Your Wikipedia page says you live in Ohio. Based on that the panels should pay for themselves in under a decade without any tax breaks. Do you have massive amounts of shade over your roof or something?
Yes, no, and yes.
Here's a map of solar availability in the United States: http://cdn2.hubspot.net/hub/18... I live in that green part, labelled "3.78 to 3.91 kW-hr/m^2/day". Not the absolutely worst part of America for solar availability (that would be the Northwest), but nowhere near the best. Compare this to the dark red part, labelled "6.65-6.78 kW-hr/m^2/day". So, right to start with, solar panels are going to produce about half as much power as they would produce in most of the southwest. Electricity costs in Ohio are about 11 cents per kilowatt hour, which is not incredibly low, but compared to say California, electricity would be 15 cents per kilowatt hour, or 18 cents per kilowatt hour in New York. (But the net-metering cost is about 6 cents per kilowatt hour, and our home electrical demand is low at noon most days, so net metering is probably the price to use).
Ten years is a very optimistic estimate for payback time. My quick calculation is that 11 years would be the rough payback time for the panels alone (purchased at a dollar a watt)-- but not the inverters and regulators, nor the installation costs, both of which will easily exceed a dollar a watt.
But, that might not be entirely a deal breaker if it were not for the main problem, which is that our lot is heavily shaded, and our house has neither a flat nor a south-facing roof.
Tax breaks paid for 60% of my solar system. The only way it made economic sense.
Really? You must live in an extremely marginal area for the panels not to pay for themselves and start saving you money in under a decade, without tax breaks.
Exactly!
Economics of solar electrical production is all about location.
...People are gonna claim it's proof that renewables don't work.
As an electrical engineer that works for a company that installs solar systems, they don't work. Well, when you add the government subsidies, that we all pay for in taxes, they're only bad instead of horrible.
As an electrical engineer that works on solar systems, they do work. The economic payback, however, depends sensitively on location (and electricity price, which also depends on location.)
A real problem is that a lot of people want to install solar because they want to install solar, not because they are in a particularly good spot. For my northern-Ohio, tree-shaded house, not very good economics. In the best location, however (high solar availability; high daytime electrical prices), solar economics work very well.
As the real estate people say: the three most important parts about installing solar are: location, location, location.
It isn't that they don't work. it's that they aren't as mature as other industries.
They ate mature, it is just one flipping business plan that failed. There are hunderts of other companies which do renewables.
Closer.
In case you haven't noticed, the energy market is in a major upheaval. SunEdison is in trouble because of their 2-billion dollar purchase of Vivint. Vivint is in trouble because their business model, selling residential panels on a fixed-price-for-electricity basis, is in trouble because the price of energy has been dropping, and their business has turned into the equivalent of subprime loans.
This particular failure isn't a technology maturity problem-- it's a problem of a business model being blindsided by external events.
(added to a problem of a company making a really bad purchase for a very large price)
The code was a post-hoc white-house mandated change, which provided no added security.
That's right-- if you set the code to all-zero's, and then prominently post instructions saying "the code is all zeros, do not change", it provides no added security.
Yes, the article seems to be trying to manufacture outrage out of nothing.
It's a make-versus-buy decision. Industry does these decisions all the time. When your applications are unique, the decision tends to go toward "make your own;" when your application is something that many other people also do, the decision tends to go toward "buy the commercial product".
Buying off the shelf comes with hidden costs unless what is available exactly meets your need-- if you need to write a new contract for every change (and since you still haven't designed the system you're launching, there will be a lot of changes needed, as you keep refining requirements) every single change is a chance for the vendor to demand large dollar payments.
And the article's statement "why doesn't NASA just use what Space-X used" is absurd. Ten years ago, Space-X was an unknown company who had just launched their first rocket. Which failed. As did their next launch. And the one after that.
There is no software on the planet that is more scrutinised and more meticulously developed than software for spacecraft
There's at least one. Software for US nuclear weapons systems. I once watched a USAF nuclear safety audit over the course of a few years. I was thoroughly impressed with the quality of the work.
...and then, as an added assurance to make sure that nothing would slow down the ability to launch missiles, the code to launch missiles was set to all zeros, and never changed.
They are done by the private industry... The Cygnus spacecraft is owned by Orbital, not NASA (the article summary used here isn't very clear on that). NASA contracts ALL U.S. resupply missions out to Orbital ATK and SpaceX.
