And while we're on the topic of dangerous, let's talk about automobiles? They're not a great deal safer than the space shuttle...
Will some astronauts die? Of course. And they know that. It's the risk they signed up for. Why not let them be the ones to decide whether or not it's worth it.
Hmm. I don't have all the numbers, but a quick Google search suggests over 40,000 people die a year in the USA from traffic related accidents. However, I can't imagine how many millions of car journeys actually take place. Now, the Shuttle on the other hand has lost 14 crew members in about 100 flights. That looks to me like it's dangerous.
Not that I'm not particularly pro-cars (British, use publc transport), and it's not my space programme either. The thing is, whilst your astronauts at NASA are exceedingly well qualified and trained, they don't have much choice about their management. They can calculate the odds of being hit by a dropped wrench at 20,000mph, but not the odds of a human giving in to political/peer-pressure and ordering a dangerous launch. They really are brave.
I recently learned that LCDs can get a "retained pixel charge" problem, not entrirely unlike a CRT's phosphor burn. A colleague's screen saver had caused some pixels to leave a ghosting effect on his desktop. Oops.
It turns out that this is a known phenomenon and is somtimes described in the manufacturers instruction leaflet. Like anyone reads that. Unlike a CRTs, it's reversible in many cases, which is a big plus.
Here's some guys DSL webserver for you to/. http://www.dslwebserver.com/main/lcd-screen-burn.h tml
I'm in the UK. I watched the series _because_ I saw the pilot first via P2P. I feared for a remake of BSG, but it turns out that they've been fairly creative and made an intelligent modern version of a classic sci-fi TV show.
I have two complaints; one about the article, and the second about other posts.
First, I hate that the article contains the submitter's favourite: 'The natural world began forming its own hydrogen economy 3 billion years ago, when it developed photosynthesis to convert CO2, water, and sunlight into hydrogen and oxygen'. What crap. Photosynthesis generates saccharides - chains of sugars, which are used by plants in to generate energy from respiration, just as animals do. There may be a brief moment where water molecules are split into H. and OH. radicals, but no hydrogen gas is produced or used as an energy store. Bury the plants deep undergound for a few million years and you have fossil fuels, not hydrogen gas pockets.
Now, for those of you pointing out how crap hydrogen's energy density is - you're right! It sucks. It's so hard to deal with the stuff. I mean, the only way they make it work for the Space Shuttle is to deep freeze it so that it liquifies, and it takes yet more energy to cool it down which makes it suck more...
If you read the article, it admits that using hydrogen in vehicles is very challenging. A tank full of H2 is unlikely to ever happen on this planet. Instead, the suggested vehicle storage solutions include nanostructure materials, surface absorbption/adsorption, or ionic compounds. However, cars and planes are not everything in the world. H2 gas could be used in homes and businesses instead of natural gas. Various methods of generating H2 gas from a much denser hydrogen store - such as water - are suggested: heating it up to 3000C (~5400F) using solar collectors or nuclear power, bacterial processes, and catalysts (see figure 2 in the article - looks fancy doesn't it?).
So, OK, some of the style of the article feels bad to me, but there is some useful physics in there.
Woo hoo:( Roll on the summer holiday madness, when baggage handlers go on strike at Heathrow and the Spanish/French/German/Brit air traffic controller's strike, causing re-routing chaos?:)
The appropriate (original radio show) Hitchhiker's Guide quotes are along the lines of "We are currently awaiting delivery of our supply of lemon soaked paper napkins. Until then there will be a short delay. Please return to your seats."
Thank you for the transcript link. I think I can see how the words:
"During my service in the United States Congress, I took the initiative in creating the Internet."
could be taken out of context. I mean, it has the participle 'creating' which is conceptually similar to 'inventing' in my mind. He could have said "ensuring that the development of the Internet had the funding it deserved", but that's not so snappy.
I think it's just the way things are that there's a tendency towards ambiguous statements in politics. That way, if you fsck up you can always try and claim you meant something else.
