Another way: Rail guns. The ore is pulverized to gravel. It's then sacked in 10 Kg sacks. Sacks are made from spun glass cloth, made from the non-metallic rocks.
The rail gun has sleds and acceleration track, and a decelleration track. The bag is loaded into the sled, the sled accelerated down the track to proper velocity, the bag released, the sled then is declerated, putting power back into the system for the next load.
Catching them at the earth is trickier. DeltaV will be roughly the difference in kinetic energy between Earth orbit and asteroid orbit. 10 km/s? The accuracy required to do the sled in reverse is a bit daunting. However, once you have a reasonable mass, you can put the mass in the bottom of a large (km scale) sack, let the bags of gravel impact it, and catch the debris in the sack.
The result of the impacts would be to heat the mass up to molten temperatures which makes fractionating it easier.
You still have to deal with the momentum issues. Keeping the catcher on station will be tricky. However if multiple rail guns are used, an appropriate mix of bags coming in in retrograde orbits and prograde orbits could be used. Trouble is the retrograde rocks come in with about twice Earth orbital speed (18 km/s around the sun) more than the others. A bag of rocks coming in at 50 km per second is going to smoke your catcher's mitt.
Stine proposes this in his book, "The Third Industrial Revolution" for working with lunar mass. Much smaller energy requirements, as it's only 2 km per second, not 10 or so.
While the basalt basement rocks recycle regularly, the granitic continents tend to float, like foam, on top. Most of the Canadian Sheild (Aka Precambrian Shield, aka Laurentian Shield) is over 2 billion years old. Basement rocks in the Grand Canyon are even older.
If you plot large ore bodies and the age of the surrounding rock, you find that old rock is over-represented. So the previous poster's comments about meteoric sources for metals may not be totally out to lunch.
Indeed, current theory is that the Sudbury mining district in Ontario is the result of a 9 km impact about 1.9 GY ago.
Ore body formation is non-simple science. Metals dissolve, move, are precipitated. In some cases bacteria have a role changing the pH or producing sulfides to bind metalic ions.
You certainly don't want to bobble the course corrections.
If you do it right, you can take a lot of energy out using the moon. Like using Venus flybies to get to Jupiter. In general I think you can get a deltaV of good fraction of the orbital velocity.
Presumably you have some engine that uses rock as reaction mass to get it started from the belt in the first place. E.g. Very large solar concentrators that are fed a stream of rock dust, boil it into plasma, which can then be flung through a linear accelerator. Physically possible. Interesting engineering problem.
So you fly your rock by Mars, shed energy and momentum there, drop down take a swing by Venus and lose a couple more km/s, Do it right, and it arrives at Earth/Luna with the right energy and momentum to do a capture orbit around the moon. Now continue to use your ion engines to tweak the orbit.
Your billion ton rock is quite valuable. If it's a metalic rock it runs about 45% nickle iron -- almost stainless steel -- Scrap steel runs about 200 bucks a ton, nickle is more than that, so just as scrap it's worth about 200 billion. But the rare earths, and the platinum group are much better represented in metalic meteors than they are on earth. Lots of iridium, indium, platinum, gold.
But if you look at it as mass that is in orbit already, then it is far more valuable. Now it has a value equal to the lift cost -- currently several hundred dollars per kilogram. So electrolyze the O2 you need from the silcate rocks. Instead of hauling it up from earth. Build habitat from spun metal and foamed glass instead of hauling it up from earth.
Hydrogen is scarce, so for the time being, that will still need to be shipped from Earth. But that means that a pound of hydrogen can be used to make 9 pounds of water.
And it's in short supply only until we can capture a comet with all of it's ammonia and methane and water ices.
The asteroids (metals, carbon) and the rings of Saturn (Water) are the cheapest way to industrialize space. The entrance fee is high. So are the rewards.
1. Buy the archive of the back issues of Mother Earth News. Not all the ideas are practical, but many are, and the rest can lead to further ideas.
2. Smaller is greener.
3. If you are innovating in construction technique, build so that it can be modified.
* Build in access to pipes. * Wire in conduits. * Extra conduits so you can network, or put in 12v DC, or whatever later. * Attic access for later addition of fans. * Power outlets in the attic. * Steep pitched roof so that most of your attic access is not on your hands and knees. * Use screws whereever you think you MIGHT want to change things.
4. Zone your heating/cooling system.
5. Do your best calculation for heating needs -- then put in a unit half that size. But leave room to add a second one later. This will give you redundancy, at some increase in expense.
HVAC people seem to overestimate heating and underestimate ventilation. Put in bigger exhaust fans than they tell you.
6. If you are in a net heating environment, design your house to have most of the windows on the south.
7. In our climate (10000 degree days, central Alberta) a dual glazed south facing window has better net performance than triple glazing.
8. Don't bother with argon/krypton. The gas is gone in 5 years.
9. In a well made window, a sizeable amount of the heat loss is on the edges. Use fewer but larger units.
10. If you are building a single floor house in a heating climate, considering building it partially underground. I've seen houses that were essentially walkout basements.
11. The most energy efficient shape for a two story house is a butter cube, oriented east west.
12. Conifers on side to the prevailing winter wind makes your house use a lot less heating, and makes your gardening less problematic.
I keep reading that Business wants people who are 'generalists' 'self-starters' 'good communicators'
Yet when I go and search on Monster.com, the only job descriptions that include the word generalist are for HR managers.
As an exercise, I created a 'technical generalist' resume with all kinds of techy skills from troubleshooting computer networks, various kinds of programming, general construction skills, with experience in figuring things out on my own from tech manuals and O'Reilly books. Kept it running for 3 years. Never got a call.
Given that even in hunting season, there aren't enough fish and game officers to check more than a small fraction of the deer tags, just how would you enforce this?