I disagree: ***selling price*** of PV panels is coming down. However, the energy cost of creating solar panels isn't.
Of course it is. They wouldn't be cheap if it wasn't. Silicon manufacture is getting much more efficient than it was.
The rare earths are, not surprisingly, rare, and both mining and refining them have not changed much.
Silicon solar panels-- the ones that are cheap-- don't use rare earths. You're thinking of the thin films. But the rare materials used in thin film solar cells are literally micron thick layers (which is why they'r cheap)-- and in any case, the panels that have become extremely low in price lately are silicon, not thin films.
(Also, rare earths aren't actually rare).
...As a longer-term issue, is the declining performance of PV panels over time.
You mean degradation? Hasn't been a problem for silicon panels.
You'd need more than 1½ million to make a sucessfull GP Airship these days.
For a full-sized airship, maybe. But this request is only for something to carry 10 kilograms; not all that much more than the high-altitude balloons that high school students keep sending up to "the edge of space".* If you're clever, I wouldn't be surprised if you could probably do it for a few tens of thousand dollars.
--
(And, boy, am I glad that slashdot got tired and stopped posting those "students send random object to the edge of space" stories.)
Your numbers are low. However, the more egregious statement I'll take exception to is this one:
We have no evidence that a planet 8c warmer than it is now would be incompatible with human life.
No, 8 degrees C is not "incompatible with human life"!!
That's a strawman argument. Eight degrees C of warming would be a catastrophe in pretty much every way-- people are currently arguing about how bad two degrees of warming would be-- but if you are hearing people say that it would be "incompatible with human life," figure out who those people are and stop listening to them.
With no new exploration, oil production would eventually decline... but not "within 2-3 years, 5 years tops". It currently takes typically ten years to go from discovery to production! Oil exploration now won't have any effect whatsoever for ten years (although if the incentive were high, it could be shorter). In any case, proved reserves (the oil that we already know is there, no exploration needed) are currently estimated at 1656 billion barrels, while world usage is 96 billion barrels per year. So with no new oil fields developed at all, it would take 17 years for production to stop.
People often make the mistake of assuming that the old monopolies were created by evilness and killing. Really when you look at it, every one of them made huge advance in technology and innovation. They did it by being better than the competition.
That's true for some monopolies, but not Standard Oil. John D. Rockefeller put Standard Oil together by driving competitors out of business and buying them up. The main "innovation" he pioneered was that of making deals with railroads to ship his product at rates not offered to his competitors.
But, to be fair, collusion wasn't illegal until after the Sherman act, and wasn't nearly as vicious as some of the other shady business practices going on in other industries.
I don't think the gp was referring to the evidence of human activities being a major cause so much as the overwhelming evidence that we're not going to do more than talk about reducing those activities.
Fair enough, you can read it that way.
I'm a techno-optimist; there are other energy technologies out there, and we can chose the ones we want to use.
I get the whole Greenwashing that happened there, but seriously - no matter the {whatever} you hold concerning AGW, three things are constant:
1) Barring thermonuclear warfare or a wayward asteroid, global climate will change no matter what we do (or don't do),
Yes to the first part: Yes, human sources of climate change are not the only source of climate change; the other sources are still there.
and will continue on its current trend.
...and no to the second. There is very very good evidence that the current trend is due to human activities. There simply are no natural sources of change that have this magnitude of effect this quickly that we would not be able to see. (Remember, we do measure solar output. One thing we know: the current trend is not due to solar variability. If we stop these activities, the current trend will stop. (Although it will take a while to do so.)
2) Barring the invention of commercially viable electrical generation from fusion (or some similar massive source of energy)
You just said "unless there are other sources of energy, we have to use the current sources of energy." That statement is a tautology.
OK, so it is desirable to develop new sources of energy if we don't want to use the current sources. Fair enough. Let's get to it.
...
Plastics (made from petroleum) are the backbone of technology and civilization at this time - no viable replacement has yet arisen that doesn't require even more damage to the ecosystems, or can last nearly as long when the requirements call for longevity/durability. (e.g. yeah you can make plastic from corn, but it'll be much shorter-lived and will require massive up-scaling in agriculture, which presents problems of its own.)
1. Plastics account for so small an amount of the hydrocarbon usage that you can't even notice it on the pie chart. 2....and plastic isn't the problem, since turning fossil hydrocarbons into plastics puts the carbon into the plastic, not into the atmosphere.
