most of the plate movement is predomanently east/west due to north/south plate faults.
Which doesn't imply it was that way in the past. This link shows North America lying on its side on the equator 510 million years ago (earlier than palm trees).
The data that everybody else has been talking about comes from multiple satellites and spans several decades. And no, there is not "considerable day to day variation." Most of the variation comes on a monthly cycle, the approximate amount of time it takes the sun to rotate once as seen from Earth. Your "upward trend from 1996 to 2000, and then some dropof" comes from the last solar maximum. In considering long term trends, it is far better to have data from more than one solar cycle, and the recently released data was used to compare the average solar irradiance during two consecutive solar minimums.
The units come with the variables in the equation, the Gravitational constant G, and the constant c (the speed of light in a vacuum), and thus it is a complete equation.
mks units (favored by many physicists): G= 6.673x10^-11 N(m/kg)^2
cgs units (those wacky astronomers!): G= 6.673x10^-7 dyne (cm/g)^2
And my point was that the dust is absolutely irrelevant to distance measurements using redshift. Now if we were using the object's magnitude to measure its distance (assuming it's one of those objects with a known absolute magnitude), then dust reddening would matter. QSO luminosities vary so much we'd never use a magnitude technique to guess their distances.
Only large black holes will have accretion disks. The radiation coming from a black hole is negligible until the black hole itself is tiny. It is my guess that the radiation pressure from a black hole would never be enough to prevent a net gain of mass.
You need it. The nearest star is Proxima Centauri at 4x10^13 km (also, your numbers for Alpha Centauri are erroneous). The 9 billion solar mass black hole's radius is thus.0225% of that distance.
Atoms produce very specific patterns of absorption or emission in the light spectrum depending on species. A familiar example, is the solar spectrum, which is created by absorption of narrow bands in the spectrum by a large number of different elements in different states of ionization. Redshift causes the entire set of these lines to be moved towards the red end of the spectrum. They retain the spacing between themselves, so they can still be recognized in their new positions, and their new positions tell us how fast the object that created them is moving. Reddening caused by dust doesn't move these absorption lines. Instead it scatters light preferentially at the blue end of the spectrum, causing the entire end of that spectrum to dim, rather than creating narrow bands in it or moving narrow bands around. These two different processes are usually distinguishable.
In the parent post, I was pointing out that technology that seems to be right around the corner often isn't. Arthur C. Clarke was the obvious choice for this task, as he popularized the idea of a space elevator. I can see my post as being Funny or Insightful (to paraphrase timothy's definition: puts a new spin on a given story... an analogy you hadn't thought of, or a telling counterexample).
"Troll --... This is a prank comment intended to provoke indignant (or just confused) responses. A Troll might mix up vital facts or otherwise distort reality, to make other readers react with helpful "corrections."...." -timothy
It was not my intention to provoke indignant or confused responses. I did not mix up vital facts or distort reality: I used elements from the plot of a famous movie. It is my strongly held opinion that whoever modded me Troll has an economic interest in one of the two corporations mentioned in the article on space elevators, or is a rabid Arthur C. Clarke fan. Either way, that moderator is the Troll.
Re:Weeks is appropriate
on
Gamma Ray Burst
·
· Score: 2, Informative
I think the conventional 0.01s to 1000s figures are how long they last in gamma rays. Do the bursts last longer in other forms of light?
That was exactly the point in my last post. When the gamma rays are gone the show isn't over.
From this one might assume Wolf-Rayet stars might already have undergone an event which might have caused a GRB (gamma ray burst)?
No. These massive stars have (usually) burned through most of their supply of hydrogen and are furiously burning helum. They are losing their outer layers in a fierce wind, rather than an explosion, which will continue for years. Their mass loss is driven by the absorption of light by C,N, and O that they have cooked up. Super- and hypernovae lose mass due to the sudden collapse of their cores; the explosive energy comes from gravitational potential energy, mostly. Two different processes. I should note that Wolf- Rayet stars are generally close to blowing up as supernovae, or if we're lucky, a hypernova with its jet pointed at us (a.k.a. a GRB). This link for another over-simplified answer.