I've taken groups into Northern Saskatchewan on canoe trips for over 30 years, and have NEVER met any kind of Lands officer outside of an office, This included a trip where we spent two weeks dodging forest fires, changing our route 3 times. (Not a serious problem -- the Churchill river country has a lOT of lakes.) Every couple of days we would phone into the local forestry office (gotta love sat phones) reported our present position, got threat estimates of the 14 fires in the area, and let them know where we were going. They were agreeable with our strategy.
The only interested incident was when a large fire jumped the line. We were having lunch at Grand Marais rapids when the sky got a lot darker, and ash began to fall. We cut lunch short, finished the portage, and got on the water. The portage burned 3 hours later.
I suppose you could enforce like they do vehicle insurance. Loss of vehicle and 10,000 fines for being found without insurance. (By contrast having an unregistered vehicle is a $150 fine.)
Since the vast majority of people in the back country take care of themselves a better system would be something like this:
The first time you need rescue you pay $xx dollars per month until the cost of rescue is paid off, or forever. If it happens again, you are billed the full amount up front, driving you into bankruptcy if needed.
Guy is canoeing in Ontario's north country. Screws up in a rapid, and loses his canoe. Does the 'build 3 fires' thing, and Ontario Forestry picks him up. Gets a slap on the wrist and a "bad puppy, no biscuit"
Next year he's out canoeing again. There is a total fireban on, as the woods are tinder dry. He's not gotten any better at canoeing, and wrecks his canoe, and is stranded on a good sized island in the river.
So he builds 3 fires.
Ontario Forestry comes by and waterbombs him. Getting hit with a swimming pool of water is no joke. The water slams him into a tree, breaking his arm, and adding various minor injuries.
Two hours later, a chopper comes by. They arrest him for starting a fire. In court he's ordered to pay for the entire fire suppression action. (1 water bomber flight, 1 helicopter flight, and assorted overhead for people's time and bother) The bill comes out to about $100K.
Ontario Forestry made sure that the news was spread around. Don't ask for help unless you are willing to pay for it.
* I can have most of my music collection with me. * I can listen to my favorite radio shows on my schedule through podcasts. * I can have many playlists. (To me smart playlists were a big breakthrough. I have tons of lists now that are of the form, "genre = celtic AND rating >= 3 stars" * I can get books on disk from the library, import to iTunes, put on my ipod, play through earphone ear protectors while I'm working with the tractor or chainsaw. Makes the day a lot less boring.
The ipod touch/iPhone was a game changer.
Tons of apps. My stepson says that on the last cross country flight he did he got out his laptop -- just to charge his iPhone. He was doing all his work on the iPhone.
The next game changer in this stream of technology?
Voice recognition.
iPhone, Wake up.
Yes boss?
Text message to Sid. "Running late. Won't be there until ten" (pause) End message. Show me.
(Iphone fills in the recipient, and puts in the text message)
Confirm.
iPhone Go to sleep.
***
"Hey Boss, new email"
"Read it to me"
From your wife: "Don't forget we have that PTA potluck supper tonight. Pick up a salad at Superstore on your way home."
"Acknowledged. iPhone, Add to Todo list. Remind me when we are a half kilometer from Superstore on our way home." iPhone, go to sleep.
Right now there is limited support for this sort of thing, with extremely limited domains. (My wife has bluetooth voice phone in her car. Half the time it can't tell between 'home' and 'mobile' and has an absurd number of confirmations -- necessary, because it doesn't get much right the first time.)
To be ground breaking it has to:
* Accept normal speech patterns. * Have enough AI to put in the correct homonym and near homonyms. (Their, there, they're; to, two, too) * Be able to understand simple process/workflow sequences.
I think I can consider myself a pro. For 30 years I ran or was navigator on multiweek back country expeditions, about 6 weeks worth a year.
Map and compass is sufficient most of the time. No batteries required.
I have had a few situations that the GPS saved my bacon.
Much of the Canadian Shield has low relief. Hills are glacial till, or gently rounded granite. There are many stretches where the hills are only 30-40 feet tall -- comparable to the scrub pine and spruce.
Many of these hills look very similar -- the glaciers came down and moved in one general direction, so their crests are more or less parallel.
Fortunately the lakes have unique features.
Small windy streams embedded in heavy forest cover are tough. You can't see the hills around you. The stream channel is embedded in peatmoss and willow, and has shifted greatly in the 30 years since the map photography is done. Best you can do without a GPS is track general direction, and use dead reckoning.
One time I was trying to find a portage trail through a 10 year old burn. The fire had flashed through, leaving most of the trunks intact. They fell, and left a 3 foot thick layer of pick-up sticks on the forest floor. Meanwhile the jackpine grew in, so the landscape was covered in 3-12 foot christmas trees on one foot spacing. To see, you had to be up on the pick up sticks. To move you were constantly climbing carefully up and down. (branch stubs were sharp)
It was overcast with not even a bright spot to indicate sun position. No wind. Raining.
There was less than 20 feet of land relief over the entire 2 km span of the portage.
I found that even with a compass I was many degrees off my bearing after even 50 yards.
After that trip, I had a GPS. It lived with my camera in the pelican case most of the time. Sometimes whole trips would go by and it would never come on.
1. Energy density of about twice that at the surface of the earth, running 24/7.
2. No gravity.
1 and 2 mean that making kilometer sized aluminum coated plastic film mirrors to concentrate sunlight is relatively easy.
3. Asteroids that run better than 45% Fe + Ni. (Essentially stainless steel)
4. Whole moons made of ice.
5. Comets of dust, water ice, methane.
6. Whole planets of dirty hydrogen.
The energy to get to space is trivial. Rockets are exceedingly inefficient, as the vast majority of their energy is used to move the fuel/oxidiser.
We're not good enough at engineering to make a rocket engine that will run 8000 hours between major overhauls. (Which is the mandated overhaul interval for a typical small plane engine.)