Sadly I think this would actually happen to more people than just myself, which would eventually erode teh human specis into non-existance.
I agree that it'd happen to others, but not the whole species. It'd just get rid of those prone to being addicted to living in a fantasy. So that's all the D&D geeks, video gamers,/. readers, crazy liberal artists - we'd be left with a world full of dull suits. Great.
Of course, some would argue that TV has already started the process...
will you have to be one of the wealthy elite of a first-world-nation in order to be immortal?
With birthrates where they are now, and no one dying of old age we'll need to move billions of people into space.
In the scenario suggested by the author Kim Stanley Robinson (the Mars trilogy), it is indeed the wealthy individuals and nations that get access to anti-aging treatments. Economists might argue that if they develop it, why shouldn't they get it first. I ask you though, do you really want to see more crap singles and dumb TV programs from the current generation of performers, for 9 more centuries?
He also points out that moving billions off the planet is unlikely to be a solution to population growth. The problem is that as fast as you can ship a million people to a new colony/moon-base/asteroid, the remaining 6+ billion people on the planet are still bonking each other's brains out and producing more children. The problem is on Earth, so fix it on Earth.
I recently borrowed a book from the local library called How to clone the perfect blonde. It covers a few topical science subjects in a manner that's fairly easy to understand. I picked it up because of the title of course.
Excuses aside, it also contains a chapter called "How to build a domestic goddess". They call their domestic robot either a Jeeves or a Nigella. Hmm. I'm told she's way more popular in the States than here in the UK. A least there's a ready and waiting market for anyone who figures out how to build a Nigellabot.
The attractive thing about fusion with deuterium and helium-3 is that the main reaction does not produce neutrons. There are side reactions that will still produce neutrons, but overall I think the process is cleaner. Neutrons wlll irradiate the surrounding structures of any fusion plant:(
Recently, BBC News reported that Europe might finally get on with the job of building ITER - the next stage of fusion power plant development. I believe ITER will use D/T fuel.
The concentration of He3 in the lunar surface may be very low. It could require processing many 100's of tonnes to get a gram/ounce/drop-in-the-ocean of He3. Of course, you could build an automated solar powered mining facility on the lunar surface to do it. You'd need serious $$$ though.
Getting it back to Earth might be a pain. You could probably wrap it up in some aluminium projectile also mined on the moon, and fire it at Earth with a linear induction track or somthing. The projectile could have an ablative heat shield to protect the tiny precious cargo. More $$$ though.
You need an efficient fusion power plant to 'burn' the stuff in and convert the heat to electrical energy.
Rather than using it on earth to generate electricity, it might be better used as a propellant for interplanetary spacecraft. The British Interplanetary Society once had plans for something called Daedalus which I think was designed to use He3 mined from the atmosphere of Jupiter. Is that even crazier?
> I note that the systemin use is a single frequency hologram
> not a white light hologram. thus the play back has to be
> done by a monochromatic light source.
Why is that? Isn't the single frequency of the laser also present in normal daylight to enough extent to view the hologram? Or does it have to be a coherent source of the single frequency to view it?
I did this in high school. We didn't have a nice optics bench that could prevent vibrations, so the solution was a paving slab resting on a partially inflated bicycle inner tube, and a sign in the corridor to tell people to trend lightly and not slam the door.
Suprisingly it worked fairly well. We produced a few small holos of toy cars and stuff, using some Ilford film (can't remember which type) a HeNe laser, and guessing the exposure time. Fixing the film didn't seem to work well though - the holograms tended to start fading or something after a few days.
Do kids get to do stuff like this in school these days? I would like to think that cool science things are routinely taught now, since technology like lasers are everywhere. Probably wishful thinking.
Previous reviews on Anandtech and Tom's Hardware have suggested 16x is the DVD limit. Blu-ray and HD might given better performance by cramming more in the same space rather than spinning the disk faster. The media will probably still be expensive when it first appears of course.
