If the plume of water/slush ice is 100+ miles high, imagine the PSI!
Don't imagine. Calculate!
The surface gravity of Europa is [what] factor lower than that of Earth - where you've learned your reflexes.
Then you need to look at the spread of the plumes - which will giv you the ratio of the against-gravity velocity versus the expansion from diffusion of vapour.
Are you a mystic, or a scientist?
Wikipedia gives me the surface gravity as 0.13 g - less than 1 part in 7 of what you'd need on Earth (in nozzle psi pressure difference). Big difference to what you imagine. (Bigger, given that the gravity field will decay faster than you're used to on Earth. Europa being smaller than Earth.)
While there is no consensus on the thicknesss of Europa's stiff crust, a conservative guess-timate would be 10-20 km (from the spacing of fractures). For a 10 km thickness, a 1% exsolution of gasses (CO2, whatever) would froth the liquid for 8-9km of the ascent, reducing the back presure at the bottom of the fissure to - negligible. The complexities of 2-phase or 3-phase flow (gas-liquid, or gas-liquid-solid) and their pressure drops are... complex. Ask a pipeline engineer why they like to de-gas fluids like crude oil. But I don't see any reason to expect large pressure differentials near the base of the fissure.
The solar corona is, by all terrestrial measures, a really hard vacuum, and emits a radiation with a black-body equivalent temperature up in the order of a million degrees (Kelvin, or Celsius, it doesn't much matter). The heat capacity on the other hand, is pretty low, due to the density being pretty low.
I got cooled to absolute zero, but I'm 0K now.
You absorbed that one at your mother's tit, I guess. It's old enough ti have lichen on it. The joke, that is.
And here I was only thinking it'd make a really spectacular view for a second honeymoon...
I think the radiation environment would probably make the honeymoon a bit of an experience. Possibly a terminal experience. But you never know - you might conceive Johnny-Two-Heads a nice hermaphrodite sibling with three arms.
With 43 papers on Arxiv answering to that author surname, I suspect that the paper will be there some day. (That search's most recent result was "1. arXiv:1512.02135 Soficity, short cycles and the Higman group " ; other papers in the results relate to work on primes, so it looks as if this is the correct author.)
Linking to that, when the (draft) paper goes up is much more appropriate than mucking around with emailing pre-prints.
Well, it looks as if no-one has bothered to find the actual source, instead of relying on some clickbait advertising site's cut'n'paste.
Well, that took about 3 minutes. The paper is in Science. If you don't have a subscription, you'll need to try something like Sci-hub.
Abstract: The history of atmospheric O2 partial pressures (P-O2) is inextricably linked to the coevolution of life and Earthâ(TM)s biogeochemical cycles. Reconstructions of past P-O2
rely on models and proxies but often markedly disagree. We present a record of P-O2 reconstructed using O2 / N2 ratios from ancient air trapped in ice. This record indicates that P-O2 declined by 7 per mil (0.7%) over the past 800,000 years, requiring that O2 sinks were ~2% larger than sources. This decline is consistent with changes in burial and weathering fluxes of organic carbon and pyrite driven by either Neogene cooling or increasing Pleistocene erosion rates. The 800,000-year record of steady average carbon dioxide partial pressures (P-CO2) but declining P-O2 provides distinctive evidence that a silicate weathering feedback stabilizes P-CO2 on million-year time scales.
So, for starters, it's evident that the researchers (though not the non-geologists at Giz-wotsit) appreciate the difference between erosion (the mechanical break up and movement of rock) and weathering (the chemical alteration of the minerals that comprise that weathered rock). They're also well aware that with two processes in place, and a critical factor (temperature) being considerably variable in both time and space, then deconvolving what is actually going on is going to be quite difficult, if not impossible without more data (perhaps from looking at mineralogy variations in sediments deposited in different areas with different mean temperatures.
contrary to the impression that many people have got (I guess from Giz-thingy, the researchers were specifically not looking at air bubbles in the ice, but at air dissolved in the ice. "(ii) Only analyses of bubble-free ice with clathrates were considered. (para 3)" (Do I need to remind people that "clathrate" does not only mean "crystalline compound of hydrocarbon gases and water"? Probably.) They also look at the argon - nitrogen ratio to monitor for changes in the dissolution of oxygen, argon and nitrogen relative to each other due to changes in the immediate environment of the accumulating snowpack.