More like half a billion years. As the sun ages it gets hotter. One of the reasons we could have so much more CO2 during the carboniferous era was that the sun was substantially dimmer then.
Current stellar evolution theories put the sun as hot enough to cause run-away greenhouse effect and boil the oceans in about a half billion years.
Of course, if we put up sun screens in cis-lunar space we may be able to buy a few million years more.
***
In the long run it doesn't have to be a cooperative effort of all of humanity. Once it becomes economically viable to be in space, some company will do it. After that I would expect a permanent self sufficient space going culture within a thousand years.
I once had a yen to learn some higher math. So I went out onto the 'Net to look for tutorials. Specifically I wanted to understand the difference between algebraic and differential topology.
I knew I wouldn't be able to start there, but figured I could start with number theory and higher algebra and work up.
I figured I first needed to find some document that had a recommended sequence for taking math courses. Aside from decoding the course catalogs of university math departments I was unable to find much on that.
I couldn't find online textbooks that were any good. I couldn't find tutorials at all. Tried Wikipedia, and while they have a lot of stuff on math, there is no sequence to it. It's a jumble of jigsaw puzzle pieces.
A good 'teach yourself' text needs to have the following: * Good presentation of the abstract concepts. * Good presentation of examples -- at lots of them. * Good problem sets with many fully worked solutions.
Most math books at the best of times are weak on all three. They depend on students having access to profs or grad students to clarify the missing bits. At the otehr end of the spectum they are incomprehensible.
***
I watched a fellow teacher get his masters from U of Phoenix. Talk about a joke. Kerry was a PE teacher, and fit all the archetypes of PE teachers. He was literate, but only read when he had to. His writing was less than clear. Yet he consistently got 90's on his essays. I read one of them, and I would not have given it a mark better than 60 had it been turned in by a grade 10 high school student.
***
I'm currently a tree farmer. (My third career) I looked into taking an online horticulture course from U of Waterloo. The course consisted of 40 modules. Each module had some written material, and a 10 question multiple choice quiz at the end of it. You could review and retake the quiz as often as you wished. (Questions changed from iteration to iteration)
They had 3 sample modules online. The contents of each were trivial. I was able to to all three and get 90% on the questions (there's always one that has ambiguous answers...) in about 45 minutes.
They wanted $400 for the course.
***
My conclusion is that Universities are in no danger of losing their education role to the internet.
Much teaching, outside of the math related fields can be done well with a a teacher surrounded by a cluster of students.
Having a projector to put images of maps up for geography and history; art and artifacts for cultural studies; rocks & formations for geology has some merit.
Math is not a spoken language (at least not easily) and so a chalkboard is useful.
A white board is the next level up, in part because it is easier to use multiple colours to highlight things.
Certain topics lend themselves to models, graphics, animations. E.g. Stepwise refinement showing how slope is the limit in rise/run as two points converge on a curve. An energy flow chart showing proportions in an ecology. A chunk of programming text. Animation showing the same collision in lab frame of reference and center of mass frame of reference. Functions of multiple variables. (Sketching bessel functions clearly on a chalkboard is tough)
Because an azimuth mount is insanely hard to do right and get tracking properly.
With an equatorial mount you only have to control one axis of the motion of the instrument, and for lots of use that part is a simple clock motor run by sidereal 60+ hertz.
With an azimuth mount, you have to have variable speed motors on both the altitude, the azimuth, and the rotation of the telescope cage. Worse the rotation rates for each depend on where the instrument is pointing, so you also have to have inputs for that.
I bet that the cost figure is an antique from when disks were much lower in capacity.
Now a days terabyte is a single disk. It wasn't that long ago that at terabyte was a couple of 3U rack slots.
A lot of this depends on scale too. If you are a small division, then you don't one guy who sole job is provisioning disk space. I've found with anything with computers, it's "use it or lose it" If you aren't doing something on a routine basis, then when you do have to do something, you have to crack the docs, and review.
How much speed do you need? At one point for database access the rule was to put in as many spindles as you could afford. YOu wanted to keep the queues for each disk as short as possible
Finally how much data integrity do you need? If the entire database has to be considered a huge binary object with zero tolerance for errors you have a different level than if you are satisfied with 4 nines of your Word docs loading without crashing word.
I'm not a database admin. Just a hasbeen sysadmin. The pros can comment on other circumstances that can drive the costs up.
Why, in any given year, are cars available in so few colours? It seems we go through phases when all the manufacturers have decided that this year is black, silver and earth tones. 5 years from now bright blue and green are in. I once had a civic that was dark chocolate. Haven't seen that colour in years. If you want a car that is pumpkin orange or school bus yellow you either have to special order it, or get it repainted at Maaco.
Sure I can see that a given company doesn't want to deal with 100 different colours of paint, but I'd expect more variation between companies.
Our current Subaru is a cadet blue. I've seen one other from Japan this colour. So currently it's the bottom end of the popularity curve. I sure love being able to spot it in a parking lot.
Kia, I think it was, one year offered a car with a harlequin paint job. Hood was green. Front quarter panels were yellow. Front doors were blue. Rear doors were red. I thought it looked cool.
While this is a brick and mortar school story, it should be applicable to the current age.
I grew up in Idaho. Idaho is a non very wealthy state, quite conservative. School funding is local, and spotty. The constitution of the state specifies that anyone who graduates from high school has to be admitted to University.
Some high schools offered only the minimum required courses. Some offered Calculus, 2nd year sciences, advanced English.
So the university was faced with a wide spectrum of freshmen each year.
Their solution:
* The math stream started with Algebra and Trig. If you took Calculus I and passed it, you were automatically credited with the earlier two courses.
* I walked into Biology 200 -- intro to biology, and was told, "The computer screwed up -- we have 30 more people that the room will hold. Monday will be a test. The top 15 will receive credit for this course, and can take Bio 201 or 202. The bottom 15 will be transferred to Bio 100 -- Biology for people who didn't take bio in high school.
