OK, I'll start off by saying that I have now, and TTBOMK have always had, pretty shit hearing. Friends who have finally comprehended that I really mean it when I say "I can't hear what you're talking about", have asked me if I didn't try to get my hearing repaired when I realised there was a problem, and then continued to look puzzled when I say that I don't have a hearing problem, I just hear different things to them. Their experience of "hearing" may be different to mine, but I don't have any reason to believe that their hearing is "better" in any important meaning.
So I'm a bit surprised to find myself in a position to FP a musical story.
The summary is, as is a stereotypical Slashdot response, shit. But then the Kickstarter website linked to is utterly uninformative.
As far as I know (and I'll reiterate the above point - this is an entirely intellectual effort ; there are reports of interesting physical and mathematical characteristics in the Goldberg variations). What the hell they sound like, or whether they're actually worth listening to, I neither know nor care. That there are apparently other people interested suggests that they may actually be interesting. "Meh." I'll leave it to someone who gives a shit to correct the links.
But for a story in "news for nerds, stuff that matters" to not even make an attempt to explain this allegedly interesting history... major fail. Maybe I shouldn't be surprised that this allegedly interesting background is taken for granted, but it sounds to me like the tyranny of the musically-interested over the musically-deturdate.
Crap summary, of a seemingly crap article, which may actually have an interesting subject. Whoever originally posted it needs to revise their understanding of what interests people on this site.
Speak for your own government's system, but most theories of prison I've heard combine elements of punishment, prevention (by having people isolated from the society they've harmed in the past ; hence you're not allowed to continue running your crack-dealership from a mobile phone in the Big House), and most cost-effectively, rehabilitation (so they don't want to do [whatever] again).
Of course, if you've got private organisations or individuals profiting from the incarceration business, then their interests lie precisely away from having an effective penal system. It their treatment of prisoners were effective at stopping crime, they'd put themselves out of business.
As long as they are running, they'll make the day either longer or shorter.
Not quite. While your flywheel(s) is(are) being spun-up(down) they would speed up or slow down the day, the sign of day-change depending on the orientation of the flywheel axis w.r.t. the Earth's rotation axis.
Hmmm - flywheels with an axis orthogonal to the Earth's spin axis wouldn't have this effect. Or to be more precise, it would have COS(inclination angle) effect.
So are we agreed then that it's not the absolute amount of radioactivity that matters it's the concentration of that material?
No, because that's not the claim that "Nick Ives (317)" made. His claim was that burning coal produced radioactivity in the coal ash ; I sarcastically rebutted that what he's actually describing is concentrating radioactivity by removing non-radioactive elements from your sample.
At no point did I make any claim that coal, bananas, radioactivity, or ash are safe.
Great we can now dispose of nuclear waste by burying it at sea and letting the water currents disperse the products into harmlessly low concentrations.
Yeah, just off the San Diego, California coast would sound fine to me. Or just pour it into the sewers and let the ants/ rats/ homeless feed on it.
More seriously... define "harmless concentration". Ah, now we get into some meat : do you follow the linear model for (low)dose-response relations, or do you think that even arbitrarily low doses still have an effect on radiation damage levels?
Me, I'm pragmatic - there is no reliable evidence that the inhabitants of (naturally) high-radioactivity cities like my residence in Aberdeen have a significantly (even at the 10% level) higher cancer rate than other lower radiation cities. So, reducing radiation to levels comparable to background levels in such a city is going to be as near as wiping out the radiation problem as you need go on a public health basis.
It's the old idea that you don't need to worry as much about highly radioactive materials because they have short half lives and are soon safe. Likewise you don't have to worry about materials with long half lives because they're not very radioactive.
Well, on geological timescale, you're quite right there. But people tend to worry about shorter timescales. I never had any concerns about keeping my vial of undepleted uranium in the home-brew vat - to freak the hippies and just possibly give the bugs a chance of higher alcohol tolerance. I wouldn't boil my radium-painted watch hands in the teapot though.
especially the dangers of being exposed to it are a complex subject
The dangers of exposure are quite simple - death in a number of different and unpleasant ways ; people's reactions to it are complex, for reasons in your next point.
I just wish i understood why it seems to be such a polarizing topic that people seem to be either rabidly for or against.
There's a well-understood list of things that hit people's fear/disgust buttons. Invisible dangers are scarier than visible ones (viz paedophiles lurking near schools against children being run down by other children's parents when being picked up from school). Disfiguring wasting illnesses are scarier than dieing young and staying pretty (so, cancers are scarier than choking on your drunken vomit). Having control feels better than giving control to faceless bureaucrats (so, dieing in a car crash on the way to the airport is perceived a less important risk than that of dieing in a hijacked plane). This is not an exhaustive list. But radiation poisoning ticks a lot of general-purpose "dread" and "disgust"buttons for many many people. Hence fear of radiation becomes a really emotive topic.
