/coast feature that the grandparent article is referring to.