This surprises me; I had thought that, despite the Moon's lower gravity, the ~29-day rotational period of the Moon would have required an extremely long cable, long enough to intersect the Earth.
That's because you're only considering the two-body version of gravity with that simple cable. In the two body (elevator is one body, moon is the other) problem, there's only one orbit that's stationary in the corotating frame: synchronous orbit. For the Moon, that's at the Earth's orbit, more or less.
Keep in mind what you want, though. What you're looking for are stationary orbits: that is, in the corotating frame, you want an orbit that doesn't move. The trick here is to realize that if you're corotating with the Moon, you're also coorbiting the Earth. And we know of 5 stationary orbits in the coorbiting frame: the Lagrange points. One of them is pointless (L3, as you'd build the elevator through the Earth), two of them are too far (L4/L5), but the other two are perfectly usable (L1 and L2).
The reason the lunar elevator is so much shorter is because you build the elevator to the Lagrange points, and not to lunar synchronous orbit (which is Earth's orbit). In essence, Earth helps pull the cable more taut than its orbit would.
isn't the Earth the equivalent of Luna-synchronous orbit (since we always hang at the same point in the sky in comparison)?
Earth is at the location of the "two body" space elevator location for the Moon. That is, if the Moon was sitting in the middle of nowhere, the Earth's orbit is where you'd want to put a lunar space elevator.
The moon, however, is not sitting in the middle of nowhere. You could put a space elevator heading to any of the 4 Lagrange points visible from the lunar surface (the "three body" space elevator locations). Those would be considerably shorter than the two-body location (about 56000 km, as opposed to 380,000 km).
Except Camille had considerably higher recorded wind-speeds than Katrina did.
Which I never said it didn't. If you continued the Saffir-Simpson scale by a new category every ~20 mph winds, Katrina would've been a Cat 6, and Camille would've been a Cat 7 (barely).
Stop hyperbolizing.
How am I hyperbolizing? By calling it an "off the scale" hurricane? It's an open ended scale - it doesn't have a top end to go over. If you had some device which measured hurricane strength, then a Category 5 would look "off the scale" because the top of the scale would be the division between Cat 4 and Cat 5.
An impossible hurricane with wind speeds of 500 mph would still be Category 5. Saying "it's on the scale, it's normal" doesn't stress the fact that Category 5 is the "oh my God" category for hurricanes.
And, what do you know! There it is. You don't go to "lunostationary" orbit. That would be the Earth's orbit, so to build a "classical" lunar space elevator you'd need a cable reaching from the Earth to the Moon. Instead, you can just go to a libration point: L1 or L2 would work fine. Both of those are far, far shorter than halfway to the Earth: L1 is 56,000 km above the Moon, and L2 is 67,000 km up.
The distance from the Moon to the Earth is 380,000 km.
A lunar elevator is more useful than you think. Lunar orbit to the Lunar surface normally takes a delta V of 2 km/s. Earth's surface to Lunar orbit is about 13 km/s, so it saves about 16% of the delta-V required. You could actually save a lot more if the cable extended past the Lagrange points, possibly as much as 30-40%.
It also almost completely removes the fuel cost for launching things from the lunar surface as well.
A lunar space elevator is not silly. It's extremely smart, especially given the fact that we could build one now. No nanotubes required - Kevlar is strong enough.
It depends how you use ice age. If you use it to mean "a period where ice exists in any permanent form at the poles" then yes, we're in an ice age.
If you use it to mean "a period where ice covers a large portion of North/South America" then no, the most recent Ice Age ended 10,000 years ago. The public confusion of "glacial period" and "ice age" is understandable.
There's no reason to think we're coming out of the current ice age (human activity can't touch events on that scale)
Did you read the article? That's exactly what this article is saying - it's talking about loss of glaciers from Greenland. Greenland is one of the two ice sheets that make the current time period by definition an ice age.
If they're right, and Greenland's ice sheets are no longer stable, that's very bad - and we may have just pushed ourselves really out of the current ice age - where "ice age" means the first definition above. This, of course, depends on what happens in the Antarctic, but losing the Greenland ice sheet is not comforting.
I'm merely pointing out that there is more at work here than a simple CO2->temp relationship.
It is a simple CO2 -> temp, if all other factors are held constant. I don't understand how pointing out that there's another variable (that isn't changing) affects this.