* ANY course could be challenged. There was a $25 per credit fee which payed for someone to set the test, and a grad to mark it. You could not have more than a third of your credits as challenges.
This last rule was a shock to certain departments that had a reputation for sand piling -- notably business and education. The regents weren't sympathetic, and said that the material for the course content had to be available at the book store or at the Library.
This then, is the answer for online education. Good placement tests to determine what you know. Modular instruction to fill in the gaps.
Years ago I avidly read BYTE every month. Jerry Pournelle commented that the natural evolution of computers would be away from moving parts of any kind. Disk drives were a momentary aberation. At that point we were running into the first of the disk hurdles involving disks that had more than 32 MB of storage couldn't be addressed with FAT 16.
I expect the same effect to happen with SSD's. New technology is intrinsically difficult to predict.
Now it may not be the exact SSD tech we use now. Disk drives are much cleverer about recording and reading data, using some very different physics from the first ones.
But soon some form of solid state data storage device, where the only thing moving are the electrons will take over from the disk drive.
I suspect there will be an intermediate time, when disk drives become the new tape. Day to day stuff is on the SSD, and the drive is only used for archiving.
I used to work for St. John's School of Alberta, and their sister school in Manitoba. We did major trips in the lake country and in the mountains. (3 week canoe trips, 10 day hikes)
Before sat comm, we used SBX 11 radios. They weighed about 12 lbs, and used 9 D cells. The antenna was another 3-4 lbs. Both were bulky enough that the radio + antenna was one person's total share of the group gear. At that point the phone company had mobile operators. The Alberta school had it's own base station and frequency.
My recollection is that the two frequencies we used most were 7 and 5 MHz -- made for long antennas. Getting them high enough was a chore, as well as finding a clear patch.
Typically we would try to communicate each evening, on the hour starting from 7 p.m. to 10 p.m. If we didn't get through we'd try one more time before breaking camp.
It was a crap shoot. We'd get through every 3-4 days and let people know we were all right.
Once satellite communication became available, we dropped the SSB radios. A sat phone rented for about $300 per month -- cheap when you are taking other people's kids into the bush. Probably cheaper now.
For individuals, I'd recommend the SPOT system. Your local mountain equipment stores may rent them.
If you are clever you can communicate a lot more than "I'm ok" "I need help" by using the intervals between communications to send info.
If you are a large mail provider you could simply flag messages for X hours after you saw a new source domain.
Combine that with a filter that looks at the number of recipients.
New domain + large recipients list - known mailing lists = hold.
Create an index of the number of unique words you expect to see from 1000 email messages that come from individuals, and compare that to the number of unique words you get from this domain. If this index shows that messages are too similar, drop, block, and publish.
If outfits like gmail, hotmail, and yahoo did this, then smaller ISPs could piggyback on the published lists.
The net result would be that spammers could use a new domain for only a few hundred messages.
Or that spammers would only send to small mail service providers.
Small providers in practice could do the same thing by running the indexer on the messages, forwarding the index data to one of the big companies. This in effect pools the small providers data. It would make them a bit slower.
And why would google and the like do this? If they can make spam more difficult, they reduce the number of servers they have to use for filtering.
Not clear why you would need nano second accuracy for computer work. But every GPS receiver provides that. GPS relies on knowing what time it is to within, I think, 10 ns. (A ns is about a 9" error. Non-differential GPS with WAIS is good to about 10 feet = about 13 ns
But suppose there is a 3 foot per second = 1 meter/sec
F = m delta_t/delta_v Assume you have to push the water sideways armound your pipe, then delta_v is roughly root 2 times the velocity = 1.4 m/sec
A cubic meter of water masses 1000 kg.
So every square meter of cross section of fabric bag has about 1400 newtons of force on it. 5000 foot depth = 1500 meters = 2100000 newtons per meter width of cross section of the bag.
The bag itself has to either be strong enough to contain the flow, or it has to be large enough in cross section to allow the oil to rise through the internal water column of the bag. Likely a compromise: The rising column of oil will carry a water with it which will be separated out at the tanker, however the discharge of 20,000-100,000 bbl/day from a 2 foot pipe is not going to peacefully and gently rise through a 2 foot diameter bag.
I don't know what today's guess as to the volume of the leak, but suppose it is 1 bbl/sec, putting it a the upper end of the various estimates I've heard. Fast and furious that's 200 liters per second. If you have a 1 square meter cross section bag, it has to flow at 0.2 m/sec. Hmm. Doesn't seem unreasonable.
Another problem however is that a large fraction of the discharge is methane. If confined, it forms methane ice clathrate, and plugs the plumbing.
My suspicion is that you have to bring several times as much water as oil to prevent this from happening.
Further as the oil rises, the methane comes out of solution, and you have the effect of a coffee percolater. A mixture of gas and water rising faster and faster as the gas expands, creating a larger and larger pressure differential between the inside and outside of the bag.
Computers to a great extent are commodity items. Most critters will give reasonable performance as a desktop.
Look instead at other TCO factors:
1. Reliability: How often do they fail? 2. Vendor support. How fast can they get you a new part? 3. Lifecycle Longevity. Can you buy the same unit a year from now? Two? Three? Dell had their optimus program that guaranteed a life cycle of 3 years, with the only difference being CPU speed. 4. Driver support.
Slashdot Mirror
Hmm.
Axe versus ironwood tree.
Axe versus punk tree.
Axe versus young poplar grove with 10,000 sub finger diameter ramets.
Axe versus grass.
Perhaps a different tool?
See my earlier post.
Another way: Rail guns.
The ore is pulverized to gravel. It's then sacked in 10 Kg sacks. Sacks are made from spun glass cloth, made from the non-metallic rocks.
The rail gun has sleds and acceleration track, and a decelleration track. The bag is loaded into the sled, the sled accelerated down the track to proper velocity, the bag released, the sled then is declerated, putting power back into the system for the next load.
