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User: Rei

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  1. Re:Why sunglasses still matter... on The Blind Spots In the Nuclear Test Monitoring System · · Score: 1

    No, this kind of blind spot.

    Expect Russia to become even more paranoid and trigger happy than usual.

    (This is, of course, what happens when you try to modernize every last system in your arsenal at once even when you're *not* under sanctions.. almost all of these programs can be expected to be behind schedule and underdeliver)

  2. Re: Drop it on Europa on NASA Releases Details of Titan Submarine Concept · · Score: 2

    I'm not just talking about Europa. I'm talking Enceladus and half a dozen other moons that were thought to be most assuredly dead but turned out to have liquid water geysers, for example. I'm talking about the unexpected internal heat in our moon. I'm talking about Titan's apparent level of internal activity in excess of predictions. I'm talking about how Io's volcanoes are in the wrong spot based on what we know about how it should be heating. I'm talking about how there's even considered 50-50 odds right now that Ceres has geysers (guess we'll find out the answer to that later this year ;) ), and there's essentially zero tidal heating there. I'm talking the discovery of mega-storms on Uranus, whose fueling heat is still a mystery. I'm talking about not simply the fact that Jupiter and Saturn release more heat than they receive from the sun, but that counterintuitively Saturn's ratio of heat received to heat emitted is more extreme than that of much larger Jupiter. And on and on.

    About 3-4 times a year I hear some planetary scientist or another baffled about where the heat is coming from to explain something they're observing in some body or another. I never hear the opposite, never "why is this colder / less energetic than expected". Perhaps there's not one cause, there could be many. But clearly we're not very good at our expectations of how hot celestial bodies should be internally, for whatever reasons.

    Who wants to bet that this summer we're going to be hearing, for some reason or another, planetary scientists boggling over New Horizons data, asking "where is the heat coming from to explain X that we're seeing on Pluto? That shouldn't be there."

  3. Re:Landing Pad on SpaceX Falcon 9 Launches, Rocket Recovery Attempt Scrapped · · Score: 1

    Still, even in the case of a barge landing, it could potentially be just a "basic inspection and refuel" stop before flyback to the shore, where any more serious maintenance would be done and the craft prepared for its next space launch. The engines are fully restart capable, after all, and the burn time would be relatively low.

  4. Re: Drop it on Europa on NASA Releases Details of Titan Submarine Concept · · Score: 1

    Except that it always seems to be in excess of what they calculate. It's just one "there's more heat than we expected' after the next... one kind of begins to wonder if they need to figure out why their expectations always seem to be wrong.

  5. Re:why Titan? send it to Europa on NASA Releases Details of Titan Submarine Concept · · Score: 2

    go where the water is and there's a lot of water on Europa

    There's also a lot of water on Titan, so again, your point? Titan is one of two bodies in the solar system (the other being Europa) where there's a high degree of confidence that there's a global subsurface ocean deep enough to fully decouple the crust from the mantle / core. The subsurface tides on Titan are so strong that the whole mercury-sized moon buckles 10 meters depending on where it is in its orbit.

    So again, why the obsession with Europa and not Titan? Europa = subsurface ocean, fine. Titan = subsurface ocean, extensive organic chemistry, weather, an atmosphere that facilitates exploration, surface hydrocarbon seas, and tons more. Not to mention that its five times bigger.

  6. Re:why Titan? send it to Europa on NASA Releases Details of Titan Submarine Concept · · Score: 1

    How do you know that Europa's subsurface water seas aren't sterile and that Titan's subsurface water seas don't have little fishies?

  7. Re:Titan's Crust on NASA Releases Details of Titan Submarine Concept · · Score: 2

    They're talking about the exposed hydrocarbon seas. They're mainly confined to the poles. The largest, Kraken Mare, is larger than the Caspian Sea, though is only believed to be about a tenth as deep. There's still some question as to whether the surfaces freezes, and if so, whether it's for how long. For any frost to float it would have to contain nitrogen bubbles. Some very small waves are believed to have been observed.