A number of the ones on the list are, though not all. From the shorter version ( http://www.popecenter.org/comm... ) the ten most oppressive colleges were: 1. Mount St. Mary’s University in Maryland ("recently thrown into turmoil by president Simon Newman’s firing of two faculty members who criticized his idea that the school should reduce its freshman class by “drowning some of the bunnies” (i.e., culling out academically weak students).") 2. Northwestern University, 3. Louisiana State 4. University of California—San Diego 5. Saint Mary’s University in Minnesota 6. University of Oklahoma 7. Marquette University 8. Colorado College 9. University of Tulsa, 10. Wesleyan University
So, the religious universities on that list are Mount St. Mary’s University, Saint Mary’s University, Marquette University, and Wesleyan University. Four out of ten. Doesn't seem too bad, but only 20% of the US Universities are religiously affiliated, so it's about twice what you would expect.
The article (and summary headline) is not justified by the article.
The summary headline says "One of the worst disasters in U.S. history". The first paragraph of the article says "one of the largest environmental disasters in US history." Big difference.
But even that is not ever discussed in the text of the article; the article never discusses the environmental consequences or whether they are "a disaster." It does give a number, 97,100 metric tons of methane emitted--- but that's trivial. World methane emissions are hundreds of gigatons. A hundred kilotons emitted in a leak is irrelevant. http://cdiac.ornl.gov/trends/m...
No candidate can win the convention on the first ballot unless they have a majority in 8 states.
A majority of delegates. This is not the same as a majority of the primary vote! In winner-take-all states, you just need a plurality of the primary vote to win all the delegates.
The roll call of states' delegates continues until a candidate emerges. This is not necessarily on the first round!
None of the candidates are currently poised to do this.
Only four states have even had primaries yet! And half of those were caucuses.
... It's very possible for any candidate to lose a plurality but win the nomination.
Don't confuse the voting of the delegates with the popular vote. A candidate can lose a plurality of the popular vote, but a proposed candidate needs not merely a plurality, but a majority of delegates to win the party candidacy. And if no proposed candidate gets a majority on the first round, the convention keeps on repeating the votes of delegates until one does.
Non-technical users should use a Mac, as it simply works.
Since I use a mac, I really really wish that were true... but it's not.
Well, the problem is that the cost to buy (including maintenance) a Mac is a lot more expensive than to buy a PC... $500 may be little to you, but it could be a much higher value to many others...
Yes... but no. The purchase cost of a computer really is the least important cost. If it is frustrating to use and wastes your time, saving a few hundred dollars on purchase was a poor bargain.
Depends on what you want to do, of course. Either option has advantages for some things. Windows machines do have some bargain basement units... but you may have to make up that cost in problems. Or you may not. Depends on what you need it for.
It is unlikely to be real but your claim that the error level is higher than the measured effect is AFAIK wrong. We also have replication in 3 separate places with separate groups of people using different hardware which reduces some error sources.
No, sorry, but I will challenge that last statement. There are three separate groups which have produced different results which are inconsistent with each other.
Most recently, the NASA Johnson "Eagleworks" group has tried to replicate both the EM drive proposed by Shawer and a result on a similar concept in China claimed by Yang-- and falsified both of these results. The EM drive proposal stated that the purported drive worked because of a specific asymmetry, but the Eagleworks test showed that the result was the same whether or not the asymmetry is present: the Shawer driver does not work as proposed. They also tested the Yang result, and got a result... but the result was orders of magnitude different than the claimed Yang result. The net answer is that neither result was replicated.
Also, the test that was reported at a conference was not done in vacuum (although they only mentioned this detail in the "further work" section of their paper.) There has been a post to an internet forum saying that they have now tested it in vacuum, and gotten yet different results-- but internet forums are not scientific publications.
I'm in favor of good experimental work testing these ideas... but so far, it's way premature to suggest that the results have been replicated. They're not. The results are very, very small, and no two experiments seem to show the same thing.
Here's a Wired article from last year (which was the last anybody heard anything new) with some more discussion. (Sorry it's in Wired, which apparently everybody hates now, but that's where it is.) http://www.wired.com/2015/05/n...
Apple may or may not be able to remotely change this or that software, or alter this or that firmware, and reflash this or that ROM remotely-- but that is not what this specific issue is about. This specific issue is not about remote access.