If you want to reduce other emissions as well, that's fine also. But the other gases, according to the IPCC, have a smaller radiative forcing compared to CO2 (CO2: 1.46 W/m^2, CH4: 0.48 W/m^2, NOx: 0.15 W/m^2).
CO2 is the one that needs to come down, and unfortunately, it's also the one that you pretty much can't beat with cleaner burning.
And, as you so correctly point out, CO2 is a minor player in the heat retention ability of our atmosphere (about 2% of the greenhouse effect, at current levels).
Depends how you measure it. It isn't additive. According to the IPCC, If you removed all greenhouse gases save CO2, the greenhouse forcing would be 25% of what it is now.
Yup, I was talking about geological timescales, not the blink of an eye that the Vostok data represents.
But what's your point? That other things affect temperature besides CO2? Well, that's definitely true. If you massively change the Earth's albedo, or boil off all of the water on the planet, that'll have an effect.
Pointing out that temperature was low and CO2 was high in past time periods just confuses the issue. There were other things going on then that are not going on now.
Is it possible that there is something going on now that we don't understand that might cause climate change? Yes. But is there an explanation that we have that doesn't need to invoke an unknown? Yep, and it has to do with that ridiculously high spike in CO2.
You can see that during the late Ordovian and early Silurian CO2 levels were 10-12 times todays levels (by this model, anyway) and temperatures were actually colder than today's.
The Ordovician and Silurian is not the Quaternary, and it certainly isn't the Holocene.
Look up the Ordovician period. Most life was confined to the sea. There weren't continents at the poles - so sea levels were very high.
One of the major continents (Gondwana) drifted south during the Ordovician. And when it drifted over the pole, suddenly sea levels started tumbling, because water began being trapped on land, and temperatures plummeted as the albedo of the planet changed massively.
Also, remember that CO2 is not the only greenhouse gas: water vapor contributes a huge amount. Ignoring levels of the other gasses over huge regions is crazy.
Anyway, my entire point here is, again, the Ordovician is not the Quaternary, and definitely not the Holocene. Sure, temperatures were low then, and CO2 high, but that does not mean that the two aren't related . Just that other factors affect temperature as well. But we know this. And none of the other factors related to temperature are over 100% higher than their natural variation like CO2 is.
Unless you're talking about shoving North America north into the North Pole to try to lower sea levels to compensate for rising CO2, I don't think the Ordovician really applies to today.
The main argument on that page is that the Ordovician had obscene CO2 levels, and temperatures indicative of the current age "so greenhouse has to be wrong!". That fact is true, for a short period. This ignores the fact that the main cause of the temperature drops were due to the dropping sea levels due to Gondwana drifting over the pole. Unless that page is suggesting we shove South America, Africa, and Australia into Antarctica to combat global warming, I don't think this is really that applicable.
Of course, it's also been suggested that a GRB is actually what caused the Ordovician temperature drop, and I don't think anyone's recommending that as a method, either.
Where are you getting this from? The Vostok data shows a clear, amazingly unambiguous correlation between temperature and CO2 levels for the past several hundred thousand years.
I think he's misreading the Vostok data charts on that page. The temperature chart has an extra line "Relative to Present" which shoves the temperature about oh, about 10,000 years to the left. So he thinks the CO2 stayed stable, and the temperature dropped, but in truth, they both dropped.
This doesn't explain what he's talking about (which is here) but this page is kindof confusing timescales. Yah, CO2 used to be at obscenely higher levels in the atmosphere, but the Earth was a much, much different place then. Saying "hey, look, our models that are based on the modern geography/biosphere/atmosphere don't work half a billion years ago!" isn't exactly surprising. It also doesn't invalidate them for predicting climate in the current world.
Temperatures spike from -8 or -9 degrees (C) below present to 2 or 3 degrees above present in about 5000 years... along with a gigantic spike in CO2 levels, usually on the order of 75 ppmv.
Hey, that amount sounds familiar!
During the previous cycle CO2 levels stayed at the ~275ppm level for 10,00 years but temperatures dropped nearly 10 degrees during that time anyway - why?
What, exactly, are you looking at? The period from ~125K to ~150K years ago? CO2 levels were at about 275 for about 10K years, so that seems right. But the temperature sure as devil didn't drop 10 degrees.