Weeks is appropriate
on
Gamma Ray Burst
·
· Score: 5, Informative
what observers were able to see in the "weeks" (which is a long time for a gamma ray burst)
The gamma rays themselves persist anywhere from.01 to 1000 s. Even with HETE-2, we have almost no chance of pinpointing the location of the short GRBs. But the long ones last long enough to pinpoint their location with X-ray telescopes. If that happens, then the GRB can be observed across the energy spectrum from X-rays to radio waves. They often take weeks before they dim to the point they can't be distinguished from their host galaxies. The misperception that gamma rays bursts are fleeting comes from the days before the BeppoSAX satellite launch in 1996, when positions could not be located precisely enough for follow up observations in other regions of the spectrum.
Long GRBs (such as the one lst October) are probably caused by hypernovae or collapsars, where a massive star (at least 20x our sun's mass, not the 10-15 solar mass star mentioned in the Sydney Morning Herald) has its core collapse into a black hole, perhaps after collapsing into an intermediate neutron star. The short GRBs are probably the result of mergers between massive compact objects like white dwarfs, neutron stars, and black holes.
A.C. Clarke has confidently predicted that in the year 2001, we will have a commercial space station, regular manned flights to the moon, and manned expeditions to Jupiter.
Or I'm wrong. Recent reports indicate that it could be a new influenza virus. If so, it must be radically different, otherwise the standard flu tests would have detected it by now.
What's the difference between this latest outbreak and any other outbreak?
So how is this new disease different?
The new illness is probably not influenza. The flu does not present as a pneumonia, although it can weaken the respiratory tract and allow secondary infection by opportunistic bacteria or viruses. Furthermore, there are rapid tests available for the diagnosis of the flu virus. I presume these have been performed and came back negative. So this is a new, dangerous, highly-infectious disease.
I tend to categorize Christians into several categories, and I wasn't trying to implicate all of them. There are the actual Christians, regardless of sect, who actually pay attention to the teachings of one Jesus of Nazareth. To these people, phrases like "love thy neighbor" and "turn the other cheek" actually mean something. Teachings like this even some Buddhists accept. And then there are the "Christians" who will only give up their guns from their cold dead fingers, who can't accept paying taxes for social services, who consider the killing of innocent civilians to be merely "collateral damage," who can't see past the color of skin.
Credible scientists as well as the lunatics were claiming the stains were a sign of water quite a while ago. What is new about this most recent observation is that newstains have been found (i.e. we now have photos before and after their formation). This just strengthens an old argument; it isn't a new argument.
Let's see what simple economics has to say about it. Let's pretend there is a 1 km diamond asteroid within our own solar system (just to make it plausible to reach it). People consider, briefly, mining it. Then they realize that it would overwhelm the diamond market with shere volume. Diamonds would become cheap even before the ship bearing them landed back on Earth (notice how oil has gotten expensive and the war hasn't started yet?). They couldn't give those damn diamonds away for free.
aging is a natural part of the life cycle, not a disease.
Odd statement, really. Disease is also a natural part of the life cycle. There's no reason not to think of aging as a disease. Antibiotics weren't invented to ease the suffering of patients as they died, they were invented to save lives, i.e. increase life expectancy.
Can't help but think that this discussion would be entirely different in a Buddhist or Hindu culture. Christians seem particularly afraid of death. I suspect heaven and hell are such unnatural and implausible places, sounding more like the figments of overactive imagination, that Christians are secretly afraid they don't exist.
The hippocampus is a very dynamic area of the brain (see here). In particular, the hippocampus grows more neurons to deal with more complex environments, partly explaining the hippocamus's special role in spatial memory (for example, the large hippocampi of London taxi drivers). An inverse correlation with hippocampus size and depression has also been noted. Drugs like Prozac take 3 weeks to become effective, possibly because they act by stimulating neuron growth (neurogenesis) in the hippocampus.
Given all that, a great danger of giving a patient an artificial hippocampus is creating a severely depressed individual who can never learn where the bathroom is.