... And I've got to take the wife to college now, so I'll return to this later.
Running cars on nukes will require lots of new reactors, a complete overhaul of the grid, better battery technology, and
... a fleet of electric trolley buses will have most of the benefits without all of those problems.
Oh, you want the future to be JUST THE SAME as today, ONLY NOT A BIT DIFFERENT.
If you chose to live somewhere that you can't operate without a car, that's fine. When you can't fuel cars, then you'll probably find yourself bankrupt because you won't be able to sell the house to anyone anyway. No problems!
"Mummy, dinner keeps asking if I'd like to take his place in the pot!" (mine)
"Tonight's menu : Roast leg of insurance salesman."
"I won't let another man past my lips"
"You used to be a regular anthropopaguy"
"If the JuJu had meant us not to eat people / He wouldn't have made us of meat!"
"You might as well say 'Don't fight people' ! " [howls of derisive laughter from rest of tribe] (all Flanders + Swann, 1957)
"Kuru, anyone?"
First bear : "Hunter leg?" ; Second bear : "No thanks, I caught tricninosis from one of those once."
Not to mention the tidal forces make the Earth's surface flex about 1ft (as evidenced by my GPS) per day.
I find that very hard to believe. If there is any flexing of the Earth's surface, I don't believe it to be more than a fraction of a millimeter (unless shown convincing evidence to the contrary).
"Earth tides" have been perfectly familiar to surveyors and geologists for a long, long time. Their detection was barely new news when I first started studying geology in the mid-70s.
As I recall, the moon itself protects the planet from some amount of meteors and asteroids. Might reduce the chances of life getting wiped out too early.
No astronomer I've heard of has claimed that. Please cite your sources.
First approximation - the Moon is 1/4 of the Earth's diameter and 1/16 of it's area ; therefore the Earth gets hit by around 16 times as many meteors as the Moon.
Second approximation (mass matters) : the Earth is 81 times the mass of the Moon, so gets hit by 81 times the number of meteors as the Moon.
Third try : the Moon is ahead of the Earth in it's orbital motion around the Sun, uhh, half the time... so the Earth gets hit... nope, this one isn't going to work either.
The Moon is a singularly ineffective guardian.
The tides, within reason, are a reasonable speculation. But of course, the Moon isn't the only source of tides ; the Sun produces tides too, but smaller.
Maybe today there is "only" a 2.21 percent difference,
The difference is a factor of 2.21. viz, if at one location the solar contribution to the tides is 1m, then the corresponding lunar contribution to the tide would be 2.21m and the total tide height 3.21m. (Actually, the ratio is between the forces, not the resultant tide heights ; the tide height is also influenced by all sorts of complexities including resonance between 12h tides (solar) and 12h25m approx (lunar) tides against the seabed shape at your location.)
Back up the clock a few billion years, and the moon is much closer to us, and the tidal forces are massive, both on the seas, and on the crustal surface.
The tidal forces are much higher, but because the tidal forces are higher, then the forces exerted on the Moon (and on the Earth) are also higher, meaning that the situation moves to a greater Earth-Moon distance faster the closer they are. So the period of really high tides would have occurred very soon after the Moon's formation, and not have lasted very long as the Moon acquired angular momentum from the Earth.
During the period immediately after the Giant Impact which formed the Moon (most likely ; there are no credible alternatives in the field), the surface of the Earth would have been pretty close to completely molten. Which is not very conducive to organic chemistry happening in liquid water.
Actually, when the surface cooled sufficiently for (cometary? probably) water to condense and rain out to form the first oceans, that dense fluid incomplete skin would have greatly improved the transfer of energy and angular momentum between Earth and Moon as the rotation of the Earth would have dragged the "tidal bulge" ahead of the sub-lunar point, applying an increased torque to the Moon (compared to before the oceans started to form). It would have taken some time for water temperatures to drop to the point at which life-relevant chemistry was common.
So, yes, during the OOL period, the tides would have been higher, and the Earth's spin faster. But it's not as huge a difference as you're concerned by because the period of really really high tides predated the period relevant for OOL studies.
The details of what happened in this period is still under vigorous debate.
what is the probability that the molecular structures [of life on a putative distant planet] are going to be mirror images? A reasonable guess is 50/50.
Reasonable.
But I can think of a couple of reasons it could be less likely. Maybe there are laws of physics that would prevent life from working the same if all the molecules were mirrored.
Maybe. List them.
My memory tells me that there is only one physics interaction that fundamentally distinguishes between "left" and "right", which is the weak nuclear force. In practice, this was first demonstrated in 1957 (C. S. Wu, E. Ambler, R. W. Hayward, D. D. Hoppes, and R. P. Hudson, Experimental test of parity conservation in beta decay, Phys. Rev. 105, 1413-1415) in decay of Cobalt-90.