I think you're misreading that graph. That chart actually sucks a little bit, because the "Relative to Present" on the Y-axis prevents the two from being obviously lined up, and they never show a "temperature deviation vs. CO2 level" plot, but the correlation's pretty obvious.
That drop doesn't correlate with the flat period. It correlates with the drop from 275 ppmv to less than 250 ppmv. You have to shift the bottom graph to the left.
You make a valid point, but most astrophysicists don't do their own PR, which is part of the point of the article that started this discussion.
It should be noted that I've already been interviewed twice for magazines - and once for a television special (not sure if it ever aired...).
A friend of mine has a full-page article in a Brazilian magazine as well. In fact, most of the professors - and even a lot of the grad students - I know have been interviewed already.
Yah, we do do our own PR. And some of us are really, really terrible, and others are better. Public relations is more important than you think.
Heck if I know what the keyboard actually is. All I know is that all of the labelled keys are labelled in french "Arret defil" "Impr ecran" "Entree", but the keyboard layout is QWERTY. It's also got the funky > French quotes right beside the Z key, although they just show up as single 's in the layout that I've got now.
I can do | and ` from muscle memory, as well as ~, #, all the letters, +, all the digits, all the various brackets and basically every key except the three above.
Assuming that they're not in slightly different locations - like on a laptop.
I've got a keyboard that's got Canadian placement for special characters, and I can use it pretty well. But I remember | from my laptop keyboard, and it's not in the same location - on the laptop, it's above the Enter key. On the desktop, it's three to the right of the L key.
Special characters get moved around a bunch. I think it's far more important to learn the normal set as fast as you can.
And the control keys - (insert, home, etc.) - god, they could be anywhere.
OK, I'm a fast typer. Really fast - I tend to average between 80-100 wpm (I'm juuusst a bit below the highscores on TyperA).
I've got a keyboard that's essentially the same. It's a Canadian keyboard layout, which has a QWERTY layout, but all of the auxiliary stuff is labelled wrong (shift-2 is ", for instance). But I've got it on an English layout.
I can type on it - reasonably well. But sometimes I still have to guess as to where the | key is, or exactly which one is the ]. It hasn't really sped things up.
I would've preferred leaving labels on for the non-letter characters. Especially considering that not all special character layouts are the same on keyboards - especially laptops (where the heck is the delete key!).
Mine WHAT? The economics and physics of the situation are such that Martian material is valuable for using on Mars or in Mars orbit. That's IT.
Actually, it's very easy to get to LEO from Mars orbit. See here. Easier than getting to the Moon, in fact.
Mars does seem a little silly. Asteroids have much higher mineral wealth, especially some rarer minerals. Though the problem is that the world economy has kindof evolved to not need them - flooding the world with them will just collapse that economy, not bring you unlimited wealth.
It's not. You only move the source of pollution away from the highly visible tail pipe.
Ignoring anything else: what you're saying here is that you're moving the pollution away from where people live. If you've ever lived in a massively crowded area (Los Angeles, or any of the major cities in India) this pollution is probably the most severe.
Besides, centralizing pollution production is smart. That way instead of 100 million catalytic converters attempting to minimize pollution, you just have a few plants to do the same thing. Modernizing the plants is far easier than replacing 100 million catalytic converters.
Electrolyzing water is short sighted at best. The second law of thermodynamics (which we obey in this house!) dictates that it will always take more energy to get the free hydrogen that you can ever get back in a fuel cell.
Yes, oddly enough, you have to have a source of energy to store it. It's short sighted? Space solar satellites, beaming down power to an electrolysis plant offshore via microwave rectification. If you want to get really silly, you can do it in the Arctic.
We need fuel in the long run, and any renewable fuel will take more power to create than it does to use it. Fuel cells are ridiculously efficient at creating electricity, which is in turn ridiculously efficient at turning motors. Barring a breakthrough in conventional electrical batteries, I don't see the problem with hydrogen.
Those're electroweak-scale interactions only, right? As in, it's e+/e- -> Z -> nu + nu-bar. Those interactions have to be significantly less than the Urca process due to phase space concerns, I'd imagine.
Heavy element production occurs there, and it occurs exactly as you would expect from shock acceleration. You wouldn't expect this sort of production from a magnetic pinch, as you need a relativistic long-lived shock in order to account for the observed elements.