Catching them at the earth is trickier. DeltaV will be roughly the difference in kinetic energy between Earth orbit and asteroid orbit. 10 km/s? The accuracy required to do the sled in reverse is a bit daunting. However, once you have a reasonable mass, you can put the mass in the bottom of a large (km scale) sack, let the bags of gravel impact it, and catch the debris in the sack.
The result of the impacts would be to heat the mass up to molten temperatures which makes fractionating it easier.
You still have to deal with the momentum issues. Keeping the catcher on station will be tricky. However if multiple rail guns are used, an appropriate mix of bags coming in in retrograde orbits and prograde orbits could be used. Trouble is the retrograde rocks come in with about twice Earth orbital speed (18 km/s around the sun) more than the others. A bag of rocks coming in at 50 km per second is going to smoke your catcher's mitt.
Stine proposes this in his book, "The Third Industrial Revolution" for working with lunar mass. Much smaller energy requirements, as it's only 2 km per second, not 10 or so.
While the basalt basement rocks recycle regularly, the granitic continents tend to float, like foam, on top. Most of the Canadian Sheild (Aka Precambrian Shield, aka Laurentian Shield) is over 2 billion years old. Basement rocks in the Grand Canyon are even older.
If you plot large ore bodies and the age of the surrounding rock, you find that old rock is over-represented. So the previous poster's comments about meteoric sources for metals may not be totally out to lunch.
Indeed, current theory is that the Sudbury mining district in Ontario is the result of a 9 km impact about 1.9 GY ago.
Ore body formation is non-simple science. Metals dissolve, move, are precipitated. In some cases bacteria have a role changing the pH or producing sulfides to bind metalic ions.
You certainly don't want to bobble the course corrections.
If you do it right, you can take a lot of energy out using the moon. Like using Venus flybies to get to Jupiter. In general I think you can get a deltaV of good fraction of the orbital velocity.
Presumably you have some engine that uses rock as reaction mass to get it started from the belt in the first place.
E.g. Very large solar concentrators that are fed a stream of rock dust, boil it into plasma, which can then be flung through a linear accelerator. Physically possible. Interesting engineering problem.
So you fly your rock by Mars, shed energy and momentum there, drop down take a swing by Venus and lose a couple more km/s, Do it right, and it arrives at Earth/Luna with the right energy and momentum to do a capture orbit around the moon. Now continue to use your ion engines to tweak the orbit.
Your billion ton rock is quite valuable. If it's a metalic rock it runs about 45% nickle iron -- almost stainless steel -- Scrap steel runs about 200 bucks a ton, nickle is more than that, so just as scrap it's worth about 200 billion. But the rare earths, and the platinum group are much better represented in metalic meteors than they are on earth. Lots of iridium, indium, platinum, gold.
But if you look at it as mass that is in orbit already, then it is far more valuable. Now it has a value equal to the lift cost -- currently several hundred dollars per kilogram. So electrolyze the O2 you need from the silcate rocks.
Instead of hauling it up from earth. Build habitat from spun metal and foamed glass instead of hauling it up from earth.
Hydrogen is scarce, so for the time being, that will still need to be shipped from Earth. But that means that a pound of hydrogen can be used to make 9 pounds of water.
And it's in short supply only until we can capture a comet with all of it's ammonia and methane and water ices.
The asteroids (metals, carbon) and the rings of Saturn (Water) are the cheapest way to industrialize space.
The entrance fee is high. So are the rewards.
1. Buy the archive of the back issues of Mother Earth News. Not all the ideas are practical, but many are, and the rest can lead to further ideas.
2. Smaller is greener.
3. If you are innovating in construction technique, build so that it can be modified.
* Build in access to pipes.
* Wire in conduits.
* Extra conduits so you can network, or put in 12v DC, or whatever later.
* Attic access for later addition of fans.
* Power outlets in the attic.
* Steep pitched roof so that most of your attic access is not on your hands and knees.
* Use screws whereever you think you MIGHT want to change things.
4. Zone your heating/cooling system.
5. Do your best calculation for heating needs -- then put in a unit half that size. But leave room to add a second one later. This will give you redundancy, at some increase in expense.
HVAC people seem to overestimate heating and underestimate ventilation. Put in bigger exhaust fans than they tell you.
6. If you are in a net heating environment, design your house to have most of the windows on the south.
7. In our climate (10000 degree days, central Alberta) a dual glazed south facing window has better net performance than triple glazing.
8. Don't bother with argon/krypton. The gas is gone in 5 years.
9. In a well made window, a sizeable amount of the heat loss is on the edges. Use fewer but larger units.
10. If you are building a single floor house in a heating climate, considering building it partially underground. I've seen houses that were essentially walkout basements.
11. The most energy efficient shape for a two story house is a butter cube, oriented east west.
12. Conifers on side to the prevailing winter wind makes your house use a lot less heating, and makes your gardening less problematic.
I keep reading that Business wants people who are 'generalists' 'self-starters' 'good communicators'
Yet when I go and search on Monster.com, the only job descriptions that include the word generalist are for HR managers.
As an exercise, I created a 'technical generalist' resume with all kinds of techy skills from troubleshooting computer networks, various kinds of programming, general construction skills, with experience in figuring things out on my own from tech manuals and O'Reilly books. Kept it running for 3 years. Never got a call.
Given that even in hunting season, there aren't enough fish and game officers to check more than a small fraction of the deer tags, just how would you enforce this?
I've taken groups into Northern Saskatchewan on canoe trips for over 30 years, and have NEVER met any kind of Lands officer outside of an office, This included a trip where we spent two weeks dodging forest fires, changing our route 3 times. (Not a serious problem -- the Churchill river country has a lOT of lakes.) Every couple of days we would phone into the local forestry office (gotta love sat phones) reported our present position, got threat estimates of the 14 fires in the area, and let them know where we were going. They were agreeable with our strategy.
