IR sensors/cameras: ice/(different kinds of) snow/water/hail are distinguishable
standing water/hydroplaning,
turn rate sensors/accelereometers/steering wheel angle: The on-board computer already
has a pretty good picture of how the car should behave, used for all those assistive
technologies. Detecting hydroplaning using this data is feasible, and I believe already
done by Mercedes (and probably by others too).
sand/gravel on the road is a mystery.
Microphones. Seriously, by listening to the sound the tyres make on the ground,
quite bit can be inferred about what this ground is.
I'm not saying the system mentioned does all this - but there already is an awful
lot of sensing equipment in a modern car, and it will not take too long for cars to
have complete situational "awareness". Heck, I'm sure even today's high-end cars
already are better at it than some of the drivers out there.
You would need significant background in aerospace and safety engineering to be able to conduct such a thing, and most of these folks are not.
Actually, most of these folks are
What do you think astronauts are? Some kind of toilet trained space monkey? They are highly qualified, very smart people.
Okay I know it's important for big server farms, but personally speaking I'm not interested in performance per watt at all. I'm only interested in one thing: Which processor/motherboard/graphics card/OS combination gives me the biggest bang for the bucks for my gaming, compilation, and simulation needs?
So you don't pay for your electricity consumption?
On the not-so-long term, energy costs outweigh hardware costs.
As ridiculous as those questions are, they serve a near-sensible purpose:
If somebody is caught doing $bad_thing he denied planning on the form,
even if the case is tricky, he can be prosecuted for lying to immigration.
In the UK to establish copyright you used to be able to send yourself a stamp addressed envelope containing the relevant work. So long as it remained unopened the postmark served as both a mark of authenticity and also as a timestamp.
Not really, no. The Royal Mail will gladly deliver your unsealed empty envelope to you, complete with postmark, and ready to
receive any content you want to "prove" is yours. You'll need at least some credible witness confirming your story.
Eaven easier: Wind turbines don't move around - in other words: Their location is known and doesn't change.
It should be trivial to filter those out. What a non-story.
But this news is not entirely awful. It just means that DNA is no longer quite so useful in proving that a person is guilty. It is still perfectly useful in the much more important task of proving not guilty.
Is it? Not finding your DNA at a crime scene does not prove that you have not been there.
That wikipedia article describes the _characteristics_ of that type of scattering, but it doesn't really explain WHY the light gets scattered that way.
The gremlins do it. Seriously, "why" is not a question that is scientifically meaningful. The only sensible answer is "because".
Of course, the Rayleigh scattering can be explained using quantum physics - but this would just shift your "why" to why things
in the quantum world behave like they do. And finally, it will always arrive at a point where science has no clue.
Science is descriptive and predictive, it will however never deliver some kind of "justification" for the behaviour of stuff.
"Why" implies a motivation to do something one way and not another - the universe doesn't deliver those. The scientific question is
a simple "how?".
My understanding is that it's density differences. Light bends when it goes from air to water, for example, because of the difference in density. Now air has small density variations. For the short-wavelength blue light, it is going through air whose density is continually changing. So it's path goes all over the place.
But for the red light, with almost twice the wavelength, the density changes are lot more averaged (since it's bigger), so it doesn't see the density changes so much, so pretty much goes in a straight line.
Your understanding is - sorry - entirely wrong. The wikipedia article actually does a more or less decent job at explaining it: http://en.wikipedia.org/wiki/Rayleigh_scattering
The basic thing: Light scatters off the molecules of the air (no density variations needed). The higher the lights frequency (i.e. the bluer it is), the more it scatters.
So we see lots of scattered blue from all directions, but a lot less of scattered red, yellow, green, etc.
And because the atmosphere isn't thick enough to scatter a large amount of the colours on the red end of the spectrum, those come through more or less unscattered.
At dusk or at dawn, the light you see travels much longer distance in the atmosphere, and other colours scatter too. That's the main reason why sunrises and
sunsets are red - that's the only colour making it through.
A good example is to look at how YouTube has ads baked into the flash.
Those ads are still individual streams, and not part of the main video. Adblock Plus
takes care of those without any problems - it sees "object subrequests".
Have you ever seen the American casualty count just to take Iwo Jima and Okinawa?
Iwo Jima: 23, 573
Okinawa: 50, 000
You do know of course that in the military context, casualties = killed + wounded, right?
I don't want to lessen anything, but the numbers of (american) soldiers actually killed are quite a
bit lower:
Iwo Jima: ~7,000
Okinawa: ~13,000
This does of course not include japanese and civilian losses, wich were massive. And it does in no way counter
the point of the nuclear bombs' net life-saving effect. I'm still entirely undecided about that.
