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User: randall77

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  1. Cameras on Ask Slashdot: Best Biometric Authentication System? · · Score: 5, Interesting

    Just buy a point-of-sale camera system that department stores use. They keep weeks of video from dozens of cameras available for review. Requires 0 overhead in the common case when no audit is required. It is really easy to find out who did what given a time and camera ID. Use humans for your facial recognition, they're actually really good at it.

  2. Re:Just build it horizontally on LiftPort Wants To Build Space Elevator On the Moon By 2020 · · Score: 1

    Yes, except substitute "aircraft carrier" with "maybe a 1m target" and "landing at 100mph" to "entering at 5400mph" (the escape velocity of the moon, a reasonable order-of-magnitude guess) and "miss and you lose an aircraft, maybe damage the ship a bit" to "miss and you blow your mass driver to smithereens".

  3. Re:Just build it horizontally on LiftPort Wants To Build Space Elevator On the Moon By 2020 · · Score: 5, Insightful

    Because catching a bullet with a gun is just as easy as shooting a bullet from a gun...

  4. Re:One other thing a Space Elevator needs... on LiftPort Wants To Build Space Elevator On the Moon By 2020 · · Score: 2

    First we need a fusion reactor.

  5. Re:er.. does the moon rotate fast enough?? on LiftPort Wants To Build Space Elevator On the Moon By 2020 · · Score: 1

    The moon does rotate, just at the same speed that it orbits (once every ~28 days).

  6. Re:Just build it horizontally on LiftPort Wants To Build Space Elevator On the Moon By 2020 · · Score: 1

    Non-uniformity only helps you, as you can take advantage of it to orient your mass driver above horizontal. The problem with a mass driver is the generated orbit intersects the moon again quite quickly (unless you go for escape velocity?). You need to redirect the payload once it is launched, with its own rockets or some sort of catching mechanism.

  7. Re:Space elevator orbiting the moon? on LiftPort Wants To Build Space Elevator On the Moon By 2020 · · Score: 1

    The upper point needs to be beyond the Lagrange point in order to hold up the elevator. Probably well beyond, depending on its mass relative to the cable.

  8. Re:Fantastic on Do Solo Black Holes Roam the Universe? · · Score: 1
    > Black holes at the edge of the universe - you've been there? You purport to know what happened in the first ms, seconds, minutes, and hours of the universe? Please do enlighten the rest of us. We have absolutely no idea what's further out from the prototype galaxies.

    I think you're confusing time with space. There is clearly a "time" edge to the universe, the big bang itself. But there is no evidence for a space edge of the universe. Yes, we don't have much evidence for what exists time-beyond the prototype galaxies. But we have lots of evidence for what is space-beyond the prototype galaxies. Namely, it will look like every other region of space that we can see. Relativity and the isotropy of space demand it. (i.e. if an alien grew up in one of those prototype galaxies that is ~13+ billion light years from here, and space beyond it was different somehow, then space wouldn't be isotropic for that alien. And that alien would have the same question about what is beyond our galaxy - we WERE the 13+ billion light year distant prototype galaxy for lots of the observers in the universe.)

    In any case, knowing what happened in the early universe is completely irrelevant for what is causing the dark matter effect in galaxies today (other than, of course, whatever causes the dark matter effect was probably created in the early universe). Flying spaghetti monsters could have roamed the early universe, it doesn't matter. Only things that survived until today can be causing it.

  9. Re:Of course: if stars can be slungshot out on Do Solo Black Holes Roam the Universe? · · Score: 1

    Because we've looked for them. See the Wiki about MACHOs: http://en.wikipedia.org/wiki/Massive_compact_halo_object

  10. Re:Fantastic on Do Solo Black Holes Roam the Universe? · · Score: 1
    > That would only apply if there were stars on the other side of them (from us) to generate light so that we could see the lens effect.

    True. That experiment has been done, see http://en.wikipedia.org/wiki/Massive_compact_halo_object

    There is much wrong with everything else you say. First, black holes can't be only at the edge of the universe. There is no edge - the universe is isotropic, as far as we know. Unless you suggest that the black holes were in the early universe but have somehow vanished over time. But in any case, that is totally irrelevant. We see dark matter effects IN galaxies NEAR us that we can see ALL of. If all the black holes are at the edge of the universe, they aren't affecting the dynamics of the galaxies we can see, and thus can't be cause of the dark matter effect.

