I think that is true with the solid rocket boosters on the shuttle, but I'm pretty sure with a liquid rocket you can just turn off the valves and pumps supplying the liquid fuel.
But then again, NASA wasn't building the earlier rockets either, was it? So what exactly is new in this endeavour?
NASA more or less spec'd what the rocket had to do, rather than designing the rocket and hiring subcontractors to build it.
But the main difference is that SpaceX can make this rocket in a way they deem efficient, rather than building some parts in one congressman's district, shipping them along a special rail line to another location, etc.
Yeah, we picked a house on the same block as the day care and about half-a-mile from the elementary school, so we walk the kids to school each morning... but then it's a car ride after that!
We used to live in Manhattan, and there it is trivial to live without a car. But part of that was because I worked from home, day care was in the 2nd floor of our building, and my wife worked across the street:)
Once you start loading 3+ people into a car though, most mass transit in the world starts to look bad.
This probably is as much a commentary on how poorly most mass transit is run as it is on the relative efficiency of the two methods of transit.
Also, they run the same big-ass train whether there are 1000 people on it or 3, which seems wasteful. I always wonder why they don't run regular city buses or even short busses (modified, of course) on the tracks during off-peak hours. Naturally, anything running on the track should be automated.
That's true, but who's out of space? Is it such a bad thing to have farmland and estates interspersed with mid and high-density residential?
Also, in this suburb, the line branches several times. So they aren't single spokes that radiate out from the city, but a series of branches. This covers much more area. The way this area developed is there are townhouses and rental complexes directly adjacent to the track (high-density). Each station is surrounded by a small "downtown" with a few restaurants, a dry cleaner, and other things like that. A block or so off, it becomes single-family residential. Once you pass a reasonable walking distance, there are more public areas: churches, cemeteries, parks, schools, libraries, etc. Finally you have larger estates and golf courses. Of course, in the last 50 years most of the estates and golf course type uses have become housing developments that are not convenient to the train, so they added parking to the train stations. They've also built big shopping centers on some of them, which killed off some of the little downtowns surrounding the stations. Nevertheless, it is still easy to see how development worked when it was rail-centric.
Plus, that might work OK for your suburb, and for the single use case of going to work and back, assuming "work" is in the middle of this hub-and-spoke model.
There's a feedback mechanism involved. "Work" would stay in the middle because there is no convenient way to travel around the spoke. There will obviously be jobs out on the spokes - people need groceries, dry cleaners, restaurants, etc. But industry would stay in the middle - which is much more efficient than having it all spread out anyway.
If you are hell-bent on providing a way to get from branch-to-branch, you can put in a "beltway" line - just like we do with highways.
We have the technology to do better now.
Highways with individual cars are horribly space-inefficient. You need 8x the lanes compared to tracks to carry the same number of passengers. And while trains certainly are subject to delay, they do not have something akin to a traffic jam. I hope you're not referring to highways and cars as "the technology to do better now"!:)
No, you don't understand the concept of free speech at all.
I don't think that's true - I think you are using the terms "free speech" and "censorship" interchangeably. The quotes you took out of my post are referring to your discussion of "censorship", not free speech in general. I maintain that they are different, but related, concepts.
Whatever valid arguments there were for not letting the UN take over, have now been trumped by the fact that the US is now guilty of all the things people have claimed the UN may (but most likely wouldn't) be guilty of.
Well, I'm with you and against you:) I'm with you in that it would be helpful to have an international body take over administration of the internet. I'm still not convinced that the General Assembly is the right venue - even if all it is doing is setting up a committee. I believe the internet is a very important outlet of political speech in the modern world, and it would be too easy to silence it. I don't think it is laughable at all, since the number of countries without free speech protection outnumbers those that have it.
Last time Comcast paid a contractor to come out and plug in my cable box, he ripped out my brand-new cable line to the TV - presumably because he could then charge Comcast for the "repair".
Those kinds of things are either non-existent or infeasible outside the northeast, except in small parts of California.
Yeah, that was kind of my point... it seems insane that a privately-owned, privately-maintained car can be a lower-cost option. We really have a weird transportation system. It should be cheaper to maintain a set of train tracks than a highway. It should be cheaper to maintain a fleet of identical vehicles than for each individual to keep up their own.
One thing I didn't do is include the capital cost of my car in the calculation. That's roughly $0.27/mile if the car lasts 100,000 and has zero value at the end. So that adds $162 to my Philly-to-Boston round-trip. But even then, I'm still cheaper than Amtrak for 4 people.
