After years of thinking I knew rocket propulsion -- via SF novels and popular works and, well, building small ones -- I took a policy course on space travel at CMU. Professor Morel (sp?) insisted that we learn the science first. I got all sorts of good stuff, and started poking around the engineering library for more.
I found, while researching my term project, a great book on advanced propulsion topics. This wasn't some popular work, but a collection of hard-core equation-filled research papers. There was stuff on what could be the next generation of fission drives, various fusion drive concepts, and antimatter propulsion.
Beyond the obvious containment issues, there is a BIG problem with antimatter propulsion:
The problem of opacity.
Antimatter / matter reactions produce gamma rays. These are extremely energetic and readily penetrate many materials.
This means that they are very inefficient when it comes to heating up a working fluid. The detail -short linked-to article glibly talks about shooting gamma rays into propellant. They will heat up the hydrogen or water or whatever you are using for a working fluid, but a lot of the energy will simply keep on going, and whiz right through the outside wall of the "combustion" chamber.
The one research paper which described a "pure" antimatter rocket heated the propellant indirectly. The positrons would be shot into a block of tungsten alloy dense enough to intercept an appreciable amount of the energy produced by the matter / antimatter reaction. Working fluid passed through channels in the block would heat up, turn to gas, and produce thrust.
The rated Isp was, as I recall, about 5,000 seconds. This is way more than conventional fluid / chemical rockets (500 seconds) and fission rockets (1,000 seconds) but only a little higher than existing ion thrusters (3,100 seconds for that solar-powered testbed that ran a few years back).
The one advantage this rocket would have over ion thrusters would be the amount of thrust. Ion rockets produce just a trickle of thrust. The antimatter thermal rocket would probably produce a fair amount of thrust, although probably not enough for a ground-to-orbit booster.
Most of these villains will indeed die from their radar-ranging, but if comics have taught me anything a small percentage will develop mutant powers and become a far worse menace to society.
A bunch of work was done in the 70s to develop cheaper methods of air conditioning.
One was ice ponds. Freeman Dyson and (mind fart) Taylor worked on them, as I recall.
Roughly put: You would build, while laying out an office building's parking lots, several big pits lined with pipes.
After snow falls, plows pile the snow and ice scaped off of the walks and driveways into the pits, which can be covered to keep out sun and rain.
If sufficiently insulated, the pits will remain full of ice and snow well into summer. The building's air conditioning system uses the pits as a heat sink, greatly reducing the energy required to cool and dehumidify the air.
I imagine the melted snow could be used to water the lawns and landscaping . . . a small but important win.
Stefan
Non-disposable equivalent on sale at Target
on
Disposable Camcorder
·
· Score: 2, Informative
(Note: I have no financial or emotional connection with the company that makes the products mentioned below. I just want to point out that for a little more you can have to keep a far more flexible product.)
This week, Target is selling for $97 the non-disposable equivalent of this gimmick, the Aiptek "IS-DV."
The IS stands for "Image Stabilization."
It records to internal memory or a SD stick. A 256 mb stick holds about 60 minutes of MPEG4 video.
It is also a still camera (5 mp, but with a non-adjustable lens), voice recorder, and MP3 player. It comes with a tripod, A/V cable, headphones, and USB cable.
I've had an earlier version, the DV4500, for about six months. It's a great little toy. I bought it so I'd have a cheap camera I wouldn't be afraid to carry around everywhere. The image quality is pretty good:
* Garbage disposal, including of Objects of Power of the sort that seemingly vanquished evil galactic overlords require for their return to total mastery.
* Practical jokes. "Star? Your planet orbited a star? I don't see a star around here, do you?"
* Sex toys for transcended superbeings who exist as fluctuations in the quantum foam but who have not forgotten what it was like to be carbon based, young, and in estrous on the sunny plains of Ghyr'd'tos.
Really pretty eye-candy, but Christensen and Portman were awful. Maybe they saw read the script, saw their lines, and just gave up. I'm talking major league sucky dialog delivered unconvincingly.
Dang, even Jackson kind of wanders through his role.
Someone will come up with a non-slashdottable web server.
"Twenty miles . . . twenty miles . . . twenty miles. Eight thousand cube miles of rackspace, powered by fifty sub-atomic reactors, all designed to respond to the subconcious urges of the ancient Krell web-surfers."
At the beginning of the original second series, someone mentions that she was carried away by Galactic Shriners.
I didn't even know they did a third series. I LOVED the cliffhanger at the end of the second series, and didn't care much for how the books carried the story along.