Fair enough, and thanks for the numbers. Interesting to see that the SSO hybrid has an ISP around 250. I believe that he shuttle's SRBs have an ISP of a little over 270. Do you think then, that if someone can build a hybrid using LOx or perhaps NO2, wouldn't the performance be much better, with lighter oxidiser tanks? Then you'd have a nice reusable, booster or fist stage that you could throttle.
O3? Sounds like a mutant SGI computer from last century.
People have however talked about Helium-3, which can be used in fusion reactions, giving minimal nasty radioactive by-products. Some people think that the moon's surface is covered with the stuff due to years of bombardment by the solar wind. The costs of extracting it, however, may be prohibitive.
Not all of them were built just to win the X-prize. Here in the UK, Steve Bennett's Starchaser Industries is developing a fairly traditional liquid fuelled engine. This should be powerful enough to allow an orbital launch vehicle to be built.
Carmack's Armadillo team are working with hydrogen peroxide monopropellant engines. Although less powerful than bipropellants (eg. liquid oxygen and kerosene), these might also reach orbit if enough stages and/or boosters are used. They've probably still got a better specific impulse than the hybrid engine in Space Ship One.
Also, even if all these things were built just to win the X-prize, the knowledge gained can still be built upon to take the nxt (much more challenging) step.
It will fall eventually, same as the ISS is slowly falling all the time due the ever so slight effects of air resistance slowing it down.
Some of the junk could be thrown 'out the back' of the ISS to try and help maintain the station's orbit, but the effects would be minimal. Unless it's a really large amount of poo at very high speed.
If your engines are 'burning' antimatter, it'll be really difficult to get useful thrust out of them, since it's likely the matter-antimatter reaction will produce a large amount of fairly nasty radiation. It might be possible to trap the radiation and use it to heat up and vapourise some normal matter in order to produce thrust, but you'd want to do it in deep space for interstellar travel, not in the Earth's atmosphere which we all need to breathe.
Whilst any space shuttle replacements would benefit from improved efficiency fuels, the real cost savings will be from more efficient maintenance and ground systems. Once the orbiter lands back on Earth, the time and cost to turn it around and launch again is currently far too much.
One mechanism for "wear and tear" in metals that might be appropriate to consider here is the one that happens due to crack propagation along crystal boundaries. Now, if these MEMS devices are smaller than a normal individual crystal, then there's much less chance of breakage.
The article describes the design as a "beam-and-pad design... , carving the switches from wafers made of single-crystal layers of silicon and silicon oxide". I would guess the beam does not have anything we'd recognise as a hinge, and just flexes along its length when it swiches position. Neat.
Yes, it's called "... That Thou Art Mindful of Him" and the robots are small birds designed to eat insect pests from crop fields. They are conceived by two other robots (JG models George Nine and Ten) as a means of ensuring the future success of the United States Robotics and Mechanical Men Company.
More interesting is how Asimov tests his three laws in this story. The George robots aren't concerned with physical appearances (hence robo-birds). Therefore they decide humans are really evaluated based on their minds and character. Since they worked out a way to save the US Robotics company and ensure a nice future partnership between humans and robots, they decide they are smarter than normal humans, and thus in fact actually are humans and superior ones at that. Oops.
Slashdot Mirror
If 1 man dies it's an accident. If a million die it's a tragedy. Or something like that...
Will some astronauts die? Of course. And they know that. It's the risk they signed up for. Why not let them be the ones to decide whether or not it's worth it.
Hmm. I don't have all the numbers, but a quick Google search suggests over 40,000 people die a year in the USA from traffic related accidents. However, I can't imagine how many millions of car journeys actually take place. Now, the Shuttle on the other hand has lost 14 crew members in about 100 flights. That looks to me like it's dangerous.
Not that I'm not particularly pro-cars (British, use publc transport), and it's not my space programme either. The thing is, whilst your astronauts at NASA are exceedingly well qualified and trained, they don't have much choice about their management. They can calculate the odds of being hit by a dropped wrench at 20,000mph, but not the odds of a human giving in to political/peer-pressure and ordering a dangerous launch. They really are brave.