Hydrogen requires energy to be made. The most convenient form of energy right now is still fossil fuels. Energy gets lost when converting it from one form to another (basic thermodynamics). We would be worse off if we tried to convert to hydrogen now. Solar energy is still a pipe dream, hydro power destroys once-pristine rivers, nuclear power is toxic. We are basically screwed without the development of fusion.
The Earth's oblateness (as measured by changes in the gravity field) has been increasing since about 1997. Speculation points to net movement of water from rapidly melting mountain and subpolar glaciers to the equator. One would suspect this would change the Earth's moment of inertia more than would changes in wind, but it is not mentioned in this most recent article.
Slashdot Mirror
Which doesn't imply it was that way in the past. This link shows North America lying on its side on the equator 510 million years ago (earlier than palm trees).
The following links have graphs and images. Here and here.
The data that everybody else has been talking about comes from multiple satellites and spans several decades. And no, there is not "considerable day to day variation." Most of the variation comes on a monthly cycle, the approximate amount of time it takes the sun to rotate once as seen from Earth. Your "upward trend from 1996 to 2000, and then some dropof" comes from the last solar maximum. In considering long term trends, it is far better to have data from more than one solar cycle, and the recently released data was used to compare the average solar irradiance during two consecutive solar minimums.
Unfortunately that doesn't rule out the possibility that Michigan has changed latitude. You have heard of plate tectonics?
mks units (favored by many physicists):
G= 6.673x10^-11 N(m/kg)^2
cgs units (those wacky astronomers!):
G= 6.673x10^-7 dyne (cm/g)^2
And my point was that the dust is absolutely irrelevant to distance measurements using redshift. Now if we were using the object's magnitude to measure its distance (assuming it's one of those objects with a known absolute magnitude), then dust reddening would matter. QSO luminosities vary so much we'd never use a magnitude technique to guess their distances.
Only large black holes will have accretion disks. The radiation coming from a black hole is negligible until the black hole itself is tiny. It is my guess that the radiation pressure from a black hole would never be enough to prevent a net gain of mass.
You need it. The nearest star is Proxima Centauri at 4x10^13 km (also, your numbers for Alpha Centauri are erroneous). The 9 billion solar mass black hole's radius is thus .0225% of that distance.
Atoms produce very specific patterns of absorption or emission in the light spectrum depending on species. A familiar example, is the solar spectrum, which is created by absorption of narrow bands in the spectrum by a large number of different elements in different states of ionization. Redshift causes the entire set of these lines to be moved towards the red end of the spectrum. They retain the spacing between themselves, so they can still be recognized in their new positions, and their new positions tell us how fast the object that created them is moving. Reddening caused by dust doesn't move these absorption lines. Instead it scatters light preferentially at the blue end of the spectrum, causing the entire end of that spectrum to dim, rather than creating narrow bands in it or moving narrow bands around. These two different processes are usually distinguishable.
"Troll -- ... This is a prank comment intended to provoke indignant (or just confused) responses. A Troll might mix up vital facts or otherwise distort reality, to make other readers react with helpful "corrections." ...." -timothy
It was not my intention to provoke indignant or confused responses. I did not mix up vital facts or distort reality: I used elements from the plot of a famous movie. It is my strongly held opinion that whoever modded me Troll has an economic interest in one of the two corporations mentioned in the article on space elevators, or is a rabid Arthur C. Clarke fan. Either way, that moderator is the Troll.
That was exactly the point in my last post. When the gamma rays are gone the show isn't over.
From this one might assume Wolf-Rayet stars might already have undergone an event which might have caused a GRB (gamma ray burst)?
No. These massive stars have (usually) burned through most of their supply of hydrogen and are furiously burning helum. They are losing their outer layers in a fierce wind, rather than an explosion, which will continue for years. Their mass loss is driven by the absorption of light by C,N, and O that they have cooked up. Super- and hypernovae lose mass due to the sudden collapse of their cores; the explosive energy comes from gravitational potential energy, mostly. Two different processes. I should note that Wolf- Rayet stars are generally close to blowing up as supernovae, or if we're lucky, a hypernova with its jet pointed at us (a.k.a. a GRB). This link for another over-simplified answer.