The equipment required to extract fuel from the Martian atmosphere will necessarily be pretty hefty. You'd need a nuclear reactor or a really large array of solar panels.
It would cost a fair amount to develop, manufacture, and transport this equipment.
If you are only planning a small sample return mission, it would be a waste to heft all that stuff there.
BEFORE we can plan a Mars mission, especially one that will depend on locally extracted fuel, we're going to have to know a lot more about Mars' surface conditions. I think it is entirely justified to send a whole bunch of relatively low-tech probes first.
As for the general idea of propulsion research, sure. But there is no real reason to wait until we have plasmonic hyperdrives to check out the territory
"It is the business of the future to be dangerous;
on
Precision Gene Editing
·
· Score: 4, Interesting
"and it is among the benefits of science that it equips the future for its duties."
Yeah, all this nonsense about freedom and autonomy and choice and privacy is whack.
May as well metaphorically roll over on your back and piss on yourself in the face of Big Brother now and get to feel all cool about being an early adopter.
I know, let's ditch human dignity altogether and get a big ol' cattle tag clamped on our ears! Let people know whose herd you belong to!
Times were different back then. No PC nonsense, and his science demonstrations were always geared to practical things of use to awkward young science fans growing up in the conformist 1950s.
Like the time Mr. Wizard showed you how to perform a prefontal lobotomy on a school bully using a #2 pencil, an American History text book, and a pipe cleaner.
The guest star / subject was "Whitey" from Leave it to Beaver. He was never the same after that. Of course, what actually slowed him down -- the operation or the home-brewed benzine-based anesthesia -- wasn't clear.
Don Herbert -- still alive and functioning enough to have done a pretty fun interview last year -- hasn't been on the air on a regular basis for a couple of decades, so only a portion of/.ers will remember him.
OTOH, chances are both young and old/.ers watched Bill Nye.
. . . for putting the line from the Clarke novel right in the intro and getting it out of the way.
This will eliminate about half of the impulse entries on this subject.
That said . ..
Heyyyyy, how 'bout them Probes! Whoooo! Go probes!
Stefan
EXCLUSIVE! A peek at Issue #2's Table of Contents
on
'Make' Premier Issue
·
· Score: 2, Funny
* Grass-trimming Hybrid from Hell: Hacking together your Roomba and a riding mower.
* SpaceShip Two plans.
* Wood: Where does it come from?
* Trap Doors 101
* The wacky world of George Foreman Grill hacking.
* The first article of a five part series on DIY genetic engineering, describing how to modify your colonic bacteria so that your farts smell like orange potpourri. (The issue with part five, "Catgirls," is predicted to be best-seller.)
Freeman Dyson gave a talk in Portland last year. He presented several case studies on how technology planning went right and wrong.
One of the anecdotes was about a research team he was invited to join during the Carter administration. A multidiciplinary team of eggheads got together to come up with ways to make housing cheaper.
They analyzed the factors that made housing expensive, and came up with a list of proposals to make homes cheaper. Factory building components, standardization . . . it all came together nicely.
Before they delivered their findings, they decided to look them over . . . and realized that they'd reinvented the Mobile Home.
When I lived in the Bay Area, I listened to a LOT of radio stations. There were two full-power NPR stations alone, with very different formats.
New York City and Pittsburgh had a pretty good variety of stations as well.
Portland OR, where I now live, is probably better than a lot of places around the contry, but I really only listen to three or four stations, and only one has stuff I'd be interested in recording.
Larry Niven coined the word "rishathra" for sex between different species of hominids.
Since our ancestors killed off our hominid cousins, perhaps it could be used to describe sex between primates.
Of course, they'd have to be intelligent primates. So until we get some kind of Uplift program going, a monkey getting off on human porn would almost certainly find warts and hair sprouting from his palms. (And vice-versa, so don't get any ideas!)
I was around when speculation about a new ice age was a topic of pop-science articles.
The concern over global warming is not in the same category.
The "chicken little" strawman is yet another entry in the stream of sophistry, twisted facts and lies that gets churned out by the Cato Institute, the Global Climate Coalition and other fossil fuel industry front groups and bought-out think tanks.
Slashdot Mirror
After years of thinking I knew rocket propulsion -- via SF novels and popular works and, well, building small ones -- I took a policy course on space travel at CMU. Professor Morel (sp?) insisted that we learn the science first. I got all sorts of good stuff, and started poking around the engineering library for more.
I found, while researching my term project, a great book on advanced propulsion topics. This wasn't some popular work, but a collection of hard-core equation-filled research papers. There was stuff on what could be the next generation of fission drives, various fusion drive concepts, and antimatter propulsion.
