But the Moon also appreciably increases the Earth's impact cross section by widening the effective gravity field from the 1/r^2 of a simple system.
There is an awful lot of extrapolation done from the sample of one evolutionary system that we have, and happen to be living in the middle of. And a lot of awful extrapolation.
I haven't been keeping a count, but I do read the daily listings of new papers on Arxiv and I'm more or less up to date (one submission on my desktop at this time) there have been on the order of a dozen proposals from various sources trying various models of tholin/ dust crusting the surface of 'Oumuamua. While it's not exactly an exciting position to take, it is a consensus position.
Do your own homework. I have, to match the extent that I care about the topic.
Would something you "hollow out" be anything like an optimal shape for maximising area of rotational pseudo-gravity interior surface versus external mass of radiation shielding (bagged dirt)? Personally, I'd suspect that the near-optimal strategy would be to reconstruct a (small) nickel-iron rich asteroid into your habitat then wrap it with (bagged) debris from another dirty-snowball to put something like 10m water-equivalent of radiation-shielding between the population and the outside universe. Since most of the fime-of-flight would be in the "dark of outer space" (cue Star Trek style voiceover), optimising the shape to use "free" "sun"-light to feet the plants would probably be a WOMBAT.
I suppose I'd better RTFA before commenting further. But a 10:1 end-over-end light curve does not sound very optimal to me.
A ship which housed some 3000 crew, and got about 18 feet per gallon of oil burned.
That sounds in the scale for an aircraft carrier? Sounds rather overkill. I can think of around a half-dozen "floatels" ("floating hotels") which include their own medical suites, helipads and hangers, craneage, marine and stewarding personnel (and medical too), which can take complements of 200 to 500. OK, most are on medium- to long-term lease alongside various fixed oil installations and the like to support (re-)construction. But it's a mature market, with assets being shipped between corners of the globe in response to tenders for hire. Certainly worth considering on cost.
BUT, it's not "shiny" - more likely rusty - so it's quite unlikely that the idea would get past the PR department.
I understand the need for elephants in space [...] so you need to send the same number of turtles.
Ummm, no. You need a minimum of three elephants per turtle in order to form a turtle-elephant bilayer in your stack of turtles. Otherwise the stack becomes unstable. If your elephants and turtles are of uniform size then you can have more elephants per turtle, but three is the minimum.
Of course, since they're both countable infinities, they're the same size (see Hilbert's Hotel argument), even if one has infinitely many elephants per turtle, you'd still have the same number of of turtles and elephants.
A self driving car should protect its passengers first or they wouldn't sell.
And as soon as that happens... the inflatable "plastic passengers" which are used to fool surveillance cameras on "dual occupancy" or car pool lanes will start being weighted, so the car thinks it has an actual passenger on board, and therefore be more likely to protect the driver by proxy.
My first guess would be that users would fill the inflatable legs and torso with water, to trip the weight sensor in the seat.
More ikely the issue with Mars is that it's only about 1/10 the mass of Earth (0.1075 from my notebook) so it's just a lot easier for the atmosphere to get ablated. Yes, the lack of magnetic field is a component of Mars' atmospheric loss, but not the main one.
Step 1 - that's going to be pretty tricky. Judging from the work that has been done w.r.t Earth, you're looking at an impactor around the size of Mars.
Now, don't get me wrong - I don't have any intrinsic objection to using Mars to terraform Venus. But some of the people left on Earth might be a little concerned about you manoeuvring such a lump of rock past their windows. Maybe move them out somewhere else while you're doing the "heavy lifting".
Step 2Hmm, you're going to have to move around 80% of the mass of the planet temporarily into orbit while you're spinning up your core. (Actually, for a geodynamo, you probably need differential rotation between two solids, separated by a conducting fluid. Slightly different to your scenario. Tricky. Might it not be easier to just call up Slartibartfast and get a quote from the Magratheians?
Steps 3 and 4 need to be inverted.
It's a plan. Version 0.1 ; let's rework to 0.2 before going for an ICO?
But the mass isn't humans, or even agriculture; it's the ascent vehicle. More specifically, the propellant in the ascent vehicle.Or, or a long term mission, the heavy life support machinery (the equivalent of Biosphere 1 & 2's "oceans") hangs down there. Along with any "ascent vehicle" that you're in the process of refuelling, for those faint hearts and administrators (or non-convicts) who might want to go back to Earth.
I don't think I've seen the episode of Twilight Zone to which you refer, but "meh".
An attempt to terraform Venus would certainly make more sense than trying to terraform Mars, because you wouldn't need to find and transport millions of volatile rich bodies from the outer solar system. Which bodies might simply not exist, or might be spread at multi-million km spacings through the outer 10^30-odd km^3 of the Solar system. Enjoy the hunt - it'll take the rest of your life.
