with none of the radiation hazards of x-ray or gamma-ray detectors now used at border crossings.
Yeah, right. It will harmlessly pass through a bag of water like a human body, because water is such a lousy material at stopping radiation. That's why it's not used in nuclear reactors or cosmic ray detectors...
I wouldn't say that. Extremely low-mass stars are very faint and not much hotter than the most massive planets (especially when the body in question receives heat from a much hotter companion star, as is the case with this object).
Still, there should be a clear difference in the radiation dependeing on if the energy comes from inside, or only from outside.
If it comes only from the outside, then the "night side" should much cooler than the "day side", which should be visible in the temperature range of the radiation.
Also, if there's *any* fusion in the star, there must be quite a lot of it, enough to stop the collapse of the entire, enormous mass of the mini-star (since the core of a star necessarily has lower density because of the fusion energy, than if it were just a brown dwarf with equal mass. So if there is fusion, it should increase the energy output a lot, making the surface much hotter than a cooling brown dwarf can ever be.
I may be off here, but its density seems insanely high though.
Well, I suppose it would have enough mass to collapse into a white dwarf, which would be much denser and smaller still. So it being that big is no great mystery when you think of it that way.
It's just that the pesky H starts fusing at some point before getting to the white dwarf density, stopping the collapse, for now anyway. Even at that slow rate of fusion I don't think the star will last more than a few hundred times longer than our Sun.
I don't know about other life forms, but could these galaxies perhaps make up some of what we call "dark matter"?
Since they're so far back in time, more likely is that they're just regular galaxies in early stages of development, perhaps a bit special galaxies if they have exceptional amounts of dust or something but still normal matter.
Furthermore, neutron stars aren't dead -- they often radiate a hell of a lot of energy.
Yes they are. Compare to a dead human body, it too radiates heat until it's at the ambient temperature. That's exactly what's going on with neutron stars, too, a dead body radiating left-over energy (both heat and rotational energy, radiated in different ways).
For me, 33m/s is much easier to visualize than 118.8 km/h.
Well, let me guess, you don't drive a car? Or if you do, it has miles per hour speedometer? Because anybody with a km/h speedometer pretty much knows how fast is 118.8km/h because they experience that speed often, even daily. But they have no direct idea how much is 33m/s.
All the confusion rises from the fact that time is not base ten. If it were, let's say there were a 1000 "seconds" in an hour, then it'd be easy, 10 meters per second would be 10 kilometers per hour ("kilosecond").
But, alas, it's not so! Our system of units is imperfect still!
Easiest way to change would be to keep the second, but scrap minutes and hours. The inconvenience would be that one day would not be any even number of kiloseconds or anything, but in everyday life that would not be a big problem since usually our days are punctuated by sleeping, which would "reset" the count anyway.
But for example, HH:MM:SS DD-MM-YYYY is also pretty bad since it puts the biggest first in the time and in the date the biggest at the end. Also not very consistent.:-)
It's very consistent from human point of view, because natural cycle of life is one day long. Hour is more important than minutes (since minutes without hour usually means nothing), but mostly you know what month and year implicitly, so you only need the day (often just weekday is enough).
Wether time or date should be first is another matter (and often irrelevant), but it's most practical to put hours before minutes and day before month before year in everyday non-computer use.
Yes, I'll admit that this was funny, but why would you mod it so? It was equally (if not more so) insightfull. By modding it as 'funny' you've actually deprived the OP of total karma. I wish more/. mods would realize that +1 FUNNY actually detracts from total Karma.
And why would anybody care? There's a karma cap you know, and just writing "normally" makes pretty sure you'll reach that cap pretty soon, so a few points here and there makes *no* difference...
I do not say the PC will die, but it will never more be high-tech. Just like there are very sophisticated alloys, still hacksaws are made of good old steel, because nobody would pay 10 times for the ultra modern alloy.
If only Cell could do what is reguired of a desktop processor... Ie running tens of processes with total hundreds of threads (This WinXP PC currently has 61 Processes and 523 threads running, current memory usage at half a gigabyte) at the same time, with seamless virtual memory with disk swapping and process level memory protection. Cell can't do this, and if it were optimized for stuff like this, it'd have to lose most of the parallel vector processing capabilities, ie the entire point of the processor would vanish.
As it is, Cell has no place in the desktop, except perhaps as a co-processor, provided they convince MS to define DirectX support for utilizing Cell expansion card for vector processing etc.
