Actually, black holes as small as you're describing would evaporate very quickly due to Hawking radiation.
I suspect that any black hole up to the job of clearing out space debris would present serious dangers to the atmosphere, but I haven't done any calculations. Hand-waving justification: to effectively clear things, it would have to have enough mass to 'accelerate' (I know this term is incorrect from a strictly GR standpoint) objects toward it, in which case the tidal forces would be significant.
Power = Voltage times Current. Assuming Ohm's Law is valid in this situation, that means the power loss goes as P = Current squared times resistance. The whole point of superconducting power lines is that the resistance is zero, meaning transmission loss is zero.
I'm not sure how much energy will be required to maintain the liquid nitrogen infrastructure, nor how long it will take for the energy savings from using this system will repay the cost of building the infrastructure.
On the other hand, it will have to be replaced eventually, so this is less of a concern.
From the original release by Fermilab, it seems to me like they had this sitting in a drawer somewhere. Sure, technically it went 'unsolved', but no one was really looking for a solution.
I've always done scientific work using the ROOT analysis framework: root.cern.ch. Granted, it's designed and been developed with particle physics in mind, but it's free, it's actively developed, and it works. Is there any reason why one would use a general purpose office program (MS or OOo) over something more suited to scientific analysis?
The galaxies are in front of the quasars.
The galaxies, which are about 7 billion light years from Earth, have until now been difficult to detect, because they lie in front of bright, distant objects known as quasars. What made them tough to see was that the quasars were so bright, that they drowned out the signal of these galaxies. The thing that's interesting about this finding is that they were able to use observations in the infrared range to differentiate the signal of the galaxies from the background of the quasars.
They're actually hiding in front of quasars:
The galaxies, which are about 7 billion light years from Earth, have until now been difficult to detect, because they lie in front of bright, distant objects known as quasars.
Yes, that is possible, but the point is that right now we're headed in the 'warming' direction, and it would probably be wise to do what we can to curb it.
However, you do emphasize correctly that any climate change is problematic for us. From that, I think we should take away the realization that right now it's more important to be developing cheap, clean, renewable energy (e.g. fusion) than just curbing carbon emissions for global warming's sake. If we have that, then maybe we can grow crops artificially and not worry too much about climate's effect on arable land. Moreover, the goal of developing such energy sources coincides with the immediate goal of reducing carbon emissions.
The big idea, though, is that using the fact that we don't really understand what's going on as an excuse to just sit back and watch what happens is unwise to say the least. I certainly don't see any harm in developing fusion.
Maybe we're technically still in an ice age, but it certainly seems that for a while now (a few thousand years) we've been on the warm side of the spike following the most recent ice age.
Of course there are other causes of global climate change, but current levels of CO2 are significantly higher than they have been in the past half million years, and we're the cause. The latter fact is cause for concern, but I think the former fact is cause for even more concern. We don't really understand what's going on. There are tipping points that we don't understand and that we may be past. An appropriate analogy is a canoe: while the wind and the waves affect its stability, the passenger's activities are also significant. We as humanity are doing a jig in the climate canoe.
Of course there are natural mitigating mechanisms, but it seems silly to wait around and hope these take effect.
And it's very probable that things will eventually repeat themselves, but by the time they do, the consequences of climate change will have already come to pass. These consequences are what really worry me. The past 10,000 years have been fairly stable and temperate. Do you think it's a coincidence that all of human civilization developed in that time? When the climate changes, which it will regardless of humanity's activities (as you amply pointed out), there may very well be drastic reductions in the carrying capacity of the Earth. Population is getting to be a problem now; if we can't combat climate change, we're talking about a lot of dead people. That's to say nothing of mass migration and competition for resources and their geopolitical effects.
I'm all for being green overall, but the present climate is the thing upon which all civilization rests. Its importance is not to be underestimated.
I disagree with the statement that "we are (geologically speaking) getting out of an ice age." If you look at a graph of temperature over the past 400,000 years or so, for example the graph 3rd from the bottom of this page: http://www.ccs.neu.edu/home/gene/peakoil/node3.html, you see that the passage from ice age -> warm period is much quicker than warm period -> ice age. You also see that at the present time, we're in one of those warm periods following a relatively recent (10,000 years ago) ice age. I think that it's reasonable to say that based on past behavior, things would not be getting any warmer as part of this natural cycle (since in the past the maximum temperature was reached fairly quickly after an ice age).
And moreover, you see that the concentration of CO2 has increased far above its natural levels, and that CO2 and temperature have been correlated in the past. And I don't think many would disagree that humanity has caused the increase in CO2. I will grant that this is not by any means proof that we're responsible for current temperature increases, but it's definitely (I think quite compelling) circumstantial evidence.
Perhaps this illustrates a significant problem with the current computing paradigm that everyone has their own PC. I mean, it's fine for anyone reading/. to perform administrative tasks, mess around with the operating system, etc. etc., but for most people this doesn't really make sense. For a common user who only wants to do basic things like web browsing, email, or maybe word processing, wouldn't a thin client on a not-particularly-powerful machine with most applications and things server-side make more sense? This way you could do away with having to deal with software updates, virus scans, and other annoying administration that is not really necessary to use applications.
From http://lanl.arxiv.org/pdf/0706.3699
The milestone WMAP measurement is the first single, self-contained data set capable
of placing meaningful constraint on the inflationary model space. Inflation has passed
the test with flying colors. The basic predictions of the inflationary model are all supported
by the data So at the moment, Inflation is supported by real data, whereas string theory isn't even testable.
