The difference is that you can (and a lot of people do) request your gold bars to be delivered to a specific shipping address, and make them into jewelry, electronics or medicines. Or even plate your Ferrari.
Gold has tangible value of a metal with legit technical and artistic uses. Law always treats it as commodity, not currency.
Even dollars would be more 'commodity' than bitcoin: you can get a big bag of pennies, drill holes in the middle and use them as washers for nails of your roofing. There is absolutely no practical use for it other than value carrier = currency.
Because it's primarily collector / novelty item and only coincidentally carries monetary value. You don't get the physical bitcoins to pay for wares, but to keep it in display case. And you pay more than 1BTC for it.
Regardless, that would only apply to the *coin* version of bitcoin - these gadgets that are coins with tamper-evident sticker with a btc wallet data contained within.
It would be very weird if purely electronic currency was covered by noble metal items trade laws.
Let me see you build a device from a walmart clock and a pencil case, that will get you a nation-wide fame, invitation to the White House and Google, and a Quatar scholarship. It may be lousy at measuring time, or as a showcase of technical skill, but it was totally awesome at earning him publicity. Shun the technical side all you want, the clock was a true masterpiece of social engineering.
Your point breaks at "grabbed a bar". No, they didn't grab any bar anywhere where the rotation would act as "simulated gravity". They appeared as if sucked into the tube, which would work with air moving there; moving in freefall they won't be dragged anywhere. They might crash against the wall of the tube and then be dragged "downward", but as long as they don't touch any of the structure, the virtual centripetal force doesn't appear.
But at the same time, when light is coming from LED lighting, you have to account for stray lighting (light that's not hitting your grow area) and efficiencies at generating PAR, which are 20-30% for proper grow lights, lower for normal room lights (as the phosphor wastes part of the light energy to make it a comfortable white rather than a painful pink).
Did you account for PAR fraction of sunlight? LED growth lights have a significantly better PAR coefficient than sunlight - which covers much wider "waste" spectrum than normal room lights. And actually, solar panels have a pretty wide absorption spectrum, so, while we aren't there *quite* yet, it may be in the future that grow-light - solar panel combo will be more efficient than direct sunlight over the same area - and especially with extra batteries storing energy above the saturation level and expending it during weaker sunlight.
As for stray light - With large area growth, stray light isn't that much of a problem. The light that doesn't hit the square below the lamp, hits the neighbor square, and the loss is then covered by stray light from the neighbor lamp. As for the rest, I believe LED efficiencies already account for directionality, light absorbed by the LED casing.
Not even close. Your solar array too has a capacity factor - in the ballpark of 15% if fixed, maybe 35% or so if tracking. Then you have your panel efficiencies. The best large scale commercial panels are 22-23% efficiency. You might get 30%-ish if you used absurdly-crazy-expensive spectrolab cells. Then factor in dust constantly settling on the panels - say 25% loss even with regular cleaning. And Mars's solar constant is only 588W/m^2 *in space*. Earth's is about 1kW/m^2 *on the surface*, 1,4kW in space.
I went with 50% efficiency reduced to 0.7 by morning/evening angles with lack of tracking (Acidia Planitia is equatorial latitudes). That's 2035 space-quality technology. Dust with daily cleaning is non-factor; Opportunity operated for years within some 40-50% loss due to dust, so with daily cleanings it's really non-issue, maybe 2% loss, your 25% would take months of negligence. Due to thin atmosphere, Mars is only something like 560W on surface.
6kW of power consumption for LED lights on a rover?
Only when it switches all of them on. There's a difference between "driving usage" where it may be 500W, and switching the search-lights for emergency when you, say, search for a lost astronaut. In that case 6KW is reasonable.
How the heck would you even cool a 500W LED spotlight (let alone 1kW, let alone 12 of them) in the near-vacuum atmosphere of Mars?
I'd need to come up with estimate of radiation of the surface of Hab, but it's large, white and in very cold environment. There's a plenty of cooling capacity in environment this cold. Yes, air-cooling capacity is poor, but radiational capacity is pretty good considering the radiating surface and the temperature gradient.
I wish you were here so I could show you what a 600W LED grow light looks like. It's blinding. The whole world looks pink for a while afterward. And they're massive, heavy things. To put it another way: 600W LED is equivalent to about 5000W incandescent.