    Exactly what makes them up, their source, how they behave, etc is all quite speculative right now. Wikipedia describes them thusly:

    The exact blend of hydrocarbons in the lakes is unknown. According to a computer model developed by Daniel Cordier of the University of Rennes,[23] three-quarters of an average polar lake is ethane, with 10 per cent methane, 7 per cent propane and smaller amounts of hydrogen cyanide, butane, nitrogen and argon. Benzene is expected to fall like snow and quickly dissolve into the lakes, although the lakes may become saturated just as the Dead Sea on Earth is packed with salt. The excess benzene would then build up in a mud-like sludge on the shores and on the lake floors before eventually being eroded by ethane rain, forming a complex cave-riddled landscape.[24] However, the chemical composition and physical properties of the lakes probably varies from one lake to another (Cassini observations in 2013 indicate Ligeia Mare is filled with almost pure liquid methane ... Temperatures close to the freezing point of methane (90.4 Kelvins) could lead to both floating and sinking ice - that is, a hydrocarbon ice crust above the liquid and blocks of hydrocarbon ice on the bottom of the lake bed. The ice is predicted to rise to the surface again at the onset of spring before melting. ... Cyclones driven by this evaporation and involving rain as well as gale-force winds of up 20 meters per second are expected to form over the large northern seas only (Kraken Mare, Ligeia Mare, Punga Mare) in northern summer during 2017, lasting up to ten days.

  8. Re:Drop it on Europa on NASA Releases Details of Titan Submarine Concept · · Score: 4, Interesting

    Hmm, just another thought which I haven't seen anywhere else. Orbital velocity through Titan's ionosphere would be about 1500 m/s, if my calculations are right. Exhaust velocity on ion engines ranges from tens of thousands to millions of meters per second. So a ram scoop to refill propellant is plausible, your drag should be well less than your ability to reboost with the propellant you acquire, even if efficiency is low; in practice you should be able to capture much faster than your burn rate. While all ion engines have certain elements which are "optimal" in terms of performance, you can generally use whatever ions you want without too dramatic of a sacrifice in terms of isp and thrust (so long as there's no corrosion problems or the like).

    So, for a sample return mission:

    1) A probe with detachable, flying lander (each RTG-powered) is boosted to LEO. As for the lander, I personally like the tilt-wing design, as it allows easy of landing and requires only a small RTG (it can fly in short hops, replenishing batteries on the ground while during surface science), but allows the high speed and range of travel of a fixed-wing plane.

    2) The probe begins a decade or more ion-propelled journey to Saturn, with only enough propellant to reach a stable orbit in Titan's upper atmosphere (and possibly some minor exploration of the Saturnian system en-route).

    3) The lander drops off, aerobrakes over the course of a few weeks, and then explores the planet for a year or so while the orbiter replenishes itself. A tilt-wing aircraft could probably explore all of the most interesting places on the planet in that timeframe and take numerous small samples). The lander only needs a small antenna, as the orbiter can act as a repeater to Earth.

    4) When exploration and propellant refill are done, the lander then flies back up through the atmosphere to as high and fast as it can, then activates a rocket stage (1500-2000 m/s delta-V) to re-rendezvous with the probe. The spent stage is ejected.

    5) The probe returns to Earth on ion power using its propellant from Titan (possibly with some minor exploration of the Saturnian system en-route). Upon return to Earth, the leftover propellant could itself be studied as a sample return in its own right (it could even be gathered into different tanks from different altitudes via an elliptical orbit if so desired).

  9. Re:25 Years from now? on NASA Releases Details of Titan Submarine Concept · · Score: 5, Interesting

    You joke, but the ability to reconfigure spacecraft on the fly even on the smaller scale has proven itself valuable time and time again. I love how they came up with a trick after New Horizons was launched to nearly double its communication rate. It has two radio transmitters, one primary and one backup, and one dish. When they launched, it seemed obvious that only one could be used at a time - but en route someone figured out that if you have one transmit with right-handed polarization and the other with left-handed, they can both transmit at the same time, and then on Earth the two signals can be separated out. But since the spacecraft wasn't designed for enough power to use them at once (that was never supposed to be necessary), they needed to find a trick to get more power. And it's not easy, given that there's not a lot of things running when the probe is just drifting in deep space - what are you going to do, shut down your guidance computer? Well... yes, that's exactly what they came up with - when they've filled up their memory, they align the antenna, then spin up the spacecraft, shut down the guidance computer, transmit at double speed until the memory is free, then restart guidance and stop the spin so that they can resume data collection.