Slashdot Mirror
Actually, black holes as small as you're describing would evaporate very quickly due to Hawking radiation. I suspect that any black hole up to the job of clearing out space debris would present serious dangers to the atmosphere, but I haven't done any calculations. Hand-waving justification: to effectively clear things, it would have to have enough mass to 'accelerate' (I know this term is incorrect from a strictly GR standpoint) objects toward it, in which case the tidal forces would be significant.
Power = Voltage times Current. Assuming Ohm's Law is valid in this situation, that means the power loss goes as P = Current squared times resistance. The whole point of superconducting power lines is that the resistance is zero, meaning transmission loss is zero. I'm not sure how much energy will be required to maintain the liquid nitrogen infrastructure, nor how long it will take for the energy savings from using this system will repay the cost of building the infrastructure. On the other hand, it will have to be replaced eventually, so this is less of a concern.
I'm just guessing, but the bicycle may not be the best means of transportation in the winter, particularly in Montreal.
Ice on the surface is further north, but they expect the top meter of soil to be about 80% ice at the landing site.
From the original release by Fermilab, it seems to me like they had this sitting in a drawer somewhere. Sure, technically it went 'unsolved', but no one was really looking for a solution.
What makes you think this one is v1.0?
That is to say: http://root.cern.ch/
I've always done scientific work using the ROOT analysis framework: root.cern.ch. Granted, it's designed and been developed with particle physics in mind, but it's free, it's actively developed, and it works. Is there any reason why one would use a general purpose office program (MS or OOo) over something more suited to scientific analysis?
... BOINC? http://science.slashdot.org/article.pl?sid=07/02/21/2326240
... where are you getting the time to read /. ?
The point is not the distance (as the parent to your comment has pointed out), nor the galaxies themselves, but the technique used.
According to wikipedia http://en.wikipedia.org/wiki/Starburst_galaxy, starburst galaxies generally require a large amount of gas (in order to form all the new stars) and are triggered frequently by close encounters with other galaxies. It really seems unlikely that enough matter could be generated from pair production (http://en.wikipedia.org/wiki/Pair_production) to create stars, if that's what you're talking about. Perhaps you have it confused with pair instability supernovae http://en.wikipedia.org/wiki/Pair_instability_supernova?
You forget that the universe is expanding, and there's no such thing as universal simultaneity.
Yes, that is possible, but the point is that right now we're headed in the 'warming' direction, and it would probably be wise to do what we can to curb it.
However, you do emphasize correctly that any climate change is problematic for us. From that, I think we should take away the realization that right now it's more important to be developing cheap, clean, renewable energy (e.g. fusion) than just curbing carbon emissions for global warming's sake. If we have that, then maybe we can grow crops artificially and not worry too much about climate's effect on arable land. Moreover, the goal of developing such energy sources coincides with the immediate goal of reducing carbon emissions.
The big idea, though, is that using the fact that we don't really understand what's going on as an excuse to just sit back and watch what happens is unwise to say the least. I certainly don't see any harm in developing fusion.
Would this not be regulated by the market? If you don't want to use the extra bandwidth, don't use the product/service.
Maybe we're technically still in an ice age, but it certainly seems that for a while now (a few thousand years) we've been on the warm side of the spike following the most recent ice age.
Of course there are other causes of global climate change, but current levels of CO2 are significantly higher than they have been in the past half million years, and we're the cause. The latter fact is cause for concern, but I think the former fact is cause for even more concern. We don't really understand what's going on. There are tipping points that we don't understand and that we may be past. An appropriate analogy is a canoe: while the wind and the waves affect its stability, the passenger's activities are also significant. We as humanity are doing a jig in the climate canoe.
Of course there are natural mitigating mechanisms, but it seems silly to wait around and hope these take effect.
And it's very probable that things will eventually repeat themselves, but by the time they do, the consequences of climate change will have already come to pass. These consequences are what really worry me. The past 10,000 years have been fairly stable and temperate. Do you think it's a coincidence that all of human civilization developed in that time? When the climate changes, which it will regardless of humanity's activities (as you amply pointed out), there may very well be drastic reductions in the carrying capacity of the Earth. Population is getting to be a problem now; if we can't combat climate change, we're talking about a lot of dead people. That's to say nothing of mass migration and competition for resources and their geopolitical effects.
I'm all for being green overall, but the present climate is the thing upon which all civilization rests. Its importance is not to be underestimated.
I disagree with the statement that "we are (geologically speaking) getting out of an ice age." If you look at a graph of temperature over the past 400,000 years or so, for example the graph 3rd from the bottom of this page: http://www.ccs.neu.edu/home/gene/peakoil/node3.html, you see that the passage from ice age -> warm period is much quicker than warm period -> ice age. You also see that at the present time, we're in one of those warm periods following a relatively recent (10,000 years ago) ice age. I think that it's reasonable to say that based on past behavior, things would not be getting any warmer as part of this natural cycle (since in the past the maximum temperature was reached fairly quickly after an ice age).
And moreover, you see that the concentration of CO2 has increased far above its natural levels, and that CO2 and temperature have been correlated in the past. And I don't think many would disagree that humanity has caused the increase in CO2. I will grant that this is not by any means proof that we're responsible for current temperature increases, but it's definitely (I think quite compelling) circumstantial evidence.
Perhaps this illustrates a significant problem with the current computing paradigm that everyone has their own PC. I mean, it's fine for anyone reading /. to perform administrative tasks, mess around with the operating system, etc. etc., but for most people this doesn't really make sense. For a common user who only wants to do basic things like web browsing, email, or maybe word processing, wouldn't a thin client on a not-particularly-powerful machine with most applications and things server-side make more sense? This way you could do away with having to deal with software updates, virus scans, and other annoying administration that is not really necessary to use applications.
As with most new technology, the price will come down if it's widely used.