However, I don't get why an invasion was seen as so inevitable. Japan is an island! Just lock them in and wait - I'm
pretty sure that complete air and sea superiority could have been achieved - the Sowjets would even have helped.
Then why were there such problems during the post Columbia stand down?
Space flights still take quite a bit of advanced planning - so just sending other spacecraft instead of scheduled Shuttle flights wasn't an immediate option.
(Hint: It's because the Shuttle provides the majority of cargo upmass
Provided - after finishing construction, there's no immediate need for huge single flight
hauling capacities - delivering supplies can be achieved instead by several flights by lower capacity
carriers from there on.
and a significant amount of reboost capacity.
As established above: No. It's a nice bonus, saving ISS refueling flights (and thereby money) - but it's not vital.
After all large pieces are delivered, the Shuttle is not irreplaceable for normal ISS operations.
Well, except maybe for transporting some very big spare parts, something like a replacement
module - but if you need to replace one of those, you're in trouble either way.
I'm not saying it'll be easy, I'm not saying it's possible right now. But it can (and I think will)
be done. And considering the huge cost of a Shuttle launch, it's even entirely possible that the Shuttle-less
ISS operation phase will be cheaper. How much do the russians launch into LEO for half a billion dollars?
A Proton launch to LEO costs something around $100 million and delivers 22,000kg - so this gets us over 100 tonnes
of payload for the price of one single Shuttle launch (24 tonnes).
I don't see any problems in filling the "Shuttle gap" - provided someone is willing to pay for it. That's probably
the biggest problem of all: Will the US Congress agree to pay $lotsofcash for some foreign launches?
Isn't there a fourth option? Namely- use Soyuz to transport people from now on
Without Shuttle to provide the cargo upmass and reboosts - there isn't a fourth option. Soyuz and Progress can't do it, ATV won't fly often enough, and HTV is still largely in the vaporware category [...]
"Most reboosts use the Progress attitude control thrusters, however larger burns are done using the Progress main engines.
When there is no Progress docked to the Service Module (SM) aft, the SM's two (or just one of the two) main engines could also
be used to perform a reboost. Finally, the Orbiter [i.e., the Shuttle] does generally perform a reboost of ISS during a docked
mission. Due to the fact that a majority of the Orbiter's thrusters cannot be used when docked (due to concerns of plume impacts
on ISS), they don't really get much more delta V out of the Orbiter than they do the Progress or SM. The largest benefit is
that it uses Orbiter propellants, not the limited supply that is maintained on ISS."
Or, if you don't like that source, nasaspaceflight.com:
"Generally ISS reboosts are performed by the Progress resupply ship thrusters"
So no, a lack of Shuttle flights will not result in a lack of ISS reboosts. And now that they can recycle their water,
fresh water isn't that high a priority for cargo flights any more either. It'll mean a couple more transporter flights (and,
someone will have to pay for those of course) but the ISS can survive without any Shuttle flights at all without any problems.
Exactly, I hate when the Plebians call things based on what they look like, taste like, and are manufactured in identical processes too,
Kraft "Parmesan" "Cheese" (quotes are there for a reason) does neither look like, taste like, nor is it manufactured like real Parmigiano.
It's a lousy imitation you'll never touch again if you've tasted the real one.
I just watched the video - and while it definitely is a cool concept, what immediately came
to mind is the increased complexity of the system. I counted five separations (the launch itself
would be a separation in reality) of some piece or another and multiple chute deployments before the
crew capsule was safely floating down on its main parachutes.
I'm sure there's redundancy in there so a single failure wouldn't be fatal (although not dropping the
casing preventing main chute deployment would be bad), but it is quite a step up from the regular
"separate, fire one solid booster, wait a bit, deploy chutes" apporach.
For example, it seems to me like a "full" drive seems to physically weigh more than a blank one, sort of like a full battery is noticeably heavier than an empty one.
Wrong on both counts. A "full" magnetic hard drive platter just has its magnetic domains aligned in a certain pattern.
Those domains are physically there whether they are used for data storage or not. So the weight will be indentical.
A battery does indeed become lighter when "emptied" - according to E = mc^2 and the energy that came out of it.
However, this is way, way, way under anything you would be able to notice.
Hubble was never meant to be serviced in space, that's why it was such a pain in the rear to do so.
But of course it was. The first service mission was planned even before HST launched. The schedule got mixed up
a bit because of the corrective optics that needed to be made, but manned service missions were part of the
design from the beginning. That's one of the reasons why HST's orbit is where it is: As far out as possible
within the constraints of "can still be reached by the Shuttle".