Beyond the obvious containment issues, there is a BIG problem with antimatter propulsion:
The problem of opacity.
Antimatter / matter reactions produce gamma rays. These are extremely energetic and readily penetrate many materials.
This means that they are very inefficient when it comes to heating up a working fluid. The detail -short linked-to article glibly talks about shooting gamma rays into propellant. They will heat up the hydrogen or water or whatever you are using for a working fluid, but a lot of the energy will simply keep on going, and whiz right through the outside wall of the "combustion" chamber.
The one research paper which described a "pure" antimatter rocket heated the propellant indirectly. The positrons would be shot into a block of tungsten alloy dense enough to intercept an appreciable amount of the energy produced by the matter / antimatter reaction. Working fluid passed through channels in the block would heat up, turn to gas, and produce thrust.
The rated Isp was, as I recall, about 5,000 seconds. This is way more than conventional fluid / chemical rockets (500 seconds) and fission rockets (1,000 seconds) but only a little higher than existing ion thrusters (3,100 seconds for that solar-powered testbed that ran a few years back).
The one advantage this rocket would have over ion thrusters would be the amount of thrust. Ion rockets produce just a trickle of thrust. The antimatter thermal rocket would probably produce a fair amount of thrust, although probably not enough for a ground-to-orbit booster.
Stefan
Most of these villains will indeed die from their radar-ranging, but if comics have taught me anything a small percentage will develop mutant powers and become a far worse menace to society.
Stefan
A bunch of work was done in the 70s to develop cheaper methods of air conditioning.
One was ice ponds. Freeman Dyson and (mind fart) Taylor worked on them, as I recall.
Roughly put: You would build, while laying out an office building's parking lots, several big pits lined with pipes.
After snow falls, plows pile the snow and ice scaped off of the walks and driveways into the pits, which can be covered to keep out sun and rain.
If sufficiently insulated, the pits will remain full of ice and snow well into summer. The building's air conditioning system uses the pits as a heat sink, greatly reducing the energy required to cool and dehumidify the air.
I imagine the melted snow could be used to water the lawns and landscaping . . . a small but important win.
Stefan
(Note: I have no financial or emotional connection with the company that makes the products mentioned below. I just want to point out that for a little more you can have to keep a far more flexible product.)
_ wide.JPG
h oop.asf (3.3 mb ASF video)
This week, Target is selling for $97 the non-disposable equivalent of this gimmick, the Aiptek "IS-DV."
The IS stands for "Image Stabilization."
It records to internal memory or a SD stick. A 256 mb stick holds about 60 minutes of MPEG4 video.
It is also a still camera (5 mp, but with a non-adjustable lens), voice recorder, and MP3 player. It comes with a tripod, A/V cable, headphones, and USB cable.
I've had an earlier version, the DV4500, for about six months. It's a great little toy. I bought it so I'd have a cheap camera I wouldn't be afraid to carry around everywhere. The image quality is pretty good:
http://home.comcast.net/~stefan_jones/valley_view
The video quality is "OK." Note that this film was done under less than optimal lighting conditions:
http://home.comcast.net/~stefan_jones/kira_jumps_
I bought a IS-DV so I can give the DV4500 to a relative.
Stefan
* Garbage disposal, including of Objects of Power of the sort that seemingly vanquished evil galactic overlords require for their return to total mastery.
* Practical jokes. "Star? Your planet orbited a star? I don't see a star around here, do you?"
* Sex toys for transcended superbeings who exist as fluctuations in the quantum foam but who have not forgotten what it was like to be carbon based, young, and in estrous on the sunny plains of Ghyr'd'tos.
Saw it in the theater this morning.
Shheeee-at.
Really pretty eye-candy, but Christensen and Portman were awful. Maybe they saw read the script, saw their lines, and just gave up. I'm talking major league sucky dialog delivered unconvincingly.
Dang, even Jackson kind of wanders through his role.
What a let-down.
Stefan
It's true!
In fact, Lucasfilm's HQs will someday become the Academy's freshmen dorms.
Using a transporter during this interval is just begging to end up in a parallel universe, or split into good and evil halves.
Google is out of business as soon as PETA finds the location of their pigeon farm and circulates the photographs.
Someone will come up with a non-slashdottable web server.
"Twenty miles . . . twenty miles . . . twenty miles. Eight thousand cube miles of rackspace, powered by fifty sub-atomic reactors, all designed to respond to the subconcious urges of the ancient Krell web-surfers."
Stefan
At the beginning of the original second series, someone mentions that she was carried away by Galactic Shriners.