Isn't law supposed to be equal for all? If Joe Sixpack kills someone and is forgiven, why shouldn't anyone else be? While that is an extreme (and criminal) analogy, it is unfair that the law does not treat everyone equally.
Not really, circumstances matter. An extreme example: an enemy soldier that kills soldier on your side in a battle is not guilty of murder even though he's an enemy (and vice versa your side killing enemy soldiers). But if you purposefully kill a soldier on your side, you're not only guilty of murder, but possibly of treason/sabotage also, even if you're a soldier too.
Do you call that unfair, too?
I'm sure a good lawyer could argue out this point - if X can be exempted, why can't Y be exempted if his reasons are quite similar?
Well, in this case it'd mean the lawyer would have to show that Y has legal (or moral or somesuch) obligation to do something which requires breaking the copy protection... I wouldn't bet on success, no matter how good the lawyer was at twisting words.
The Earth has gone through quite a few ice ages and then reversals -- right now I believe we're in the reversion from a mini ice age. While humans do have a lot of impact on our planet, it is remarkable how we think that the Earth is a static const, when in reality it's a volatile dynamic variable.
Sure it's volatile, but we humans are one quite a big variable. But we're a special variable, because we can conciously control what kind of variable we are. Or try to... Which entire global warming debate is all about. Should we try to control our impact, or just not care, just deal with whatever happens when it happens and accept to economical and humanitarian cost as act of nature.
IMHO it just sounds a tad stupid to not at least try to keep things nice, ignoring the fact that we *do* have a significant impact on many things (eg CO2 levels, which in turn have significant impact on global climate). A bit like not buying a coat for winter (since you have "better" use for the money), and stoically accepting that if you get a flu, then you get a flu and deal with it, but no point worrying about it beforehand, let alone trying to not get the flu in the first place...
Are you really too stupid to understand that you have a legal expectation of privacy in some situations and not in others? Are you completely unable to discern the difference between the two? Or are you just being obstinant?
I bet you'd be ok with all cars having GPS trackers as standard equipment, and the police tracking every car all the time, too... I mean, it's only a difference of scale, not difference of principle (that any car can be GPS-tracked secretly without any kind of control like a warrant).
How about a GPS tracker secretly put in your shoes? After all, you mostly only wear shoes in places where you're not alone, so surely it would not be any kind of invasion of privacy if the police tracked where you go with your shoes, any more than it's invasion of privacy to secretly track where you go with your car...
This is no different than simply following the person, except that well you don't have to follow the person around constantly.
Just like capturing emails of a person is no different than standing behind him when he reads and writes emails... IMHO that's quite a difference.
As another poster put it, there is no expectation of privacy regarding your location as your driving along the road.
Your friend seeing what you're browsing then web when he's visiting is no invasion of privacy. Your friend installing a spyware that tracks your browsing is invasion of privacy. Same thing with planting GPS tracker in a car, it should only be legal with a warrant.
There the only human-produced input energy is the energy required to produce the photovoltaic cell, with the sun providing the actual energy to perform the work. Currently the efficientcy of this process is about 32%, with some setups getting up to 80%.
Indeed, in that scenario the sun is what gives the energy to *us*, and *we* bind it to hydrogen. But about those figures, do they include the energy needed to store the hydrogen in usable forms (compression)? If not, then compression will drop the overall efficiency radically...
Well, hopefully we don't have to compress that gaseous hydrogen, but can instead store it in some solid form that can be created without large non-recoverable energy input...
Neither can be used as an energy *Source*, by your definition...if i understand your definition correctly. With oil, you're just utilizing ancient, fossilized sunlight.
In this context I'm talking about what we humans can do with it. We can take oil (or whatever form of stored energy) and get *more* oil (by drilling) that you originally had (and sell the surplus). We can't take Hydrogen (or oil or whatever form of energy) and produce *more* Hydrogen. That's the simple distinction wether oil or hydrogen are energy sources in our economy.
The distinction becomes very clear when you think about the "Peak Oil" scenario (which is inevitable, it's just a questions of when it'll happen). At that point, all the energy you get from oil is needed to pump up more oil, so you end up with no surplus, and oil stops being an energy source. It'll still remain a fuel and a raw material, but it'll have to be drilled and refined with other energy (nuclear or coal, possibly solar in the sunny parts of the world).
If you want to look at the *big* picture and not just human economy, then the only energy source in the universe was big bang, which created matter and energy and stored a tiny fraction of that energy into Hydrogen and Helium nuclei. Everything else since then has been just using, transforming and recycling this original energy stored in Hydrogen and Helium... But this broad perspecitve is not very useful here.