The only interested incident was when a large fire jumped the line. We were having lunch at Grand Marais rapids when the sky got a lot darker, and ash began to fall. We cut lunch short, finished the portage, and got on the water. The portage burned 3 hours later.
I suppose you could enforce like they do vehicle insurance. Loss of vehicle and 10,000 fines for being found without insurance. (By contrast having an unregistered vehicle is a $150 fine.)
Since the vast majority of people in the back country take care of themselves a better system would be something like this:
The first time you need rescue you pay $xx dollars per month until the cost of rescue is paid off, or forever. If it happens again, you are billed the full amount up front, driving you into bankruptcy if needed.
True Story:
Guy is canoeing in Ontario's north country. Screws up in a rapid, and loses his canoe. Does the 'build 3 fires' thing, and Ontario Forestry picks him up. Gets a slap on the wrist and a "bad puppy, no biscuit"
Next year he's out canoeing again. There is a total fireban on, as the woods are tinder dry. He's not gotten any better at canoeing, and wrecks his canoe, and is stranded on a good sized island in the river.
So he builds 3 fires.
Ontario Forestry comes by and waterbombs him. Getting hit with a swimming pool of water is no joke. The water slams him into a tree, breaking his arm, and adding various minor injuries.
Two hours later, a chopper comes by. They arrest him for starting a fire. In court he's ordered to pay for the entire fire suppression action. (1 water bomber flight, 1 helicopter flight, and assorted overhead for people's time and bother) The bill comes out to about $100K.
Ontario Forestry made sure that the news was spread around. Don't ask for help unless you are willing to pay for it.
To me, iPod + iTunes was game changing:
* I can have most of my music collection with me.
* I can listen to my favorite radio shows on my schedule through podcasts.
* I can have many playlists. (To me smart playlists were a big breakthrough. I have tons of lists now that are of the form, "genre = celtic AND rating >= 3 stars"
* I can get books on disk from the library, import to iTunes, put on my ipod, play through earphone ear protectors while I'm working with the tractor or chainsaw. Makes the day a lot less boring.
The ipod touch/iPhone was a game changer.
Tons of apps. My stepson says that on the last cross country flight he did he got out his laptop -- just to charge his iPhone. He was doing all his work on the iPhone.
The next game changer in this stream of technology?
Voice recognition.
iPhone, Wake up.
Yes boss?
Text message to Sid. "Running late. Won't be there until ten" (pause) End message. Show me.
(Iphone fills in the recipient, and puts in the text message)
Confirm.
iPhone Go to sleep.
***
"Hey Boss, new email"
"Read it to me"
From your wife: "Don't forget we have that PTA potluck supper tonight. Pick up a salad at Superstore on your way home."
"Acknowledged. iPhone, Add to Todo list. Remind me when we are a half kilometer from Superstore on our way home." iPhone, go to sleep.
Right now there is limited support for this sort of thing, with extremely limited domains. (My wife has bluetooth voice phone in her car. Half the time it can't tell between 'home' and 'mobile' and has an absurd number of confirmations -- necessary, because it doesn't get much right the first time.)
To be ground breaking it has to:
* Accept normal speech patterns.
* Have enough AI to put in the correct homonym and near homonyms. (Their, there, they're; to, two, too)
* Be able to understand simple process/workflow sequences.
I think I can consider myself a pro. For 30 years I ran or was navigator on multiweek back country expeditions, about 6 weeks worth a year.
Map and compass is sufficient most of the time. No batteries required.
I have had a few situations that the GPS saved my bacon.
Much of the Canadian Shield has low relief. Hills are glacial till, or gently rounded granite. There are many stretches where the hills are only 30-40 feet tall -- comparable to the scrub pine and spruce.
Many of these hills look very similar -- the glaciers came down and moved in one general direction, so their crests are more or less parallel.
Fortunately the lakes have unique features.
Small windy streams embedded in heavy forest cover are tough. You can't see the hills around you. The stream channel is embedded in peatmoss and willow, and has shifted greatly in the 30 years since the map photography is done. Best you can do without a GPS is track general direction, and use dead reckoning.
One time I was trying to find a portage trail through a 10 year old burn. The fire had flashed through, leaving most of the trunks intact. They fell, and left a 3 foot thick layer of pick-up sticks on the forest floor. Meanwhile the jackpine grew in, so the landscape was covered in 3-12 foot christmas trees on one foot spacing. To see, you had to be up on the pick up sticks. To move you were constantly climbing carefully up and down. (branch stubs were sharp)
It was overcast with not even a bright spot to indicate sun position. No wind. Raining.
There was less than 20 feet of land relief over the entire 2 km span of the portage.
I found that even with a compass I was many degrees off my bearing after even 50 yards.
After that trip, I had a GPS. It lived with my camera in the pelican case most of the time. Sometimes whole trips would go by and it would never come on.
Space is empty?
Let's see:
1. Energy density of about twice that at the surface of the earth, running 24/7.
2. No gravity.
1 and 2 mean that making kilometer sized aluminum coated plastic film mirrors to concentrate sunlight is relatively easy.
3. Asteroids that run better than 45% Fe + Ni. (Essentially stainless steel)
4. Whole moons made of ice.
5. Comets of dust, water ice, methane.
6. Whole planets of dirty hydrogen.
The energy to get to space is trivial. Rockets are exceedingly inefficient, as the vast majority of their energy is used to move the fuel/oxidiser.
We're not good enough at engineering to make a rocket engine that will run 8000 hours between major overhauls. (Which is the mandated overhaul interval for a typical small plane engine.)
More like half a billion years. As the sun ages it gets hotter. One of the reasons we could have so much more CO2 during the carboniferous era was that the sun was substantially dimmer then.