The area lit by them shouldn't be brighter than sunlit area - actually, 25% of sunlight strength would suffice.
Could have, would have, should have. But as it stands, it's 2-3 orders of magnitude off.
We can agree to disagree, I'd say about an order:) But yes, I can accept the botany part of the book was borked. There are more serious errors. Had Weir played Kerbal Space Program for several days, the whole "blowing up the airlock" would be gone - at 2mm/s^2 making a perfect encounter with target moving 12m/s relative to you is some 8 hours.
Still, I have to give it to him: he tried, he did his best, he only made errors because he failed to research even more even though he researched a plenty. We can now hope for a book more accurate, with better science and less errors, now that he's opened the path and showed there's a demand for accurate sci-fi. Even if his own failed to be very accurate.
sh1t, did some serious math, then accidentally closed the tab. First, 1KW light output is if you want Earth's equatorial sunlight, which is far more than plants need - they saturate their input at far less than that. I arrived at 500W (input) of LEDs to produce the needed output for 1m^2, and about 2.5m^2 of solar panels to power them up.
Still, obtaining the needed lamps - yep, 1m^2 per spotlight, 12 per rover (per movie), 10 from other sources, Hab lighting for another 4 or so meters... weaker sources focused on individual plants not to waste energy on lighting up empty soil... that still runs awfully short of the goal, something like 1/3 of what he planned. Not nearly as bad as you predicted, but not nearly as good as Weir thought.
I wonder how much could be saved by adapting growth density. Say, he could light up all the saplings with 2-3 lights, but as plants grow, they need more space. So instead of one massive harvest, to make it so that the grown plants take half the available light, grown in 3/4 half of the remainder, half-grown half of the remainder of that, and so on.
Alternatively, how lethal would space radiation be to potatoes? An extra "tunnel" from transparent plastic, where mature plants would use direct sunlight.
oh, wait. One more thing. As ludicrous you might think the "iron man"...
The only thing really impossible about the whole mission plan is the budget.
A mission like Ares 3 could have been launched today, if NASA budget had never been cut after the Apollo program.
Now, if one of the astronauts was left behind, stranded, getting him back to Earth would be far trickier and quite likely impossible. But the Ares 3 mission plan was sound and doable. It's the events triggered by completely impossible storm that were a serious stretch.
Give the habitat spotlights from Rover 1, spotlights from MDV, spotlights from Hab's outside lighting and all the spare bulbs for everything.
The solar panels are hindered by fixed angle and distance from the Sun, but boosted by equatorial latitude and thin atmosphere not dissipating nearly as much light as Earth. Although yeah, 11% is lousy. Let's assume space technology of 2035, and give them a healthy 65%, blaming the 11% on Mark being a botanist.
Remember, individual care of individual plants, optimal temperature and humidity, exploiting the soil to the max, battery power for extended "daylight".
don't products of decay of Pu-238 create all other kinds of radiation than Alpha? With it sitting there for a couple years, there would be quite a few...
It's not *that* bad - he used electric lighting and the solar farm was much bigger than Hab, so consider sunlight->electricity->light used that way a kind of lensing. His plan to condense moisture was silly but it wouldn't come to it with the water reclaimer and the dry soil acting as a sponge. Never mind any running electronics would be warmer than the walls exposed to near-vacuum on the other side, meaning a plenty of condensing surface long before the electronics would be endangered. But yeah, he'd first have to purify the soil. Doable, not very hard, but not done. And his growing methods were... uh, "unorthodox";)
Well, a tested method in the army here, to get a few days off e.g. missing some heavy exercises, was to eat a couple raw potatoes. Guaranteed heavy diarrhea and a bit of fever.
They aren't so poisonous as to "eat one and you die" and I guess a few slices surely won't hurt, but a few potatoes eaten raw just cause a severe indigestion. I believe it's completely apart from solanine, simply human digestion is incapable of dissolving any bigger pieces of them properly.
unlikely to be soon - too early after cinema premiere. BTW, for the story, read the book, it's vastly superior. For the visuals go to 3D theater, they made Mars beautiful. Home-viewing quality of the movie is the worst of both worlds.
Not entirely impossible, just unlikely. There was a lot that could go wrong, and very likely to go wrong. The deceleration through blowing the airlock would most likely send Hermes spinning instead of decelerating, the opening not being a precise nozzle but a random hole directing the air outside at a random angle. The rocket would most likely be unbalanced after such heavy strip-down, sending it spinning again.
