We could spend the next thousand years developing technology, populating the Solar System with our robots, then travel at 0.01c to the nearest 10 planetary systems, and still not have a species which is 1% older than today.
That's unobtanium-free physics, but I do gloss over the difficulty of crewing and running a generation ship for the thick end of a millennium. It might be easier to develop some form of suspended animation for wombs, and ship frozen embryos for robots to develop, once the robots have built a sufficient space industry at the destination.
I'm sure that I'm never going to see humanity's First Contact moment. If I wasn't dead when it happens, I'd be astonished if any human which even knew it's 21st century ancestors names were involved. (I don't know the names of any of my ancestors even 5 generations back, let alone 30 or so).
A species doesn't need to travel at a significant fraction of c in order to colonise the galaxy. Our society probably couldn't do it in any meaningful sense (are we the same society as a thousand years ago - do you speak Old English, or Norman Frankish?), and maybe our species would have speciated into multiple descendant species by the time they get into other spiral arms. But that isn't "never" - just a very long term plan.
you need a few star lifetime iterations to produce enough "metals" (for astronomers anything above hellium is a metal) for life to be viable.
This is probably true. But those stellar generations are not the generations of common stars (dwarf stars, up to, for example, the Sun's mass), but the lifetime of larger, faster evolving stars. You don't get metals further up the periodic table than carbon from a Sun-mass star. The lifetimes of such stars (say, more than 3 Sun masses ; I forget where the exact dividing line is for stars getting up to burning silicon to iron. It's somewhere near that mass.) is much shorter - more like a half billion years, The time for the ejecta from a supernova to become incorporated into the next generation of stars is more significant than the lifetime of the stars.
Interestingly, there is a fair correlation between the metallicity of a host star and it hosting a "super-Jupiter," but that correlation breaks down for smaller (Neptune-size and Earth-size) planets. While they still form around stars with a solar-similar metallicity on average, they're not more common around higher metallicity. That's odd. There's something going on there that works against the obvious expectation of how things go. I don't know about you, but I'd take that as a sign to pay more attention to observational data than theory.
they have other problems that are harmful to life in our sense
The study was (as is normal) carried out with the assumption of the stability zone of liquid water as the criterion for "habitable zone". No other constraint. You might be interested in finding something that would find William Shatner attractive - even if only as food - but that's not the only thing "life" could plausibly mean. A prokaryote-grade of organism with a non-nucleic acid genetic system would be far more interesting than something that beat Shatner at chess with an RNA-world type genetic system.
Diamonds are not as rare as some other gemstones. It's only the massive market manipulation that gives them their value.
A touch over-blown, but certainly DeBeers have done a great job of driving up the price of their product through damned effective marketing. Kind-of like Apple. Now, personally I wouldn't buy an Apple product (had a Mac ; didn't like it), but I recognise their marketing skill. And apparently, their hardware is pretty good too, if over-priced.
It's so much more romantic to give diamonds that were mined by people on subsistence level wages in terrible conditions
There are "blood diamonds". There are also gem-quality diamond mines in Siberia (not the greatest place in the world, but not the worst, by a long chalk), Canada (same comment), Australia (same comment), Brazil (same comment, but probably the least desirable of the countries I've listed so far)... and then you get to the list of West- and Central- African states where their mining has been used for funding wars. Oh, I forgot Namibia/ Angola's offshore diamond-dredging operations which take place on 100M$ vessels replete with air conditioning and a pan-national workforce.
Short version - it depends where you get your diamond from.
Personally, I'd never buy a cut diamond. Cutting and polishing them takes away all the fascination of their surface and internal structures. It just leaves them as sparkly stuff. Un-cut diamonds are far more interesting, and for that you absolutely need the provenance, down to the mine.
These are matters that the paper discusses. It only takes a couple of hours to read the 44 pages.
Short version - some close-in planets will be tidally locked, but not necessarily all of them. And (as discussed), the fact that M-dwarfs covers more mass variation than the next three classes of stars combined (F-dwarfs, G-dwarfs like the Sun and K-dwarfs) so it would be safe to expect a considerable variation in the behaviour of planets around M-dwarfs.
Consider tidal locking in a system with an M-dwarf star, a "hot Jupiter" and our Planet of Interest (PoI). If in orbit around either the hot Jupiter or the star, the PoI might become locked. But with the three in relatively close interaction, the PoI could be disturbed between locking to one, or the other, or alternating, or spinning irregularly. Feel free to use a planet with an irregular - literally chaotic, even - rotation in an SF scenario of your choice.
I think the concept is similar to most color high magnification microscopy
I'm a geologist, you insensitive clod!
The interference colours we see under crossed polarisers are real colours, intrinsic to the material, it's orientation and the radiation impacting it. (Also, pleochroism visible under polarised illumination without the analyser in the optical assembly.) No stains involved. (Though we do sometimes use stains to improve contrast too, e.g. Aliziarin Red to differentiate between different carbonate minerals.)
I agree with APressButton below - for once this is an AC comment worth recognition.
The headline annoyed the fuck out of me when I saw it in Google Science News. So I looked it up on Arxiv (costing Giz... whoever they were... some eyeball-seconds).
