If we stick with only 1.0G, then we wouldn't need artificial gravity for the people on board. We could maintain 1.0G acceleration on the way there, then spin the ship around (so the floor is pointing towards the destination) and maintain 1.0G deceleration for the second half of the journey.
The problem is, even if that means the people on board only experience 5-25 years, how much time will pass on Earth before we found out what this exploration team discovers there? (Remember, once they get there after however many years (hundreds? thousands?), they'd have to send their data by radio at light-speed, which would take yet another 28 years.) If we were to pony up the money to finance a mission like this, we, our children, our grandchildren, and our great-grandchildren would never find out the results, if any. We'd probably develop FTL in that time and have a colony already established on any viable planets in the 61 Virgo system before this team even arrived!
1G = 7 years internal time, 30 years as time is measured on Earth. So you'd be getting messages back with 60 years.
0.01G = 100-odd years internal time, 107 years as time is measured on Earth. Messages back about 210 years after departure.
Note that 1G sustained isn't going to be practical for a very long time, but that 0.01G sustained (for 100+ years) is a maybe within the century.
Note that if we launched a 0.01G ship day after tomorrow, then sometime around 2185 we launched a 1G ship, the 1G ship would get there first.
On the other hand, I don't think a generation ship is entirely beyond the realms of possibility within the next 50 years. Yes, it would require some incredible engineering to get it done. But it wouldn't require as much new technology as one might think - the sheer size allows you to get away with things that aren't practical in a smaller ship. Like lakes, fields, forests, that sort of thing.
Slow and steady acceleration wins the race. You're not going to do that with a chemical rocket, but with an on-board nuclear reactor and a few advancements in ion propulsion or vacuum propellers, we could make the trip. We could easily launch a probe to start making the journey in the next five years, if we allocated the budget to do so. Humans could make the trip as well, given the right accommodations--only a few years would be passing on-board.
Not so few as you might think. At 0.01G, we're talking about 100 years as measured by clocks on the ship.
If we define "a few years" as "five or less", we'd need about 1.5G constant boost to reach 61 Virgo in "a few years". Which, by the by, translates to a mass ratio of about 2700 if we're using a photon drive, or a number that's the next best thing to infinity if we're using any drive we can foresee in the next couple decades.
the thing is that, ALL of these extreme and minimal changes all around the world is going to get averaged into a 1 to 3 degrees rise in AVERAGE world temperature.
in layman's terms it will be disaster.
I don't have a problem with anything but this last little bit. Yes, that 1-3C increase is an average. Yes, some places will get hotter, some cooler, some stay the same. Yes, we don't know which places will do which.
All that said, it doesn't follow from that that "it will be a disaster". Maybe it will. Maybe we'll get lucky and all the changes will be either non-issues or favourable changes - we just don't know.
Asserting in one paragraph that we won't know the result, then in the next that we, well, DO know the result makes you look disingenuous, at best.
So NASA says "Hey guys, we've found an asteroid that has a 90% chance of hitting the Earth in a hundred years. We don't really know what'll happen, but we're pretty sure it'll be bad."
If NASA were to say that, I'd assume they were full of crap - they can't predict an orbit that accurately that far in the future.
(there will be far more than just the radioactivity from the remains of the weapon, since much of that soil will have been exposed to extreme neutron flux and transmuted into unstable isotopes).
Well, if by "much of that soil" you really meant "a minute fraction of that soil", then you're pretty much right.
Do note, for the record, that most of those "unstable isotopes" fall into either:
(A)long lived, and thus not very radioactive, or
(B)short lived, and thus not radioactive very long.
Translation: We're really fuckin' scared of other countries and will fucking kill you if you wink at us the wrong way.
Translation: the rest of the world is letting the USA do the grunt work of all those "foreign interventions" that used to be done by European powers up till WW2.
No. I can prove to you that peoples' risk calculations are fubared.
By all means, please do.
People freak out over the swine flu and terrorism and yet heart disease which kills a thousand times more people doesn't seem to get that much attention; certainly not enough for people to consider changing their diets and exercising a little more.