Could this be an artefact of measurement? Well, they've certainly considered (and rejected) that : "Our hypothesis is further supported by the observation that data from all four ice cores individually exhibit the same general trends and magnitudes of decreasing dO2/N2 with time (table S3), even though each was drilled, stored, and analyzed differently." So, they think it's a genuine atmospheric change.
CO2 recorded in the cores does not change sufficiently or sufficiently consistently to explain the changes observed, so they ascribe a lot of the change to the weathering of pyrite - a reduced iron mineral - into oxidised iron salts ("rust", or iron-rich clays e.g. the glaucony/ glauconite familes).
There's a reason that people write papers, instead of using journalists to report their findings. It's because the details matter.
I'm looking for the actual paper behind this, because it's evident that the people who cut'n'paste things for Gizmodo don't understand the difference between erosion and weathering.
Having at different times had fairly strong alkali (fortunately not strong enough to burn, just to hurt. A lot.) spray into my eyes in the darkroom, and picked metal shards out of the front surface of my sun glasses, I'm perfectly fine with dorky glasses for regular wear and Triplex safety glasses for when I'm actually working.
You don't like dorky glasses? Well, they're you're eyes. Enjoy them while you've got them.
Yes, yes, we all learned the difference between deflagration and detonation the first time we blew up the school chemistry lab. It is, after all, one of the prime purposes of chemistry labs.
if we were good at maintaining LOX-composite compatibility, we'd be making the stages themselves out of composites rather than aluminum.
I get that LOX plus composites are an un-good mix. But even with passivation, are aluminium and LOX really that much better? There's still a nerve-twanging amount of free energy in there.
Actually, despite it's frequent mentions, I'm not even sure what Reddit's address is, but that's a by the by.
If people are using it for advice about things like IT, then it's obviously not an American company, with any American employees (subject to TLA pressure), and none of it's servers would be located in US jurisdictions. So this "House Committee," whoever they are can either blow, or get the records from the NSA already.
I know Slashdot is American, which is why nobody posts interesting security-related questions here. If Reddit are getting such questions, then obviously they're not American.
Why would they throw away a burnt hunk of metal? They should have kept the smoldering remains!
As evidence of purchase and the presence of a major fault, yes. Precisely.
When you have a car crash, do you not take photos? Record the names and addresses of witnesses, and the registration numbers of vehicles involved, even if only trivially? The simple failure to do such things is in itself something that an insurance investigator would take as a priori evidence of fraud and use it as justification for a deep investigation of the claim.
Which is not considered a thing - neither a good thing nor a bad thing. This whole stupid thing of having choice is just stupid. You're not thinking like an economic planner.
Tourism will see a boost in the coming months thanks to that guy.
This will not happen, and even if it did (it can't) would not be considered a good thing.
How are you going to have a boost in tourism? People would have to get visas and then get trains in (tickets won't be sold, if there are non-freight trains at all), ferries (again, only freight ferries with no provision for passengers), or planes (for which you need a visa).
Have you seen the tourism levels at Area 51? That place gets free advertising coming out of it's ears, and the number of tourists is going through the roof. There might even be one, one of these decades - a huge increase on the past levels.
Disclosure : most of the 2000s, until 2011, I was trying to get work in North Korea. Bloody politicians always getting in the way.
Just get one fucking interface, stop changing things and let us get on with using it instead of changing things every fucking day. Do you have any idea how harmful this is for adoption.
I don't even know the name of the desktop environment that I'm using, and I care less. I just want to not have to re-learn it at some random time in the future, chosen by someone I've never heard of for reasons I don't care about.
It's a more complex subject than most people give it credit for. Divers have to pay more attention to the physiology of breathing than the man on the Clapham omnibus, but that is nothing compared to the real complexities of the situation.
With university level chemistry, you'd think that the bond energies and the concentrations of reactants would determine the rates of the reactions in either direction. That they don't indicates that there is some non-equiibrium chemistry going on there - different enzymes catalysing each direction of the equilibrium being a good guess. But enzymes are involved everywhere in biochemistry, so that's still not a very useful answer!