Lucky you! I used to live next to the company that I work at, so I walked into work. Then I got married and had kids. Now instead of "where's the closest apartment complex to work" I had to optimize based on school systems and distance to both my work and my wife's. I think we did pretty well - I have a 10-mile commute and she has a 5-mile commute... not quite splitting the difference distance wise, but time-wise my commute is actually better because about half of mine is highway. I can't bike without taking my life into my hands. Neither can she, since she drives through an absolutely horrible part of the city.
So for us, an electric car would be perfect, but they can take their time... at less than 5000 miles/year, that Camry will last a looooong time.
Your data must be old. Diesel engines, horsepower for horsepower are not heavier than a gasoline engine.
At a cost of about $5000:)
Diesel is not a by product of the refining product because it is an actual component product (intentionally manufactured).
If you don't "crack" the petroleum and just do fractional distillation, then you will end up with some proportion of diesel and some proportion of gasoline. Yes, they are intentionally making diesel - but it's not as if they could reconfigure the plant and make much of that into gasoline without other tradeoffs. This certainly isn't my field, but when I last looked into it, most of the refineries that can crack the fuel are in Texas - with Chavez striking a deal with China to build one their as well. It's a relatively expensive process, so you don't do it unless you have to - but once you have the capability you can make the diesel/gas ratio almost anything you want. Obviously, they make this ratio match the market - as you mention in your post. In Europe, the market is distorted - not only does the government tax diesel lower, but the refineries there simply make more diesel than the market would otherwise need. I'm not saying that the European refineries can't crack hydrocarbons - they've been doing that since the early 20th century - but they are geared for the high-quality stuff from the Middle East, while the US has to deal with oil sand sludge from Canada and the almost unusable stuff from South America (a barrel of Venezuelan crude only provides about 5 gallons of gasoline in a normal refining process). You wouldn't build that kind of a refinery in Europe because you have easier access to high-quality crude. Here is an excellent primer that includes a discussion of cracking.
When you get kids and a wife, you'll probably (not certainly, but probably) wind up owning two cars. I have a Camry and a minivan - I would gladly trade the Camry in on an electric car if my payback period were not infinite. I'd still have the minivan for longer trips.
Indeed you can't beat the price of a car for trips when you have multiple passengers. Well, maybe the bus.... Last time I looked it was still only about $12 to take the bus from Philly to NYC, which is hard to beat.
As an aside, we have a fundamental problem with our nation's infrastructure when it costs less to drive my own car into a major city than it costs to take transit of some form. Even given the atrocious parking fees, tolls, wear-and-tear, and gas, it will be cheaper for me to make the 6-hour trip up to Boston with my family of four by car than by Amtrak. Amazing.
The question is whether they will bother making a nice car that only has a 40 mile range. Currently I'd have to overpay for a Leaf, which still isn't as nice as my Camry. Then again, if a kw-h only adds $200 to the price of the car, then I might not care if it is a bit over-spec'd. The Leaf has a 24 kw-h battery - currently, the 100-mile range battery pack in the Leaf costs $18,000. Perhaps if they sold a 30-mile Leaf with a $12,000 discount I would have considered it:)
I don't think it's much of a moving target... electric needs to reach a 600 mile range and charge in 10 minutes.
I think cost is at least as important a criteria as range and charge time. I'd have one electric car if they were cheaper, even if it took overnight to charge and had only 40 miles of range. My wife's commute is 10 miles round-trip, so we put less than 5000 miles on her car each year. At today's battery pack prices, an electric would never be cost effective.
I've looked into it before. It's complex, but the "big four" are: 1. Diesel engines are heavier and more expensive. So sure you can buy a diesel that performs similarly to a gasoline engine, but it will cost about $5000 more and probably still be a bit heavier. Any technology that you can apply to diesels to make them rev faster or be constructed lighter can also be used in gasoline engines - so there will always be a cost and weight differential. 2. Diesel engines have more particulate emissions. In Europe, they do not regulate these as heavily as in the US. Meeting the US standard means more cost, complexity, and weight. 3. In Europe, diesel tends to be taxed at a lower rate than gasoline. 4. In Europe, they get high-quality crude and the refineries make diesel as a natural byproduct. In the US, we import a lot of really low-quality crude from Venezuela and Canada that needs to be "cracked". Once you are taking that additional step in the refining process, you can adjust the proportion of diesel and gasoline to suit the market... diesel is no longer a natural byproduct of the refining process. Diesel uses more crude than gasoline (it contains more energy - more carbon, per gallon), so there is little incentive for the refiners to produce it unless it is priced higher than gasoline.