For Venus, the volatiles are there already. Some of them (well, 96% or so of them) need to be stripped out and thrown on the ground. Which is convenient, as we have multitudes of microbes that can convert the material (most) of Venus' atmosphere into materials that when heated will release water, oxygen and refractory carbon. OK, it'll take a few millennia to drop 95% of the atmosphere to the surface as carbon dust, and we'd probably need to do something to absorb some of the oxygen released. But hey, it's going to be orders of magnitude quicker than trying to collect the volatiles Mars needs.
maybe this stuff could be used on hypersonic aircraft or spacecraft heat shields.The material is a mix of tungsten metal, tungsten and zirconium carbides and zirconium metal, with minor copper. Densities of 19.3 - 17.6 (g/cc ~= Mg/m^3, room temperature to melting point, W), 15.6 to 6.7 (WC to ZrC, proportions unclear) and 6.5 - 5.8 (Zr). Those densities are not good for flying anything. Indeed, if possible, for moving at all.
Back in the early 1980s, I had an exam exercise to work out whether aluminium or copper would be better for making power line cables, and present reasons. I spotted the trap, did the appropriate calculations on the data provided, and showed that aluminium would weigh about half what a copper cable would do, saving considerably in the cost of the support structures as well as the raw metal cost. You need to do equivalent calculations for these materials. At 1023K and 20MPa (200 atmospheres, modest pressure), you might get better weight/ performance ratio from tough steel ("HSS", or equivalent) with a platinum interior lining.
At this point it's unlikely he would be killed.You can write this after the cock-sucking that Trump has been giving to Saudi Arabia over the killing of Jamal Khashoggi in Istanbul? A problematic fucker like Assange is going to have the life expectancy of a snowflake in hell if the American get hold of him. Or one of their stooges, like the Swedes. He is completely justified in his expectation of death for being politically inconvenient.
Or did you, for some deluded reason, think that "America is better than that"? Oh, man, that's such an Obama-era "alternative fact".
This kind of sloppy programming needs to come with easy-to-litigate civil remedie$ and then maybe it will stop.Didn't you read the fucking software agreement before using it? The bit that disclaimed it's fitness for any particular purpose, and limited all liability to the sale value of the software. At least, that's how I read typical EULAs.
Errr, let's see. That would be for a PP(O2) of 2 atmospheres, and for normal air at 20% v/v O2, that implies a total air pressure of 10 atmospheres. I get that at between 20 and 30km depth, depending on the model of atmospheric compression you choose.
Ah, you've been watching that "rip an arm off every second day" comedy series. They're in the Aleutian chain, aren't they. Just over 53deg N. They'd probably need to add deck-mount fuel tanks to be able to cruise up to the edge of the area. Or refuel at Nome.
The areas under consideration start north of 64degN. That's 1200+km north from the relatively clement seas they operate in. Hell, I've worked at sea further north than that, and I don't consider myself arctic-specification. Abigail and Miguel spent much more time in the North on the Greenland job (and they're just people I've shared cabins with!)
(Why reliable ones still so expensive?)Because sensors drift (or are extremely expensive), and so need calibration. Which takes time, expertise and continuing documentation. None of which come cheap.
The sonar gear used to do deep scans doesn't take up that much space.Up to a second or so of two-way time (TWT). But since the power requirements scale as more than 4d^2 for increasing d(istance), you won't get far with that. For my interpretative work, we're normally needing 8 to 10 seconds TWT. For that, you need to release many MJ per shot. And to improve signal-to-noise ratio, you would want to stack shots at least 16 fold, and preferably 64-fold, which is largely determined by thee length of your hydrophone streamer and engine power for towing it.
The toy systems you're talking about will penetrate a couple of hundred metres of water, ping off intermediate fish shoals (main market) or tell you about the top few centimetres of the seabed (mud, sand, metal give different signals, for the second market).
A one-way sonar spread (geophones lowered downhole) for use in 5km of water depth, and to penetrate to the drilling limit of 6.5 km of rock comprises 2x 40ft shipping containers for the diesel power packs, several stowage containers for the gear, a workshop container for repairs, a 30ft control and recording container, and 7 bedspace. About $100k/day, depending on contract length. Square the power needs for two-way.
Shocking, isn't it, to discover that there is a whole science out there which you've never met before. Three of my classmates went into this industry, and I have to use it on a frequent basis.
A remotely operated floating bed of instruments with GPS.That'd be wonderful. Perhaps I could use the same technology to guide me underwater when I'm caving. Oh, but hang on... aren't radio signals blocked by seawater (and slightly less effectively, in proportion to the water conductivity, by fresh water)? Perhaps that is why I've never once seen an advert for an underwater GPS device. (I have however seen hundreds of adverts though for waterproofed, boat ready GPS units for use on the air-ventilated parts of boats.)