Look, the FBI wrote a clear and specific statement of what they want Apple to do. It does not involve remote software updates. Period. Some other issue may be about remote software updates, but not this one.
There seem to be so many people say "well, what the FBI specifically, clearly, and directly asked for is that, but that's not how I would do it, I would do it this other way, and that would be really easy; so that must what the FBI actually wants even if it isn't what they said, and Apple must be lying, and I know that because if they did it my way it would be really really simple."
Anyone know if you can use a solar sail to get 'lift' as well as push?
"Lift" is defined relative to the direction of motion (it is the component of force on a wind perpendicular to the airflow). The force on a lightsail is defined relative to the incident direction of the beam.
If you were to define "drag" as force in the direction of the beam, and "lift" as force perpendicular to the beam, then, yes, you can have lift on the sail.
Nobody actually does define lift and drag on a lightsail that way, but if you think of the laser (or solar) beam as the "incident wind", then in fact it is exactly analogous to the lift and drag on a wing, in the Newtonian approximation.
Why try to make all that laser energy on Earth. The Sun has all we need. Just...
collumate the light into a beam to power your ships.
For quick reference, you can't collimate incoherent light into a beam that doesn't diverge-- the "collimated" beam of solar light will still fan out with a solid angle exactly equal to the solid angle of the incident solar light no matter what you do to it optically. If you get closer to the sun, the intensity is higher but the solid angle is higher; if you get farther from the sun the solid angle is narrower but the intensity is lower.
This is the "law of conservation of etendue" (which if you want to, you can derive from thermodynamics. Or from the Liouville theorem, take your pick.). That's a little bit obscure, I'm afraid, but if you just think of it as the brightness theorem, you've got the important part of it.
Slashdot Mirror
Some citations (other than Huff Post):
http://www.smh.com.au/interact...
http://www.dailymail.co.uk/new...
http://www.stuff.co.nz/busines...
http://www.stuff.co.nz/busines...
http://www.stuff.co.nz/busines...
Your Wikipedia page says you live in Ohio. Based on that the panels should pay for themselves in under a decade without any tax breaks. Do you have massive amounts of shade over your roof or something?
Yes, no, and yes.
Here's a map of solar availability in the United States:
http://cdn2.hubspot.net/hub/18...
I live in that green part, labelled "3.78 to 3.91 kW-hr/m^2/day". Not the absolutely worst part of America for solar availability (that would be the Northwest), but nowhere near the best. Compare this to the dark red part, labelled "6.65-6.78 kW-hr/m^2/day". So, right to start with, solar panels are going to produce about half as much power as they would produce in most of the southwest. Electricity costs in Ohio are about 11 cents per kilowatt hour, which is not incredibly low, but compared to say California, electricity would be 15 cents per kilowatt hour, or 18 cents per kilowatt hour in New York. (But the net-metering cost is about 6 cents per kilowatt hour, and our home electrical demand is low at noon most days, so net metering is probably the price to use).
Ten years is a very optimistic estimate for payback time. My quick calculation is that 11 years would be the rough payback time for the panels alone (purchased at a dollar a watt)-- but not the inverters and regulators, nor the installation costs, both of which will easily exceed a dollar a watt.
But, that might not be entirely a deal breaker if it were not for the main problem, which is that our lot is heavily shaded, and our house has neither a flat nor a south-facing roof.
Poor location for solar.
Tax breaks paid for 60% of my solar system. The only way it made economic sense.
Really? You must live in an extremely marginal area for the panels not to pay for themselves and start saving you money in under a decade, without tax breaks.
Exactly!
Economics of solar electrical production is all about location.
...People are gonna claim it's proof that renewables don't work.
As an electrical engineer that works for a company that installs solar systems, they don't work. Well, when you add the government subsidies, that we all pay for in taxes, they're only bad instead of horrible.
As an electrical engineer that works on solar systems, they do work. The economic payback, however, depends sensitively on location (and electricity price, which also depends on location.)
A real problem is that a lot of people want to install solar because they want to install solar, not because they are in a particularly good spot. For my northern-Ohio, tree-shaded house, not very good economics. In the best location, however (high solar availability; high daytime electrical prices), solar economics work very well.
As the real estate people say: the three most important parts about installing solar are: location, location, location.
It isn't that they don't work.
it's that they aren't as mature as other industries.
They ate mature, it is just one flipping business plan that failed. There are hunderts of other companies which do renewables.