OTOH everyone overestimates the "one chance" they had at the encounter.
You're moving 12m/s away from the target. To reach 12m/s at 2mm/s^2 you need 6000s or 100 minutes. That puts the target at 72km distance. Now give it a chase. Accelerate for half of that distance, decelerate the other half. 6m/s top speed, average 3m/s relative speed. That's another 6.6 hours. Mark would need to spend about 8 hours waiting for Hermes to smoothly make a perfect rendez-vous after failing the initial encounter. There's no time pression of time like with suborbital trajectory - they are both on escape trajectory. Hermes would get a little off Purnell Maneuver trajectory, but 72km offset and 12m/s error is practically nothing for this kind of mission. The whole panic was simply unnecessary.
Andy Weir explained in one of the interviews that it was the only point where he used his artistic license against hard science. "I wanted Mars to deliver the first punch". He said he could have done this differently, but he wanted this to be Nature's fault, not a human shortcoming.
He stayed true to science best to his ability the rest of the time. Not that he didn't make any mistakes - he made quite a few, but none of them were intentional violations, just his lack of universal knowledge - or developments that happened after he wrote the book.
To name a few: - water content in soil, making Hydrazine burning moot. - Chlorides content in soil, making it totally unsuitable for plants and harmful to health, unless purified. - raw potatoes being merely "awful" while in reality they are quite poisonous. - hydrazine reaction heat being neglected (someone calculated it would heat up the Hab to 400C). - space radiation being handwaved away by "Hab is radiation-proof" while it's an inflatable structure.
When Mozilla - the new browser - was becoming muddled with senseless features and cumbersome crap, someone forked it and created project Phoenix. It was lean, simple, fast and reliable. People loved it and switched to it en masse.
Due to trademark problems, Phoenix was renamed to Firebird, and later to Firefox.
Mozilla team mostly abandonned Mozilla, leaving only a slowly dying "Seamonkey" branch, and moved to Firefox. And they immediately began shitting it up just like they did with original Mozilla. Currently the shit-up is reaching its apogeum.
Someone needs to fork it again and start a new Phoenix. And don't let the current team touch it!
Uh, I believe they use it already. There was a movie about one of them, particularly successful, entered the canon of classics. The title was "Scarface".
Slashdot Mirror
If you RTFA you'll see the exact opposite of what you claim. Would you please stop misinforming people?
The difference is that you can (and a lot of people do) request your gold bars to be delivered to a specific shipping address, and make them into jewelry, electronics or medicines. Or even plate your Ferrari.
Gold has tangible value of a metal with legit technical and artistic uses. Law always treats it as commodity, not currency.
Even dollars would be more 'commodity' than bitcoin: you can get a big bag of pennies, drill holes in the middle and use them as washers for nails of your roofing. There is absolutely no practical use for it other than value carrier = currency.
Because it's primarily collector / novelty item and only coincidentally carries monetary value.
You don't get the physical bitcoins to pay for wares, but to keep it in display case. And you pay more than 1BTC for it.
The coin dealer charges fee, service fee, etc are taxable, so you're paying for the coin, for the service, and tax on the service.
OTOH you can just pay for a hot-dog with a silver coin, and there would be no tax (other than normal sales tax).
I believe even the seller could give you the silver dollar as change for said hot-dog and no tax on that would appear (only on the hot-dog purchase).
It all changes though, if you want to charge $10 for a $1 coin... in this case it's not a currency exchange, it's an item trade.
Regardless, that would only apply to the *coin* version of bitcoin - these gadgets that are coins with tamper-evident sticker with a btc wallet data contained within.
It would be very weird if purely electronic currency was covered by noble metal items trade laws.
I'd say the invention was quite brilliant.
Let me see you build a device from a walmart clock and a pencil case, that will get you a nation-wide fame, invitation to the White House and Google, and a Quatar scholarship.
It may be lousy at measuring time, or as a showcase of technical skill, but it was totally awesome at earning him publicity. Shun the technical side all you want, the clock was a true masterpiece of social engineering.
Yellowstone is one... are there any others? How many? Where?