During a systematic search for supermassive black holes (SMBHs) not in galactic nuclei, we identified the compact symmetric radio source B3 1715+425 with an emission-line galaxy offset ~8.5 kpc from the nucleus of the brightest cluster galaxy (BCG) in the redshift z=0.1754 cluster ZwCl 8193. B3 1715+425 is too bright (brightness temperature â¼3Ã--10^10 K at observing frequency 7.6 GHz) and too luminous (1.4 GHz luminosity â¼10^25 W/Hz) to be powered by anything but a SMBH, but its host galaxy is much smaller (â¼0.9 kpc Ã-- 0.6 kpc full width between half-maximum points) and optically fainter (R-band absolute magnitude â¼â'18.2) than any other radio galaxy. Its high radial velocity â¼1860 km/s relative to the BCG, continuous ionized wake extending back to the BCG nucleus, and surrounding debris indicate that the radio galaxy was tidally shredded passing through the BCG core, leaving a nearly naked supermassive black hole fleeing from the BCG with space velocity >2000 km/s. The radio galaxy has mass
So, yes, a really interesting discovery. Not as pumped up as the headline writers (though even the paper-writers fell to the temptation of "A NEARLY NAKED SUPERMASSIVE BLACK HOLE."
The discussion upthread between several participants about how this black hole could be escaping from the collision, in a gravitationally bound system. Utterly astonishingly, the paper's authors considered this point too (page 7 of the paper):
[Brightest Cluster Galaxies] BCGs can have nuclear escape velocities up to 3000 km s^â'1, so the fleeing radio galaxy may still be gravitationally bound to the BCG and/or the cluster
ZwCl 8193. [...] The high [SuperMassive Black hole] SMBH velocity relative to the BCG is consistent with (1) gravitational recoil following the merger of two spinning SMBHs or slingshot ejection of one SMBH from a triple system in the BCG or (2) the velocity of a galaxy that fell into the gravitational potential well in the center of the massive cluster ZwCl 8193.
[With reasons, the authors reject case (1)]
This leaves case (2), a formerly normal galaxy that fell into ZwCl 8193, was tidally stripped as it passed near the BCG nucleus, and is now rapidly moving away from the BCG. Only the SMBH and the small central portion of that galaxy denser than the BCG core remain intact,
Someone else asked where to point his telescope. The answer is (J2000 coords) RA 17d 17' 19.20" Dec +42d 26' 59.0" (check Simbad for Zwicky Cluster 8193)
You realize that *eventually* we'll probably need to synthesize various sorts of hydrocarbon-based fuels, right?
Fuels - maybe. But then again, industrial chemistry text books in the 1930s were berating people for being stupid enough to burn oil, instead of using it for something useful. As feedstock for the chemistry industry (most of the plastics you've ever used, including in your 3d-printer), for lubricating materials... liquid hydrocarbons will continue to be used. Like it or lump it.
Besides which, we need to process our sewage anyhow. Why not turn it into something useful?
Well, people have been using it for fertilizer for... well, millennia certainly. Probably since the establishment of the first permanent villages. So let's say, 10 thousand years. The 1-2% or so of that time which (some) people have been able to consider the problem "flushed away" is lost in the noise.
Whether converting it into liquid hydrocarbons is more energetically efficient than using it for making food... short question, long (and locally variable) answer.
Considering that Joe Haldeman's "Forever War" was written as a riposte to "Starship Troopers", it would be really interesting to see the same crews (director, writers, actors, SFX, possibly even props) do both "Starship Troopers" and "Forever War" for back-to-back release.
OTOH, there continue to be rumours that Ridley Scott is working on a script for the Forever War, which is good news in itself, but bad news for this idea.
as a "civilian" (non-citizen) are only allowed to have 1 child.'
That sounds more like "Ender's Game" than a Heinlein. Heinlein (as an author) was all for having as many children on his daughters and mother as possible.
Then again, Heinlein's main characters were almost always members of the 1% (honourable exceptions to "Citizen of the Galaxy" and "Farmer's Freehold", possibly others).
WWII Both the Nazis and the Japanese entertained ideas of landing forces on both coast to conduct terror attacks and sabotage. The heavily armed population is generally accepted to have had an impact on not putting those ideas into action.
Bulshit.
On the alleged influence of the "armed population", not on whether or not the Germans/ Japanese/ Italians had any plans for landing saboteurs on either coast.
Sabotage and/ or infiltration programmes depend on secrecy, not fire power. Being recognised is normally time to bug out and fade away. That worked for the resistances in France, Yugoslavia, Ukraine, and Poland - until they engaged with a military (or police : same difference) force, they kept as low a profile as possible. Then hit and then faded away.
I would suspect that the main reason for the Germans and Japanese not landing appreciable sabotage/ fifth column efforts in America was the same as for them not being noticeably successful in Britain : they couldn't find enough turncoats willing to stay brought. That raises (again) another significant question about how much contact the Italian fascists had with the Mafia. And of course, whether the Mafia stayed brought, or took the bribes then shopped the agents anyway.
Have the script writers actually read the book and understood it
Have you considered the possibility that they read the book and understood it in a different way to how you did?
Heinlein does strike me as a right-wing nut job with some serious incest hangups, but he does occasionally show some signs of different, less stereotyped, thinking.
In the books I vaguely recall that the bugs weren't primitive or stupid and were a deadly foe.
For most of the book, almost nothing was known about "the bugs," including what their capabilities were. At several points in the book, events looked as if "the bugs" were learning from the humans, as the humans were trying to learn from the "the bugs".