Closer.
In case you haven't noticed, the energy market is in a major upheaval. SunEdison is in trouble because of their 2-billion dollar purchase of Vivint. Vivint is in trouble because their business model, selling residential panels on a fixed-price-for-electricity basis, is in trouble because the price of energy has been dropping, and their business has turned into the equivalent of subprime loans.
This particular failure isn't a technology maturity problem-- it's a problem of a business model being blindsided by external events.
(added to a problem of a company making a really bad purchase for a very large price)
The code was a post-hoc white-house mandated change, which provided no added security.
That's right-- if you set the code to all-zero's, and then prominently post instructions saying "the code is all zeros, do not change", it provides no added security.
Yep.
Yes, the article seems to be trying to manufacture outrage out of nothing.
It's a make-versus-buy decision. Industry does these decisions all the time. When your applications are unique, the decision tends to go toward "make your own;" when your application is something that many other people also do, the decision tends to go toward "buy the commercial product".
Buying off the shelf comes with hidden costs unless what is available exactly meets your need-- if you need to write a new contract for every change (and since you still haven't designed the system you're launching, there will be a lot of changes needed, as you keep refining requirements) every single change is a chance for the vendor to demand large dollar payments.
And the article's statement "why doesn't NASA just use what Space-X used" is absurd. Ten years ago, Space-X was an unknown company who had just launched their first rocket. Which failed. As did their next launch. And the one after that.
There is no software on the planet that is more scrutinised and more meticulously developed than software for spacecraft
There's at least one. Software for US nuclear weapons systems. I once watched a USAF nuclear safety audit over the course of a few years. I was thoroughly impressed with the quality of the work.
...and then, as an added assurance to make sure that nothing would slow down the ability to launch missiles, the code to launch missiles was set to all zeros, and never changed.
http://arstechnica.com/tech-po...
http://www.theguardian.com/wor...
http://foreignpolicy.com/2014/...
They are done by the private industry... The Cygnus spacecraft is owned by Orbital, not NASA (the article summary used here isn't very clear on that). NASA contracts ALL U.S. resupply missions out to Orbital ATK and SpaceX.
So far.
But they just added Sierra Nevada to the list of commercial resupply providers:
https://www.nasaspaceflight.co...
http://www.sncorp.com/AboutUs/...
I disagree: ***selling price*** of PV panels is coming down. However, the energy cost of creating solar panels isn't.
Of course it is. They wouldn't be cheap if it wasn't. Silicon manufacture is getting much more efficient than it was.
The rare earths are, not surprisingly, rare, and both mining and refining them have not changed much.
Silicon solar panels-- the ones that are cheap-- don't use rare earths. You're thinking of the thin films. But the rare materials used in thin film solar cells are literally micron thick layers (which is why they'r cheap)-- and in any case, the panels that have become extremely low in price lately are silicon, not thin films.
(Also, rare earths aren't actually rare).
...As a longer-term issue, is the declining performance of PV panels over time.
You mean degradation? Hasn't been a problem for silicon panels.
You'd need more than 1½ million to make a sucessfull GP Airship these days.
For a full-sized airship, maybe. But this request is only for something to carry 10 kilograms; not all that much more than the high-altitude balloons that high school students keep sending up to "the edge of space".* If you're clever, I wouldn't be surprised if you could probably do it for a few tens of thousand dollars.
--
(And, boy, am I glad that slashdot got tired and stopped posting those "students send random object to the edge of space" stories.)
Your numbers are low. However, the more egregious statement I'll take exception to is this one:
We have no evidence that a planet 8c warmer than it is now would be incompatible with human life.
No, 8 degrees C is not "incompatible with human life"!!
That's a strawman argument. Eight degrees C of warming would be a catastrophe in pretty much every way-- people are currently arguing about how bad two degrees of warming would be-- but if you are hearing people say that it would be "incompatible with human life," figure out who those people are and stop listening to them.
With no new exploration, oil production would eventually decline... but not "within 2-3 years, 5 years tops". It currently takes typically ten years to go from discovery to production! Oil exploration now won't have any effect whatsoever for ten years (although if the incentive were high, it could be shorter).
In any case, proved reserves (the oil that we already know is there, no exploration needed) are currently estimated at 1656 billion barrels, while world usage is 96 billion barrels per year. So with no new oil fields developed at all, it would take 17 years for production to stop.
data:
Reserves: https://www.eia.gov/cfapps/ipd...
world consumption: https://www.iea.org/aboutus/fa...