I mean everything is moving over the next two decades to electric anyway.
Electric has a moving target to hit, just as it has for the last 100+ years. Batteries are not the only technology that can improve in the next two decades.
And the nature of the error - if it is Gaussian and you are calculating a position, the errors will average out to zero over time. TFA doesn't say whether the errors are Gaussian, though.
I'd be interested in how a speed payoff is going to be beneficial given you don't know whether you got the correct answer
I imagine certain applications that run in a loop, where the results from the previous calculation are fed back into the next calculation... so long as the error is within some limits, all you would do is increase the number of iterations - which may not be a problem if you can run them 15 more times than you could before.
And of course there are some applications where you are just running in a loop forever - depending on the nature of the error (are they Gaussian?) - it might be perfectly acceptable to have dead-reckoning errors in a phone's GPS/location routine for instance. Compressing voice in a phone, perhaps? The input is already messy analog audio, so maybe a little "digital" noise won't be too noticeable - like in that picture they use in TFA.
In political censorship it is political bodies such as governments that censor, in commercial censorship it is corporations, what they actually censor will often overlap, so one is just as bad as the other.
That's not really true - the government can (and does) also censor commercial speech (criminal penalties of copyright law), and corporations often censor political speech - a moderated message board being a simple example, but even choosing the callers on a radio program is a form of censorship.
What I mean is that it is far more critical to a democracy to have a free press and the ability to speak one's opinion without risk of jail or bodily harm, especially at the hand of government forces (or a proxy of the same). When the "opposition" is in jail, or when dissidents are routinely beaten up and their families threatened, when "hostile" newspapers are shut down, when unfriendly radio and TV stations are shut down - that's a much more dangerous sign than the government yanking the DNS record of a site that links to copyrighted files. I'd rather the latter didn't happen as well, but I see a major distinction between the two kinds of censorship.
The problem the UN in general has is that it's negatively tarred with the brush of the security council, which is the most often in the news component in the UN, but only a tiny, tiny fragment of what the UN is or does. The UN has far, far more good bits, than it does bad bits.
I think it is negatively tarred with things like the human rights commission getting headed up by some of the biggest offenders. The UN is great for dry, relatively uncontroversial international matters and the security council so far has kept us out of another world war. Some of the hunger and health committees are also very well respected. But unless we are talking about dry architectural issues and such, the UN is not a good place for managing the more controversial aspects of the internet.
I see your point, but I regard political speech to be far more important than commercial speech. I'd hate to see political speech subjected to the same sorts of negotiations that commercial speech is currently subjected to. I also disagree with the premise that an unelected "leader" should have any legitimacy at all on issues of policy. I accept the UN General Assembly's existence on pragmatic grounds, but don't see the need to extend that model beyond where it is absolutely necessary.
Re:how'bout u first prove beyond doubt that its sa
on
Vermont Bans Fracking
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I'm very pessimistic about anyone's ability to stop mankind from harvesting all of the fossil fuels. I hope I'm wrong.
That said, even if you totally ignore carbon, coal is not the greatest choice. You can scrub out the mercury, but you are still sending radioactive material into the air and the mining of coal presents some serious environmental and aesthetic challenges. Oil comes with the obvious baggage of war and the outflow of $300 billion in wealth each year. There are also some environmental consequences like spills and the nasty air pollution associated with refineries. Natural gas has a relatively good safety record, is reasonably clean-burning with little refining, and is found in large deposits domestically. Does the extraction create some environmental challenges? Sure. Do I think they are as serious as coal or oil? Not IMHO.
By the way, I also like nuclear, though the way we just stockpile the waste is unacceptable (and solvable... solved, actually).
Solar is great but nowhere near ready for the scale of nuclear or coal... the largest solar plant in the world is about 500MW, which is the output of a single small nuclear reactor - and you can't put those everywhere and they don't work at night. Wind is somewhat more promising... the largest farms already produce as much as a full-sized nuclear reactor and it looks like we might get as much as 20% of our power from wind in the next 20 years. Hydro is pretty much tapped out in the US.
Slashdot Mirror
I think that is true with the solid rocket boosters on the shuttle, but I'm pretty sure with a liquid rocket you can just turn off the valves and pumps supplying the liquid fuel.
But then again, NASA wasn't building the earlier rockets either, was it? So what exactly is new in this endeavour?