ALL that matters is that you've accepted a THEORY as FACT without sufficient proof.
It appears that you have as well: it appears that you've accepted the theory that I've accepted a theory as fact without sufficient proof. Especially considering I never claimed it as fact.
Anyway.
There are two claims here: one is "dark matter is the cause of flat light curves+CMBR peaks+gravitational lensing" and the second is "dark matter exists".
The second is essentially fact. The evidence for neutrinos existing is quite overwhelming. So is the evidence for neutrinos having mass. Neutrinos certainly fall under the category of non-baryonic, non-light emitting matter. So they're dark matter, by definition. Whether there exists other weakly interacting massive particles, I don't know. I have no idea, and make no claim. But the existence of "some" dark matter is definitely fact.
The first claim is a theory supported by a lot of evidence, but I definitely don't claim it as fact. I just haven't seen any evidence or reason to discount it. The claims that it's an ad-hoc theory and not elegant are immaterial. Nature is not required to be elegant. This claim is quite simply an appeal to ridicule, and nothing more.
Let me stress this again. I do not hold it as fact. It is merely the best explanation for the data currently, and I haven't seen any compelling reason to discount it.
This is exactly what a scientist is supposed to do. As opposed to blustering loudly and referring to evidence without mentioning it.
(p.s.: using italics tags rather than capitals makes a sentence much easier to read.)
but saying that the curves existence proves dark matters existence is bunk.
He didn't say it proved it. You can't prove a theory. You can only support it.
And the data he's quoting does support a dark matter model, and rejects several others. Based on the available data, a dark matter model is the best fit.
Slashdot Mirror
This surprises me; I had thought that, despite the Moon's lower gravity, the ~29-day rotational period of the Moon would have required an extremely long cable, long enough to intersect the Earth.
That's because you're only considering the two-body version of gravity with that simple cable. In the two body (elevator is one body, moon is the other) problem, there's only one orbit that's stationary in the corotating frame: synchronous orbit. For the Moon, that's at the Earth's orbit, more or less.
Keep in mind what you want, though. What you're looking for are stationary orbits: that is, in the corotating frame, you want an orbit that doesn't move. The trick here is to realize that if you're corotating with the Moon, you're also coorbiting the Earth. And we know of 5 stationary orbits in the coorbiting frame: the Lagrange points. One of them is pointless (L3, as you'd build the elevator through the Earth), two of them are too far (L4/L5), but the other two are perfectly usable (L1 and L2).
The reason the lunar elevator is so much shorter is because you build the elevator to the Lagrange points, and not to lunar synchronous orbit (which is Earth's orbit). In essence, Earth helps pull the cable more taut than its orbit would.
isn't the Earth the equivalent of Luna-synchronous orbit (since we always hang at the same point in the sky in comparison)?
Earth is at the location of the "two body" space elevator location for the Moon. That is, if the Moon was sitting in the middle of nowhere, the Earth's orbit is where you'd want to put a lunar space elevator.
The moon, however, is not sitting in the middle of nowhere. You could put a space elevator heading to any of the 4 Lagrange points visible from the lunar surface (the "three body" space elevator locations). Those would be considerably shorter than the two-body location (about 56000 km, as opposed to 380,000 km).
Except Camille had considerably higher recorded wind-speeds than Katrina did.
Which I never said it didn't. If you continued the Saffir-Simpson scale by a new category every ~20 mph winds, Katrina would've been a Cat 6, and Camille would've been a Cat 7 (barely).
Stop hyperbolizing.
How am I hyperbolizing? By calling it an "off the scale" hurricane? It's an open ended scale - it doesn't have a top end to go over. If you had some device which measured hurricane strength, then a Category 5 would look "off the scale" because the top of the scale would be the division between Cat 4 and Cat 5.
An impossible hurricane with wind speeds of 500 mph would still be Category 5. Saying "it's on the scale, it's normal" doesn't stress the fact that Category 5 is the "oh my God" category for hurricanes.
A Moon based space elevator would reach almost halfway to the Earth since the Moon only rotates once per month.
Sigh.