However, some of the things that got fixed/swapped/serviced on this year's mission were indeed not intended
for in-orbit maintenance.
And then there's - admittedly a bit more speculative and potentially vapourware-y - Superwind,
a Danish university project to design a superconducting 10-20MW wind generator: http://www.superwind.dk/
I'm a bit sceptical about those superconducting designs - even very good insulation will not prevent
all icing, and uncontrolled icing isn't a good thing, especially when it is in lousy weather a good distance
off shore. But even conventional (i.e. non-superconducting) technology will probably reach 10MW
not too far in the future. Pretty cool.
Oh, and for the really crazy ideas, have a look at the 1GW Maglev Wind Turbine
At the time being, this is a "looks good on paper" design. However, it might actually be feasible,
but is certainly still a long time away.
Just to clarify: -273.05C equals 0.1 Kelvin. That looks much more impressive, as it
indicates how close to absolute zero it is - and even is easier to grasp in my opinion.
Come on, we're on Slashdot, dammit!
Slashdot Mirror
How it will detect ice, snow,
IR sensors/cameras: ice/(different kinds of) snow/water/hail are distinguishable
standing water/hydroplaning,
turn rate sensors/accelereometers/steering wheel angle: The on-board computer already
has a pretty good picture of how the car should behave, used for all those assistive
technologies. Detecting hydroplaning using this data is feasible, and I believe already
done by Mercedes (and probably by others too).
sand/gravel on the road is a mystery.
Microphones. Seriously, by listening to the sound the tyres make on the ground,
quite bit can be inferred about what this ground is.
I'm not saying the system mentioned does all this - but there already is an awful
lot of sensing equipment in a modern car, and it will not take too long for cars to
have complete situational "awareness". Heck, I'm sure even today's high-end cars
already are better at it than some of the drivers out there.
WTF is this link-less entry supposed to be?
Here's the story mentioned above:
http://www.ifixit.com/Teardown/iPod-touch-3rd-Generation/1158/2
You would need significant background in aerospace and safety engineering to be able to conduct such a thing, and most of these folks are not.
Actually, most of these folks are
What do you think astronauts are? Some kind of toilet trained space monkey? They are highly qualified, very smart people.
Picked at random from http://en.wikipedia.org/wiki/List_of_astronauts_by_name:
Okay I know it's important for big server farms, but personally speaking I'm not interested in performance per watt at all. I'm only interested in one thing: Which processor/motherboard/graphics card/OS combination gives me the biggest bang for the bucks for my gaming, compilation, and simulation needs?
So you don't pay for your electricity consumption?
On the not-so-long term, energy costs outweigh hardware costs.
As ridiculous as those questions are, they serve a near-sensible purpose:
If somebody is caught doing $bad_thing he denied planning on the form,
even if the case is tricky, he can be prosecuted for lying to immigration.
It's a sort of legal backup.
In the UK to establish copyright you used to be able to send yourself a stamp addressed envelope containing the relevant work. So long as it remained unopened the postmark served as both a mark of authenticity and also as a timestamp.
Not really, no. The Royal Mail will gladly deliver your unsealed empty envelope to you, complete with postmark, and ready to
receive any content you want to "prove" is yours. You'll need at least some credible witness confirming your story.
Also, http://www.copyrightauthority.com/poor-mans-copyright/ and http://www.snopes.com/legal/postmark.asp
Eaven easier: Wind turbines don't move around - in other words: Their location is known and doesn't change.
It should be trivial to filter those out. What a non-story.
The entire radio miniseries is available on the BBC website linked above, and is drenched in Adam's usual style.
It's not if you happen to be outside the UK: "Not available in your area".
Much of the fun in the books come from the unique descriptions Mr. Adams used.
Exactly. How do you film a spaceship that hangs in the sky in much the same way that a brick doesn't?
But this news is not entirely awful. It just means that DNA is no longer quite so useful in proving that a person is guilty. It is still perfectly useful in the much more important task of proving not guilty.
Is it? Not finding your DNA at a crime scene does not prove that you have not been there.
Did anyone else read the title as... "Genetic Mutation Enables Less Sheep"?
Y-e-e-e-e-e-s.
That wikipedia article describes the _characteristics_ of that type of scattering, but it doesn't really explain WHY the light gets scattered that way.
The gremlins do it. Seriously, "why" is not a question that is scientifically meaningful. The only sensible answer is "because".