Got to go shopping, so don''t have time to follow up on any papers referenced in the Wiki article you cite (yet).
I'm aware that Paabo and cow-orkers have improved the coverage of the Neanderthal genome over the years. But that's a hard question for species recovery, if for no other reason than the very close coupling between nuear genes and mitochondrial genes. There are enough known problems under the general heading of "mitochondrial disease" in present humans to anticipate real problems mixing genes from multiple Neanderthals and (possibly) modern sapiens mitochondria. That looks like a minefield we're not really able to negotiate at the moment, with our pogo-stick techniques.
I'm happy to welcome our Neanderthal Overlords as being humans. But given that a significant proportion of modern humans struggle to accept humanoids with different coloured skins to them, or speaking different languages, as being "human", I think you'll find hard pushback on accepting Neanderthals as being "human," whatever the science says.
I would suspect that the legal and ethical minefield would pretty much vanish if (1) the genome you attempted to clone was from a dozen or two partial genomes glued together (which is immensely more likely than getting a single genome from a single sample), and (2) you were working with non-human animals. We still don't provide any legal support for chimps, so anything other than a bona fide hoomin is going to be short on luck.
Ethical considerations don't extend beyond national boundaries, so if someone decided to do it, and could solve the technical problems, then they'd find somewhere that they could work. They'd already answered the ethical question for themselves, and that is where control of ethics stops.
Oh no. Dead serious. There has been fuck all success in controlling the movement of ivory, or the poaching. Stringing up a few of the end-users in public might be more successful. Similarly, sine the "War on Drugs" has been sooooo successful, then maybe simply stopping people on the street, checking their blood for blow or coke, and if they fail shooting them there and then would probably reduce demand. No demand, and the business chain collapses.
That this is not done - at least, not in the consuming countries - is an extremely unsubtle hint to the rest of the world that the consuming countries do not want to stop the trade. It is also noted that the consuming countries are the ones screaming for action, anywhere but on their home streets.
What's that line from Apocalypse Now? "I love the smell of hypocrisy in the morning."
Do Slashdot editors even understand the articles they submit?
Ought they?
(Incidentally, whoever is behind that AC has clearly never even attempted to submit a story, so he (or she ; unlikely but not impossible) doesn't know what the editors actually do do.)
Some Japanese (and/ or Korean) people are talking about this. I haven't heard of them making significant progress though. For example, in selecting samples to work from.
Considering that "mammoth" covers a lot of sins, you're going to have to be pretty careful about your sample selection. You wouldn't, comparably, want to mix DNA from an Indian Zebu cow, a walking corpse in a McDonalds feed lot in America, and an aurochs only a thousand or so years older than the other two samples. And we haven't even got onto getting the mtDNA in the host ovum right. Or the immunology of the pregnancy.
Neanderthals, using DNA fragments from 40,000 yo frozen specimens
Do these exist? I haven't heard of them, and I have heard Svante PÃÃbo bemoaning the lack of such samples just a few years ago. Therefore you're talking about a new discovery.
Slashdot Mirror
Don't imagine. Calculate!
The surface gravity of Europa is [what] factor lower than that of Earth - where you've learned your reflexes.
Then you need to look at the spread of the plumes - which will giv you the ratio of the against-gravity velocity versus the expansion from diffusion of vapour.
Are you a mystic, or a scientist?
Wikipedia gives me the surface gravity as 0.13 g - less than 1 part in 7 of what you'd need on Earth (in nozzle psi pressure difference). Big difference to what you imagine. (Bigger, given that the gravity field will decay faster than you're used to on Earth. Europa being smaller than Earth.) ... complex. Ask a pipeline engineer why they like to de-gas fluids like crude oil. But I don't see any reason to expect large pressure differentials near the base of the fissure.