Google: lunar space elevator - ooh, a link to:
Wikipedia: lunar space elevator
And, what do you know! There it is. You don't go to "lunostationary" orbit. That would be the Earth's orbit, so to build a "classical" lunar space elevator you'd need a cable reaching from the Earth to the Moon. Instead, you can just go to a libration point: L1 or L2 would work fine. Both of those are far, far shorter than halfway to the Earth: L1 is 56,000 km above the Moon, and L2 is 67,000 km up.
The distance from the Moon to the Earth is 380,000 km.
A lunar elevator is more useful than you think. Lunar orbit to the Lunar surface normally takes a delta V of 2 km/s. Earth's surface to Lunar orbit is about 13 km/s, so it saves about 16% of the delta-V required. You could actually save a lot more if the cable extended past the Lagrange points, possibly as much as 30-40%.
It also almost completely removes the fuel cost for launching things from the lunar surface as well.
A lunar space elevator is not silly. It's extremely smart, especially given the fact that we could build one now. No nanotubes required - Kevlar is strong enough.
It's on the scale.
The Saffir-Simpson scale has no upper bound on wind speeds - it stops at category 5. There's no way it couldn't've been on the scale.
Category 5 hurricanes would better be described as "off the scale" to give a proper representation of how strong they are.
It depends how you use ice age. If you use it to mean "a period where ice exists in any permanent form at the poles" then yes, we're in an ice age.
If you use it to mean "a period where ice covers a large portion of North/South America" then no, the most recent Ice Age ended 10,000 years ago. The public confusion of "glacial period" and "ice age" is understandable.
There's no reason to think we're coming out of the current ice age (human activity can't touch events on that scale)
Did you read the article? That's exactly what this article is saying - it's talking about loss of glaciers from Greenland. Greenland is one of the two ice sheets that make the current time period by definition an ice age.
If they're right, and Greenland's ice sheets are no longer stable, that's very bad - and we may have just pushed ourselves really out of the current ice age - where "ice age" means the first definition above. This, of course, depends on what happens in the Antarctic, but losing the Greenland ice sheet is not comforting.
That's an itsy bitsy teenie weenie fraction.
Can I put an itsy bitsy teenie weenie fraction of chlorine gas in your immediate vicinity, then?
Small quantities of things cause large effects.
I'm merely pointing out that there is more at work here than a simple CO2->temp relationship.
It is a simple CO2 -> temp, if all other factors are held constant. I don't understand how pointing out that there's another variable (that isn't changing) affects this.
If you want to reduce other emissions as well, that's fine also. But the other gases, according to the IPCC, have a smaller radiative forcing compared to CO2 (CO2: 1.46 W/m^2, CH4: 0.48 W/m^2, NOx: 0.15 W/m^2).
CO2 is the one that needs to come down, and unfortunately, it's also the one that you pretty much can't beat with cleaner burning.
And, as you so correctly point out, CO2 is a minor player in the heat retention ability of our atmosphere (about 2% of the greenhouse effect, at current levels).
Depends how you measure it. It isn't additive. According to the IPCC, If you removed all greenhouse gases save CO2, the greenhouse forcing would be 25% of what it is now.
Yup, I was talking about geological timescales, not the blink of an eye that the Vostok data represents.
But what's your point? That other things affect temperature besides CO2? Well, that's definitely true. If you massively change the Earth's albedo, or boil off all of the water on the planet, that'll have an effect.
Pointing out that temperature was low and CO2 was high in past time periods just confuses the issue. There were other things going on then that are not going on now.
Is it possible that there is something going on now that we don't understand that might cause climate change? Yes. But is there an explanation that we have that doesn't need to invoke an unknown? Yep, and it has to do with that ridiculously high spike in CO2.
You can see that during the late Ordovian and early Silurian CO2 levels were 10-12 times todays levels (by this model, anyway) and temperatures were actually colder than today's.
The Ordovician and Silurian is not the Quaternary, and it certainly isn't the Holocene.
Look up the Ordovician period. Most life was confined to the sea. There weren't continents at the poles - so sea levels were very high.
One of the major continents (Gondwana) drifted south during the Ordovician. And when it drifted over the pole, suddenly sea levels started tumbling, because water began being trapped on land, and temperatures plummeted as the albedo of the planet changed massively.
Also, remember that CO2 is not the only greenhouse gas: water vapor contributes a huge amount. Ignoring levels of the other gasses over huge regions is crazy.