And if it is true that life came from space, then maybe life on multiple planets could have originated from one source.
Apart from the philosophical discomfort of running away from the problem of origin of life (if we got it from $THERE$, where did $THERE$ get it from?), there are reasonably good reasons for thinking that life, as we know it, could not have originated all that much earlier than it did on Earth because earlier generations of stars than the Sun's did not have sufficient "metals" (matter that isn't hydrogen or helium), which accumulate in successive generations of stars. (That's not to say that life couldn't have originated on a planet that formed 7.5 billion years ago compared to our 4.5 billion years ago ; but 10 billion years ago is probably stretching it.) Also the problem of how to get the life from $THERE$ to $HERE$ is non-trivial. Much more non-trivial than panspermia, as this idea is often called, enthusiasts like to think about.
There's a softer version of panspermia where compounds that become important for generating life on a planet are generated in space by cooking comets with ultraviolet light and things like that. Which is not impossible, but to most geologists, biologists and chemists studying OOL (Origin Of Life), it's unnecessary. Sufficient quantities of sufficiently interesting compounds can be formed on the early Earth without needing to invoke "soft" panspermia.
Another question is how you would find out if it was actually mirrored. Imagine we somehow got a radio link with another civilisation,
The parity-violation sub-atomic particle interaction mentioned above should allow discrimination between "right" and "left" remotely. ASSUMING that the other end of the communications link isn't also antimatter. Which makes the question a touch important before the first date. I think we'd have noticed if they were time-inverted compared to us. EDIT "I like to think we'd..."
I would think that creationists differ on the opinion
Who, apart from someone child-abusive enough to send someone else's children to creationism-indoctrinating schools, gives a shit what creationists "think"?
OK - Dawkins and such people who have to deal with the results of creationist assaults on thinking care because they have to, but even they sound revolted by having to deal with the living arguments for retroactive birth control.
So. What. Unless we somehow rewrite the laws of physics we will never communicate or even know of them before our star burns out.
Depending on your opinions on the precise conditions inside the sun and a few other factors, the Sun has between a couple of billion years and about 5 billion years before it leaves the main sequence, and a fraction of a billion years after that until it is unable to continue producing energy (note that it will continue to radiate energy for much longer. Say it takes 2 billion years. Let's also assume that the speed of light really is a speed limit.
In that time, our ambassadors could round trip to a civilisation on the other side of the galaxy, at a top speed of 0.1c, a thousand times.
Here's a list I composed because I'm bored: Kepler's Laws - 59 words. Balfour Declaration - 67 words. Munich Agreement - 520 words. First Geneva convention - 8628 words. Hammurabi's Code of Laws - 9502 words. Magna Carta - 14416 words.
At the (literally) incredible communication rate of one word per round trip, you'd be able to communicate somewhere between a Munich Sell-out and a Geneva Convention. I do not for one second believe that that communication rate could not be bettered.
How long would it take us to set up that communications link... well, at a top speed of 0.1c, there's around a million years of travelling time there. Let's allow as much preparation time as travel time, for 2 million years total. Archaeologists are debating whether our ancestors had full control of fire 2 million years ago. That's around 100,000 generations, assuming no huge biological changes (implausible with the pace of medical advance these days).
You're unduly pessimistic.
Note that I've avoided the use of unobtanium and the dilithium crystals remain firmly in the holodeck. Essentially I've posited your descendants becoming travellers on "generation ships", then travelling the galaxy ; the absence of directed communications is implausible, but even in it's absence there's a lot of things that could be done. Once we stop hugging the planet's surface.
By contrast, if we stay hugged onto the planet's surface, then we're likely to get hit, badly, by an asteroid well before the million year mark.
The trouble with astronomical timescales is that they're geologically comfortable.
Dryeo has already corrected your mistake about tides.
2) A moon stabilizes the orbital inclination of the planet. A planet without a moon is much more likely to do a gyroscopic tumble.
I know that it's Slashdot and there is a joke about never reading the fucking article. But the site also has a "news for nerds" slogan, which rather implies that you'll be held to nerd standards of understanding and application, not the knuckle-dragging idiocies of the general population.
The fucking article exactly disagrees with this second point of yours.
Oh, you just want to go with your idee fixee prejudices, not actually learn anything new? Well, if that's the case, please do let the door hit you on the arse as you leave.
I was trying to think of a way to work Uranus into this, but failed.
Anything that mentions the Giant Impact Hypothesis has an automatic link to Uranus : the most credible explanation (that I've hear) for a high-obliquity spin axis on a planet is a large impact late in it's formation. Earth-Moon (23.5deg) ; Uranus (98deg) ; Pluto-Charon-Hydra-Nix (between 102 and 126deg, Icarus vol. 55, Aug. 1983, p. 231-235.) ; Venus (close to 180deg) are all thought to have had giant impacts; though only two of the examples generated giant moons from their giant impacts.