Heinlein was, in part, looking at the questions of "What if we met an enemy that was as good as us? How much effort would we put into 'jaw jaw' instead of 'war war'?" And as a military man, Heinlein was quite sure that humanity would put a lot more effort into 'war war' then into 'jaw jaw'.
Maybe just an audio detector though since drone motors/rotors are pretty distinctive.
That's probably the most useful suggestion I've seen yet on this thread.
OTOH, with a 3-d printer of modest capabilities, making new patterns of rotors is almost trivial. 7 blades with an edge band to suppress tip-noise? No problem. Different numbers of rotors on each motor? Not much problem.
Better solution, mount an EMP gun on the roof and shoot them down. [...] Or maybe even a sharpshooter with a real rifle.
In Britain? Are you joking? Cops aren't armed with nything more lethal than a pepper spray, and the police force struggle to recruit enough existing officers to take firearms training to maintain the numbers of officers who can be armed. The prison service don't have any armed resources at all. Not a pop-gun, nor any legal or practical infrastructure to start one.
Nope, that's a complete non-starter. Getting global support from all drone manufacturers would be easier.
It means they require the technical skill to hack a drone or fly it unassisted.
Or, as an alternative, they need enough money to rent the technical skill...
There are many vectors whereby this could be attacked. Try this one for size: commodity GPS receivers - the $5 (or whatever price) modules that you include in your $200 drone - are going to be made for bulk sales. So they're not going to have encryption on their output because that would reduce sales by complicating integration into products.
So for a fairly robust family of attacks, I'd put together a system that takes the serial (NEMA? something like that; ben a while since I needed to poke my nose under the skin of GPS tech) output stream from the GPS, and if it includes coordinates in [programmed area] it will alter the serial stream to be 2km to the west - or whatever else. So you can then fly your drone in prohibited airspace, while the drone thinks it's in open airspace. And no-one in the entire universe other than the person programming the flightpath waypoints and the... "Adjustment Chip" will know just how they're going to set that up.
The same logic applies to GLONASS chips (incorporated into commodity satellite navigation chipsets for the last several years) and is likely to apply to Galileo ones too. Not having the same commercial concerns as GPS and Galileo (arguable for GLONASS), the Chinese system-to-be may or may not be vulnerable to similar attacks.
Take a look at that earthquake map for a second again - I did. (Partly because it taught me where Oklahoma is. Not my country - I never needed to know this before I saw that map, but I'd formulated the question before I saw the map. I may have been conflating Oklahoma and Ohio, because I'd got a more NE location in mind.)
Look at the other concentration of earthquake events in the middle of the continent. Even with my loose handle on USian geography, I can trace the outlines of the Missouri and Missippiissi rivers (it doesn't surprise me that they form state borders, but again, that's never been on my "need to know" list), then just south of where they join... a NE-SW oriented ellipse of earthquakes. That's New Madrid, that is. Interesting place - some of the most severe earthquakes in the written history of the North American continent occurred there. And that is including the big threats on the West Coast.
Weird thing about New Madrid - it's been more or less quiet since 1812. Just enough activity to keep people worried. Enough quietness to lull people into a false sense of security. That's a really dangerous combination.
While I'm perfectly happy about a correlation between production, injection and earthquakes (the Rocky Mountain Arsenal waste disposal well was literally a text book case in my youth, before people started to pay me to be a geologist), there are some real questions about the actual distribution of earthquake risk in North and South America because the written record is so short - a mere 3 to 4 centuries. It's not much better for most of Africa too (thanks China for having some written records!).
I'm not too happy with one part of the SciAm article you link to. At one point the authors say
Unfortunately, the lessons of Rangely and the Rocky Mountain Arsenal were apparently forgotten by the early 2000s, when fossil-fuel companies embarked on the shale-gas boom.
nope. The lessons were never forgotten. They were perfectly well known. There's a definite shift in the subject over the next few of sentences:
âoeScores of papers on injection-induced earthquakes were published in the geophysical literature in the following 40-plus years, and the problem was well understood and appreciated by seismologists,â says Bill Ellsworth, [biog]. He believes professional skepticism slowed the formation of a consensus. âoeThere were a lot of doubts expressed by very good petroleum engineers that [earthquakes caused by injection wells] were even possible,â
Literally, the Rocky Mountain Arsenal results were in the text books. If Petroleum Engineers don't read geology text books, then there is definitely something lacking in their education (considering that their entire subject revolves around stuff you find in rocks). But that knowledge was never "forgotten".
Perfectly true. If you're on an institutional network with a subscription to Bull.Seimol.Soc.Amer then you can get the paper here, or for the rest of the human race you can get it from Sci-hub here.
So, what does the paper actually say. By the Noodly Appendage, that is one dull paper. Oh, there's an interesting paper on pseudotachylite too. Yes, there's a moderate degree of correlation, but there are also a lot of problems with the pre-instrumental earthquake reports and locating the earthquakes. The lead author (Hough) is a well-respected seismologist, but this isn't an earth-shatteringly great paper.
The flow rates reported for some of these wells, given that they're for natural production without even produced gas re-injection to maintain reservoir pressure or to provide gas lift, makes me think that many of these structures were probably significantly over-pressured before they were drilled, so reports of multiple blowouts in some of the wells are utterly unsurprising. Unfortunately, the extremely primitive degree of data acquisition during this period (remember - we're back in cable-tool days here. Rotary drilling was in the future for these guys) means that the data to analyse the wells properly likely doesn't exist, and never was collected. "Tatties ower the side!" as my pore pressure instructor would say. Oh - sorry. For the non- pore pressure analysts in the audience, tthe (inferred) over pressure alone would increase the likelihood of ground subsidence as the structures are depressurised.