    While 3d printing and robotic arms for assembly is a stretch at present, the importance of having hardware flexibility is increasingly being demonstrated in space missions.

  10. Re:I'm thinking there's a bigger problem... on NASA Releases Details of Titan Submarine Concept · · Score: 1

    If the properties of longer-chain hydrocarbons apply to that of supercooled liquid short-chain hydrocarbons, then it should be pretty transparent to RF. That said, if it was a problem, the solution is as simple as "surface".

  11. Re:Drop it on Europa on NASA Releases Details of Titan Submarine Concept · · Score: 1

    And speaking of liquid water under the surface, has anyone else noticed how almost every body in space that people point a camera at long enough seems to have evidence of "unexpectedly large" amounts of heat under its surface, esp. at surprisingly shallow depths? I really want to know what it is that people are overlooking because it keeps happening again and again, people expect to see dead rocks drifting through space and find out that they're still surprisingly alive with some process or another that means internal heat.

  12. Re:Drop it on Europa on NASA Releases Details of Titan Submarine Concept · · Score: 5, Informative

    What you're describing is an incredibly challenging tasks. One needs several missions to get to better know Europa in general, and specific potential entry areas in particular, first. These missions are going to be expensive and have long lead times. And an actual boring / submersible mission is going to be extremely expensive.

    Titan has one main strike against its exploration, that it's so dang far away. But almost everything else about it is tailor-made for exploration. It's ideal for aerocapture. It's trivial to stay aloft, at an altitude of your choice, be it by hot air or lifting gas balloon, blimp (likewise), helicopter, fixed-wing aircraft, tilt-wing aircraft, etc. Low temperatures pose some difficulties but can be nice for electronics, and the rate of heat loss (even in a hot air balloon concept) is so low at such low temperatures that you don't need very big heat sources. The hydrocarbon seas are permanently exposed for whatever means of exploration (aerial, boat, submarine) you choose. Ascent requirements (sample return, for example) are surprisingly low versus a body of that size due to the ability to fly so high in the significant pressure / low gravity environment before needing to fire rockets. And so forth. And there's so darn much we don't know about Titan, perhaps even more than Europa. There's constant complex organic chemistry going on in the upper atmosphere of which we know almost nothing, and probably even some on the surface. There's probable liquid water under the surface and cryovolcanoes that erupt it to the surface. There's earthlike weathering processes done with/to completely different materials, and the entire gas cycle is a giant mystery right now. So yes, I'm pretty excited about whatever mission goes to Titan next.

    Too bad the next launch window to Saturn (2018, 4,13km/s delta-V, 8,2 years) is simply not going to happen. : There's not going to be such a low delta-V/time window for a long time - 2020 is 5,18 km/s / 11,0y; 2021 is 4,80km/s / 8,8y; 2024 is 4,81km/s / 10,4y; etc. So if we're lucky maybe we could get the 2021 window (though the increased delta-V reqs would significantly hurt the payload)... otherwise, there won't be a spacecraft getting to Saturn before the mid 2030s. :

  13. Re: Unsettling science on US Gov't To Withdraw Food Warnings About Dietary Cholesterol · · Score: 2, Insightful

    Really? You don't believe in acid rain damage? So who's been f*ing up statues? Is it evil environmentalists? Are they also the ones rigging the pH meters? Did they fake the science about how SO2 oxidizes to SO3 and then hygroscropically forms H2SO4 droplets? Damn them!