(This isn't as strongly supported as the Giant Impact Hypothesis for generating the Earth-Moon system, but it is the most popular position.)
The URL says it all. Burning stuff makes radioactive waste.
[SIGH]
No.
Burning coal that has a few ppm of natural radioactivity in it (it is well established that organic matter in a geological context concentrates uranium and thorium from circulating ground water - this is why my clients sometimes pay for use of spectral gamma ray detectors to differentiate between a clay's potassium radiation and the U+Th radiation associated with organic matter in that clay), will leave the radioactive material concentrate into the non-volatile ash, as you've just removed 90%+ of the mass of your sample as CO2.
Take two bananas off the shelf at the grocers and measure their radioactivity - so many decays per kilo per second. Eat one banana (either one, it doesn't matter which), wait a few hours for it's components to be distributed around your body, then measure the radioactivity of the banana distributed through around 100 times as much of not-very-radioactive you ; the reading in decays per kilo per second will be lower.
Take the other banana, stick it in an incineration tube passing oxygen over it, heat it to dry it out and burn off the carbon (if you want to, you can run the CO2 through a mass spectrometer and get a C14 date for it. Or you could just read the label on the box.) and leave the non-volatile elements behind. Measure the radioactivity of the few grammes of ash - it will have a high radioactivity expressed in decays per kilo per second.
Voila - you have just changed the radioactivity of two otherwise undistinguished batches of potassium atoms, using chemical processes alone. Or have you just changed the dilution of the radioactive material?
(I'm not going to repeat the infant-school text book assertion that you cannot affect rates of radioactive decay by chemical processes. But I'll leave it as an exercise for the reader to find out what effects you can have and why. They don't apply in the coal ash case.)
Many populations, for instance those in Europe, have evolved a high degree of tolerance to it.
I think that needs the full reasoning stated.
... Because those populations have many generations had cow-milk-tolerating populations having more grandchildren than the cow-milk-non-tolerating populations, because cow-milk is a significant source of nutrition for those populations.
Most of the fears of GM foods are unreasonable and just bizarre if you've passed 6th grade science class.
Errr, you've just lost something like 90% of your potential audience there. (What is "6th grade" by the way? In terms of age-of-pupil-when-normally-taught.)
Sad, but probably close to true.
Am I going to have to get my bivouac gear out again and the night-vision binoculars? For the war on science.
In the days before LED lamps, the Fx2 (two 'F' cells, packaged) was very popular in the UK. Let the sniggering begin.
They're still available. Then someone thought to try making a triple pack (inspired by Eccentrica Gallumbits) and later a pentuple pack.
(Actually, they've stopped selling those now, due to the discontinued consumer supply of NiCad cells, not because the design is "wrong" per se. They use D-cells instead. BFD.)
Around a decade ago there was a condensed-matter physicist (IIRC, he worked in magnetic field detection by lasers, or something ; it was vaguely related to petrophysics stuff I had to understand) who provided the ICR with impressive-looking mathematical models that he purported provided some sort of model for a Young-Earth-Creationist universe with the appearance of an Old-Earth-Creationist universe (i.e., our universe). Which sounded great for them. Until someone with adequate maths waded through the papers and pointed out the errors.
Which I'm sure did the guy's career no good at all.
I'm trying to remember the guy's name now... it'll come back to me.
Sounds almost idyllic. Shame you posted the location to Slashdot - either the powers-that-be will descend upon you like vengeful Furies for daring to be happy, or Slashdot readers will descend upon you like... well, you get the message.
It is my understanding that the lunar-formation impact has to occur after the Earth was already wet, so hydrous geology in the lunar mantle implies the impact hypothesis needs to be revisited.
The disruption of the Giant Impact (I think it's big enough to deserve capitals ; in the Earth-Moon system, there is only one such event, though it seems more common in the solar system as a whole) was such as to vaporise or finely disperse a large proportion of the volume of the proto-Earth - a quarter or so. That went up into short lived orbit, and would have degassed quite effectively, and several percent of it stayed up to form the Moon while the rest re-impacted over a few years. 750ppm is a lot of water to remain after that, and to survive the heat of re-accumulation too.
This is quite a problem.
The easiest way I can see for getting around it is to have the Giant Impact happening during the period of the "cometary" impacts that delivered water to Earth.
The Bad Astronomer says, in his TFA:
Iâ(TM)ll note that in another study, using similar samples from Apollo 15, these same authors found that the ratio of deuterium to hydrogen in the lunar samples was indistinguishable from that of terrestrial water! That implies very strongly (to me at least) that the water on the Moon came from the Earth, or they both came from the same source. The D to H ratio changes across the solar system, meaning conditions in the early stages of the planetsâ(TM) formations were different depending on their distance from the Sun.