It's weird looking back at these well reports to see such shallow depths. Even the deeper wells they discuss barely top 6000ft - not even 2km. I haven't drilled a well that shallow in... I can't remember. Re-phrase : every well I've drilled in almost 30 years in the game has gone through those depths in the process of getting to somewhere interesting. No, tell a lie - two wells I've drilled in that time have evaluated structures that shallow - but for waste disposal, not hydrocarbon production.
Magnitude (both the Richter system introduced shortly after the period of this study, and the modern system) is a logarithmic scale. Two orders difference (e.g, from M 3.5 to M 5.5) would be a thousand-fold difference in released energy.
Voting machines! (Assuming you manage to legally acquire one).
Is there a law preventing one from buying a voting machine?
Say that I run... let's say, the Student's Union (managing the pub, laundry, band practice room, and cafe) of Smallsville University (dedicated to the memory of Derek Smalls)... and I approach Diebold (I may remember the name wrongly) to buy a voting machine for conducting our Union's internal democracy, then they'd turn me away citing [law number and section, of year].
Diebold may choose to tell me they only consider orders of ten thousand or more machines, for whatever reasons of business, policy or prejudice against Derek Smalls (Messiah on Mondays through Wednesdays) ; but that's a different thing to being prevented by law from selling me one.
Is there any law preventing me from buying one second-hand? You'll note that I've set up the scenario so I have perfectly reasonable grounds for wanting one - there's no nefarious intent to complicate matters.
Do you replace everything when the warranty expires?
I certainly don't. In fact, I can't think of anything that I've ever replaced when the warranty has expired, because the warranty has expired.
I'm not even sure that could be a rational decision. Costs-wise, if it's still working, but the warranty has expired, then you continue to use it until it fails, and then assess the cost of repair. Possibly, if it's a leased or rented bit of equipment and the warranty expires, then it would become rational to say to the owners "New widget, please!" Which is one of the reasons (apart from tax advantages) for leasing instead of owning. But then the device isn't (and never has been) yours to hack anyway. That probably covers cars being brought under finance deals too (they belong, at least in part, to the finance company ; as such, if you want to hang furry dice from the rear view mirror then technically you need to have the co-owner's written permission before stating the modification.
Errr, right. So the ground station now knows the time of arrival of the carrier wave. To a timing accuracy of one half of the wavelength of the carrier signal. For a 1m accuracy, that'd imply a wavelength of less than 2m, and a frequency of upwards of 150 MHz. That's no problem electronically.
What sort of ground stations are you going to need. Oh right, you're doing triangulation - presumably by signal arrival timing variation. So we don't need to worry about Rayleigh criteria for the frequencies involved. You'd need 4 ground stations minimum (3 for a fix, one for error checking), and you'd need sufficient to have 4 on the appropriate face of the planet at any arrival time. So that's a minimum of 6 ground stations, distributed as octahedrally as possible. Doable.
Now, the big question - how does the ground station know when the signal was transmitted? That is why the signal from GPS satellites contains the time of transmission in the signal packet. (I assume the same is true for GLONASS and Galileo... GLONASS, confirmed ; not sure on Galileo, or on the Chinese system). So... you've got to put a pretty good quality radiation hardened atomic clock quorum onto each of your satellites.
A pill-sized RTG.
Something like this. With RTGs there is an obvious relation between mass, power and half-life. The design linked above will produce 100W after 14 years, which is probably at the limit of acceptability, considering the distance this constellation is going to have to cover. However, at 45kg, that's a big pill to swallow.
Smaller RTGs will have lower power output, or shorter lifetimes, or both. Unless there is some isotope of unobtanium with more desirable properties.
A good supercapacitor.
I was going to make comments about more unobtanium, but it seems that despite the Star Wars style name, electric double-layer capacitors are becoming available. Scanning the applications exampled in the Wikipedia article, I don't see anyone claiming better than a decade lifetime, but that's a credible technology gap to pass. I'm more worried about the radiation sensitivity of them - they're not happy with voltage spikes. I've not heard of them making it into space technology yet, but that's probably just timing. There are rocket scientists in the world after all. (Or maybe they've come up with other ways of managing power which obviate the need for radiation-sensitive components.)
Now, how many of these are you going to need? I'm going to assume that they're all sped out using Jupiter gravity assists with the same sort of speed as New Horizons. So that's a 10 year time of flight to approach the search region. Something like 30 years to cover the projected perihelion interval (and depending on Planet 9's orbital eccentricity, 2x to 4x to cover the regions out to aphelion). (Incidentally, if we could start launching these tomorrow at 09:00, the telescopic searchers still have 10 years before they face any competition.)
That gives a search volume of... 7.98E+30 cu.km, IF Planet 9 has an orbital inclination similar to everything else in the Solar system (we explicitly don't know that - some authors are making serious arguments for Planet 9 being inclined at right angles to the main ecliptic plane. In that case the search volume goes up to the order of 2.2E+031 cu.km).