    What about ozone don't you believe? That humans were extensively emitting CFCs? That CFCs have been measured in the stratosphere via sounding rockets, balloons, and aircraft? That CFCs at the levels measured demonstrably catalytically destroy ozone, and that it's a rather simple lab experiment to prove it? That ozone was on a demonstrably measurable decline and UV demonstrably measured on the rise? That the decline has significantly tapered off and even started to reverse a little since there was a crackdown on CFCs? Or, contrarily, do you accept all that but think that UV is harmless to humans?

    Peak oil and peak food are not sciences. They're common in the popular press, in books, etc (and nowadays on blogs and forums), but have received rather limited review in scientific journals. Don't get me wrong, there have been some, but compared to other fields rather little, and the results have been mixed to say the least.

  14. Re:Unsettling science on US Gov't To Withdraw Food Warnings About Dietary Cholesterol · · Score: 5, Informative

    Even in this case, it should be pointed out that for about one in three adults, levels of dietary cholesterol do have a significant effect on the levels of cholesterol in the blood. But even for them, the effect is half as much as the effect of saturated fat intake on blood cholesterol.

    There's all sorts of potential health info one could write on a package. Every additional bit you add takes attention off every other that's already there. Mandating listing cholesterol when it's not as major of an issue as other information on there, like saturated fat, trans fat, salt, etc is probably not justified.

    As for the GP, anyone who lumps all fats together as if they're one substance is an idiot. Different fats need to be treated differently. If you think eating mainly saturated and trans fats comprises a healthy diet and will lead to a long lifespan, you're flatly in contradiction to the overwhelming body of research. But if you eat a lot of monounsaturated and omega 3 fats**, this could well be true (though there's lots of niggling details - for example, mono is probably great if you're heart-risk prone but not if you're breast cancer prone). And even these sorts of categories are still broad generalizations; each is comprised of many different individual fat molecules, and each one may carry its own benefits and risks.

    Note on omega 3s... this means as a general rule uncooked omega-3 rich foods. Omega-3s are heat-unstable, they break down under cooking (not to mention it ruins the flavor). They should ideally be stored refrigerated as well. There have been some studies that certain herbs, such as rosemary, can help heat-stabilize omega-3s - but its a limited effect. Also, as mentioned above, not all omega-3s are identical. For example, the EPA and DHA from oily fish or krill are believed to be more effective than the APA from plants, which the body has to convert at low efficiency. But the usually bad taste of the former has discouraged use, while most omega-3 rich plant oils (flax, walnut, hemp, etc) are quite flavorful (really, I have no clue why they're not used more often in salad dressings and the like just for that reason alone). Also, you aren't just what you eat, but also what what you eat eats. For example, eggs from hens fed green plants and omega-3 rich feeds generally are several times higher in omega-3s than hens fed a standard grain feed. The same applies to levels in meats.

  15. Re:Bitcoin and criminals on The Technologies That Betrayed Silk Road's Anonymity · · Score: 2

    Yep. Base your operations in Russia or another country reluctant to extradite to the west, and then use bitcoin to get the money to you so it can't be readily blocked. Even if they identify you, they probably can't extradite.

    Seems to be the strategy that the CryptoWall folk are using, at least.

  16. Re:More than a little retarded on The Technologies That Betrayed Silk Road's Anonymity · · Score: 2

    Haha, I knew right from your second paragraph that you must be a furry. ;)

    While I don't personally get it, power to you, man. :) Rrrawr! And my sympathies for having to be in the closet about it. :(

  17. Re:Stupidity is a technology now? on The Technologies That Betrayed Silk Road's Anonymity · · Score: 1

    The problem is not his particular slip-ups - it's the widespread nerd belief that Tor, Bitcoin and crypto are going to keep you safe from whoever-you're-a-thorn-in-the-side-to. The list of potential ways to accidentally leak your identity is massive; sooner or later, you're going to slip up. Just like what happens with all "perfect crimes".

    Honestly, if you really want to be safe from arrest (at least for a while), move to Russia, pay off and/or befriend the right people, be a Putin supporter, and only do things that are a PITA to people in western countries. In the current political climate they're more likely to give you a medal than deport you.