The gamma rays themselves persist anywhere from .01 to 1000 s. Even with HETE-2, we have almost no chance of pinpointing the location of the short GRBs. But the long ones last long enough to pinpoint their location with X-ray telescopes. If that happens, then the GRB can be observed across the energy spectrum from X-rays to radio waves. They often take weeks before they dim to the point they can't be distinguished from their host galaxies. The misperception that gamma rays bursts are fleeting comes from the days before the BeppoSAX satellite launch in 1996, when positions could not be located precisely enough for follow up observations in other regions of the spectrum.
Long GRBs (such as the one lst October) are probably caused by hypernovae or collapsars, where a massive star (at least 20x our sun's mass, not the 10-15 solar mass star mentioned in the Sydney Morning Herald) has its core collapse into a black hole, perhaps after collapsing into an intermediate neutron star. The short GRBs are probably the result of mergers between massive compact objects like white dwarfs, neutron stars, and black holes.
A.C. Clarke has confidently predicted that in the year 2001, we will have a commercial space station, regular manned flights to the moon, and manned expeditions to Jupiter.
Or I'm wrong. Recent reports indicate that it could be a new influenza virus. If so, it must be radically different, otherwise the standard flu tests would have detected it by now.
It wasn't even necessary to read the article, just the /. blurb, to figure out they were talking about mass fractions of lunar soil.
So how is this new disease different?
The new illness is probably not influenza. The flu does not present as a pneumonia, although it can weaken the respiratory tract and allow secondary infection by opportunistic bacteria or viruses. Furthermore, there are rapid tests available for the diagnosis of the flu virus. I presume these have been performed and came back negative. So this is a new, dangerous, highly-infectious disease.
I tend to categorize Christians into several categories, and I wasn't trying to implicate all of them. There are the actual Christians, regardless of sect, who actually pay attention to the teachings of one Jesus of Nazareth. To these people, phrases like "love thy neighbor" and "turn the other cheek" actually mean something. Teachings like this even some Buddhists accept. And then there are the "Christians" who will only give up their guns from their cold dead fingers, who can't accept paying taxes for social services, who consider the killing of innocent civilians to be merely "collateral damage," who can't see past the color of skin.
Credible scientists as well as the lunatics were claiming the stains were a sign of water quite a while ago. What is new about this most recent observation is that newstains have been found (i.e. we now have photos before and after their formation). This just strengthens an old argument; it isn't a new argument.
Perhaps if you had said Charlton Heston, it would have been funnier. Don't forget the footprints.
Let's see what simple economics has to say about it. Let's pretend there is a 1 km diamond asteroid within our own solar system (just to make it plausible to reach it). People consider, briefly, mining it. Then they realize that it would overwhelm the diamond market with shere volume. Diamonds would become cheap even before the ship bearing them landed back on Earth (notice how oil has gotten expensive and the war hasn't started yet?). They couldn't give those damn diamonds away for free.
Odd statement, really. Disease is also a natural part of the life cycle. There's no reason not to think of aging as a disease. Antibiotics weren't invented to ease the suffering of patients as they died, they were invented to save lives, i.e. increase life expectancy.
Can't help but think that this discussion would be entirely different in a Buddhist or Hindu culture. Christians seem particularly afraid of death. I suspect heaven and hell are such unnatural and implausible places, sounding more like the figments of overactive imagination, that Christians are secretly afraid they don't exist.
Now watch my karma go down in flames.
Given all that, a great danger of giving a patient an artificial hippocampus is creating a severely depressed individual who can never learn where the bathroom is.
Hydrogen requires energy to be made. The most convenient form of energy right now is still fossil fuels. Energy gets lost when converting it from one form to another (basic thermodynamics). We would be worse off if we tried to convert to hydrogen now. Solar energy is still a pipe dream, hydro power destroys once-pristine rivers, nuclear power is toxic. We are basically screwed without the development of fusion.
it will be good for materials research in general. The building looks more like a stadium than an accelerator.
The Earth's oblateness (as measured by changes in the gravity field) has been increasing since about 1997. Speculation points to net movement of water from rapidly melting mountain and subpolar glaciers to the equator. One would suspect this would change the Earth's moment of inertia more than would changes in wind, but it is not mentioned in this most recent article.