It turns out that this is a known phenomenon and is somtimes described in the manufacturers instruction leaflet. Like anyone reads that. Unlike a CRTs, it's reversible in many cases, which is a big plus.
Here's some guys DSL webserver for you to /. http://www.dslwebserver.com/main/lcd-screen-burn.h tml
I'm in the UK. I watched the series _because_ I saw the pilot first via P2P. I feared for a remake of BSG, but it turns out that they've been fairly creative and made an intelligent modern version of a classic sci-fi TV show.
First, I hate that the article contains the submitter's favourite: 'The natural world began forming its own hydrogen economy 3 billion years ago, when it developed photosynthesis to convert CO2, water, and sunlight into hydrogen and oxygen'. What crap. Photosynthesis generates saccharides - chains of sugars, which are used by plants in to generate energy from respiration, just as animals do. There may be a brief moment where water molecules are split into H. and OH. radicals, but no hydrogen gas is produced or used as an energy store. Bury the plants deep undergound for a few million years and you have fossil fuels, not hydrogen gas pockets.
Now, for those of you pointing out how crap hydrogen's energy density is - you're right! It sucks. It's so hard to deal with the stuff. I mean, the only way they make it work for the Space Shuttle is to deep freeze it so that it liquifies, and it takes yet more energy to cool it down which makes it suck more...
If you read the article, it admits that using hydrogen in vehicles is very challenging. A tank full of H2 is unlikely to ever happen on this planet. Instead, the suggested vehicle storage solutions include nanostructure materials, surface absorbption/adsorption, or ionic compounds. However, cars and planes are not everything in the world. H2 gas could be used in homes and businesses instead of natural gas. Various methods of generating H2 gas from a much denser hydrogen store - such as water - are suggested: heating it up to 3000C (~5400F) using solar collectors or nuclear power, bacterial processes, and catalysts (see figure 2 in the article - looks fancy doesn't it?).
So, OK, some of the style of the article feels bad to me, but there is some useful physics in there.
The appropriate (original radio show) Hitchhiker's Guide quotes are along the lines of "We are currently awaiting delivery of our supply of lemon soaked paper napkins. Until then there will be a short delay. Please return to your seats."
Sorry, tired. Sounded funny at the time.
"During my service in the United States Congress, I took the initiative in creating the Internet."
could be taken out of context. I mean, it has the participle 'creating' which is conceptually similar to 'inventing' in my mind. He could have said "ensuring that the development of the Internet had the funding it deserved", but that's not so snappy.
I think it's just the way things are that there's a tendency towards ambiguous statements in politics. That way, if you fsck up you can always try and claim you meant something else.
I guarantee if you can duplicate R2's projector, they will catch on. Nah, if they can duplicate Leia in a gold bikini, they will catch on.
I agree that it'd happen to others, but not the whole species. It'd just get rid of those prone to being addicted to living in a fantasy. So that's all the D&D geeks, video gamers, /. readers, crazy liberal artists - we'd be left with a world full of dull suits. Great.
Of course, some would argue that TV has already started the process...
With birthrates where they are now, and no one dying of old age we'll need to move billions of people into space.
In the scenario suggested by the author Kim Stanley Robinson (the Mars trilogy), it is indeed the wealthy individuals and nations that get access to anti-aging treatments. Economists might argue that if they develop it, why shouldn't they get it first. I ask you though, do you really want to see more crap singles and dumb TV programs from the current generation of performers, for 9 more centuries?
He also points out that moving billions off the planet is unlikely to be a solution to population growth. The problem is that as fast as you can ship a million people to a new colony/moon-base/asteroid, the remaining 6+ billion people on the planet are still bonking each other's brains out and producing more children. The problem is on Earth, so fix it on Earth.
Excuses aside, it also contains a chapter called "How to build a domestic goddess". They call their domestic robot either a Jeeves or a Nigella. Hmm. I'm told she's way more popular in the States than here in the UK. A least there's a ready and waiting market for anyone who figures out how to build a Nigellabot.