And if you think this is proof, you're mistaken. It is, at best, anecdotal evidence, and at worst, your opinion.
Oddly enough, I don't know ANYONE who is especially worried about swine flu or terrorism.
And while people certainly do pay less attention to heart disease than perhaps they should, that's not proof that they don't evaluate risks properly. It's proof that they don't think the exercise and diet are worth the extra year or three of life.
Then can you explain why people continue to text/use their cell phone while driving knowing that it increases their risk of dying in a car accident? THe problem is that most people do not have a good grasp of the actual magnitude of risk * probability.
No, the problem is that people DO have a good grasp of the actual risk * probability.
And it's simply not that high. Yeah, you have a higher chance of an accident if you're texting/talking while driving. But it's not like you raise your chances of an accident to even 0.001.
And most people aren't all that worried about 1 chance in 1000 of having a bad day.
Considering that CO2 levels will continue to rise for 1000 years afterwards -- we really will have missed a chance to build a sustainable economy. By analogy, you won't save the building from fire, because you want to measure exactly how hot the flame is, to within 0.5C, to prove that the house is really in danger.
Bad analogy guy strikes again. I know a house can be destroyed by fire. I don't yet know that the world as we know it will end if we don't stop emitting CO2 RIGHT NOW THIS INSTANT!!!
In assessing certainty, one cannot simply pull number like 500, 5000 and 0.05C out of thin air. There is a confidence interval that goes with the measurement. Do you know what that confidence interval is? Didn't think so.
Yes, actually I do know what a confidence interval is. I'm also aware that the numbers I used were largely arbitrary. However, when one is talking about SMALL changes, large numbers of precise measurements are better than small numbers of imprecise measurements. And most of what we know about the climate more than 200 years ago is "small numbers of imprecise measurements".
Note also that the number of sites and precision I specified were by no means difficult to accomplish, since there are far more weather monitoring sites than that in the world today, with instruments that can easily handle the precision I specified. The 500 years might be a bit tricky, but in 450 years we should be able to manage that just fine as well.
On the other hand, climate scientists *do* know what their confidence interval is. It is all in the ipcc [realclimate.org] reports. Ever read one? Didn't think so.
Yes, in fact I have. And in spite of that, I still don't believe that it has been reasonably demonstrated that we have to act RIGHT THIS MINUTE OR WE'LL ALL DIE!!!
Face it, the argument over Climate Change (Anthropogenic or otherwise) is filled with people with political agendas, plus a large number of people (myself included) who really don't care who is right (and, in my case at least, aren't really bothered by the idea that the climate might change again), plus a really tiny number of people who just want to do good science.
Alas, not all the people doing the science of AGW are in that last group. Which is the problem, of course.
Unless of course, you're in one or the other of the political groups. In which case the problem, as you see it, is that people are still allowed to disagree with you.
Note, by the way, that you asked for "an objective criteria from which to assuage your skepticism". When I offered one, you told me I was wrong. If you didn't really want "an objective criteria from which to assuage your skepticism", then why bother asking for it? Or did you just assume that anyone who disagreed with you couldn't possibly come up with an objective criterion.
If you were reasonable, you'd would offer an objective criteria from which to assuage your skepticism. Try it, and see what happens. Really.
I'd settle for 500 years of accurate, precise (with an error no greater than 0.05C) temperature measurements from at least 5000 sites scattered reasonably uniformly over the globe.
Plus CO2 levels at each site at the same times as the temperature measurements.
No, tree rings won't do. Nor will ice cores. Because we have less than 100 years of temperature measurements to calibrate them with.
Oh, and I'd like to be able to see the raw data, the massaged data, and the formulae used to do the massaging. Note that the CRU people can't or won't provide the raw data - either of which is a big warning sign in my book.
the ideal of efficiency and conservation will be promoted in the public eye.
Nonsense! The "public" neither knows nor cares what type of patents are being issued, so they'll not even notice "the ideal of efficiency and conservation" being "promoted".
Even if the Singularity did happen, who's to say a pain-free energy source actually exists? What if the new super computer brain comes back with, "nuclear fission is your best bet"?