While there is no consensus on the thicknesss of Europa's stiff crust, a conservative guess-timate would be 10-20 km (from the spacing of fractures). For a 10 km thickness, a 1% exsolution of gasses (CO2, whatever) would froth the liquid for 8-9km of the ascent, reducing the back presure at the bottom of the fissure to - negligible. The complexities of 2-phase or 3-phase flow (gas-liquid, or gas-liquid-solid) and their pressure drops are
The solar corona is, by all terrestrial measures, a really hard vacuum, and emits a radiation with a black-body equivalent temperature up in the order of a million degrees (Kelvin, or Celsius, it doesn't much matter). The heat capacity on the other hand, is pretty low, due to the density being pretty low.
You absorbed that one at your mother's tit, I guess. It's old enough ti have lichen on it. The joke, that is.
I think the radiation environment would probably make the honeymoon a bit of an experience. Possibly a terminal experience. But you never know - you might conceive Johnny-Two-Heads a nice hermaphrodite sibling with three arms.
No, seriously. Anyone. In the slightest little bit. Surprised?
Linking to that, when the (draft) paper goes up is much more appropriate than mucking around with emailing pre-prints.
Well, that took about 3 minutes. The paper is in Science. If you don't have a subscription, you'll need to try something like Sci-hub.
Abstract: The history of atmospheric O2 partial pressures (P-O2) is inextricably linked to the coevolution of life and Earthâ(TM)s biogeochemical cycles. Reconstructions of past P-O2 rely on models and proxies but often markedly disagree. We present a record of P-O2 reconstructed using O2 / N2 ratios from ancient air trapped in ice. This record indicates that P-O2 declined by 7 per mil (0.7%) over the past 800,000 years, requiring that O2 sinks were ~2% larger than sources. This decline is consistent with changes in burial and weathering fluxes of organic carbon and pyrite driven by either Neogene cooling or increasing Pleistocene erosion rates. The 800,000-year record of steady average carbon dioxide partial pressures (P-CO2) but declining P-O2 provides distinctive evidence that a silicate weathering feedback stabilizes P-CO2 on million-year time scales.
So, for starters, it's evident that the researchers (though not the non-geologists at Giz-wotsit) appreciate the difference between erosion (the mechanical break up and movement of rock) and weathering (the chemical alteration of the minerals that comprise that weathered rock). They're also well aware that with two processes in place, and a critical factor (temperature) being considerably variable in both time and space, then deconvolving what is actually going on is going to be quite difficult, if not impossible without more data (perhaps from looking at mineralogy variations in sediments deposited in different areas with different mean temperatures.
contrary to the impression that many people have got (I guess from Giz-thingy, the researchers were specifically not looking at air bubbles in the ice, but at air dissolved in the ice. "(ii) Only analyses of bubble-free ice with clathrates were considered. (para 3)" (Do I need to remind people that "clathrate" does not only mean "crystalline compound of hydrocarbon gases and water"? Probably.) They also look at the argon - nitrogen ratio to monitor for changes in the dissolution of oxygen, argon and nitrogen relative to each other due to changes in the immediate environment of the accumulating snowpack.
Could this be an artefact of measurement? Well, they've certainly considered (and rejected) that : "Our hypothesis is further supported by the observation that data from all four ice cores individually exhibit the same general trends and magnitudes of decreasing dO2 /N2 with time (table S3), even though each was drilled, stored, and analyzed differently." So, they think it's a genuine atmospheric change.
CO2 recorded in the cores does not change sufficiently or sufficiently consistently to explain the changes observed, so they ascribe a lot of the change to the weathering of pyrite - a reduced iron mineral - into oxidised iron salts ("rust", or iron-rich clays e.g. the glaucony/ glauconite familes).
There's a reason that people write papers, instead of using journalists to report their findings. It's because the details matter.
I'm looking for the actual paper behind this, because it's evident that the people who cut'n'paste things for Gizmodo don't understand the difference between erosion and weathering.
You don't like dorky glasses? Well, they're you're eyes. Enjoy them while you've got them.
Yes, yes, we all learned the difference between deflagration and detonation the first time we blew up the school chemistry lab. It is, after all, one of the prime purposes of chemistry labs.
I get that LOX plus composites are an un-good mix. But even with passivation, are aluminium and LOX really that much better? There's still a nerve-twanging amount of free energy in there.