Your point breaks at "grabbed a bar". No, they didn't grab any bar anywhere where the rotation would act as "simulated gravity". They appeared as if sucked into the tube, which would work with air moving there; moving in freefall they won't be dragged anywhere. They might crash against the wall of the tube and then be dragged "downward", but as long as they don't touch any of the structure, the virtual centripetal force doesn't appear.
One thing more:
Did you account for PAR fraction of sunlight? LED growth lights have a significantly better PAR coefficient than sunlight - which covers much wider "waste" spectrum than normal room lights. And actually, solar panels have a pretty wide absorption spectrum, so, while we aren't there *quite* yet, it may be in the future that grow-light - solar panel combo will be more efficient than direct sunlight over the same area - and especially with extra batteries storing energy above the saturation level and expending it during weaker sunlight.
As for stray light - With large area growth, stray light isn't that much of a problem. The light that doesn't hit the square below the lamp, hits the neighbor square, and the loss is then covered by stray light from the neighbor lamp. As for the rest, I believe LED efficiencies already account for directionality, light absorbed by the LED casing.
I went with 50% efficiency reduced to 0.7 by morning/evening angles with lack of tracking (Acidia Planitia is equatorial latitudes). That's 2035 space-quality technology. Dust with daily cleaning is non-factor; Opportunity operated for years within some 40-50% loss due to dust, so with daily cleanings it's really non-issue, maybe 2% loss, your 25% would take months of negligence. Due to thin atmosphere, Mars is only something like 560W on surface.
Only when it switches all of them on. There's a difference between "driving usage" where it may be 500W, and switching the search-lights for emergency when you, say, search for a lost astronaut. In that case 6KW is reasonable.
I'd need to come up with estimate of radiation of the surface of Hab, but it's large, white and in very cold environment. There's a plenty of cooling capacity in environment this cold. Yes, air-cooling capacity is poor, but radiational capacity is pretty good considering the radiating surface and the temperature gradient.
The area lit by them shouldn't be brighter than sunlit area - actually, 25% of sunlight strength would suffice.
We can agree to disagree, I'd say about an order :) But yes, I can accept the botany part of the book was borked. There are more serious errors. Had Weir played Kerbal Space Program for several days, the whole "blowing up the airlock" would be gone - at 2mm/s^2 making a perfect encounter with target moving 12m/s relative to you is some 8 hours.
Still, I have to give it to him: he tried, he did his best, he only made errors because he failed to research even more even though he researched a plenty. We can now hope for a book more accurate, with better science and less errors, now that he's opened the path and showed there's a demand for accurate sci-fi. Even if his own failed to be very accurate.
sh1t, did some serious math, then accidentally closed the tab.
First, 1KW light output is if you want Earth's equatorial sunlight, which is far more than plants need - they saturate their input at far less than that. I arrived at 500W (input) of LEDs to produce the needed output for 1m^2, and about 2.5m^2 of solar panels to power them up.
Still, obtaining the needed lamps - yep, 1m^2 per spotlight, 12 per rover (per movie), 10 from other sources, Hab lighting for another 4 or so meters... weaker sources focused on individual plants not to waste energy on lighting up empty soil... that still runs awfully short of the goal, something like 1/3 of what he planned. Not nearly as bad as you predicted, but not nearly as good as Weir thought.
I wonder how much could be saved by adapting growth density. Say, he could light up all the saplings with 2-3 lights, but as plants grow, they need more space. So instead of one massive harvest, to make it so that the grown plants take half the available light, grown in 3/4 half of the remainder, half-grown half of the remainder of that, and so on.
Alternatively, how lethal would space radiation be to potatoes? An extra "tunnel" from transparent plastic, where mature plants would use direct sunlight.
oh, wait. One more thing. As ludicrous you might think the "iron man"...
The only thing really impossible about the whole mission plan is the budget.
A mission like Ares 3 could have been launched today, if NASA budget had never been cut after the Apollo program.
Now, if one of the astronauts was left behind, stranded, getting him back to Earth would be far trickier and quite likely impossible. But the Ares 3 mission plan was sound and doable. It's the events triggered by completely impossible storm that were a serious stretch.
He ate them raw at one point. That's why he decided for the microwaving spree.
Give the habitat spotlights from Rover 1, spotlights from MDV, spotlights from Hab's outside lighting and all the spare bulbs for everything.
The solar panels are hindered by fixed angle and distance from the Sun, but boosted by equatorial latitude and thin atmosphere not dissipating nearly as much light as Earth. Although yeah, 11% is lousy. Let's assume space technology of 2035, and give them a healthy 65%, blaming the 11% on Mark being a botanist.