Since I happen to think nuclear fission is our best bet, that wouldn't bother me.
Or, "a lot of problems would be solved within 100 years if you just quit making babies"?
On that subject, I noticed in the news today that Taiwan now has a birthrate of 1.0 babies per woman. Which is about 1.2 babies per woman below replacement rate....
Lately I've been wondering how worthwhile attempts to e.g. stop climate change are when, if Kurzweil is right, we'll hit the Singularity in only a couple of decades and then all of humanity's environmental and technological problems may well be solved.
It's called "minimizing downside risk".
Which is a fancy way of saying "well, and what if the Singularity does NOT occur on schedule?"
Personally, I don't think anyone is taking the whole "global warming" thing seriously yet - they're just posturing with another unenforceable (and largely meaningless) Treaty meant to placate the global warming lobby while otherwise doing not very much at all.
Gerson Lehrman Group, a New York consulting firm, estimates that even if 500,000 cars powered by lithium ion batteries were produced in 2015, they would use less than 10 percent of last year's global lithium output. And global output continues to climb.
Of course, worldwide auto production is a lot closer to 10,000,000 per year....
Carriers are 100X easier to build than battleships. If we had our full compliment of battleships we would have ended the pacific theater war far earlier.
Carriers back then were simple as hell to build compared to the 18" thick hulls of the Big Iowa class battleships.
You are aware that we lost only two battleships permanently as a result of Pearl Harbor?
And that none of the Iowa class ships (4), or South Dakota class ships (4) had even been completed when Pearl Harbor happened?
It's silly to think that we could have finished the war far sooner if only we'd had those two 25 year old battleships that we lost at Pearl, in addition to the eight brand new battleships already in the ways.
There are two ways to affect change in this case: The stick and the carrot. The stick hasn't worked in 25 years. He's chosen to give the carrot a try.
Based on the reaction of Iran's government to the "carrot", it's not going to work either. "What? You're going to be nice to us? Great, thanks, we'll start enriching more uranium now"
Note, by the way, that saying bad things about Iran isn't quite the same thing as using "the stick" on them. The "stick" is usually delivered from a Buff...
The current war in Iraq is not a "War on Terrorism" because the people attacking the US military there are not "Terrorists", they are merely defending their country and their ideology from invaders.
It should, perhaps, be pointed out that the overwhelming majority of the attacks in Iraq are Muslim "terrorists/freedom-fighters" blowing up other Muslims. While they do attack our soldiers from time to time, most of their effort is directed at softer targets....
Dunno about India but China has pledged to lower emissions by an absurd* 45% by 2020.
That's odd. In the news this morning, I read that China has rejected Copenhagen's target of 50% reduction in CO2 output by 2050.
What China said was that they'd reduce emissions per unit output by 45% (compared to 2005 levels) by 2020. Which will mean a net rise in emission from China, not a reduction, since their economy is growing rapidly.
Also, pay close attention to that "compared to 2005 levels". Kyoto (and Copenhagen) used 1990 levels as a baseline, not 2005 levels. Since China almost tripled its CO2 emissions between 1990 and 2005, a "45% reduction from 2005 levels" would be about a 60% INCREASE from 1990 levels.
Assuming we were talking about a real reduction, as opposed to what China actually said, of course....
Do You Have Skills That Might Be Useful On Mars or on the Shuttle?
I've got skills that are potentially useful, but nothing that 10,000 other people don't have, so I'll leave that as "maybe"
Frankly, I don't want to waste my tax dollars on your joyride. I'd rather send someone who has a really good reason to be there. However, some of those people have wives and children and don't really want to risk their lives in the name of science.
You're taking this way too seriously. My point was that not everyone insists on 100.0% chance of success before setting off.
Note also that I wouldn't want to go "in the name of science". I'd go in order to advance the "frontier", but I don't think it's worth bothering with Mars (or ieven with space) if we're not going to go there to stay.
Slashdot Mirror
Umm, no. Five Earth masses at the same density as Earth means about 1.7G.