Current stellar evolution theories put the sun as hot enough to cause run-away greenhouse effect and boil the oceans in about a half billion years.
Of course, if we put up sun screens in cis-lunar space we may be able to buy a few million years more.
***
In the long run it doesn't have to be a cooperative effort of all of humanity. Once it becomes economically viable to be in space, some company will do it. After that I would expect a permanent self sufficient space going culture within a thousand years.
I once had a yen to learn some higher math. So I went out onto the 'Net to look for tutorials. Specifically I wanted to understand the difference between algebraic and differential topology.
I knew I wouldn't be able to start there, but figured I could start with number theory and higher algebra and work up.
I figured I first needed to find some document that had a recommended sequence for taking math courses. Aside from decoding the course catalogs of university math departments I was unable to find much on that.
I couldn't find online textbooks that were any good. I couldn't find tutorials at all. Tried Wikipedia, and while they have a lot of stuff on math, there is no sequence to it. It's a jumble of jigsaw puzzle pieces.
A good 'teach yourself' text needs to have the following:
* Good presentation of the abstract concepts.
* Good presentation of examples -- at lots of them.
* Good problem sets with many fully worked solutions.
Most math books at the best of times are weak on all three. They depend on students having access to profs or grad students to clarify the missing bits. At the otehr end of the spectum they are incomprehensible.
***
I watched a fellow teacher get his masters from U of Phoenix. Talk about a joke. Kerry was a PE teacher, and fit all the archetypes of PE teachers. He was literate, but only read when he had to. His writing was less than clear. Yet he consistently got 90's on his essays. I read one of them, and I would not have given it a mark better than 60 had it been turned in by a grade 10 high school student.
***
I'm currently a tree farmer. (My third career) I looked into taking an online horticulture course from U of Waterloo. The course consisted of 40 modules. Each module had some written material, and a 10 question multiple choice quiz at the end of it. You could review and retake the quiz as often as you wished. (Questions changed from iteration to iteration)
They had 3 sample modules online. The contents of each were trivial. I was able to to all three and get 90% on the questions (there's always one that has ambiguous answers...) in about 45 minutes.
They wanted $400 for the course.
***
My conclusion is that Universities are in no danger of losing their education role to the internet.
Fascinating.
I was sysadmin for a school. IT was a course, and it was pulling teeth to get the kids to do anything.
"How do I make the letters bigger in Word?" Absolute incomprehension about the use of styles. Every paragraph was reformated one by one.
Kids filling in a spread sheet by copying a friends printout -- including copying the results of calculations as just values.
I installed firefox with firebug on each computer. They wouldn't use it to debug their html code.
The only thing they wanted from the computer lab was the ability to play WoW. Which I blocked at the firewall.
Oh, and facebook.
I had no worries about clever kids hacking the system.
I'm sure that in a large school there are such clever kids. But I never saw any of them in our small school.
Much teaching, outside of the math related fields can be done well with a a teacher surrounded by a cluster of students.
Having a projector to put images of maps up for geography and history; art and artifacts for cultural studies; rocks & formations for geology has some merit.
Math is not a spoken language (at least not easily) and so a chalkboard is useful.
A white board is the next level up, in part because it is easier to use multiple colours to highlight things.
Certain topics lend themselves to models, graphics, animations. E.g. Stepwise refinement showing how slope is the limit in rise/run as two points converge on a curve. An energy flow chart showing proportions in an ecology. A chunk of programming text. Animation showing the same collision in lab frame of reference and center of mass frame of reference. Functions of multiple variables. (Sketching bessel functions clearly on a chalkboard is tough)
Because an azimuth mount is insanely hard to do right and get tracking properly.
With an equatorial mount you only have to control one axis of the motion of the instrument, and for lots of use that part is a simple clock motor run by sidereal 60+ hertz.
With an azimuth mount, you have to have variable speed motors on both the altitude, the azimuth, and the rotation of the telescope cage.
Worse the rotation rates for each depend on where the instrument is pointing, so you also have to have inputs for that.
I bet that the cost figure is an antique from when disks were much lower in capacity.
Now a days terabyte is a single disk. It wasn't that long ago that at terabyte was a couple of 3U rack slots.
A lot of this depends on scale too. If you are a small division, then you don't one guy who sole job is provisioning disk space. I've found with anything with computers, it's "use it or lose it" If you aren't doing something on a routine basis, then when you do have to do something, you have to crack the docs, and review.
How much speed do you need? At one point for database access the rule was to put in as many spindles as you could afford. YOu wanted to keep the queues for each disk as short as possible
Finally how much data integrity do you need? If the entire database has to be considered a huge binary object with zero tolerance for errors you have a different level than if you are satisfied with 4 nines of your Word docs loading without crashing word.
I'm not a database admin. Just a hasbeen sysadmin. The pros can comment on other circumstances that can drive the costs up.
Why, in any given year, are cars available in so few colours? It seems we go through phases when all the manufacturers have decided that this year is black, silver and earth tones. 5 years from now bright blue and green are in. I once had a civic that was dark chocolate. Haven't seen that colour in years. If you want a car that is pumpkin orange or school bus yellow you either have to special order it, or get it repainted at Maaco.
Sure I can see that a given company doesn't want to deal with 100 different colours of paint, but I'd expect more variation between companies.
Our current Subaru is a cadet blue. I've seen one other from Japan this colour. So currently it's the bottom end of the popularity curve. I sure love being able to spot it in a parking lot.
Kia, I think it was, one year offered a car with a harlequin paint job. Hood was green. Front quarter panels were yellow. Front doors were blue. Rear doors were red. I thought it looked cool.
While this is a brick and mortar school story, it should be applicable to the current age.
I grew up in Idaho. Idaho is a non very wealthy state, quite conservative. School funding is local, and spotty. The constitution of the state specifies that anyone who graduates from high school has to be admitted to University.