Remember, individual care of individual plants, optimal temperature and humidity, exploiting the soil to the max, battery power for extended "daylight".
How would the figures look like then?
don't products of decay of Pu-238 create all other kinds of radiation than Alpha? With it sitting there for a couple years, there would be quite a few...
yep, my mistake, noticed only after posting.
Thing is they *are* awful so you want to be done with them quickly... so no thorough chewing there usually.
It's not *that* bad - he used electric lighting and the solar farm was much bigger than Hab, so consider sunlight->electricity->light used that way a kind of lensing. ;)
His plan to condense moisture was silly but it wouldn't come to it with the water reclaimer and the dry soil acting as a sponge. Never mind any running electronics would be warmer than the walls exposed to near-vacuum on the other side, meaning a plenty of condensing surface long before the electronics would be endangered.
But yeah, he'd first have to purify the soil. Doable, not very hard, but not done. And his growing methods were... uh, "unorthodox"
Well, a tested method in the army here, to get a few days off e.g. missing some heavy exercises, was to eat a couple raw potatoes. Guaranteed heavy diarrhea and a bit of fever.
They aren't so poisonous as to "eat one and you die" and I guess a few slices surely won't hurt, but a few potatoes eaten raw just cause a severe indigestion. I believe it's completely apart from solanine, simply human digestion is incapable of dissolving any bigger pieces of them properly.
unlikely to be soon - too early after cinema premiere. BTW, for the story, read the book, it's vastly superior. For the visuals go to 3D theater, they made Mars beautiful. Home-viewing quality of the movie is the worst of both worlds.
Not entirely impossible, just unlikely. There was a lot that could go wrong, and very likely to go wrong. The deceleration through blowing the airlock would most likely send Hermes spinning instead of decelerating, the opening not being a precise nozzle but a random hole directing the air outside at a random angle. The rocket would most likely be unbalanced after such heavy strip-down, sending it spinning again.
OTOH everyone overestimates the "one chance" they had at the encounter.
You're moving 12m/s away from the target.
To reach 12m/s at 2mm/s^2 you need 6000s or 100 minutes. That puts the target at 72km distance.
Now give it a chase. Accelerate for half of that distance, decelerate the other half. 6m/s top speed, average 3m/s relative speed. That's another 6.6 hours.
Mark would need to spend about 8 hours waiting for Hermes to smoothly make a perfect rendez-vous after failing the initial encounter. There's no time pression of time like with suborbital trajectory - they are both on escape trajectory. Hermes would get a little off Purnell Maneuver trajectory, but 72km offset and 12m/s error is practically nothing for this kind of mission. The whole panic was simply unnecessary.
Andy Weir explained in one of the interviews that it was the only point where he used his artistic license against hard science. "I wanted Mars to deliver the first punch". He said he could have done this differently, but he wanted this to be Nature's fault, not a human shortcoming.
He stayed true to science best to his ability the rest of the time. Not that he didn't make any mistakes - he made quite a few, but none of them were intentional violations, just his lack of universal knowledge - or developments that happened after he wrote the book.
To name a few:
- water content in soil, making Hydrazine burning moot.
- Chlorides content in soil, making it totally unsuitable for plants and harmful to health, unless purified.
- raw potatoes being merely "awful" while in reality they are quite poisonous.
- hydrazine reaction heat being neglected (someone calculated it would heat up the Hab to 400C).
- space radiation being handwaved away by "Hab is radiation-proof" while it's an inflatable structure.
When Mozilla - the new browser - was becoming muddled with senseless features and cumbersome crap, someone forked it and created project Phoenix. It was lean, simple, fast and reliable. People loved it and switched to it en masse.
Due to trademark problems, Phoenix was renamed to Firebird, and later to Firefox.
Mozilla team mostly abandonned Mozilla, leaving only a slowly dying "Seamonkey" branch, and moved to Firefox. And they immediately began shitting it up just like they did with original Mozilla. Currently the shit-up is reaching its apogeum.
Someone needs to fork it again and start a new Phoenix. And don't let the current team touch it!
Uh, I believe they use it already.
There was a movie about one of them, particularly successful, entered the canon of classics. The title was "Scarface".
I never need my Free BSD box.
FTFY