You could probably even get oil exploration companies to help pay for it.They're much more likely to say "Here is a listing of the data we have already acquired. You tell us which areas you want to buy, and we'll tell you the price. We're not going to tell you the price for individual areas, because that might give you commercially sensitive information about which areas we consider more valuable. Oh, and here is an NDA for you to sign, if you want to take the conversation further." When I worked in the right places, I could get to read some of the Arctic contingency planning data. And when I tried to look in more depth... the system security tools would block me and report the access attempt to my line manager.
I'm not saying there's no geological activity, but I'd expect it to move at a glacial pace, so to speak.Actually, the Gakkel ridge is remarkable for being the slowest-spreading and least-active part if the spreading ridge system. It is a peculiar and relatively little-known area. Away from the ridge, the Arctic Ocean seems to be pretty quiet seismically (which can be detected around the world) - which is peculiar given that the plate motions around indicate that there must be movements up there.
P>Personally, if I were still in the business, I know where I'd go to ask. Several oil companies have done a lot of work seeking prospects up there. But equally, I'd expect to be laughed at if I made such a request without a binding contract (or at least a MoU) in place. It's valuable data, after all.
Slashdot Mirror
There is an awful lot of extrapolation done from the sample of one evolutionary system that we have, and happen to be living in the middle of. And a lot of awful extrapolation.
He can't - he's lost the keys to his Tesla.
(I'm about a third of the way through reading the paper, and I decided to check for substantive comment here. Depressing, isn't it?)
I haven't been keeping a count, but I do read the daily listings of new papers on Arxiv and I'm more or less up to date (one submission on my desktop at this time) there have been on the order of a dozen proposals from various sources trying various models of tholin/ dust crusting the surface of 'Oumuamua. While it's not exactly an exciting position to take, it is a consensus position.
Do your own homework. I have, to match the extent that I care about the topic.
I suppose I'd better RTFA before commenting further. But a 10:1 end-over-end light curve does not sound very optimal to me.
That sounds in the scale for an aircraft carrier? Sounds rather overkill. I can think of around a half-dozen "floatels" ("floating hotels") which include their own medical suites, helipads and hangers, craneage, marine and stewarding personnel (and medical too), which can take complements of 200 to 500. OK, most are on medium- to long-term lease alongside various fixed oil installations and the like to support (re-)construction. But it's a mature market, with assets being shipped between corners of the globe in response to tenders for hire. Certainly worth considering on cost.
BUT, it's not "shiny" - more likely rusty - so it's quite unlikely that the idea would get past the PR department.
Thanks for keeping up the good work.
Ummm, no. You need a minimum of three elephants per turtle in order to form a turtle-elephant bilayer in your stack of turtles. Otherwise the stack becomes unstable. If your elephants and turtles are of uniform size then you can have more elephants per turtle, but three is the minimum.
Of course, since they're both countable infinities, they're the same size (see Hilbert's Hotel argument), even if one has infinitely many elephants per turtle, you'd still have the same number of of turtles and elephants.
How did that API for programming turtles go?
And as soon as that happens ... the inflatable "plastic passengers" which are used to fool surveillance cameras on "dual occupancy" or car pool lanes will start being weighted, so the car thinks it has an actual passenger on board, and therefore be more likely to protect the driver by proxy.
My first guess would be that users would fill the inflatable legs and torso with water, to trip the weight sensor in the seat.
More ikely the issue with Mars is that it's only about 1/10 the mass of Earth (0.1075 from my notebook) so it's just a lot easier for the atmosphere to get ablated. Yes, the lack of magnetic field is a component of Mars' atmospheric loss, but not the main one.
Now, don't get me wrong - I don't have any intrinsic objection to using Mars to terraform Venus. But some of the people left on Earth might be a little concerned about you manoeuvring such a lump of rock past their windows. Maybe move them out somewhere else while you're doing the "heavy lifting".
Step 2Hmm, you're going to have to move around 80% of the mass of the planet temporarily into orbit while you're spinning up your core. (Actually, for a geodynamo, you probably need differential rotation between two solids, separated by a conducting fluid. Slightly different to your scenario. Tricky. Might it not be easier to just call up Slartibartfast and get a quote from the Magratheians?
Steps 3 and 4 need to be inverted.
It's a plan. Version 0.1 ; let's rework to 0.2 before going for an ICO?
It's a terraforming effort. Of course it's long term. Tens to hundreds of millennia, on the low side. And that's probably optimistic.
But the mass isn't humans, or even agriculture; it's the ascent vehicle. More specifically, the propellant in the ascent vehicle.Or, or a long term mission, the heavy life support machinery (the equivalent of Biosphere 1 & 2's "oceans") hangs down there. Along with any "ascent vehicle" that you're in the process of refuelling, for those faint hearts and administrators (or non-convicts) who might want to go back to Earth.