Of course, the Rayleigh scattering can be explained using quantum physics - but this would just shift your "why" to why things
in the quantum world behave like they do. And finally, it will always arrive at a point where science has no clue.
Science is descriptive and predictive, it will however never deliver some kind of "justification" for the behaviour of stuff.
"Why" implies a motivation to do something one way and not another - the universe doesn't deliver those. The scientific question is
a simple "how?".
My understanding is that it's density differences. Light bends when it goes from air to water, for example, because of the difference in density. Now air has small density variations. For the short-wavelength blue light, it is going through air whose density is continually changing. So it's path goes all over the place. But for the red light, with almost twice the wavelength, the density changes are lot more averaged (since it's bigger), so it doesn't see the density changes so much, so pretty much goes in a straight line.
Your understanding is - sorry - entirely wrong. The wikipedia article actually does a more or less decent job at explaining it: http://en.wikipedia.org/wiki/Rayleigh_scattering
The basic thing: Light scatters off the molecules of the air (no density variations needed). The higher the lights frequency (i.e. the bluer it is), the more it scatters.
So we see lots of scattered blue from all directions, but a lot less of scattered red, yellow, green, etc.
And because the atmosphere isn't thick enough to scatter a large amount of the colours on the red end of the spectrum, those come through more or less unscattered.
At dusk or at dawn, the light you see travels much longer distance in the atmosphere, and other colours scatter too. That's the main reason why sunrises and
sunsets are red - that's the only colour making it through.
A good example is to look at how YouTube has ads baked into the flash.
Those ads are still individual streams, and not part of the main video. Adblock Plus
takes care of those without any problems - it sees "object subrequests".
Have you ever seen the American casualty count just to take Iwo Jima and Okinawa?
Iwo Jima: 23, 573
Okinawa: 50, 000
You do know of course that in the military context, casualties = killed + wounded, right?
I don't want to lessen anything, but the numbers of (american) soldiers actually killed are quite a
bit lower:
Iwo Jima: ~7,000
Okinawa: ~13,000
This does of course not include japanese and civilian losses, wich were massive. And it does in no way counter
the point of the nuclear bombs' net life-saving effect. I'm still entirely undecided about that.
However, I don't get why an invasion was seen as so inevitable. Japan is an island! Just lock them in and wait - I'm
pretty sure that complete air and sea superiority could have been achieved - the Sowjets would even have helped.
Then why were there such problems during the post Columbia stand down?
Space flights still take quite a bit of advanced planning - so just sending other spacecraft instead of scheduled Shuttle flights wasn't an immediate option.
(Hint: It's because the Shuttle provides the majority of cargo upmass
Provided - after finishing construction, there's no immediate need for huge single flight
hauling capacities - delivering supplies can be achieved instead by several flights by lower capacity
carriers from there on.
and a significant amount of reboost capacity.
As established above: No. It's a nice bonus, saving ISS refueling flights (and thereby money) - but it's not vital.
After all large pieces are delivered, the Shuttle is not irreplaceable for normal ISS operations.
Well, except maybe for transporting some very big spare parts, something like a replacement
module - but if you need to replace one of those, you're in trouble either way.
I'm not saying it'll be easy, I'm not saying it's possible right now. But it can (and I think will)
be done. And considering the huge cost of a Shuttle launch, it's even entirely possible that the Shuttle-less
ISS operation phase will be cheaper. How much do the russians launch into LEO for half a billion dollars?
A Proton launch to LEO costs something around $100 million and delivers 22,000kg - so this gets us over 100 tonnes
of payload for the price of one single Shuttle launch (24 tonnes).
I don't see any problems in filling the "Shuttle gap" - provided someone is willing to pay for it. That's probably
the biggest problem of all: Will the US Congress agree to pay $lotsofcash for some foreign launches?
Without Shuttle to provide the cargo upmass and reboosts - there isn't a fourth option. Soyuz and Progress can't do it, ATV won't fly often enough, and HTV is still largely in the vaporware category [...]
Except that actually most ISS reboosts are done by Progress, and the Shuttle in fact is pretty useless for them. :
Quoting http://www.thespacerace.com/forum/index.php?topic=1476.0
"Most reboosts use the Progress attitude control thrusters, however larger burns are done using the Progress main engines.
When there is no Progress docked to the Service Module (SM) aft, the SM's two (or just one of the two) main engines could also
be used to perform a reboost. Finally, the Orbiter [i.e., the Shuttle] does generally perform a reboost of ISS during a docked
mission. Due to the fact that a majority of the Orbiter's thrusters cannot be used when docked (due to concerns of plume impacts
on ISS), they don't really get much more delta V out of the Orbiter than they do the Progress or SM. The largest benefit is
that it uses Orbiter propellants, not the limited supply that is maintained on ISS."