  11. Re:Also good news for... on Texter Not Responsible For Textee's Car Accident, Rules Judge · · Score: 1
    > The job of the lawyer is to suggest all possible avenues of recourse.

    No it isn't. The job of the lawyer is to advocate for his client. Suggesting to the clients dumb ideas which won't work and will only end up costing them legal fees is not advocating.

  12. Re:Too complicated... on Swiss To Build Orbital Cleaning Satellite · · Score: 1

    Use a laser (from the ground) to keep it warm.

  13. Re:US regulations prevent this from being used on Grooved Disk Spinner Cleans Up: $1M For Winner of Oil Recovery Challenge · · Score: 1

    If you're picking up 70% oil, being able to dump the 30% water back into the ocean isn't going to make a big difference. All you need is a slightly larger tanker to hold the mix. And I'm pretty sure the tanker capacity of the oil industry isn't the limiting factor...

  14. Re:Target ORR on Grooved Disk Spinner Cleans Up: $1M For Winner of Oil Recovery Challenge · · Score: 1

    I think you meant the ORE (oil recovery efficiency), not the ORR (oil recovery rate). An ORE of 70% doesn't seem bad to me, that means that 30% of your tank capacity is wasted because you can't dump the water back into the ocean. You have to take it to a shore treatment center (where you would have to take the oil anyway). I would imagine that tank capacity isn't the limiting factor, oil companies have lots of tankers. I'd agree with the competition organizers that ORR is much more important.

  15. Personal evaporative cooling system on Ask Slashdot: Large-Scale DIY Outdoor Cooling of Cairo's Tahrir Square? · · Score: 1

    Design a system where you pour water into a personal container, and have a system of pipes from that container which distributes the water over the entire surface of the skin and evaporatively cools the person.

    Oh, wait, evolution already did.

  16. Re:Yawn on 80% Improvement In Solar Cell Efficiency · · Score: 2

    That article talks about energy payback, not $ payback. That is, how long it takes for the panel to produce the energy required to manufacture it. Typically the energy payback time is much shorter than the $ payback time.

  17. The Manhattan Project on Former Truck Driver Reconstructs A-bomb · · Score: 1

    Old news. I already know how to build an A-bomb. I watched "The Manhattan Project" in 1986.

  18. Re:I was *not* plain wrong -- unlike some 'rebutta on Google Didn't Ship Relicensed Java Code After All · · Score: 5, Insightful

    Yes, they are liable, but liable for what? What damages case can you make for files that aren't actually used?

  19. Re:Ethanol 10% causes more gasoline usage. on Once-Darling Ethanol Losing Friends In High Places · · Score: 2

    Or maybe he drove the ethanol leg uphill. Or upwind. Or on a day with a different ambient temperature. So many error bars to add to his numbers, I'm not convinced what he saw on a single trial would hold up in a proper controlled experiment.

  20. Re:Ethanol 10% causes more gasoline usage. on Once-Darling Ethanol Losing Friends In High Places · · Score: 0

    Yes, ethanol doesn't have the same energy density as gasoline. But miles per gallon is not the correct comparison. Miles per dollar is what really matters. Or maybe miles per pound of CO2 released. Miles per gallon is a useless measure to compare disparate fuels (unless you really are range limited).

  21. Re:Why 0.36 megapixel chips? on 1,400 Megapixel Pan-STARRS Telescope Comes Online · · Score: 1

    But large isn't the factor that matters - you can always change a secondary mirror to make the image as large or as small as you want. If by "fantastic light buckets" you mean they are very sensitive, that could be a reason.

  22. Why 0.36 megapixel chips? on 1,400 Megapixel Pan-STARRS Telescope Comes Online · · Score: 1

    Why are they using 600x600 CCDs? That's only 0.36 megapixels. Surely there are more advanced CCDs than that.

  23. Not a halfalogue on Why Overheard Cell Phone Chats Are Annoying · · Score: 1

    Half of a dialogue should be a monologue, not a halfalogue. Or, to avoid the conflict with the usual definition of monologue, maybe a unilogue?

  24. Re:Reversing the polarity of the electron discharg on Antimatter In Lightning · · Score: 1

    Or, perhaps, "Hey Kool-aid!"

  25. Re:New ocean connecting what now? on Giant Rift In Africa Will Create a New Ocean · · Score: 1

    Looking at the map, it appears the rift would indeed connect the Red Sea to the Gulf of Aden via a second pathway, making (very approximately) an island out of half of Eritrea and all of Djbouti.