Double the density, and the planet pulls about 2.7G, but has stopped being Earthlike (density as high as silver?! ouch!).
1G = 7 years internal time, 30 years as time is measured on Earth. So you'd be getting messages back with 60 years.
0.01G = 100-odd years internal time, 107 years as time is measured on Earth. Messages back about 210 years after departure.
Note that 1G sustained isn't going to be practical for a very long time, but that 0.01G sustained (for 100+ years) is a maybe within the century.
Note that if we launched a 0.01G ship day after tomorrow, then sometime around 2185 we launched a 1G ship, the 1G ship would get there first.
On the other hand, I don't think a generation ship is entirely beyond the realms of possibility within the next 50 years. Yes, it would require some incredible engineering to get it done. But it wouldn't require as much new technology as one might think - the sheer size allows you to get away with things that aren't practical in a smaller ship. Like lakes, fields, forests, that sort of thing.
Not so few as you might think. At 0.01G, we're talking about 100 years as measured by clocks on the ship.
If we define "a few years" as "five or less", we'd need about 1.5G constant boost to reach 61 Virgo in "a few years". Which, by the by, translates to a mass ratio of about 2700 if we're using a photon drive, or a number that's the next best thing to infinity if we're using any drive we can foresee in the next couple decades.
I don't have a problem with anything but this last little bit. Yes, that 1-3C increase is an average. Yes, some places will get hotter, some cooler, some stay the same. Yes, we don't know which places will do which.
All that said, it doesn't follow from that that "it will be a disaster". Maybe it will. Maybe we'll get lucky and all the changes will be either non-issues or favourable changes - we just don't know.
Asserting in one paragraph that we won't know the result, then in the next that we, well, DO know the result makes you look disingenuous, at best.
If NASA were to say that, I'd assume they were full of crap - they can't predict an orbit that accurately that far in the future.
Well, if by "much of that soil" you really meant "a minute fraction of that soil", then you're pretty much right.
Do note, for the record, that most of those "unstable isotopes" fall into either:
(A)long lived, and thus not very radioactive, or
(B)short lived, and thus not radioactive very long.
Translation: the rest of the world is letting the USA do the grunt work of all those "foreign interventions" that used to be done by European powers up till WW2.
Note that "one girl" is an anecdote, not evidence.
And a 16 year old girl is, by definition, almost as stupid as a 16 year old boy.
Which is to say that using one 16 year old as a guideline to planning the laws of the land is almost as stupid as the 16 year old....
By all means, please do.
And if you think this is proof, you're mistaken. It is, at best, anecdotal evidence, and at worst, your opinion.
Oddly enough, I don't know ANYONE who is especially worried about swine flu or terrorism.
And while people certainly do pay less attention to heart disease than perhaps they should, that's not proof that they don't evaluate risks properly. It's proof that they don't think the exercise and diet are worth the extra year or three of life.
No, the problem is that people DO have a good grasp of the actual risk * probability.
And it's simply not that high. Yeah, you have a higher chance of an accident if you're texting/talking while driving. But it's not like you raise your chances of an accident to even 0.001.
And most people aren't all that worried about 1 chance in 1000 of having a bad day.
Bad analogy guy strikes again. I know a house can be destroyed by fire. I don't yet know that the world as we know it will end if we don't stop emitting CO2 RIGHT NOW THIS INSTANT!!!
Yes, actually I do know what a confidence interval is. I'm also aware that the numbers I used were largely arbitrary. However, when one is talking about SMALL changes, large numbers of precise measurements are better than small numbers of imprecise measurements. And most of what we know about the climate more than 200 years ago is "small numbers of imprecise measurements".
Note also that the number of sites and precision I specified were by no means difficult to accomplish, since there are far more weather monitoring sites than that in the world today, with instruments that can easily handle the precision I specified. The 500 years might be a bit tricky, but in 450 years we should be able to manage that just fine as well.
Yes, in fact I have. And in spite of that, I still don't believe that it has been reasonably demonstrated that we have to act RIGHT THIS MINUTE OR WE'LL ALL DIE!!!