The only difference between oil and hydrogen is that oil has had a few billion years head-start.
When talking about human energy economy, you don't talk about a few billion years, but more like a few thousand years at most. In that context there is an absolute difference: oil *can* be used as energy source, Hydrogen *cannot* (until fusion).
Dude, when I burn my hydrogen, then it's a fucking good energy source!
The article was about Hydrogen Economy, and in that context Hydrogen is not energy source, just a fuel that needs to be produced with some other energy source.
In the same way you could argue that oil is only a transportation medium, because once upon a time it was photosynthesized by plants. D'oh. Sure, if you talk about energy balance of the Earth over last billion years... Then fossil fuels certainly are not an energy source, just a handly way to store solar energy over a long time so that humanity can then release most of it in about 1/1000000th of the time... It's all about the context.
PS: you're only like the 10000th guy posting the same bullshit. Cool groupthink you've going on at this place...
Well, when there's such an obivious mistake in the post (no matter what's said in the actual article referenced), then it becomes a race to point the mistake out first...;-). "News for Nerds", and nerds tend to be very pedantic (selectively, about important things).
Round trip efficiency for hydrogen in current fuel cells is around 80%, which is more than that for batteries.
You forget the inefficiency of producing the electricity in the first place. So, to convert current oil guzzling economy (cars, planes, ships...) to hydrogen economy will not be nearly that efficient.
Well, I suppose there are ways to produce hydrogen more eficiently than with first making electricity, eg lots of heat (which basically requires a nuclear power plant to generate the high temperature efficiently, I think...).
but where are these nuclear and renewable energy sources? Unfortunately, the only currently viable energy source from making hydrogen is fossil fuel. So switching to "clean" hydrogen cars would produce MORE fossil fuel pollution (because of the added inefficiencies in the hydrogen creation/distribution/conversion process).
Well, nuclear power with breeder reactors would be an easy answer with nearly unlimited fuel (it can use other elements than just Uranium). Only emotional and security issues (the problem of handling the fuel so that "weapon-ready" nuclear material can not get stolen/lost), and probably oil industry lobbying power as well keeps that from becoming *the* power source of humanity.
Oh well, as soon as oil prices hit $100 per barrel or so (inflation adjusted, whenever that price level is reached), political climate will change... I'd just feel much safer if we started exploring the practical implementation *now* when we still have enough time. Doing a rush job when world is in recession caused by energy shortage is not something I'd like to do with nuclear power...
So, in order to have a large-scale hydrogen "economy", you need an alternate power source to make all that hydrogen in the first place. Basically, even though hydrogen may be extra-clean, you're just moving the pollution ardound anyways.
It's not just moving pollution around, it's more about changing the *type* of pollution. You can produce Hydrogen with nuclear power or renewable energy source, which both (debatable of course) are far safer that burning fossil fuels (which cause acid rain, CO2 emissions, Middle East wars...) to get equal amount of energy.
Hydrogen is energy storage and transfer medium, not a power source. At least not in what is generally called "hydrogen economy". It takes a lot of energy to make Hydrogen (H2) in large amounts, and only quita s small portion of that "original" power is regained when the Hydrogen is later used as fuel.
Of course fusion power would use Hydrogen as power source, but that's a totally different issue, and it happening is probably much farther in the future than "Hydrogen Economy"...
Horses, dogs and cats live in groups in the wild, and it's the groups that are territorial. That makes it easy to domesticate them, it just requires making them part of your "pack".
Slashdot Mirror
Good point. Might have been a good idea if I had RTFA before hitting reply ;-)
Yeah, right. It will harmlessly pass through a bag of water like a human body, because water is such a lousy material at stopping radiation. That's why it's not used in nuclear reactors or cosmic ray detectors...
Still, there should be a clear difference in the radiation dependeing on if the energy comes from inside, or only from outside.
If it comes only from the outside, then the "night side" should much cooler than the "day side", which should be visible in the temperature range of the radiation.
Also, if there's *any* fusion in the star, there must be quite a lot of it, enough to stop the collapse of the entire, enormous mass of the mini-star (since the core of a star necessarily has lower density because of the fusion energy, than if it were just a brown dwarf with equal mass. So if there is fusion, it should increase the energy output a lot, making the surface much hotter than a cooling brown dwarf can ever be.
Well, I suppose it would have enough mass to collapse into a white dwarf, which would be much denser and smaller still. So it being that big is no great mystery when you think of it that way.