How efficient would the search be? I'm just going to make a wild-arsed guess that if a probe passes within 10 million km of Planet 9, then it'll acquire a sufficient deflection to be detected. Total guess. So each probe has a search volume of around 3E+022. So you're going to need between 10^8 and 10^9 probes.
Is there enough plutonium (or Unobtanium-115) to build the first 10 million RTGs? And launch capacity? Or do we need to do some serious telescope work to narrow down the range of possibilities? (Which has the additional advantage of returning data a decade or several before the space probe fleet could possibly start to return useful data.)
(In the [KSR] novel, people on a generation starship discover that salt and other toxins start building up quickly in the smaller scale of their ship.)
Bo-lock-s. Unadulterated bullshit of the highest ordure.
I've read one thing by KSR that caused me to file him (well, "her" for a long time. It's only recently that I've discovered that she is a he Whatever.) under "try more". Then I waded through the first of the "Multicolour Mars" series and found it amusing but not worth further wading. But if he has really come out with that pathetic excuse for a science-driven plot-line... wow, that kicks him off the "try some more" pile of names and into the "move to next author" pile.
Does he not think that by the time the first generation ships are actually dispatched, they wouldn't have been running for. literally, generations mining and exploring the Kuiper Belt and Oort Cloud? That when these ships came back into a servicing station (e.g. in high Saturn orbit) their life-support techs wouldn't know to the gram the concentrations of elements in their discharges... because they'd be paying money for discharge of materials to the service station. I mean, what's the LS-tech going to do when s/he sees that [NaCl] is increasing in the black-water/ white water system? Ignore it? Log it, report it to the LS-manager, and increase the proportion of flow that goes through the NaCl ion-exchange resin to bring the system back within limits while concentrating the excess NaCl into a storable volume?
Has KSR never in his life read the daily water quality reports from a ship's "watermaker" system? People have been watching for problems like this for decades already.
Slashdot Mirror
We could spend the next thousand years developing technology, populating the Solar System with our robots, then travel at 0.01c to the nearest 10 planetary systems, and still not have a species which is 1% older than today.
That's unobtanium-free physics, but I do gloss over the difficulty of crewing and running a generation ship for the thick end of a millennium. It might be easier to develop some form of suspended animation for wombs, and ship frozen embryos for robots to develop, once the robots have built a sufficient space industry at the destination.
I'm sure that I'm never going to see humanity's First Contact moment. If I wasn't dead when it happens, I'd be astonished if any human which even knew it's 21st century ancestors names were involved. (I don't know the names of any of my ancestors even 5 generations back, let alone 30 or so).
A species doesn't need to travel at a significant fraction of c in order to colonise the galaxy. Our society probably couldn't do it in any meaningful sense (are we the same society as a thousand years ago - do you speak Old English, or Norman Frankish?), and maybe our species would have speciated into multiple descendant species by the time they get into other spiral arms. But that isn't "never" - just a very long term plan.
This is probably true. But those stellar generations are not the generations of common stars (dwarf stars, up to, for example, the Sun's mass), but the lifetime of larger, faster evolving stars. You don't get metals further up the periodic table than carbon from a Sun-mass star. The lifetimes of such stars (say, more than 3 Sun masses ; I forget where the exact dividing line is for stars getting up to burning silicon to iron. It's somewhere near that mass.) is much shorter - more like a half billion years, The time for the ejecta from a supernova to become incorporated into the next generation of stars is more significant than the lifetime of the stars.
Interestingly, there is a fair correlation between the metallicity of a host star and it hosting a "super-Jupiter," but that correlation breaks down for smaller (Neptune-size and Earth-size) planets. While they still form around stars with a solar-similar metallicity on average, they're not more common around higher metallicity. That's odd. There's something going on there that works against the obvious expectation of how things go. I don't know about you, but I'd take that as a sign to pay more attention to observational data than theory.
The study was (as is normal) carried out with the assumption of the stability zone of liquid water as the criterion for "habitable zone". No other constraint. You might be interested in finding something that would find William Shatner attractive - even if only as food - but that's not the only thing "life" could plausibly mean. A prokaryote-grade of organism with a non-nucleic acid genetic system would be far more interesting than something that beat Shatner at chess with an RNA-world type genetic system.
A touch over-blown, but certainly DeBeers have done a great job of driving up the price of their product through damned effective marketing. Kind-of like Apple. Now, personally I wouldn't buy an Apple product (had a Mac ; didn't like it), but I recognise their marketing skill. And apparently, their hardware is pretty good too, if over-priced.
There are "blood diamonds". There are also gem-quality diamond mines in Siberia (not the greatest place in the world, but not the worst, by a long chalk), Canada (same comment), Australia (same comment), Brazil (same comment, but probably the least desirable of the countries I've listed so far) ... and then you get to the list of West- and Central- African states where their mining has been used for funding wars. Oh, I forgot Namibia/ Angola's offshore diamond-dredging operations which take place on 100M$ vessels replete with air conditioning and a pan-national workforce.
Short version - it depends where you get your diamond from.
Personally, I'd never buy a cut diamond. Cutting and polishing them takes away all the fascination of their surface and internal structures. It just leaves them as sparkly stuff. Un-cut diamonds are far more interesting, and for that you absolutely need the provenance, down to the mine.
Short version - some close-in planets will be tidally locked, but not necessarily all of them. And (as discussed), the fact that M-dwarfs covers more mass variation than the next three classes of stars combined (F-dwarfs, G-dwarfs like the Sun and K-dwarfs) so it would be safe to expect a considerable variation in the behaviour of planets around M-dwarfs.