Or, if you don't like that source, nasaspaceflight.com:
"Generally ISS reboosts are performed by the Progress resupply ship thrusters"
So no, a lack of Shuttle flights will not result in a lack of ISS reboosts. And now that they can recycle their water,
fresh water isn't that high a priority for cargo flights any more either. It'll mean a couple more transporter flights (and,
someone will have to pay for those of course) but the ISS can survive without any Shuttle flights at all without any problems.
Exactly, I hate when the Plebians call things based on what they look like, taste like, and are manufactured in identical processes too,
Kraft "Parmesan" "Cheese" (quotes are there for a reason) does neither look like, taste like, nor is it manufactured like real Parmigiano.
It's a lousy imitation you'll never touch again if you've tasted the real one.
I just watched the video - and while it definitely is a cool concept, what immediately came
to mind is the increased complexity of the system. I counted five separations (the launch itself
would be a separation in reality) of some piece or another and multiple chute deployments before the
crew capsule was safely floating down on its main parachutes.
I'm sure there's redundancy in there so a single failure wouldn't be fatal (although not dropping the
casing preventing main chute deployment would be bad), but it is quite a step up from the regular
"separate, fire one solid booster, wait a bit, deploy chutes" apporach.
For example, it seems to me like a "full" drive seems to physically weigh more than a blank one, sort of like a full battery is noticeably heavier than an empty one.
Wrong on both counts. A "full" magnetic hard drive platter just has its magnetic domains aligned in a certain pattern.
Those domains are physically there whether they are used for data storage or not. So the weight will be indentical.
A battery does indeed become lighter when "emptied" - according to E = mc^2 and the energy that came out of it.
However, this is way, way, way under anything you would be able to notice.
An AA alkaline battery can deliver about 10000 Joules (http://www.allaboutbatteries.com/Energy-tables.html) - so
a discharged (= "empty") AA alkaline will weigh m = E/c^2 or roughly 10^-10 grams less than a charged one.
That's 0.1 nanograms. About 100 human skin cells. No, you won't notice that.
Hubble was never meant to be serviced in space, that's why it was such a pain in the rear to do so.
But of course it was. The first service mission was planned even before HST launched. The schedule got mixed up
a bit because of the corrective optics that needed to be made, but manned service missions were part of the
design from the beginning. That's one of the reasons why HST's orbit is where it is: As far out as possible
within the constraints of "can still be reached by the Shuttle".
However, some of the things that got fixed/swapped/serviced on this year's mission were indeed not intended
for in-orbit maintenance.
There's the Enercon E-126 which is rated at 6MW. It is still considered a prototype,
even though there are a couple of them already built, and it'll probably end up more
powerful still: http://www.metaefficient.com/news/new-record-worlds-largest-wind-turbine-7-megawatts.html
I've been told that 8-9MW versions are probably just a couple of years away.
Enercon are the guys with the no-gearbox design by the way.
There's also an American project - with participation of the DoE - to develop a supreconductor-based 10MW generator:
http://www.amsc.com/newsroom/pr.html?id=317
And then there's - admittedly a bit more speculative and potentially vapourware-y - Superwind,
a Danish university project to design a superconducting 10-20MW wind generator: http://www.superwind.dk/
I'm a bit sceptical about those superconducting designs - even very good insulation will not prevent
all icing, and uncontrolled icing isn't a good thing, especially when it is in lousy weather a good distance
off shore. But even conventional (i.e. non-superconducting) technology will probably reach 10MW
not too far in the future. Pretty cool.
Oh, and for the really crazy ideas, have a look at the 1GW Maglev Wind Turbine
At the time being, this is a "looks good on paper" design. However, it might actually be feasible,
but is certainly still a long time away.
A single wind turbine, the really big kind they use in wind farms, generates about 1500 kilowatts.
Uhm, no. In wind energy, that's close to ancient history. Let's say 5000 kilowatts: http://www.repower.de/index.php?id=237&L=1
And that's a model that can be bought now, there are >8MW models in development.
750kW in a car is still a lot though.
Just to clarify: -273.05C equals 0.1 Kelvin. That looks much more impressive, as it
indicates how close to absolute zero it is - and even is easier to grasp in my opinion.
Come on, we're on Slashdot, dammit!
How could an antenna for frequencies with a wavelength of a few centimeters be 18 meters wide?
In space, nobody can hear your phone - unless he has a really big reflector.