Face it, the argument over Climate Change (Anthropogenic or otherwise) is filled with people with political agendas, plus a large number of people (myself included) who really don't care who is right (and, in my case at least, aren't really bothered by the idea that the climate might change again), plus a really tiny number of people who just want to do good science.
Alas, not all the people doing the science of AGW are in that last group. Which is the problem, of course.
Unless of course, you're in one or the other of the political groups. In which case the problem, as you see it, is that people are still allowed to disagree with you.
Note, by the way, that you asked for "an objective criteria from which to assuage your skepticism". When I offered one, you told me I was wrong. If you didn't really want "an objective criteria from which to assuage your skepticism", then why bother asking for it? Or did you just assume that anyone who disagreed with you couldn't possibly come up with an objective criterion.
I'd settle for 500 years of accurate, precise (with an error no greater than 0.05C) temperature measurements from at least 5000 sites scattered reasonably uniformly over the globe.
Plus CO2 levels at each site at the same times as the temperature measurements.
No, tree rings won't do. Nor will ice cores. Because we have less than 100 years of temperature measurements to calibrate them with.
Oh, and I'd like to be able to see the raw data, the massaged data, and the formulae used to do the massaging. Note that the CRU people can't or won't provide the raw data - either of which is a big warning sign in my book.
Nonsense! The "public" neither knows nor cares what type of patents are being issued, so they'll not even notice "the ideal of efficiency and conservation" being "promoted".
Which allows you to violate copyrights to your heart's content as long as you use a frontman with a net worth of zero.
Which isn't terribly hard to do, really.
Since I happen to think nuclear fission is our best bet, that wouldn't bother me.
On that subject, I noticed in the news today that Taiwan now has a birthrate of 1.0 babies per woman. Which is about 1.2 babies per woman below replacement rate....
It's called "minimizing downside risk".
Which is a fancy way of saying "well, and what if the Singularity does NOT occur on schedule?"
Personally, I don't think anyone is taking the whole "global warming" thing seriously yet - they're just posturing with another unenforceable (and largely meaningless) Treaty meant to placate the global warming lobby while otherwise doing not very much at all.
Of course, worldwide auto production is a lot closer to 10,000,000 per year....
You are aware that we lost only two battleships permanently as a result of Pearl Harbor?
And that none of the Iowa class ships (4), or South Dakota class ships (4) had even been completed when Pearl Harbor happened?
It's silly to think that we could have finished the war far sooner if only we'd had those two 25 year old battleships that we lost at Pearl, in addition to the eight brand new battleships already in the ways.
The USA doesn't import oil from Iraq. Or Iran. Never has.
We get our oil from Canada, Mexico, Venezuela, and Saudi Arabia.
Based on the reaction of Iran's government to the "carrot", it's not going to work either. "What? You're going to be nice to us? Great, thanks, we'll start enriching more uranium now"
Note, by the way, that saying bad things about Iran isn't quite the same thing as using "the stick" on them. The "stick" is usually delivered from a Buff...
That would probably be Eritrea, 19 journalists in jail, and just over 4 million population.
Then Cuba, Iran, Burma, China, in descending order.
It should, perhaps, be pointed out that the overwhelming majority of the attacks in Iraq are Muslim "terrorists/freedom-fighters" blowing up other Muslims. While they do attack our soldiers from time to time, most of their effort is directed at softer targets....
Apparently, he told them that the first time he was caught. And then didn't bother to actually uninstall anything.
That's odd. In the news this morning, I read that China has rejected Copenhagen's target of 50% reduction in CO2 output by 2050.
What China said was that they'd reduce emissions per unit output by 45% (compared to 2005 levels) by 2020. Which will mean a net rise in emission from China, not a reduction, since their economy is growing rapidly.
Also, pay close attention to that "compared to 2005 levels". Kyoto (and Copenhagen) used 1990 levels as a baseline, not 2005 levels. Since China almost tripled its CO2 emissions between 1990 and 2005, a "45% reduction from 2005 levels" would be about a 60% INCREASE from 1990 levels.
Assuming we were talking about a real reduction, as opposed to what China actually said, of course....
Yes.