Consider tidal locking in a system with an M-dwarf star, a "hot Jupiter" and our Planet of Interest (PoI). If in orbit around either the hot Jupiter or the star, the PoI might become locked. But with the three in relatively close interaction, the PoI could be disturbed between locking to one, or the other, or alternating, or spinning irregularly. Feel free to use a planet with an irregular - literally chaotic, even - rotation in an SF scenario of your choice.
... which is counteracted by the increased number of M-dwarfs, and their increased lifetime.
I'm a geologist, you insensitive clod!
The interference colours we see under crossed polarisers are real colours, intrinsic to the material, it's orientation and the radiation impacting it. (Also, pleochroism visible under polarised illumination without the analyser in the optical assembly.) No stains involved. (Though we do sometimes use stains to improve contrast too, e.g. Aliziarin Red to differentiate between different carbonate minerals.)
The headline annoyed the fuck out of me when I saw it in Google Science News. So I looked it up on Arxiv (costing Giz ... whoever they were ... some eyeball-seconds).
Link to original paper. Link to PDF.
Abstract.
During a systematic search for supermassive black holes (SMBHs) not in galactic nuclei, we identified the compact symmetric radio source B3 1715+425 with an emission-line galaxy offset ~8.5 kpc from the nucleus of the brightest cluster galaxy (BCG) in the redshift z=0.1754 cluster ZwCl 8193. B3 1715+425 is too bright (brightness temperature â¼3Ã--10^10 K at observing frequency 7.6 GHz) and too luminous (1.4 GHz luminosity â¼10^25 W/Hz) to be powered by anything but a SMBH, but its host galaxy is much smaller (â¼0.9 kpc Ã-- 0.6 kpc full width between half-maximum points) and optically fainter (R-band absolute magnitude â¼â'18.2) than any other radio galaxy. Its high radial velocity â¼1860 km/s relative to the BCG, continuous ionized wake extending back to the BCG nucleus, and surrounding debris indicate that the radio galaxy was tidally shredded passing through the BCG core, leaving a nearly naked supermassive black hole fleeing from the BCG with space velocity >2000 km/s. The radio galaxy has mass
So, yes, a really interesting discovery. Not as pumped up as the headline writers (though even the paper-writers fell to the temptation of "A NEARLY NAKED SUPERMASSIVE BLACK HOLE."
The discussion upthread between several participants about how this black hole could be escaping from the collision, in a gravitationally bound system. Utterly astonishingly, the paper's authors considered this point too (page 7 of the paper) :
Someone else asked where to point his telescope. The answer is (J2000 coords) RA 17d 17' 19.20" Dec +42d 26' 59.0" (check Simbad for Zwicky Cluster 8193)
Fuels - maybe. But then again, industrial chemistry text books in the 1930s were berating people for being stupid enough to burn oil, instead of using it for something useful. As feedstock for the chemistry industry (most of the plastics you've ever used, including in your 3d-printer), for lubricating materials ... liquid hydrocarbons will continue to be used. Like it or lump it.
Well, people have been using it for fertilizer for ... well, millennia certainly. Probably since the establishment of the first permanent villages. So let's say, 10 thousand years. The 1-2% or so of that time which (some) people have been able to consider the problem "flushed away" is lost in the noise.
Whether converting it into liquid hydrocarbons is more energetically efficient than using it for making food ... short question, long (and locally variable) answer.
OTOH, there continue to be rumours that Ridley Scott is working on a script for the Forever War, which is good news in itself, but bad news for this idea.
That sounds more like "Ender's Game" than a Heinlein. Heinlein (as an author) was all for having as many children on his daughters and mother as possible.
Then again, Heinlein's main characters were almost always members of the 1% (honourable exceptions to "Citizen of the Galaxy" and "Farmer's Freehold", possibly others).
Bulshit.
On the alleged influence of the "armed population", not on whether or not the Germans/ Japanese/ Italians had any plans for landing saboteurs on either coast.
Sabotage and/ or infiltration programmes depend on secrecy, not fire power. Being recognised is normally time to bug out and fade away. That worked for the resistances in France, Yugoslavia, Ukraine, and Poland - until they engaged with a military (or police : same difference) force, they kept as low a profile as possible. Then hit and then faded away.
I would suspect that the main reason for the Germans and Japanese not landing appreciable sabotage/ fifth column efforts in America was the same as for them not being noticeably successful in Britain : they couldn't find enough turncoats willing to stay brought. That raises (again) another significant question about how much contact the Italian fascists had with the Mafia. And of course, whether the Mafia stayed brought, or took the bribes then shopped the agents anyway.
Do you have evidence to back up this assertion?
Have you considered the possibility that they read the book and understood it in a different way to how you did?
Heinlein does strike me as a right-wing nut job with some serious incest hangups, but he does occasionally show some signs of different, less stereotyped, thinking.
For most of the book, almost nothing was known about "the bugs," including what their capabilities were. At several points in the book, events looked as if "the bugs" were learning from the humans, as the humans were trying to learn from the "the bugs".
Heinlein was, in part, looking at the questions of "What if we met an enemy that was as good as us? How much effort would we put into 'jaw jaw' instead of 'war war'?" And as a military man, Heinlein was quite sure that humanity would put a lot more effort into 'war war' then into 'jaw jaw'.