If people are using it for advice about things like IT, then it's obviously not an American company, with any American employees (subject to TLA pressure), and none of it's servers would be located in US jurisdictions. So this "House Committee," whoever they are can either blow, or get the records from the NSA already.
I know Slashdot is American, which is why nobody posts interesting security-related questions here. If Reddit are getting such questions, then obviously they're not American.
Pretty close to zero.
As evidence of purchase and the presence of a major fault, yes. Precisely.
When you have a car crash, do you not take photos? Record the names and addresses of witnesses, and the registration numbers of vehicles involved, even if only trivially? The simple failure to do such things is in itself something that an insurance investigator would take as a priori evidence of fraud and use it as justification for a deep investigation of the claim.
I'm not surprised you dumped them if all they could offer on their service was to waste the electrons on music.
Which is not considered a thing - neither a good thing nor a bad thing. This whole stupid thing of having choice is just stupid. You're not thinking like an economic planner.
This will not happen, and even if it did (it can't) would not be considered a good thing.
How are you going to have a boost in tourism? People would have to get visas and then get trains in (tickets won't be sold, if there are non-freight trains at all), ferries (again, only freight ferries with no provision for passengers), or planes (for which you need a visa).
Have you seen the tourism levels at Area 51? That place gets free advertising coming out of it's ears, and the number of tourists is going through the roof. There might even be one, one of these decades - a huge increase on the past levels.
Disclosure : most of the 2000s, until 2011, I was trying to get work in North Korea. Bloody politicians always getting in the way.
I don't even know the name of the desktop environment that I'm using, and I care less. I just want to not have to re-learn it at some random time in the future, chosen by someone I've never heard of for reasons I don't care about.
With university level chemistry, you'd think that the bond energies and the concentrations of reactants would determine the rates of the reactions in either direction. That they don't indicates that there is some non-equiibrium chemistry going on there - different enzymes catalysing each direction of the equilibrium being a good guess. But enzymes are involved everywhere in biochemistry, so that's still not a very useful answer!
Nope. Kill the drivers.
Many of the children passing for Slashdot's readership are so young they can't even remember Skylab coming down, let alone going up.
I'm aware that Paabo and cow-orkers have improved the coverage of the Neanderthal genome over the years. But that's a hard question for species recovery, if for no other reason than the very close coupling between nuear genes and mitochondrial genes. There are enough known problems under the general heading of "mitochondrial disease" in present humans to anticipate real problems mixing genes from multiple Neanderthals and (possibly) modern sapiens mitochondria. That looks like a minefield we're not really able to negotiate at the moment, with our pogo-stick techniques.
I'm happy to welcome our Neanderthal Overlords as being humans. But given that a significant proportion of modern humans struggle to accept humanoids with different coloured skins to them, or speaking different languages, as being "human", I think you'll find hard pushback on accepting Neanderthals as being "human," whatever the science says.
ref Voltaire's "long letter" excuse.
Ethical considerations don't extend beyond national boundaries, so if someone decided to do it, and could solve the technical problems, then they'd find somewhere that they could work. They'd already answered the ethical question for themselves, and that is where control of ethics stops.
That this is not done - at least, not in the consuming countries - is an extremely unsubtle hint to the rest of the world that the consuming countries do not want to stop the trade. It is also noted that the consuming countries are the ones screaming for action, anywhere but on their home streets.
What's that line from Apocalypse Now? "I love the smell of hypocrisy in the morning."
Ought they?
(Incidentally, whoever is behind that AC has clearly never even attempted to submit a story, so he (or she ; unlikely but not impossible) doesn't know what the editors actually do do.)
Considering that "mammoth" covers a lot of sins, you're going to have to be pretty careful about your sample selection. You wouldn't, comparably, want to mix DNA from an Indian Zebu cow, a walking corpse in a McDonalds feed lot in America, and an aurochs only a thousand or so years older than the other two samples. And we haven't even got onto getting the mtDNA in the host ovum right. Or the immunology of the pregnancy.
Formidable obstacles. Deafening silence.
Do these exist? I haven't heard of them, and I have heard Svante PÃÃbo bemoaning the lack of such samples just a few years ago. Therefore you're talking about a new discovery.