People often make the mistake of assuming that the old monopolies were created by evilness and killing. Really when you look at it, every one of them made huge advance in technology and innovation. They did it by being better than the competition.
That's true for some monopolies, but not Standard Oil. John D. Rockefeller put Standard Oil together by driving competitors out of business and buying them up. The main "innovation" he pioneered was that of making deals with railroads to ship his product at rates not offered to his competitors.
But, to be fair, collusion wasn't illegal until after the Sherman act, and wasn't nearly as vicious as some of the other shady business practices going on in other industries.
I don't think the gp was referring to the evidence of human activities being a major cause so much as the overwhelming evidence that we're not going to do more than talk about reducing those activities.
Fair enough, you can read it that way.
I'm a techno-optimist; there are other energy technologies out there, and we can chose the ones we want to use.
I get the whole Greenwashing that happened there, but seriously - no matter the {whatever} you hold concerning AGW, three things are constant:
1) Barring thermonuclear warfare or a wayward asteroid, global climate will change no matter what we do (or don't do),
Yes to the first part: Yes, human sources of climate change are not the only source of climate change; the other sources are still there.
and will continue on its current trend.
...and no to the second. There is very very good evidence that the current trend is due to human activities. There simply are no natural sources of change that have this magnitude of effect this quickly that we would not be able to see. (Remember, we do measure solar output. One thing we know: the current trend is not due to solar variability. If we stop these activities, the current trend will stop. (Although it will take a while to do so.)
2) Barring the invention of commercially viable electrical generation from fusion (or some similar massive source of energy)
You just said "unless there are other sources of energy, we have to use the current sources of energy." That statement is a tautology.
OK, so it is desirable to develop new sources of energy if we don't want to use the current sources. Fair enough. Let's get to it.
...
Plastics (made from petroleum) are the backbone of technology and civilization at this time - no viable replacement has yet arisen that doesn't require even more damage to the ecosystems, or can last nearly as long when the requirements call for longevity/durability. (e.g. yeah you can make plastic from corn, but it'll be much shorter-lived and will require massive up-scaling in agriculture, which presents problems of its own.)
1. Plastics account for so small an amount of the hydrocarbon usage that you can't even notice it on the pie chart. ...and plastic isn't the problem, since turning fossil hydrocarbons into plastics puts the carbon into the plastic, not into the atmosphere.
2.
I can't figure out what's going on here. The link goes to https://science.slashdot.org/s...
Why does the link on a slashdot story go to slashdot stories? Isn't there an original somewhere to link to?
Most places are not religious institutions.
A number of the ones on the list are, though not all.
From the shorter version ( http://www.popecenter.org/comm... ) the ten most oppressive colleges were:
1. Mount St. Mary’s University in Maryland ("recently thrown into turmoil by president Simon Newman’s firing of two faculty members who criticized his idea that the school should reduce its freshman class by “drowning some of the bunnies” (i.e., culling out academically weak students).")
2. Northwestern University,
3. Louisiana State
4. University of California—San Diego
5. Saint Mary’s University in Minnesota
6. University of Oklahoma
7. Marquette University
8. Colorado College
9. University of Tulsa,
10. Wesleyan University
So, the religious universities on that list are Mount St. Mary’s University, Saint Mary’s University, Marquette University, and Wesleyan University. Four out of ten. Doesn't seem too bad, but only 20% of the US Universities are religiously affiliated, so it's about twice what you would expect.
The article (and summary headline) is not justified by the article.
The summary headline says "One of the worst disasters in U.S. history". The first paragraph of the article says "one of the largest environmental disasters in US history." Big difference.
But even that is not ever discussed in the text of the article; the article never discusses the environmental consequences or whether they are "a disaster." It does give a number, 97,100 metric tons of methane emitted--- but that's trivial. World methane emissions are hundreds of gigatons. A hundred kilotons emitted in a leak is irrelevant. http://cdiac.ornl.gov/trends/m...
Junk.
No candidate can win the convention on the first ballot unless they have a majority in 8 states.
A majority of delegates. This is not the same as a majority of the primary vote! In winner-take-all states, you just need a plurality of the primary vote to win all the delegates.
The roll call of states' delegates continues until a candidate emerges. This is not necessarily on the first round!
None of the candidates are currently poised to do this.