That's probably the most useful suggestion I've seen yet on this thread.
OTOH, with a 3-d printer of modest capabilities, making new patterns of rotors is almost trivial. 7 blades with an edge band to suppress tip-noise? No problem. Different numbers of rotors on each motor? Not much problem.
In Britain? Are you joking? Cops aren't armed with nything more lethal than a pepper spray, and the police force struggle to recruit enough existing officers to take firearms training to maintain the numbers of officers who can be armed. The prison service don't have any armed resources at all. Not a pop-gun, nor any legal or practical infrastructure to start one.
Nope, that's a complete non-starter. Getting global support from all drone manufacturers would be easier.
Or, as an alternative, they need enough money to rent the technical skill ...
There are many vectors whereby this could be attacked. Try this one for size: commodity GPS receivers - the $5 (or whatever price) modules that you include in your $200 drone - are going to be made for bulk sales. So they're not going to have encryption on their output because that would reduce sales by complicating integration into products.
So for a fairly robust family of attacks, I'd put together a system that takes the serial (NEMA? something like that; ben a while since I needed to poke my nose under the skin of GPS tech) output stream from the GPS, and if it includes coordinates in [programmed area] it will alter the serial stream to be 2km to the west - or whatever else. So you can then fly your drone in prohibited airspace, while the drone thinks it's in open airspace. And no-one in the entire universe other than the person programming the flightpath waypoints and the ... "Adjustment Chip" will know just how they're going to set that up.
The same logic applies to GLONASS chips (incorporated into commodity satellite navigation chipsets for the last several years) and is likely to apply to Galileo ones too. Not having the same commercial concerns as GPS and Galileo (arguable for GLONASS), the Chinese system-to-be may or may not be vulnerable to similar attacks.
Back to school for you, to revise what pH actually means.
Look at the other concentration of earthquake events in the middle of the continent. Even with my loose handle on USian geography, I can trace the outlines of the Missouri and Missippiissi rivers (it doesn't surprise me that they form state borders, but again, that's never been on my "need to know" list), then just south of where they join ... a NE-SW oriented ellipse of earthquakes. That's New Madrid, that is. Interesting place - some of the most severe earthquakes in the written history of the North American continent occurred there. And that is including the big threats on the West Coast.
Weird thing about New Madrid - it's been more or less quiet since 1812. Just enough activity to keep people worried. Enough quietness to lull people into a false sense of security. That's a really dangerous combination.
While I'm perfectly happy about a correlation between production, injection and earthquakes (the Rocky Mountain Arsenal waste disposal well was literally a text book case in my youth, before people started to pay me to be a geologist), there are some real questions about the actual distribution of earthquake risk in North and South America because the written record is so short - a mere 3 to 4 centuries. It's not much better for most of Africa too (thanks China for having some written records!).
I'm not too happy with one part of the SciAm article you link to. At one point the authors say
nope. The lessons were never forgotten. They were perfectly well known. There's a definite shift in the subject over the next few of sentences:
Literally, the Rocky Mountain Arsenal results were in the text books. If Petroleum Engineers don't read geology text books, then there is definitely something lacking in their education (considering that their entire subject revolves around stuff you find in rocks). But that knowledge was never "forgotten".
Perfectly true. If you're on an institutional network with a subscription to Bull.Seimol.Soc.Amer then you can get the paper here, or for the rest of the human race you can get it from Sci-hub here.
So, what does the paper actually say. By the Noodly Appendage, that is one dull paper. Oh, there's an interesting paper on pseudotachylite too. Yes, there's a moderate degree of correlation, but there are also a lot of problems with the pre-instrumental earthquake reports and locating the earthquakes. The lead author (Hough) is a well-respected seismologist, but this isn't an earth-shatteringly great paper.
The flow rates reported for some of these wells, given that they're for natural production without even produced gas re-injection to maintain reservoir pressure or to provide gas lift, makes me think that many of these structures were probably significantly over-pressured before they were drilled, so reports of multiple blowouts in some of the wells are utterly unsurprising. Unfortunately, the extremely primitive degree of data acquisition during this period (remember - we're back in cable-tool days here. Rotary drilling was in the future for these guys) means that the data to analyse the wells properly likely doesn't exist, and never was collected. "Tatties ower the side!" as my pore pressure instructor would say. Oh - sorry. For the non- pore pressure analysts in the audience, tthe (inferred) over pressure alone would increase the likelihood of ground subsidence as the structures are depressurised.
It's weird looking back at these well reports to see such shallow depths. Even the deeper wells they discuss barely top 6000ft - not even 2km. I haven't drilled a well that shallow in ... I can't remember. Re-phrase : every well I've drilled in almost 30 years in the game has gone through those depths in the process of getting to somewhere interesting. No, tell a lie - two wells I've drilled in that time have evaluated structures that shallow - but for waste disposal, not hydrocarbon production.
Magnitude (both the Richter system introduced shortly after the period of this study, and the modern system) is a logarithmic scale. Two orders difference (e.g, from M 3.5 to M 5.5) would be a thousand-fold difference in released energy.
Is there a law preventing one from buying a voting machine?
Say that I run ... let's say, the Student's Union (managing the pub, laundry, band practice room, and cafe) of Smallsville University (dedicated to the memory of Derek Smalls) ... and I approach Diebold (I may remember the name wrongly) to buy a voting machine for conducting our Union's internal democracy, then they'd turn me away citing [law number and section, of year].
