Saudi Arabia is not poor, and by that I mean the people are not poor. The government spreads the oil money around a fair bit. They import people to be poor, er, I mean to do the work the Saudis don't want to.
That's why I only said it provides a limit. The Sun hasn't been around much longer than it takes to create the observed amount of He. If it started with an anomalously large amount then it could be younger. The original poster had a good limit on how much younger.
A void won't transmit any heat at all, unless you're pushing it out.
What? How do you think the Sun's heat gets to Earth through the void? The only "pushing" the Sun is doing is being hotter than the Earth, just as the James Webb telescope is hotter than deep space, which if you're far enough out to get beyond local effects is at about 3 K.
I was explicitly talking about not being in view of the Sun, because of a sunshield. You are naturally radiating away to a very cold sink. Without exposure to the Sun it will get very cold, although at the Earth's distance from the Sun I expect there is some minor back radiation from the Sun's extended atmosphere, plus some conduction from those thin gases. Anyhow, the James Webb is supposed to be at 40 K, which I consider cold, even if perhaps not as cold as SOFIA will be.
Upper bound from the ratio of U235 and U238. In supernovae these are produced in roughly equal quantities and each has a half life measured in billions of years.
How do you know that U235 and U238 are produced in roughly equal abundance? This is not generally true of isotopes of other elements. I'm a little doubtful that the production rates can be derived accurately enough from theory to produce a useful age limit.
The amount of helium in the Sun provides a limit on the total energy it has radiated, assuming we're right about how fusion works. Combine that with the observed total radiation of the Sun and you can get what I think is a better crude limit on the Sun's age. You can do better by dating certain meteorites, which appear to have been created at about the same time as the Sun.
While "Big Government" is willing to either give away (like for the EV1 projects) or loan (recent bailout) millions or billions of dollars to the big automakers, they seemed to have no real interest in helping Tesla...
What? You think the $465 million government loan Tesla got doesn't count as help?
The micro and smaller prefixes weren't officially part of the metric system until 1960, although micro was in wide use by engineers before that. When I was very young millimicrofarad was a common unit.
Tesla uses LiCo batteries, which are relatively slow. The Nissan Leaf is capable of an 80% charge in 30 minutes using faster LiMn batteries. A 15 minute charge is possible with even faster batteries, but by that point it's starting to get expensive.
Only it isn't cheap, these are some of the most expensive minerals on the planet.
Not cheap, but not among the most expensive. Seems to run from about $75 to $500 per kg of the refined metal, depending on exactly which rare earth you want.
Rare earth metals aren't "insanely expensive". They generally cost less than silver, some much less. Their use in solar cells seems mainly to be for frequency shifting of light.
I suspect it would have been faster to look up a correct algorithm and implement it than think up this hack. Who ever came up with this was just incompetent.
Most are probably just a placebo, but not all. There have been serious safety concerns over some 4X or 5X dilutions of quite toxic ingredients on the market.
Slashdot Mirror
Is Galina Perelman or Grishna Perelman someone I should know?
Saudi Arabia is not poor, and by that I mean the people are not poor. The government spreads the oil money around a fair bit. They import people to be poor, er, I mean to do the work the Saudis don't want to.
That's why I only said it provides a limit. The Sun hasn't been around much longer than it takes to create the observed amount of He. If it started with an anomalously large amount then it could be younger. The original poster had a good limit on how much younger.
What? How do you think the Sun's heat gets to Earth through the void? The only "pushing" the Sun is doing is being hotter than the Earth, just as the James Webb telescope is hotter than deep space, which if you're far enough out to get beyond local effects is at about 3 K.
I was explicitly talking about not being in view of the Sun, because of a sunshield. You are naturally radiating away to a very cold sink. Without exposure to the Sun it will get very cold, although at the Earth's distance from the Sun I expect there is some minor back radiation from the Sun's extended atmosphere, plus some conduction from those thin gases. Anyhow, the James Webb is supposed to be at 40 K, which I consider cold, even if perhaps not as cold as SOFIA will be.
It's pretty cold in space. The James Webb telescope will operate at 40 K with just a sun shield.
How do you know that U235 and U238 are produced in roughly equal abundance? This is not generally true of isotopes of other elements. I'm a little doubtful that the production rates can be derived accurately enough from theory to produce a useful age limit.
The amount of helium in the Sun provides a limit on the total energy it has radiated, assuming we're right about how fusion works. Combine that with the observed total radiation of the Sun and you can get what I think is a better crude limit on the Sun's age. You can do better by dating certain meteorites, which appear to have been created at about the same time as the Sun.
Three half lives sounded too small to me, so I checked Wikipedia where it is claimed that a one mg sample can be dated back to about 60,000 years.
What? You think the $465 million government loan Tesla got doesn't count as help?
This isn't about AGW. It's about it being cheaper to make customers uncomfortably hot than to provide adequate power.
Sorry to undo the moderation of my AC friend, but The Game of Rat and Dragon is available from Project Gutenberg!
The micro and smaller prefixes weren't officially part of the metric system until 1960, although micro was in wide use by engineers before that. When I was very young millimicrofarad was a common unit.
It wasn't Faffe who switched them, and it was milli for mega. 4mW = 4 milliwatts, the correct number was 4MW.
Scorched means it's still edible. If it was burned we'd have to throw it away.
Wait, did you write coast? Sorry, I read that as toast. Never mind.
It's the first story dated April first, and it's a slashvertisement. Maybe that will be the theme.
I don't think so.
Flammability Concentration Limits
Hydrogen 4% to 75%
Gasoline 1.4% to 7.6%
The auto-ignition temperature is indeed higher for hydrogen, 500 Celsius compared to 280 for gasoline. I had not known that.
Tesla uses LiCo batteries, which are relatively slow. The Nissan Leaf is capable of an 80% charge in 30 minutes using faster LiMn batteries. A 15 minute charge is possible with even faster batteries, but by that point it's starting to get expensive.
Not cheap, but not among the most expensive. Seems to run from about $75 to $500 per kg of the refined metal, depending on exactly which rare earth you want.
But have you ever tried to do this on a Chinese train?
Well, that was my initial thought, but they will probably offer European class service too.
One nice thing about kelvins is they don't need degrees. That is, it's easier to type that the temperature went up 1 K than that it went 1 degree C.
A stable nucleus with strange quarks has been theorized. It is called a strangelet.
Rare earth metals aren't "insanely expensive". They generally cost less than silver, some much less. Their use in solar cells seems mainly to be for frequency shifting of light.
I suspect it would have been faster to look up a correct algorithm and implement it than think up this hack. Who ever came up with this was just incompetent.
Google suggests you might be in The Quill Cabin Boys.
Most are probably just a placebo, but not all. There have been serious safety concerns over some 4X or 5X dilutions of quite toxic ingredients on the market.