NASA more or less spec'd what the rocket had to do, rather than designing the rocket and hiring subcontractors to build it.
But the main difference is that SpaceX can make this rocket in a way they deem efficient, rather than building some parts in one congressman's district, shipping them along a special rail line to another location, etc.
Yeah, we picked a house on the same block as the day care and about half-a-mile from the elementary school, so we walk the kids to school each morning... but then it's a car ride after that!
We used to live in Manhattan, and there it is trivial to live without a car. But part of that was because I worked from home, day care was in the 2nd floor of our building, and my wife worked across the street :)
Once you start loading 3+ people into a car though, most mass transit in the world starts to look bad.
This probably is as much a commentary on how poorly most mass transit is run as it is on the relative efficiency of the two methods of transit.
Also, they run the same big-ass train whether there are 1000 people on it or 3, which seems wasteful. I always wonder why they don't run regular city buses or even short busses (modified, of course) on the tracks during off-peak hours. Naturally, anything running on the track should be automated.
That doesn't sound like a very good use of space.
That's true, but who's out of space? Is it such a bad thing to have farmland and estates interspersed with mid and high-density residential?
Also, in this suburb, the line branches several times. So they aren't single spokes that radiate out from the city, but a series of branches. This covers much more area. The way this area developed is there are townhouses and rental complexes directly adjacent to the track (high-density). Each station is surrounded by a small "downtown" with a few restaurants, a dry cleaner, and other things like that. A block or so off, it becomes single-family residential. Once you pass a reasonable walking distance, there are more public areas: churches, cemeteries, parks, schools, libraries, etc. Finally you have larger estates and golf courses. Of course, in the last 50 years most of the estates and golf course type uses have become housing developments that are not convenient to the train, so they added parking to the train stations. They've also built big shopping centers on some of them, which killed off some of the little downtowns surrounding the stations. Nevertheless, it is still easy to see how development worked when it was rail-centric.
Plus, that might work OK for your suburb, and for the single use case of going to work and back, assuming "work" is in the middle of this hub-and-spoke model.
There's a feedback mechanism involved. "Work" would stay in the middle because there is no convenient way to travel around the spoke. There will obviously be jobs out on the spokes - people need groceries, dry cleaners, restaurants, etc. But industry would stay in the middle - which is much more efficient than having it all spread out anyway.
If you are hell-bent on providing a way to get from branch-to-branch, you can put in a "beltway" line - just like we do with highways.
We have the technology to do better now.
Highways with individual cars are horribly space-inefficient. You need 8x the lanes compared to tracks to carry the same number of passengers. And while trains certainly are subject to delay, they do not have something akin to a traffic jam. I hope you're not referring to highways and cars as "the technology to do better now"! :)
No, you don't understand the concept of free speech at all.
I don't think that's true - I think you are using the terms "free speech" and "censorship" interchangeably. The quotes you took out of my post are referring to your discussion of "censorship", not free speech in general. I maintain that they are different, but related, concepts.
Whatever valid arguments there were for not letting the UN take over, have now been trumped by the fact that the US is now guilty of all the things people have claimed the UN may (but most likely wouldn't) be guilty of.
Well, I'm with you and against you :) I'm with you in that it would be helpful to have an international body take over administration of the internet. I'm still not convinced that the General Assembly is the right venue - even if all it is doing is setting up a committee. I believe the internet is a very important outlet of political speech in the modern world, and it would be too easy to silence it. I don't think it is laughable at all, since the number of countries without free speech protection outnumbers those that have it.
Yeah, I assume this new engine is similarly heavy.
Yeah might have to jump ship on this one :)
The simple fact is: public transportation doesn't work in the USA,
I submit that this is because we build roads and then watch development build up around the roads.
I live in a 70+ year old suburb that was built around train tracks. Most of the people who live here take the train into town.
Phone company manages to do that for $14/month.
Last time Comcast paid a contractor to come out and plug in my cable box, he ripped out my brand-new cable line to the TV - presumably because he could then charge Comcast for the "repair".
Those kinds of things are either non-existent or infeasible outside the northeast, except in small parts of California.
Yeah, that was kind of my point... it seems insane that a privately-owned, privately-maintained car can be a lower-cost option. We really have a weird transportation system. It should be cheaper to maintain a set of train tracks than a highway. It should be cheaper to maintain a fleet of identical vehicles than for each individual to keep up their own.