  18. Re:Stupidity is a technology now? on The Technologies That Betrayed Silk Road's Anonymity · · Score: 1

    Yes, being social and open is the opposite of being private. Plenty of people are well aware of the consequences and make that choice of their own free will.

    Then there are also idiots like Ulbricht who have pretty much a religion around Tor, Bitcoin, and crypto and think it can actually guarantee their privacy when they're doing stuff that they shouldn't be doing.

  19. Re:Lasers are easy to stop on The US Navy Wants More Railguns and Lasers, Less Gunpowder · · Score: 2, Interesting

    What do you mean by "burn through"? When you heat up a gas hot enough to change its state, the next state up is plasma. Plasma is opaque.

    Really, lasers seem much easier to defend against than to get to work right... there's so many varied potential defenses for them (ablatives, smoke, chaff, higher thermal conductivity materials, heat sinks, polished surfaces, etc, plus presenting a precisely pinpointable beacon for return fire). And any ambient scatter (and there will be a lot) will be enough to cause permanent blindness for very long distances in all directions, so you run the risk of having your weapon classified as prohibited under the rules of warfare. This might not apply to high altitude planes and missiles which can be several kilometers away from the nearest observer, but still, the balance of difficulty would seem to be in favor of the defender, not the attacker.

  20. Children are not property. on Mississippi - the Nation's Leader In Vaccination Rates · · Score: 5, Insightful

    Parents are granted a tremendous amount of leeway over what to do with their children. But at the end of the day, children are not "things" for parents to do with as they wish. They're people. A parent may have a sincere and deeply held belief that children don't actually need to eat, that if they meditate enough they can gather the energy they need from the sun. But that doesn't mean that Child Protective Services aren't going to get involved if the parents refuse to feed their child. No, there's no easy definition for where the line between parental rights / belief dominate and where child abuse begins should be. But there must be a line.

    And ignoring the fact that the person we're talking about here is too young to make informed decisions, even if that wasn't the case, it still wouldn't be a reasonable argument. Even if we were talking about adults, while you're free to endanger yourself to your heart's content, you don't have the right to endanger others. You may feel that drunk driving is perfectly safe and it's just your personal choice and drunk driving laws are an infliction on your freedom of movement, but the law sees it differently for damned good reason, and you will be punished if caught. Want to endanger yourself? Fine, go do it. Want to endanger me? Nope, and thank $DEITY that there are laws and law enforcement to stop you. You don't have an inalienable right to put your neighbors at risk of mowing them over with your car, and you don't have an inalienable right to walk around them as a disease vector.

  21. Re:The credibility of science? on Science's Biggest Failure: Everything About Diet and Fitness · · Score: 1

    Good to know that you feel fit to just wave a way a large collection of Scott Adams quotes because you don't like the website.

  22. Re:I love Alibaba/Aliexpress on Alibaba Tests Drone Delivery Service In China · · Score: 1

    How can one find reputable intermediaries?

  23. Re:I love Alibaba/Aliexpress on Alibaba Tests Drone Delivery Service In China · · Score: 1

    I've often found products there that I've had interest in but have never purchased. Because quite simply, I have no way to know how much I can trust them. How am I supposed to make a judgement call about the legitimacy of a random company in China that I know nothing about?

  24. Re:Wasteful, Inefficient, Potentially Dangerous... on Alibaba Tests Drone Delivery Service In China · · Score: 1

    Stealing a valuable object with a GPS and camera in it for laughs? I hope you find jail funny.

  25. Re:Wasteful, Inefficient, Potentially Dangerous... on Alibaba Tests Drone Delivery Service In China · · Score: 1

    What are you talking about - 15 minutes? They actually give an example delivery in TFA that they plan to make and it's nearly an hour. More to the point, there's simply no way that an as-the-crow-flies drone is going to be moving anywhere even comparable to walking speeds. Realistically you're talking an order of magnitude higher.

    And seriously, probably half the things I order are light enough to fit into a midsize delivery drone. Or even a little drone - the last thing I purchased online was a cell phone protector, for example.