Recently, BBC News reported that Europe might finally get on with the job of building ITER - the next stage of fusion power plant development. I believe ITER will use D/T fuel.
Problems:
- The concentration of He3 in the lunar surface may be very low. It could require processing many 100's of tonnes to get a gram/ounce/drop-in-the-ocean of He3. Of course, you could build an automated solar powered mining facility on the lunar surface to do it. You'd need serious $$$ though.
- Getting it back to Earth might be a pain. You could probably wrap it up in some aluminium projectile also mined on the moon, and fire it at Earth with a linear induction track or somthing. The projectile could have an ablative heat shield to protect the tiny precious cargo. More $$$ though.
- You need an efficient fusion power plant to 'burn' the stuff in and convert the heat to electrical energy.
Rather than using it on earth to generate electricity, it might be better used as a propellant for interplanetary spacecraft. The British Interplanetary Society once had plans for something called Daedalus which I think was designed to use He3 mined from the atmosphere of Jupiter. Is that even crazier?> I note that the systemin use is a single frequency hologram > not a white light hologram. thus the play back has to be > done by a monochromatic light source. Why is that? Isn't the single frequency of the laser also present in normal daylight to enough extent to view the hologram? Or does it have to be a coherent source of the single frequency to view it?
Suprisingly it worked fairly well. We produced a few small holos of toy cars and stuff, using some Ilford film (can't remember which type) a HeNe laser, and guessing the exposure time. Fixing the film didn't seem to work well though - the holograms tended to start fading or something after a few days.
Do kids get to do stuff like this in school these days? I would like to think that cool science things are routinely taught now, since technology like lasers are everywhere. Probably wishful thinking.
Previous reviews on Anandtech and Tom's Hardware have suggested 16x is the DVD limit. Blu-ray and HD might given better performance by cramming more in the same space rather than spinning the disk faster. The media will probably still be expensive when it first appears of course.
Fair enough, and thanks for the numbers. Interesting to see that the SSO hybrid has an ISP around 250. I believe that he shuttle's SRBs have an ISP of a little over 270. Do you think then, that if someone can build a hybrid using LOx or perhaps NO2, wouldn't the performance be much better, with lighter oxidiser tanks? Then you'd have a nice reusable, booster or fist stage that you could throttle.
People have however talked about Helium-3, which can be used in fusion reactions, giving minimal nasty radioactive by-products. Some people think that the moon's surface is covered with the stuff due to years of bombardment by the solar wind. The costs of extracting it, however, may be prohibitive.
Carmack's Armadillo team are working with hydrogen peroxide monopropellant engines. Although less powerful than bipropellants (eg. liquid oxygen and kerosene), these might also reach orbit if enough stages and/or boosters are used. They've probably still got a better specific impulse than the hybrid engine in Space Ship One.
Also, even if all these things were built just to win the X-prize, the knowledge gained can still be built upon to take the nxt (much more challenging) step.
If you're on a sub-orbital flight with only a couple of minutes of zero-G, then you better make sure it's just a quickie...
Some of the junk could be thrown 'out the back' of the ISS to try and help maintain the station's orbit, but the effects would be minimal. Unless it's a really large amount of poo at very high speed.
Whilst any space shuttle replacements would benefit from improved efficiency fuels, the real cost savings will be from more efficient maintenance and ground systems. Once the orbiter lands back on Earth, the time and cost to turn it around and launch again is currently far too much.
The article describes the design as a "beam-and-pad design ... , carving the switches from wafers made of single-crystal layers of silicon and silicon oxide". I would guess the beam does not have anything we'd recognise as a hinge, and just flexes along its length when it swiches position. Neat.
More interesting is how Asimov tests his three laws in this story. The George robots aren't concerned with physical appearances (hence robo-birds). Therefore they decide humans are really evaluated based on their minds and character. Since they worked out a way to save the US Robotics company and ensure a nice future partnership between humans and robots, they decide they are smarter than normal humans, and thus in fact actually are humans and superior ones at that. Oops.