One thing I didn't do is include the capital cost of my car in the calculation. That's roughly $0.27/mile if the car lasts 100,000 and has zero value at the end. So that adds $162 to my Philly-to-Boston round-trip. But even then, I'm still cheaper than Amtrak for 4 people.
LOL, yeah so far not looking good. I've done pharmaceuticals, so I have stomach for a measly 5% loss :)
Lucky you! I used to live next to the company that I work at, so I walked into work. Then I got married and had kids. Now instead of "where's the closest apartment complex to work" I had to optimize based on school systems and distance to both my work and my wife's. I think we did pretty well - I have a 10-mile commute and she has a 5-mile commute... not quite splitting the difference distance wise, but time-wise my commute is actually better because about half of mine is highway. I can't bike without taking my life into my hands. Neither can she, since she drives through an absolutely horrible part of the city.
So for us, an electric car would be perfect, but they can take their time... at less than 5000 miles/year, that Camry will last a looooong time.
Your data must be old. Diesel engines, horsepower for horsepower are not heavier than a gasoline engine.
At a cost of about $5000 :)
Diesel is not a by product of the refining product because it is an actual component product (intentionally manufactured).
If you don't "crack" the petroleum and just do fractional distillation, then you will end up with some proportion of diesel and some proportion of gasoline. Yes, they are intentionally making diesel - but it's not as if they could reconfigure the plant and make much of that into gasoline without other tradeoffs. This certainly isn't my field, but when I last looked into it, most of the refineries that can crack the fuel are in Texas - with Chavez striking a deal with China to build one their as well. It's a relatively expensive process, so you don't do it unless you have to - but once you have the capability you can make the diesel/gas ratio almost anything you want. Obviously, they make this ratio match the market - as you mention in your post. In Europe, the market is distorted - not only does the government tax diesel lower, but the refineries there simply make more diesel than the market would otherwise need. I'm not saying that the European refineries can't crack hydrocarbons - they've been doing that since the early 20th century - but they are geared for the high-quality stuff from the Middle East, while the US has to deal with oil sand sludge from Canada and the almost unusable stuff from South America (a barrel of Venezuelan crude only provides about 5 gallons of gasoline in a normal refining process). You wouldn't build that kind of a refinery in Europe because you have easier access to high-quality crude.
Here is an excellent primer that includes a discussion of cracking.
You make a good point. I'm in at $40 - let's see how the rest of the day goes :)
When you get kids and a wife, you'll probably (not certainly, but probably) wind up owning two cars. I have a Camry and a minivan - I would gladly trade the Camry in on an electric car if my payback period were not infinite. I'd still have the minivan for longer trips.
Indeed you can't beat the price of a car for trips when you have multiple passengers. Well, maybe the bus.... Last time I looked it was still only about $12 to take the bus from Philly to NYC, which is hard to beat.
As an aside, we have a fundamental problem with our nation's infrastructure when it costs less to drive my own car into a major city than it costs to take transit of some form. Even given the atrocious parking fees, tolls, wear-and-tear, and gas, it will be cheaper for me to make the 6-hour trip up to Boston with my family of four by car than by Amtrak. Amazing.
The question is whether they will bother making a nice car that only has a 40 mile range. Currently I'd have to overpay for a Leaf, which still isn't as nice as my Camry. Then again, if a kw-h only adds $200 to the price of the car, then I might not care if it is a bit over-spec'd. The Leaf has a 24 kw-h battery - currently, the 100-mile range battery pack in the Leaf costs $18,000. Perhaps if they sold a 30-mile Leaf with a $12,000 discount I would have considered it :)
I don't think it's much of a moving target ... electric needs to reach a 600 mile range and charge in 10 minutes.
I think cost is at least as important a criteria as range and charge time. I'd have one electric car if they were cheaper, even if it took overnight to charge and had only 40 miles of range. My wife's commute is 10 miles round-trip, so we put less than 5000 miles on her car each year. At today's battery pack prices, an electric would never be cost effective.
Someone here knows, I bet.
I've looked into it before. It's complex, but the "big four" are:
1. Diesel engines are heavier and more expensive. So sure you can buy a diesel that performs similarly to a gasoline engine, but it will cost about $5000 more and probably still be a bit heavier. Any technology that you can apply to diesels to make them rev faster or be constructed lighter can also be used in gasoline engines - so there will always be a cost and weight differential.
2. Diesel engines have more particulate emissions. In Europe, they do not regulate these as heavily as in the US. Meeting the US standard means more cost, complexity, and weight.