That could go with the Giant Impact happening during the "cometary wetting" phase, as long as the source of the comets accreting to proto-Earth and proto-Moon was consistent for both bodies. Which given that they'd have been sampling the flux of "comets" (wet asteroids, whatever) across the Earth-Moon-system's orbit, isn't a terribly difficult constraint, I'd think.
I think it's also important to say that I think that you don't have to have all "comets" from (say) a 2.5 to 3.5 AU snowline ; you could probably achieve the same effect with (say) 40% from 2.5 to 3.0AU and 60% from 4.0 to 4.5AU (the numbers are illustrative, not meant to assert any particular model). So if you've got a reasonably uniform flux of objects cycling around in the developing solar system, then getting a consistent mix of objects to accrete onto two objects in overlapping orbits isn't a particularly demanding constraint.
one of the thefts mentioned in the article was the theft of a safe from a lab.
We had that happen - sort-of - once. Had a safe in the office weighing around a half-ton, which the burglars dragged out into the middle of the workshop and evidently spent a lot of effort and time trying to chisel and hack and hammer their way into, to no avail. They eventually left with a few thousand pounds worth of laptops, probably when the early-start company on that street had people arrive for work.
Of course, the safe wasn't even locked - just "on the latch". We'd never had a key for it since finding it when we moved in, and it required the key to lock it. The developer used it as a place to keep the incremental backups in when he left each evening, as it was probably fairly fire and sprinkler resistant.
Slashdot Mirror
So I'm a bit surprised to find myself in a position to FP a musical story.
The summary is, as is a stereotypical Slashdot response, shit. But then the Kickstarter website linked to is utterly uninformative.
As far as I know (and I'll reiterate the above point - this is an entirely intellectual effort ; there are reports of interesting physical and mathematical characteristics in the Goldberg variations). What the hell they sound like, or whether they're actually worth listening to, I neither know nor care. That there are apparently other people interested suggests that they may actually be interesting. "Meh." I'll leave it to someone who gives a shit to correct the links.
But for a story in "news for nerds, stuff that matters" to not even make an attempt to explain this allegedly interesting history ... major fail. Maybe I shouldn't be surprised that this allegedly interesting background is taken for granted, but it sounds to me like the tyranny of the musically-interested over the musically-deturdate.
Crap summary, of a seemingly crap article, which may actually have an interesting subject. Whoever originally posted it needs to revise their understanding of what interests people on this site.
Oh, and "frosty piss" and all that jazz.
Speak for your own government's system, but most theories of prison I've heard combine elements of punishment, prevention (by having people isolated from the society they've harmed in the past ; hence you're not allowed to continue running your crack-dealership from a mobile phone in the Big House), and most cost-effectively, rehabilitation (so they don't want to do [whatever] again).
Of course, if you've got private organisations or individuals profiting from the incarceration business, then their interests lie precisely away from having an effective penal system. It their treatment of prisoners were effective at stopping crime, they'd put themselves out of business.
Not quite. While your flywheel(s) is(are) being spun-up(down) they would speed up or slow down the day, the sign of day-change depending on the orientation of the flywheel axis w.r.t. the Earth's rotation axis.
Hmmm - flywheels with an axis orthogonal to the Earth's spin axis wouldn't have this effect. Or to be more precise, it would have COS(inclination angle) effect.
And you admit it? You MUST be new here! [GRIN]
I know that feeling. "How could I NOT have heard of that before?"
No, because that's not the claim that "Nick Ives (317)" made. His claim was that burning coal produced radioactivity in the coal ash ; I sarcastically rebutted that what he's actually describing is concentrating radioactivity by removing non-radioactive elements from your sample.
At no point did I make any claim that coal, bananas, radioactivity, or ash are safe.
Yeah, just off the San Diego, California coast would sound fine to me. Or just pour it into the sewers and let the ants/ rats/ homeless feed on it.
More seriously ... define "harmless concentration". Ah, now we get into some meat : do you follow the linear model for (low)dose-response relations, or do you think that even arbitrarily low doses still have an effect on radiation damage levels?
Me, I'm pragmatic - there is no reliable evidence that the inhabitants of (naturally) high-radioactivity cities like my residence in Aberdeen have a significantly (even at the 10% level) higher cancer rate than other lower radiation cities. So, reducing radiation to levels comparable to background levels in such a city is going to be as near as wiping out the radiation problem as you need go on a public health basis.
Well, on geological timescale, you're quite right there. But people tend to worry about shorter timescales. I never had any concerns about keeping my vial of undepleted uranium in the home-brew vat - to freak the hippies and just possibly give the bugs a chance of higher alcohol tolerance. I wouldn't boil my radium-painted watch hands in the teapot though.