Anyway, my entire point here is, again, the Ordovician is not the Quaternary, and definitely not the Holocene. Sure, temperatures were low then, and CO2 high, but that does not mean that the two aren't related . Just that other factors affect temperature as well. But we know this. And none of the other factors related to temperature are over 100% higher than their natural variation like CO2 is.
Unless you're talking about shoving North America north into the North Pole to try to lower sea levels to compensate for rising CO2, I don't think the Ordovician really applies to today.
replying to myself, just to clarify:
The main argument on that page is that the Ordovician had obscene CO2 levels, and temperatures indicative of the current age "so greenhouse has to be wrong!". That fact is true, for a short period. This ignores the fact that the main cause of the temperature drops were due to the dropping sea levels due to Gondwana drifting over the pole. Unless that page is suggesting we shove South America, Africa, and Australia into Antarctica to combat global warming, I don't think this is really that applicable.
Of course, it's also been suggested that a GRB is actually what caused the Ordovician temperature drop, and I don't think anyone's recommending that as a method, either.
Where are you getting this from? The Vostok data shows a clear, amazingly unambiguous correlation between temperature and CO2 levels for the past several hundred thousand years.
I think he's misreading the Vostok data charts on that page. The temperature chart has an extra line "Relative to Present" which shoves the temperature about oh, about 10,000 years to the left. So he thinks the CO2 stayed stable, and the temperature dropped, but in truth, they both dropped.
This doesn't explain what he's talking about (which is here) but this page is kindof confusing timescales. Yah, CO2 used to be at obscenely higher levels in the atmosphere, but the Earth was a much, much different place then. Saying "hey, look, our models that are based on the modern geography/biosphere/atmosphere don't work half a billion years ago!" isn't exactly surprising. It also doesn't invalidate them for predicting climate in the current world.
Temperatures spike from -8 or -9 degrees (C) below present to 2 or 3 degrees above present in about 5000 years ... along with a gigantic spike in CO2 levels, usually on the order of 75 ppmv.
Hey, that amount sounds familiar!
During the previous cycle CO2 levels stayed at the ~275ppm level for 10,00 years but temperatures dropped nearly 10 degrees during that time anyway - why?
What, exactly, are you looking at? The period from ~125K to ~150K years ago? CO2 levels were at about 275 for about 10K years, so that seems right. But the temperature sure as devil didn't drop 10 degrees.
I think you're misreading that graph. That chart actually sucks a little bit, because the "Relative to Present" on the Y-axis prevents the two from being obviously lined up, and they never show a "temperature deviation vs. CO2 level" plot, but the correlation's pretty obvious.
That drop doesn't correlate with the flat period. It correlates with the drop from 275 ppmv to less than 250 ppmv. You have to shift the bottom graph to the left.
You make a valid point, but most astrophysicists don't do their own PR, which is part of the point of the article that started this discussion.
It should be noted that I've already been interviewed twice for magazines - and once for a television special (not sure if it ever aired...).
A friend of mine has a full-page article in a Brazilian magazine as well. In fact, most of the professors - and even a lot of the grad students - I know have been interviewed already.
Yah, we do do our own PR. And some of us are really, really terrible, and others are better. Public relations is more important than you think.
Heck if I know what the keyboard actually is. All I know is that all of the labelled keys are labelled in french "Arret defil" "Impr ecran" "Entree", but the keyboard layout is QWERTY. It's also got the funky > French quotes right beside the Z key, although they just show up as single 's in the layout that I've got now.
Eh, I can't bring myself to throw out the keyboard. It actually is a pretty good keyboard, and it only causes me a second of hesitation.
Keeps other people from using my computer, too.
I can do | and ` from muscle memory, as well as ~, #, all the letters, +, all the digits, all the various brackets and basically every key except the three above.
Assuming that they're not in slightly different locations - like on a laptop.
I've got a keyboard that's got Canadian placement for special characters, and I can use it pretty well. But I remember | from my laptop keyboard, and it's not in the same location - on the laptop, it's above the Enter key. On the desktop, it's three to the right of the L key.
Special characters get moved around a bunch. I think it's far more important to learn the normal set as fast as you can.
And the control keys - (insert, home, etc.) - god, they could be anywhere.
OK, I'm a fast typer. Really fast - I tend to average between 80-100 wpm (I'm juuusst a bit below the highscores on TyperA).