3. In Europe, diesel tends to be taxed at a lower rate than gasoline.
4. In Europe, they get high-quality crude and the refineries make diesel as a natural byproduct. In the US, we import a lot of really low-quality crude from Venezuela and Canada that needs to be "cracked". Once you are taking that additional step in the refining process, you can adjust the proportion of diesel and gasoline to suit the market... diesel is no longer a natural byproduct of the refining process. Diesel uses more crude than gasoline (it contains more energy - more carbon, per gallon), so there is little incentive for the refiners to produce it unless it is priced higher than gasoline.
I mean everything is moving over the next two decades to electric anyway.
Electric has a moving target to hit, just as it has for the last 100+ years. Batteries are not the only technology that can improve in the next two decades.
And the nature of the error - if it is Gaussian and you are calculating a position, the errors will average out to zero over time. TFA doesn't say whether the errors are Gaussian, though.
I'd be interested in how a speed payoff is going to be beneficial given you don't know whether you got the correct answer
I imagine certain applications that run in a loop, where the results from the previous calculation are fed back into the next calculation... so long as the error is within some limits, all you would do is increase the number of iterations - which may not be a problem if you can run them 15 more times than you could before.
And of course there are some applications where you are just running in a loop forever - depending on the nature of the error (are they Gaussian?) - it might be perfectly acceptable to have dead-reckoning errors in a phone's GPS/location routine for instance. Compressing voice in a phone, perhaps? The input is already messy analog audio, so maybe a little "digital" noise won't be too noticeable - like in that picture they use in TFA.
In any event, it certainly is interesting work.
In political censorship it is political bodies such as governments that censor, in commercial censorship it is corporations, what they actually censor will often overlap, so one is just as bad as the other.
That's not really true - the government can (and does) also censor commercial speech (criminal penalties of copyright law), and corporations often censor political speech - a moderated message board being a simple example, but even choosing the callers on a radio program is a form of censorship.
What I mean is that it is far more critical to a democracy to have a free press and the ability to speak one's opinion without risk of jail or bodily harm, especially at the hand of government forces (or a proxy of the same). When the "opposition" is in jail, or when dissidents are routinely beaten up and their families threatened, when "hostile" newspapers are shut down, when unfriendly radio and TV stations are shut down - that's a much more dangerous sign than the government yanking the DNS record of a site that links to copyrighted files. I'd rather the latter didn't happen as well, but I see a major distinction between the two kinds of censorship.
The problem the UN in general has is that it's negatively tarred with the brush of the security council, which is the most often in the news component in the UN, but only a tiny, tiny fragment of what the UN is or does. The UN has far, far more good bits, than it does bad bits.
I think it is negatively tarred with things like the human rights commission getting headed up by some of the biggest offenders. The UN is great for dry, relatively uncontroversial international matters and the security council so far has kept us out of another world war. Some of the hunger and health committees are also very well respected. But unless we are talking about dry architectural issues and such, the UN is not a good place for managing the more controversial aspects of the internet.
I see your point, but I regard political speech to be far more important than commercial speech. I'd hate to see political speech subjected to the same sorts of negotiations that commercial speech is currently subjected to. I also disagree with the premise that an unelected "leader" should have any legitimacy at all on issues of policy. I accept the UN General Assembly's existence on pragmatic grounds, but don't see the need to extend that model beyond where it is absolutely necessary.
I'm very pessimistic about anyone's ability to stop mankind from harvesting all of the fossil fuels. I hope I'm wrong.
That said, even if you totally ignore carbon, coal is not the greatest choice. You can scrub out the mercury, but you are still sending radioactive material into the air and the mining of coal presents some serious environmental and aesthetic challenges. Oil comes with the obvious baggage of war and the outflow of $300 billion in wealth each year. There are also some environmental consequences like spills and the nasty air pollution associated with refineries. Natural gas has a relatively good safety record, is reasonably clean-burning with little refining, and is found in large deposits domestically. Does the extraction create some environmental challenges? Sure. Do I think they are as serious as coal or oil? Not IMHO.
By the way, I also like nuclear, though the way we just stockpile the waste is unacceptable (and solvable... solved, actually).
Solar is great but nowhere near ready for the scale of nuclear or coal... the largest solar plant in the world is about 500MW, which is the output of a single small nuclear reactor - and you can't put those everywhere and they don't work at night. Wind is somewhat more promising... the largest farms already produce as much as a full-sized nuclear reactor and it looks like we might get as much as 20% of our power from wind in the next 20 years. Hydro is pretty much tapped out in the US.