Diebold may choose to tell me they only consider orders of ten thousand or more machines, for whatever reasons of business, policy or prejudice against Derek Smalls (Messiah on Mondays through Wednesdays) ; but that's a different thing to being prevented by law from selling me one.
Is there any law preventing me from buying one second-hand? You'll note that I've set up the scenario so I have perfectly reasonable grounds for wanting one - there's no nefarious intent to complicate matters.
I certainly don't. In fact, I can't think of anything that I've ever replaced when the warranty has expired, because the warranty has expired.
I'm not even sure that could be a rational decision. Costs-wise, if it's still working, but the warranty has expired, then you continue to use it until it fails, and then assess the cost of repair. Possibly, if it's a leased or rented bit of equipment and the warranty expires, then it would become rational to say to the owners "New widget, please!" Which is one of the reasons (apart from tax advantages) for leasing instead of owning. But then the device isn't (and never has been) yours to hack anyway. That probably covers cars being brought under finance deals too (they belong, at least in part, to the finance company ; as such, if you want to hang furry dice from the rear view mirror then technically you need to have the co-owner's written permission before stating the modification.
What sort of ground stations are you going to need. Oh right, you're doing triangulation - presumably by signal arrival timing variation. So we don't need to worry about Rayleigh criteria for the frequencies involved. You'd need 4 ground stations minimum (3 for a fix, one for error checking), and you'd need sufficient to have 4 on the appropriate face of the planet at any arrival time. So that's a minimum of 6 ground stations, distributed as octahedrally as possible. Doable.
Now, the big question - how does the ground station know when the signal was transmitted? That is why the signal from GPS satellites contains the time of transmission in the signal packet. (I assume the same is true for GLONASS and Galileo ... GLONASS, confirmed ; not sure on Galileo, or on the Chinese system). So ... you've got to put a pretty good quality radiation hardened atomic clock quorum onto each of your satellites.
Something like this. With RTGs there is an obvious relation between mass, power and half-life. The design linked above will produce 100W after 14 years, which is probably at the limit of acceptability, considering the distance this constellation is going to have to cover. However, at 45kg, that's a big pill to swallow.
Smaller RTGs will have lower power output, or shorter lifetimes, or both. Unless there is some isotope of unobtanium with more desirable properties.
I was going to make comments about more unobtanium, but it seems that despite the Star Wars style name, electric double-layer capacitors are becoming available. Scanning the applications exampled in the Wikipedia article, I don't see anyone claiming better than a decade lifetime, but that's a credible technology gap to pass. I'm more worried about the radiation sensitivity of them - they're not happy with voltage spikes. I've not heard of them making it into space technology yet, but that's probably just timing. There are rocket scientists in the world after all. (Or maybe they've come up with other ways of managing power which obviate the need for radiation-sensitive components.)
Now, how many of these are you going to need? I'm going to assume that they're all sped out using Jupiter gravity assists with the same sort of speed as New Horizons. So that's a 10 year time of flight to approach the search region. Something like 30 years to cover the projected perihelion interval (and depending on Planet 9's orbital eccentricity, 2x to 4x to cover the regions out to aphelion). (Incidentally, if we could start launching these tomorrow at 09:00, the telescopic searchers still have 10 years before they face any competition.)
That gives a search volume of ... 7.98E+30 cu.km, IF Planet 9 has an orbital inclination similar to everything else in the Solar system (we explicitly don't know that - some authors are making serious arguments for Planet 9 being inclined at right angles to the main ecliptic plane. In that case the search volume goes up to the order of 2.2E+031 cu.km).
How efficient would the search be? I'm just going to make a wild-arsed guess that if a probe passes within 10 million km of Planet 9, then it'll acquire a sufficient deflection to be detected. Total guess. So each probe has a search volume of around 3E+022. So you're going to need between 10^8 and 10^9 probes.
Is there enough plutonium (or Unobtanium-115) to build the first 10 million RTGs? And launch capacity? Or do we need to do some serious telescope work to narrow down the range of possibilities? (Which has the additional advantage of returning data a decade or several before the space probe fleet could possibly start to return useful data.)
Bo-lock-s. Unadulterated bullshit of the highest ordure.
I've read one thing by KSR that caused me to file him (well, "her" for a long time. It's only recently that I've discovered that she is a he Whatever.) under "try more". Then I waded through the first of the "Multicolour Mars" series and found it amusing but not worth further wading. But if he has really come out with that pathetic excuse for a science-driven plot-line ... wow, that kicks him off the "try some more" pile of names and into the "move to next author" pile.
Does he not think that by the time the first generation ships are actually dispatched, they wouldn't have been running for. literally, generations mining and exploring the Kuiper Belt and Oort Cloud? That when these ships came back into a servicing station (e.g. in high Saturn orbit) their life-support techs wouldn't know to the gram the concentrations of elements in their discharges ... because they'd be paying money for discharge of materials to the service station. I mean, what's the LS-tech going to do when s/he sees that [NaCl] is increasing in the black-water/ white water system? Ignore it? Log it, report it to the LS-manager, and increase the proportion of flow that goes through the NaCl ion-exchange resin to bring the system back within limits while concentrating the excess NaCl into a storable volume?
Has KSR never in his life read the daily water quality reports from a ship's "watermaker" system? People have been watching for problems like this for decades already.