The dangers of exposure are quite simple - death in a number of different and unpleasant ways ; people's reactions to it are complex, for reasons in your next point.
There's a well-understood list of things that hit people's fear/disgust buttons. Invisible dangers are scarier than visible ones (viz paedophiles lurking near schools against children being run down by other children's parents when being picked up from school). Disfiguring wasting illnesses are scarier than dieing young and staying pretty (so, cancers are scarier than choking on your drunken vomit). Having control feels better than giving control to faceless bureaucrats (so, dieing in a car crash on the way to the airport is perceived a less important risk than that of dieing in a hijacked plane). This is not an exhaustive list. But radiation poisoning ticks a lot of general-purpose "dread" and "disgust"buttons for many many people. Hence fear of radiation becomes a really emotive topic.
Oh, you want the future to be JUST THE SAME as today, ONLY NOT A BIT DIFFERENT.
If you chose to live somewhere that you can't operate without a car, that's fine. When you can't fuel cars, then you'll probably find yourself bankrupt because you won't be able to sell the house to anyone anyway. No problems!
Find me a white American who doesn't have a drop of nigger blood in him, and the question might be meaningful.
"Mummy, dinner keeps asking if I'd like to take his place in the pot!" (mine)
"Tonight's menu : Roast leg of insurance salesman."
"I won't let another man past my lips"
"You used to be a regular anthropopaguy"
"If the JuJu had meant us not to eat people / He wouldn't have made us of meat!"
"You might as well say 'Don't fight people' ! " [howls of derisive laughter from rest of tribe] (all Flanders + Swann, 1957)
"Kuru, anyone?"
First bear : "Hunter leg?" ; Second bear : "No thanks, I caught tricninosis from one of those once."
This presentation do for you?
"Earth tides" have been perfectly familiar to surveyors and geologists for a long, long time. Their detection was barely new news when I first started studying geology in the mid-70s.
No astronomer I've heard of has claimed that. Please cite your sources.
First approximation - the Moon is 1/4 of the Earth's diameter and 1/16 of it's area ; therefore the Earth gets hit by around 16 times as many meteors as the Moon. ... so the Earth gets hit ... nope, this one isn't going to work either.
Second approximation (mass matters) : the Earth is 81 times the mass of the Moon, so gets hit by 81 times the number of meteors as the Moon.
Third try : the Moon is ahead of the Earth in it's orbital motion around the Sun, uhh, half the time
The Moon is a singularly ineffective guardian.
The tides, within reason, are a reasonable speculation. But of course, the Moon isn't the only source of tides ; the Sun produces tides too, but smaller.
The difference is a factor of 2.21. viz, if at one location the solar contribution to the tides is 1m, then the corresponding lunar contribution to the tide would be 2.21m and the total tide height 3.21m. (Actually, the ratio is between the forces, not the resultant tide heights ; the tide height is also influenced by all sorts of complexities including resonance between 12h tides (solar) and 12h25m approx (lunar) tides against the seabed shape at your location.)
The tidal forces are much higher, but because the tidal forces are higher, then the forces exerted on the Moon (and on the Earth) are also higher, meaning that the situation moves to a greater Earth-Moon distance faster the closer they are. So the period of really high tides would have occurred very soon after the Moon's formation, and not have lasted very long as the Moon acquired angular momentum from the Earth.
During the period immediately after the Giant Impact which formed the Moon (most likely ; there are no credible alternatives in the field), the surface of the Earth would have been pretty close to completely molten. Which is not very conducive to organic chemistry happening in liquid water.
Actually, when the surface cooled sufficiently for (cometary? probably) water to condense and rain out to form the first oceans, that dense fluid incomplete skin would have greatly improved the transfer of energy and angular momentum between Earth and Moon as the rotation of the Earth would have dragged the "tidal bulge" ahead of the sub-lunar point, applying an increased torque to the Moon (compared to before the oceans started to form). It would have taken some time for water temperatures to drop to the point at which life-relevant chemistry was common.
So, yes, during the OOL period, the tides would have been higher, and the Earth's spin faster. But it's not as huge a difference as you're concerned by because the period of really really high tides predated the period relevant for OOL studies.
The details of what happened in this period is still under vigorous debate.
Reasonable.
Maybe. List them.
My memory tells me that there is only one physics interaction that fundamentally distinguishes between "left" and "right", which is the weak nuclear force. In practice, this was first demonstrated in 1957 (C. S. Wu, E. Ambler, R. W. Hayward, D. D. Hoppes, and R. P. Hudson, Experimental test of parity conservation in beta decay, Phys. Rev. 105, 1413-1415) in decay of Cobalt-90.