It's just that the pesky H starts fusing at some point before getting to the white dwarf density, stopping the collapse, for now anyway. Even at that slow rate of fusion I don't think the star will last more than a few hundred times longer than our Sun.
Since they're so far back in time, more likely is that they're just regular galaxies in early stages of development, perhaps a bit special galaxies if they have exceptional amounts of dust or something but still normal matter.
But who knows for sure at this point.
Yes they are. Compare to a dead human body, it too radiates heat until it's at the ambient temperature. That's exactly what's going on with neutron stars, too, a dead body radiating left-over energy (both heat and rotational energy, radiated in different ways).
Repeat after me...
SHA-1 is not an encryption agorithm (in the most common sense of the word).
SHA-1 is a hashing algorithm (or one-way encryption algorithm if you insist on using word "encryption").
SHA-1 can not be used to store data, only to verify that data you already have is the same data that was used to create the SHA-1 hash.
Well, let me guess, you don't drive a car? Or if you do, it has miles per hour speedometer? Because anybody with a km/h speedometer pretty much knows how fast is 118.8km/h because they experience that speed often, even daily. But they have no direct idea how much is 33m/s.
All the confusion rises from the fact that time is not base ten. If it were, let's say there were a 1000 "seconds" in an hour, then it'd be easy, 10 meters per second would be 10 kilometers per hour ("kilosecond").
But, alas, it's not so! Our system of units is imperfect still!
Easiest way to change would be to keep the second, but scrap minutes and hours. The inconvenience would be that one day would not be any even number of kiloseconds or anything, but in everyday life that would not be a big problem since usually our days are punctuated by sleeping, which would "reset" the count anyway.
It's very consistent from human point of view, because natural cycle of life is one day long. Hour is more important than minutes (since minutes without hour usually means nothing), but mostly you know what month and year implicitly, so you only need the day (often just weekday is enough).
Wether time or date should be first is another matter (and often irrelevant), but it's most practical to put hours before minutes and day before month before year in everyday non-computer use.
No. They suck.
But doesn't that just make them more fun to be with, and easier to love?
And why would anybody care? There's a karma cap you know, and just writing "normally" makes pretty sure you'll reach that cap pretty soon, so a few points here and there makes *no* difference...
If only Cell could do what is reguired of a desktop processor... Ie running tens of processes with total hundreds of threads (This WinXP PC currently has 61 Processes and 523 threads running, current memory usage at half a gigabyte) at the same time, with seamless virtual memory with disk swapping and process level memory protection. Cell can't do this, and if it were optimized for stuff like this, it'd have to lose most of the parallel vector processing capabilities, ie the entire point of the processor would vanish.
As it is, Cell has no place in the desktop, except perhaps as a co-processor, provided they convince MS to define DirectX support for utilizing Cell expansion card for vector processing etc.
I'm not holding my breath here...
If Joe Sixpack kills someone and is forgiven, why shouldn't anyone else be? While that is an extreme (and criminal) analogy, it is unfair that the law does not treat everyone equally.
Not really, circumstances matter. An extreme example: an enemy soldier that kills soldier on your side in a battle is not guilty of murder even though he's an enemy (and vice versa your side killing enemy soldiers). But if you purposefully kill a soldier on your side, you're not only guilty of murder, but possibly of treason/sabotage also, even if you're a soldier too.
Do you call that unfair, too?
Well, in this case it'd mean the lawyer would have to show that Y has legal (or moral or somesuch) obligation to do something which requires breaking the copy protection... I wouldn't bet on success, no matter how good the lawyer was at twisting words.
Sure it's volatile, but we humans are one quite a big variable. But we're a special variable, because we can conciously control what kind of variable we are. Or try to... Which entire global warming debate is all about. Should we try to control our impact, or just not care, just deal with whatever happens when it happens and accept to economical and humanitarian cost as act of nature.
IMHO it just sounds a tad stupid to not at least try to keep things nice, ignoring the fact that we *do* have a significant impact on many things (eg CO2 levels, which in turn have significant impact on global climate). A bit like not buying a coat for winter (since you have "better" use for the money), and stoically accepting that if you get a flu, then you get a flu and deal with it, but no point worrying about it beforehand, let alone trying to not get the flu in the first place...
I'm sure you're just trolling for comments, and here's one more to consider:
From the dawn of time people have died of hunger and disease. What makes us think we shouldn't now?
I bet you'd be ok with all cars having GPS trackers as standard equipment, and the police tracking every car all the time, too... I mean, it's only a difference of scale, not difference of principle (that any car can be GPS-tracked secretly without any kind of control like a warrant).