Some high schools offered only the minimum required courses. Some offered Calculus, 2nd year sciences, advanced English.
So the university was faced with a wide spectrum of freshmen each year.
Their solution:
* The math stream started with Algebra and Trig. If you took Calculus I and passed it, you were automatically credited with the earlier two courses.
* I walked into Biology 200 -- intro to biology, and was told, "The computer screwed up -- we have 30 more people that the room will hold. Monday will be a test. The top 15 will receive credit for this course, and can take Bio 201 or 202. The bottom 15 will be transferred to Bio 100 -- Biology for people who didn't take bio in high school.
* ANY course could be challenged. There was a $25 per credit fee which payed for someone to set the test, and a grad to mark it. You could not have more than a third of your credits as challenges.
This last rule was a shock to certain departments that had a reputation for sand piling -- notably business and education.
The regents weren't sympathetic, and said that the material for the course content had to be available at the book store or at the Library.
This then, is the answer for online education. Good placement tests to determine what you know. Modular instruction to fill in the gaps.
Years ago I avidly read BYTE every month. Jerry Pournelle commented that the natural evolution of computers would be away from moving parts of any kind. Disk drives were a momentary aberation. At that point we were running into the first of the disk hurdles involving disks that had more than 32 MB of storage couldn't be addressed with FAT 16.
I expect the same effect to happen with SSD's. New technology is intrinsically difficult to predict.
Now it may not be the exact SSD tech we use now. Disk drives are much cleverer about recording and reading data, using some very different physics from the first ones.
But soon some form of solid state data storage device, where the only thing moving are the electrons will take over from the disk drive.
I suspect there will be an intermediate time, when disk drives become the new tape. Day to day stuff is on the SSD, and the drive is only used for archiving.
I used to work for St. John's School of Alberta, and their sister school in Manitoba. We did major trips in the lake country and in the mountains. (3 week canoe trips, 10 day hikes)
Before sat comm, we used SBX 11 radios. They weighed about 12 lbs, and used 9 D cells. The antenna was another 3-4 lbs. Both were bulky enough that the radio + antenna was one person's total share of the group gear. At that point the phone company had mobile operators. The Alberta school had it's own base station and frequency.
My recollection is that the two frequencies we used most were 7 and 5 MHz -- made for long antennas. Getting them high enough was a chore, as well as finding a clear patch.
Typically we would try to communicate each evening, on the hour starting from 7 p.m. to 10 p.m. If we didn't get through we'd try one more time before breaking camp.
It was a crap shoot. We'd get through every 3-4 days and let people know we were all right.
Once satellite communication became available, we dropped the SSB radios. A sat phone rented for about $300 per month -- cheap when you are taking other people's kids into the bush. Probably cheaper now.
For individuals, I'd recommend the SPOT system. Your local mountain equipment stores may rent them.
If you are clever you can communicate a lot more than "I'm ok" "I need help" by using the intervals between communications to send info.
If you are a large mail provider you could simply flag messages for X hours after you saw a new source domain.
Combine that with a filter that looks at the number of recipients.
New domain + large recipients list - known mailing lists = hold.
Create an index of the number of unique words you expect to see from 1000 email messages that come from individuals, and
compare that to the number of unique words you get from this domain. If this index shows that messages are too similar, drop, block, and publish.
If outfits like gmail, hotmail, and yahoo did this, then smaller ISPs could piggyback on the published lists.
The net result would be that spammers could use a new domain for only a few hundred messages.
Or that spammers would only send to small mail service providers.
Small providers in practice could do the same thing by running the indexer on the messages, forwarding the index data to one of the big companies. This in effect pools the small providers data. It would make them a bit slower.
And why would google and the like do this? If they can make spam more difficult, they reduce the number of servers they have to use for filtering.
Not clear why you would need nano second accuracy for computer work. But every GPS receiver provides that. GPS relies on knowing what time it is to within, I think, 10 ns. (A ns is about a 9" error. Non-differential GPS with WAIS is good to about 10 feet = about 13 ns
If the water stood still, that might work.
But suppose there is a 3 foot per second = 1 meter/sec
F = m delta_t/delta_v Assume you have to push the water sideways armound your pipe, then delta_v is roughly root 2 times the velocity = 1.4 m/sec
A cubic meter of water masses 1000 kg.
So every square meter of cross section of fabric bag has about 1400 newtons of force on it. 5000 foot depth = 1500 meters = 2100000 newtons per meter width of cross section of the bag.
The bag itself has to either be strong enough to contain the flow, or it has to be large enough in cross section to allow the oil to rise through the internal water column of the bag. Likely a compromise: The rising column of oil will carry a water with it which will be separated out at the tanker, however the discharge of 20,000-100,000 bbl/day from a 2 foot pipe is not going to peacefully and gently rise through a 2 foot diameter bag.
I don't know what today's guess as to the volume of the leak, but suppose it is 1 bbl/sec, putting it a the upper end of the various estimates I've heard. Fast and furious that's 200 liters per second. If you have a 1 square meter cross section bag, it has to flow at 0.2 m/sec. Hmm. Doesn't seem unreasonable.
Another problem however is that a large fraction of the discharge is methane. If confined, it forms methane ice clathrate, and plugs the plumbing.
My suspicion is that you have to bring several times as much water as oil to prevent this from happening.
Further as the oil rises, the methane comes out of solution, and you have the effect of a coffee percolater. A mixture of gas and water rising faster and faster as the gas expands, creating a larger and larger pressure differential between the inside and outside of the bag.
Computers to a great extent are commodity items. Most critters will give reasonable performance as a desktop.
Look instead at other TCO factors:
1. Reliability: How often do they fail?
2. Vendor support. How fast can they get you a new part?
3. Lifecycle Longevity. Can you buy the same unit a year from now? Two? Three? Dell had their optimus program that guaranteed a life cycle of 3 years, with the only difference being CPU speed.
4. Driver support.