I didn't even know they did a third series. I LOVED the cliffhanger at the end of the second series, and didn't care much for how the books carried the story along.
Stefan
The equipment required to extract fuel from the Martian atmosphere will necessarily be pretty hefty. You'd need a nuclear reactor or a really large array of solar panels.
It would cost a fair amount to develop, manufacture, and transport this equipment.
If you are only planning a small sample return mission, it would be a waste to heft all that stuff there.
BEFORE we can plan a Mars mission, especially one that will depend on locally extracted fuel, we're going to have to know a lot more about Mars' surface conditions. I think it is entirely justified to send a whole bunch of relatively low-tech probes first.
As for the general idea of propulsion research, sure. But there is no real reason to wait until we have plasmonic hyperdrives to check out the territory
"and it is among the benefits of science that it equips the future for its duties."
-- Alfred North Whitehead, 1927
Yeah, all this nonsense about freedom and autonomy and choice and privacy is whack.
May as well metaphorically roll over on your back and piss on yourself in the face of Big Brother now and get to feel all cool about being an early adopter.
I know, let's ditch human dignity altogether and get a big ol' cattle tag clamped on our ears! Let people know whose herd you belong to!
Stefan
Times were different back then. No PC nonsense, and his science demonstrations were always geared to practical things of use to awkward young science fans growing up in the conformist 1950s.
Like the time Mr. Wizard showed you how to perform a prefontal lobotomy on a school bully using a #2 pencil, an American History text book, and a pipe cleaner.
The guest star / subject was "Whitey" from Leave it to Beaver. He was never the same after that. Of course, what actually slowed him down -- the operation or the home-brewed benzine-based anesthesia -- wasn't clear.
Picture it:
Bill Nye as host.
Mr. Wizard as the august commentator, put on when gravitas is called for.
Beekman as the demonstrator.
Don Herbert -- still alive and functioning enough to have done a pretty fun interview last year -- hasn't been on the air on a regular basis for a couple of decades, so only a portion of /.ers will remember him.
/.ers watched Bill Nye.
OTOH, chances are both young and old
Stefan
. . . for putting the line from the Clarke novel right in the intro and getting it out of the way.
.
This will eliminate about half of the impulse entries on this subject.
That said . .
Heyyyyy, how 'bout them Probes! Whoooo! Go probes!
Stefan
* Grass-trimming Hybrid from Hell: Hacking together your Roomba and a riding mower.
* SpaceShip Two plans.
* Wood: Where does it come from?
* Trap Doors 101
* The wacky world of George Foreman Grill hacking.
* The first article of a five part series on DIY genetic engineering, describing how to modify your colonic bacteria so that your farts smell like orange potpourri. (The issue with part five, "Catgirls," is predicted to be best-seller.)
. . . on how to walk on dirt.
I know this sounds kind of scary, but it is pretty easy, and fairly safe once you have the right equipment.
Stefan
Freeman Dyson gave a talk in Portland last year. He presented several case studies on how technology planning went right and wrong.
One of the anecdotes was about a research team he was invited to join during the Carter administration. A multidiciplinary team of eggheads got together to come up with ways to make housing cheaper.
They analyzed the factors that made housing expensive, and came up with a list of proposals to make homes cheaper. Factory building components, standardization . . . it all came together nicely.
Before they delivered their findings, they decided to look them over . . . and realized that they'd reinvented the Mobile Home.
. . . watch a rerun of Trek while the wonders of the universe flash past the windows?
When I lived in the Bay Area, I listened to a LOT of radio stations. There were two full-power NPR stations alone, with very different formats.
New York City and Pittsburgh had a pretty good variety of stations as well.
Portland OR, where I now live, is probably better than a lot of places around the contry, but I really only listen to three or four stations, and only one has stuff I'd be interested in recording.
So, I think I'll give this a pass.
Larry Niven coined the word "rishathra" for sex between different species of hominids.
Since our ancestors killed off our hominid cousins, perhaps it could be used to describe sex between primates.
Of course, they'd have to be intelligent primates. So until we get some kind of Uplift program going, a monkey getting off on human porn would almost certainly find warts and hair sprouting from his palms. (And vice-versa, so don't get any ideas!)
Stefan
I was around when speculation about a new ice age was a topic of pop-science articles.
The concern over global warming is not in the same category.
The "chicken little" strawman is yet another entry in the stream of sophistry, twisted facts and lies that gets churned out by the Cato Institute, the Global Climate Coalition and other fossil fuel industry front groups and bought-out think tanks.
Hers is a specific refutation of the "global cooling" myth.
Stefan