How about a GPS tracker secretly put in your shoes? After all, you mostly only wear shoes in places where you're not alone, so surely it would not be any kind of invasion of privacy if the police tracked where you go with your shoes, any more than it's invasion of privacy to secretly track where you go with your car...
Just like capturing emails of a person is no different than standing behind him when he reads and writes emails... IMHO that's quite a difference.
Your friend seeing what you're browsing then web when he's visiting is no invasion of privacy. Your friend installing a spyware that tracks your browsing is invasion of privacy. Same thing with planting GPS tracker in a car, it should only be legal with a warrant.
Indeed, in that scenario the sun is what gives the energy to *us*, and *we* bind it to hydrogen. But about those figures, do they include the energy needed to store the hydrogen in usable forms (compression)? If not, then compression will drop the overall efficiency radically...
Well, hopefully we don't have to compress that gaseous hydrogen, but can instead store it in some solid form that can be created without large non-recoverable energy input...
In this context I'm talking about what we humans can do with it. We can take oil (or whatever form of stored energy) and get *more* oil (by drilling) that you originally had (and sell the surplus). We can't take Hydrogen (or oil or whatever form of energy) and produce *more* Hydrogen. That's the simple distinction wether oil or hydrogen are energy sources in our economy.
The distinction becomes very clear when you think about the "Peak Oil" scenario (which is inevitable, it's just a questions of when it'll happen). At that point, all the energy you get from oil is needed to pump up more oil, so you end up with no surplus, and oil stops being an energy source. It'll still remain a fuel and a raw material, but it'll have to be drilled and refined with other energy (nuclear or coal, possibly solar in the sunny parts of the world).
If you want to look at the *big* picture and not just human economy, then the only energy source in the universe was big bang, which created matter and energy and stored a tiny fraction of that energy into Hydrogen and Helium nuclei. Everything else since then has been just using, transforming and recycling this original energy stored in Hydrogen and Helium... But this broad perspecitve is not very useful here.
When talking about human energy economy, you don't talk about a few billion years, but more like a few thousand years at most. In that context there is an absolute difference: oil *can* be used as energy source, Hydrogen *cannot* (until fusion).
The article was about Hydrogen Economy, and in that context Hydrogen is not energy source, just a fuel that needs to be produced with some other energy source.
In the same way you could argue that oil is only a transportation medium, because once upon a time it was photosynthesized by plants. D'oh.
Sure, if you talk about energy balance of the Earth over last billion years... Then fossil fuels certainly are not an energy source, just a handly way to store solar energy over a long time so that humanity can then release most of it in about 1/1000000th of the time... It's all about the context.
Well, when there's such an obivious mistake in the post (no matter what's said in the actual article referenced), then it becomes a race to point the mistake out first...
You forget the inefficiency of producing the electricity in the first place. So, to convert current oil guzzling economy (cars, planes, ships...) to hydrogen economy will not be nearly that efficient.
Well, I suppose there are ways to produce hydrogen more eficiently than with first making electricity, eg lots of heat (which basically requires a nuclear power plant to generate the high temperature efficiently, I think...).
Well, nuclear power with breeder reactors would be an easy answer with nearly unlimited fuel (it can use other elements than just Uranium). Only emotional and security issues (the problem of handling the fuel so that "weapon-ready" nuclear material can not get stolen/lost), and probably oil industry lobbying power as well keeps that from becoming *the* power source of humanity.
Oh well, as soon as oil prices hit $100 per barrel or so (inflation adjusted, whenever that price level is reached), political climate will change... I'd just feel much safer if we started exploring the practical implementation *now* when we still have enough time. Doing a rush job when world is in recession caused by energy shortage is not something I'd like to do with nuclear power...
It's not just moving pollution around, it's more about changing the *type* of pollution. You can produce Hydrogen with nuclear power or renewable energy source, which both (debatable of course) are far safer that burning fossil fuels (which cause acid rain, CO2 emissions, Middle East wars...) to get equal amount of energy.
Hydrogen is energy storage and transfer medium, not a power source. At least not in what is generally called "hydrogen economy". It takes a lot of energy to make Hydrogen (H2) in large amounts, and only quita s small portion of that "original" power is regained when the Hydrogen is later used as fuel.
Of course fusion power would use Hydrogen as power source, but that's a totally different issue, and it happening is probably much farther in the future than "Hydrogen Economy"...
Horses, dogs and cats live in groups in the wild, and it's the groups that are territorial. That makes it easy to domesticate them, it just requires making them part of your "pack".