Apart from the philosophical discomfort of running away from the problem of origin of life (if we got it from $THERE$, where did $THERE$ get it from?), there are reasonably good reasons for thinking that life, as we know it, could not have originated all that much earlier than it did on Earth because earlier generations of stars than the Sun's did not have sufficient "metals" (matter that isn't hydrogen or helium), which accumulate in successive generations of stars. (That's not to say that life couldn't have originated on a planet that formed 7.5 billion years ago compared to our 4.5 billion years ago ; but 10 billion years ago is probably stretching it.) Also the problem of how to get the life from $THERE$ to $HERE$ is non-trivial. Much more non-trivial than panspermia, as this idea is often called, enthusiasts like to think about.
There's a softer version of panspermia where compounds that become important for generating life on a planet are generated in space by cooking comets with ultraviolet light and things like that. Which is not impossible, but to most geologists, biologists and chemists studying OOL (Origin Of Life), it's unnecessary. Sufficient quantities of sufficiently interesting compounds can be formed on the early Earth without needing to invoke "soft" panspermia.
The parity-violation sub-atomic particle interaction mentioned above should allow discrimination between "right" and "left" remotely. ASSUMING that the other end of the communications link isn't also antimatter. Which makes the question a touch important before the first date. I think we'd have noticed if they were time-inverted compared to us. EDIT "I like to think we'd ..."
Who, apart from someone child-abusive enough to send someone else's children to creationism-indoctrinating schools, gives a shit what creationists "think"?
OK - Dawkins and such people who have to deal with the results of creationist assaults on thinking care because they have to, but even they sound revolted by having to deal with the living arguments for retroactive birth control.
Depending on your opinions on the precise conditions inside the sun and a few other factors, the Sun has between a couple of billion years and about 5 billion years before it leaves the main sequence, and a fraction of a billion years after that until it is unable to continue producing energy (note that it will continue to radiate energy for much longer. Say it takes 2 billion years. Let's also assume that the speed of light really is a speed limit.
In that time, our ambassadors could round trip to a civilisation on the other side of the galaxy, at a top speed of 0.1c, a thousand times.
Here's a list I composed because I'm bored:
Kepler's Laws - 59 words.
Balfour Declaration - 67 words.
Munich Agreement - 520 words.
First Geneva convention - 8628 words.
Hammurabi's Code of Laws - 9502 words.
Magna Carta - 14416 words.
At the (literally) incredible communication rate of one word per round trip, you'd be able to communicate somewhere between a Munich Sell-out and a Geneva Convention. I do not for one second believe that that communication rate could not be bettered.
How long would it take us to set up that communications link ... well, at a top speed of 0.1c, there's around a million years of travelling time there. Let's allow as much preparation time as travel time, for 2 million years total. Archaeologists are debating whether our ancestors had full control of fire 2 million years ago. That's around 100,000 generations, assuming no huge biological changes (implausible with the pace of medical advance these days).
You're unduly pessimistic.
Note that I've avoided the use of unobtanium and the dilithium crystals remain firmly in the holodeck. Essentially I've posited your descendants becoming travellers on "generation ships", then travelling the galaxy ; the absence of directed communications is implausible, but even in it's absence there's a lot of things that could be done. Once we stop hugging the planet's surface.
By contrast, if we stay hugged onto the planet's surface, then we're likely to get hit, badly, by an asteroid well before the million year mark.
The trouble with astronomical timescales is that they're geologically comfortable.
I know that it's Slashdot and there is a joke about never reading the fucking article. But the site also has a "news for nerds" slogan, which rather implies that you'll be held to nerd standards of understanding and application, not the knuckle-dragging idiocies of the general population.
The fucking article exactly disagrees with this second point of yours.
Oh, you just want to go with your idee fixee prejudices, not actually learn anything new? Well, if that's the case, please do let the door hit you on the arse as you leave.
Anything that mentions the Giant Impact Hypothesis has an automatic link to Uranus : the most credible explanation (that I've hear) for a high-obliquity spin axis on a planet is a large impact late in it's formation. Earth-Moon (23.5deg) ; Uranus (98deg) ; Pluto-Charon-Hydra-Nix (between 102 and 126deg, Icarus vol. 55, Aug. 1983, p. 231-235.) ; Venus (close to 180deg) are all thought to have had giant impacts; though only two of the examples generated giant moons from their giant impacts.
(This isn't as strongly supported as the Giant Impact Hypothesis for generating the Earth-Moon system, but it is the most popular position.)
Lead foil is poisonous.
So is tin foil, probably. (UK government limit "The regulatory limit for total tin in canned products is 200 mg/kg.")
I'd use aluminium foil. In multiple layers.
[SIGH]
No.
Burning coal that has a few ppm of natural radioactivity in it (it is well established that organic matter in a geological context concentrates uranium and thorium from circulating ground water - this is why my clients sometimes pay for use of spectral gamma ray detectors to differentiate between a clay's potassium radiation and the U+Th radiation associated with organic matter in that clay), will leave the radioactive material concentrate into the non-volatile ash, as you've just removed 90%+ of the mass of your sample as CO2.