Only four states have even had primaries yet! And half of those were caucuses.
...
It's very possible for any candidate to lose a plurality but win the nomination.
Don't confuse the voting of the delegates with the popular vote. A candidate can lose a plurality of the popular vote, but a proposed candidate needs not merely a plurality, but a majority of delegates to win the party candidacy. And if no proposed candidate gets a majority on the first round, the convention keeps on repeating the votes of delegates until one does.
Non-technical users should use a Mac, as it simply works.
Since I use a mac, I really really wish that were true... but it's not.
Well, the problem is that the cost to buy (including maintenance) a Mac is a lot more expensive than to buy a PC... $500 may be little to you, but it could be a much higher value to many others...
Yes... but no. The purchase cost of a computer really is the least important cost. If it is frustrating to use and wastes your time, saving a few hundred dollars on purchase was a poor bargain.
Depends on what you want to do, of course. Either option has advantages for some things. Windows machines do have some bargain basement units... but you may have to make up that cost in problems. Or you may not. Depends on what you need it for.
It is unlikely to be real but your claim that the error level is higher than the measured effect is AFAIK wrong. We also have replication in 3 separate places with separate groups of people using different hardware which reduces some error sources.
No, sorry, but I will challenge that last statement. There are three separate groups which have produced different results which are inconsistent with each other.
Most recently, the NASA Johnson "Eagleworks" group has tried to replicate both the EM drive proposed by Shawer and a result on a similar concept in China claimed by Yang-- and falsified both of these results. The EM drive proposal stated that the purported drive worked because of a specific asymmetry, but the Eagleworks test showed that the result was the same whether or not the asymmetry is present: the Shawer driver does not work as proposed. They also tested the Yang result, and got a result... but the result was orders of magnitude different than the claimed Yang result. The net answer is that neither result was replicated.
Also, the test that was reported at a conference was not done in vacuum (although they only mentioned this detail in the "further work" section of their paper.) There has been a post to an internet forum saying that they have now tested it in vacuum, and gotten yet different results-- but internet forums are not scientific publications.
I'm in favor of good experimental work testing these ideas... but so far, it's way premature to suggest that the results have been replicated. They're not. The results are very, very small, and no two experiments seem to show the same thing.
Here's a Wired article from last year (which was the last anybody heard anything new) with some more discussion. (Sorry it's in Wired, which apparently everybody hates now, but that's where it is.) http://www.wired.com/2015/05/n...
No, that is not what this is about.
Really.
Apple may or may not be able to remotely change this or that software, or alter this or that firmware, and reflash this or that ROM remotely-- but that is not what this specific issue is about. This specific issue is not about remote access.
Look, the FBI wrote a clear and specific statement of what they want Apple to do. It does not involve remote software updates. Period. Some other issue may be about remote software updates, but not this one.
There seem to be so many people say "well, what the FBI specifically, clearly, and directly asked for is that, but that's not how I would do it, I would do it this other way, and that would be really easy; so that must what the FBI actually wants even if it isn't what they said, and Apple must be lying, and I know that because if they did it my way it would be really really simple."
Anyone know if you can use a solar sail to get 'lift' as well as push?
"Lift" is defined relative to the direction of motion (it is the component of force on a wind perpendicular to the airflow). The force on a lightsail is defined relative to the incident direction of the beam.
If you were to define "drag" as force in the direction of the beam, and "lift" as force perpendicular to the beam, then, yes, you can have lift on the sail.
Nobody actually does define lift and drag on a lightsail that way, but if you think of the laser (or solar) beam as the "incident wind", then in fact it is exactly analogous to the lift and drag on a wing, in the Newtonian approximation.
Why try to make all that laser energy on Earth. The Sun has all we need. Just...
collumate the light into a beam to power your ships.
For quick reference, you can't collimate incoherent light into a beam that doesn't diverge-- the "collimated" beam of solar light will still fan out with a solid angle exactly equal to the solid angle of the incident solar light no matter what you do to it optically. If you get closer to the sun, the intensity is higher but the solid angle is higher; if you get farther from the sun the solid angle is narrower but the intensity is lower.
This is the "law of conservation of etendue" (which if you want to, you can derive from thermodynamics. Or from the Liouville theorem, take your pick.). That's a little bit obscure, I'm afraid, but if you just think of it as the brightness theorem, you've got the important part of it.
http://eckop.com/illumination/...