An attempt to terraform Venus would certainly make more sense than trying to terraform Mars, because you wouldn't need to find and transport millions of volatile rich bodies from the outer solar system. Which bodies might simply not exist, or might be spread at multi-million km spacings through the outer 10^30-odd km^3 of the Solar system. Enjoy the hunt - it'll take the rest of your life.
For Venus, the volatiles are there already. Some of them (well, 96% or so of them) need to be stripped out and thrown on the ground. Which is convenient, as we have multitudes of microbes that can convert the material (most) of Venus' atmosphere into materials that when heated will release water, oxygen and refractory carbon. OK, it'll take a few millennia to drop 95% of the atmosphere to the surface as carbon dust, and we'd probably need to do something to absorb some of the oxygen released. But hey, it's going to be orders of magnitude quicker than trying to collect the volatiles Mars needs.
Back in the early 1980s, I had an exam exercise to work out whether aluminium or copper would be better for making power line cables, and present reasons. I spotted the trap, did the appropriate calculations on the data provided, and showed that aluminium would weigh about half what a copper cable would do, saving considerably in the cost of the support structures as well as the raw metal cost. You need to do equivalent calculations for these materials. At 1023K and 20MPa (200 atmospheres, modest pressure), you might get better weight/ performance ratio from tough steel ("HSS", or equivalent) with a platinum interior lining.
They're interesting materials though.
Or did you, for some deluded reason, think that "America is better than that"? Oh, man, that's such an Obama-era "alternative fact".
This kind of sloppy programming needs to come with easy-to-litigate civil remedie$ and then maybe it will stop.Didn't you read the fucking software agreement before using it? The bit that disclaimed it's fitness for any particular purpose, and limited all liability to the sale value of the software. At least, that's how I read typical EULAs.
Or were you just trying to be funny?
It's a measure of strength, so it's unit is the Pascal. (In practice, for geological and engineering materials, MPa is the day-to-day unit.
My braincell assigns it to Wheeler. But IANAphysicist.
The areas under consideration start north of 64degN. That's 1200+km north from the relatively clement seas they operate in. Hell, I've worked at sea further north than that, and I don't consider myself arctic-specification. Abigail and Miguel spent much more time in the North on the Greenland job (and they're just people I've shared cabins with!)
(Why reliable ones still so expensive?)Because sensors drift (or are extremely expensive), and so need calibration. Which takes time, expertise and continuing documentation. None of which come cheap.
The toy systems you're talking about will penetrate a couple of hundred metres of water, ping off intermediate fish shoals (main market) or tell you about the top few centimetres of the seabed (mud, sand, metal give different signals, for the second market).
A one-way sonar spread (geophones lowered downhole) for use in 5km of water depth, and to penetrate to the drilling limit of 6.5 km of rock comprises 2x 40ft shipping containers for the diesel power packs, several stowage containers for the gear, a workshop container for repairs, a 30ft control and recording container, and 7 bedspace. About $100k/day, depending on contract length. Square the power needs for two-way.
Shocking, isn't it, to discover that there is a whole science out there which you've never met before. Three of my classmates went into this industry, and I have to use it on a frequent basis.
A remotely operated floating bed of instruments with GPS.That'd be wonderful. Perhaps I could use the same technology to guide me underwater when I'm caving. Oh, but hang on ... aren't radio signals blocked by seawater (and slightly less effectively, in proportion to the water conductivity, by fresh water)? Perhaps that is why I've never once seen an advert for an underwater GPS device. (I have however seen hundreds of adverts though for waterproofed, boat ready GPS units for use on the air-ventilated parts of boats.)
You could probably even get oil exploration companies to help pay for it.They're much more likely to say "Here is a listing of the data we have already acquired. You tell us which areas you want to buy, and we'll tell you the price. We're not going to tell you the price for individual areas, because that might give you commercially sensitive information about which areas we consider more valuable. Oh, and here is an NDA for you to sign, if you want to take the conversation further." When I worked in the right places, I could get to read some of the Arctic contingency planning data. And when I tried to look in more depth ... the system security tools would block me and report the access attempt to my line manager.
I'm not saying there's no geological activity, but I'd expect it to move at a glacial pace, so to speak.Actually, the Gakkel ridge is remarkable for being the slowest-spreading and least-active part if the spreading ridge system. It is a peculiar and relatively little-known area. Away from the ridge, the Arctic Ocean seems to be pretty quiet seismically (which can be detected around the world) - which is peculiar given that the plate motions around indicate that there must be movements up there. P>Personally, if I were still in the business, I know where I'd go to ask. Several oil companies have done a lot of work seeking prospects up there. But equally, I'd expect to be laughed at if I made such a request without a binding contract (or at least a MoU) in place. It's valuable data, after all.