Take two bananas off the shelf at the grocers and measure their radioactivity - so many decays per kilo per second. Eat one banana (either one, it doesn't matter which), wait a few hours for it's components to be distributed around your body, then measure the radioactivity of the banana distributed through around 100 times as much of not-very-radioactive you ; the reading in decays per kilo per second will be lower.
Take the other banana, stick it in an incineration tube passing oxygen over it, heat it to dry it out and burn off the carbon (if you want to, you can run the CO2 through a mass spectrometer and get a C14 date for it. Or you could just read the label on the box.) and leave the non-volatile elements behind. Measure the radioactivity of the few grammes of ash - it will have a high radioactivity expressed in decays per kilo per second.
Voila - you have just changed the radioactivity of two otherwise undistinguished batches of potassium atoms, using chemical processes alone.
Or have you just changed the dilution of the radioactive material?
(I'm not going to repeat the infant-school text book assertion that you cannot affect rates of radioactive decay by chemical processes. But I'll leave it as an exercise for the reader to find out what effects you can have and why. They don't apply in the coal ash case.)
I think that needs the full reasoning stated.
... Because those populations have many generations had cow-milk-tolerating populations having more grandchildren than the cow-milk-non-tolerating populations, because cow-milk is a significant source of nutrition for those populations.
Errr, you've just lost something like 90% of your potential audience there. (What is "6th grade" by the way? In terms of age-of-pupil-when-normally-taught.)
Sad, but probably close to true.
Am I going to have to get my bivouac gear out again and the night-vision binoculars? For the war on science.
In the days before LED lamps, the Fx2 (two 'F' cells, packaged) was very popular in the UK. Let the sniggering begin.
They're still available. Then someone thought to try making a triple pack (inspired by Eccentrica Gallumbits) and later a pentuple pack. (Actually, they've stopped selling those now, due to the discontinued consumer supply of NiCad cells, not because the design is "wrong" per se. They use D-cells instead. BFD.)
Around a decade ago there was a condensed-matter physicist (IIRC, he worked in magnetic field detection by lasers, or something ; it was vaguely related to petrophysics stuff I had to understand) who provided the ICR with impressive-looking mathematical models that he purported provided some sort of model for a Young-Earth-Creationist universe with the appearance of an Old-Earth-Creationist universe (i.e., our universe). Which sounded great for them. Until someone with adequate maths waded through the papers and pointed out the errors.
Which I'm sure did the guy's career no good at all.
I'm trying to remember the guy's name now ... it'll come back to me.
Sounds almost idyllic. Shame you posted the location to Slashdot - either the powers-that-be will descend upon you like vengeful Furies for daring to be happy, or Slashdot readers will descend upon you like ... well, you get the message.
The disruption of the Giant Impact (I think it's big enough to deserve capitals ; in the Earth-Moon system, there is only one such event, though it seems more common in the solar system as a whole) was such as to vaporise or finely disperse a large proportion of the volume of the proto-Earth - a quarter or so. That went up into short lived orbit, and would have degassed quite effectively, and several percent of it stayed up to form the Moon while the rest re-impacted over a few years. 750ppm is a lot of water to remain after that, and to survive the heat of re-accumulation too.
This is quite a problem.
The easiest way I can see for getting around it is to have the Giant Impact happening during the period of the "cometary" impacts that delivered water to Earth.
The Bad Astronomer says, in his TFA :
That could go with the Giant Impact happening during the "cometary wetting" phase, as long as the source of the comets accreting to proto-Earth and proto-Moon was consistent for both bodies. Which given that they'd have been sampling the flux of "comets" (wet asteroids, whatever) across the Earth-Moon-system's orbit, isn't a terribly difficult constraint, I'd think.
I think it's also important to say that I think that you don't have to have all "comets" from (say) a 2.5 to 3.5 AU snowline ; you could probably achieve the same effect with (say) 40% from 2.5 to 3.0AU and 60% from 4.0 to 4.5AU (the numbers are illustrative, not meant to assert any particular model). So if you've got a reasonably uniform flux of objects cycling around in the developing solar system, then getting a consistent mix of objects to accrete onto two objects in overlapping orbits isn't a particularly demanding constraint.
We had that happen - sort-of - once. Had a safe in the office weighing around a half-ton, which the burglars dragged out into the middle of the workshop and evidently spent a lot of effort and time trying to chisel and hack and hammer their way into, to no avail. They eventually left with a few thousand pounds worth of laptops, probably when the early-start company on that street had people arrive for work.
Of course, the safe wasn't even locked - just "on the latch". We'd never had a key for it since finding it when we moved in, and it required the key to lock it. The developer used it as a place to keep the incremental backups in when he left each evening, as it was probably fairly fire and sprinkler resistant.