I've got a keyboard that's essentially the same. It's a Canadian keyboard layout, which has a QWERTY layout, but all of the auxiliary stuff is labelled wrong (shift-2 is ", for instance). But I've got it on an English layout.
I can type on it - reasonably well. But sometimes I still have to guess as to where the | key is, or exactly which one is the ]. It hasn't really sped things up.
I would've preferred leaving labels on for the non-letter characters. Especially considering that not all special character layouts are the same on keyboards - especially laptops (where the heck is the delete key!).
Mine WHAT? The economics and physics of the situation are such that Martian material is valuable for using on Mars or in Mars orbit. That's IT.
Actually, it's very easy to get to LEO from Mars orbit. See here. Easier than getting to the Moon, in fact.
Mars does seem a little silly. Asteroids have much higher mineral wealth, especially some rarer minerals. Though the problem is that the world economy has kindof evolved to not need them - flooding the world with them will just collapse that economy, not bring you unlimited wealth.
It's not. You only move the source of pollution away from the highly visible tail pipe.
Ignoring anything else: what you're saying here is that you're moving the pollution away from where people live. If you've ever lived in a massively crowded area (Los Angeles, or any of the major cities in India) this pollution is probably the most severe.
Besides, centralizing pollution production is smart. That way instead of 100 million catalytic converters attempting to minimize pollution, you just have a few plants to do the same thing. Modernizing the plants is far easier than replacing 100 million catalytic converters.
Electrolyzing water is short sighted at best. The second law of thermodynamics (which we obey in this house!) dictates that it will always take more energy to get the free hydrogen that you can ever get back in a fuel cell.
Yes, oddly enough, you have to have a source of energy to store it. It's short sighted? Space solar satellites, beaming down power to an electrolysis plant offshore via microwave rectification. If you want to get really silly, you can do it in the Arctic.
We need fuel in the long run, and any renewable fuel will take more power to create than it does to use it. Fuel cells are ridiculously efficient at creating electricity, which is in turn ridiculously efficient at turning motors. Barring a breakthrough in conventional electrical batteries, I don't see the problem with hydrogen.
Those're electroweak-scale interactions only, right? As in, it's e+/e- -> Z -> nu + nu-bar. Those interactions have to be significantly less than the Urca process due to phase space concerns, I'd imagine.
The collision of two neutron stars is common enough to produce some of the heavy elements.
You can see the decay of heavy elements in the afterglow of a supernova.
Heavy element production occurs there, and it occurs exactly as you would expect from shock acceleration. You wouldn't expect this sort of production from a magnetic pinch, as you need a relativistic long-lived shock in order to account for the observed elements.
ALL that matters is that you've accepted a THEORY as FACT without sufficient proof.
It appears that you have as well: it appears that you've accepted the theory that I've accepted a theory as fact without sufficient proof. Especially considering I never claimed it as fact.
Anyway.
There are two claims here: one is "dark matter is the cause of flat light curves+CMBR peaks+gravitational lensing" and the second is "dark matter exists".
The second is essentially fact. The evidence for neutrinos existing is quite overwhelming. So is the evidence for neutrinos having mass. Neutrinos certainly fall under the category of non-baryonic, non-light emitting matter. So they're dark matter, by definition. Whether there exists other weakly interacting massive particles, I don't know. I have no idea, and make no claim. But the existence of "some" dark matter is definitely fact.
The first claim is a theory supported by a lot of evidence, but I definitely don't claim it as fact. I just haven't seen any evidence or reason to discount it. The claims that it's an ad-hoc theory and not elegant are immaterial. Nature is not required to be elegant. This claim is quite simply an appeal to ridicule, and nothing more.
Let me stress this again. I do not hold it as fact. It is merely the best explanation for the data currently, and I haven't seen any compelling reason to discount it.
This is exactly what a scientist is supposed to do. As opposed to blustering loudly and referring to evidence without mentioning it.
(p.s.: using italics tags rather than capitals makes a sentence much easier to read.)
If you think the difference between "proving" a theory and "supporting" it is minute, you really don't understand science.
but saying that the curves existence proves dark matters existence is bunk.
He didn't say it proved it. You can't prove a theory. You can only support it.
And the data he's quoting does support a dark matter model, and rejects several others. Based on the available data, a dark matter model is the best fit.