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User: dak664

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  1. It requires energy, not money. on Neil deGrasse Tyson Touches Off Debate With Remarks On Commercial Space (theverge.com) · · Score: 1

    While some may dream of using Earth's energy resources to acquire extraterrestrial mineral resources, it won't happen until the spacers become self-sufficient in energy, and maybe even export a little back to the home world.

  2. Re:It's always been this way. . . on Ask Slashdot: What's Out There For Poor Vision? · · Score: 1

    And tiny black slots on the side of black cases. I keep a flashlight next to the laptop so I can find them.
    And blue on gray text on websites.

    I use glasses half the needed strength so monitor and distance are equally blurry (I take off the glasses for close work and reading).
    Windows 10, 1920x1080 with 150% increase in icons and text, at two meters to a 46 incher, works for me :)

  3. Re:Important distinction: Obervable vs watching... on 'Zeno Effect' Verified: Atoms Won't Move While You Watch (cornell.edu) · · Score: 1

    Even abstracting away the surrounding environment, doesn't the cat qualify as a observer of its own death?

    How about if you take the place of the cat and securely lock the box so on one can open it - do you become immortal?

    But as you say, idealized imaginary constructs rarely model reality.

  4. Re:Important distinction: Obervable vs watching... on 'Zeno Effect' Verified: Atoms Won't Move While You Watch (cornell.edu) · · Score: 1

    Exactly, and the same point removes the paradox from Schroedinger's cat. "We" don't have to open the box to force the cat into one state or another, it's the radioactive decay that observes the cat death. We simply find out whether it has happened or not when we open the box.

    But this could be a useful phenomenon, using a light beam to switch tunneling on and off.

  5. Re:Photons and solar wind on Making Liquid Fuels From Sun and Air · · Score: 1

    That's a bit misleading, although technically correct in the center of momentum frame. In general the relativistic energy is obtained from the length of the 4-momentum m(vx, vy, vz, mc^2) which gives the oft-quoted E=mc^2 for a mass that has no motion relative to the observer. But for a massless particle (which according to the theory must move at the speed of light in every frame), E=Pc .

    So more accurately the Sun loses mass to produce light but the transfer to Earth involves only energy and momentum. Absorption by the Earth increases the velocity of bits of matter which results in a corresponding mass increase.

  6. Re:faster than light never violates Relativity on Ways To Travel Faster Than Light Without Violating Relativity · · Score: 1

    Yes, the direction of the time axis is as observer-dependent as is the rotation of spatial axes. In Cartesian geometry the distance (dx, dy, dz) between points depends on the choice of coordinate system, but the length of that 3-vector is always the same (compared to the distance between some reference pair of points)

    Similarly in space-time it is only the length of the 4-vector between events A and B that can have any physical meaning. This length can be positive, negative, or zero. A positive length means the events are outside each other's light cones ("space-like"), thus have no causal influence on each other. A negative length ("time-like") means each could have participated in the events leading up to the other.

    A zero-length ("light-like") means there is no event separation between the two, i.e. they are the SAME EVENT (this might be understood as length contraction in the direction of motion going to zero when v=c). All the points on A's light cone (which includes B) are the same event as A. All the points on B's light cone (which includes A) are the same event as B. So far there is nothing to determine the direction of time, and indeed the physics describing the transfer of action when v=c is symmetric with time.

    But there are points Z on A's cone not on B's cone and these are also part of the same event AB even if they also have space- or time-like separation from B. Even if nothing can interrupt the ZAB event, the direct ZB distance could be time-like and thus set a direction of time, B before A. If B was a causal factor for A, it is difficult to see how ZAB could not be affected by the the direct BA interaction. It seems to me, here is the collapsing wavefunction. The only way I can reconcile it, is to introduce some time average long enough to allow all these paths to interact.

  7. Re:Plot Hole on Why Scientists Love 'Lord of the Rings' · · Score: 1

    At the crucial moment Frodo could not destroy the ring! The long trek was needed to bring about the fight in which Gollum reclaims the ring and then, in his exhaustion, falls with it into the crevasse.

    Also Sauron was distracted by all the fighting and uncertainty caused by the rumors of the ring being carried around.

  8. Re:Straight to the pointless debate on Out of the Warehouse: Climate Researchers Rescue Long-Lost Satellite Images · · Score: 1

    NASA did destroy a large amount of imagery in the 1980s, despite a public outcry I certainly contributed to. The official line was that no one knew how to read the warehouses full of 7 track tapes to for conversion to CD (the 2400 foot tape could store 5 to 140 MB depending on density). The obvious reason was no one wanted to spend the money to replace all the classified pixels with innocuous ones. And so mankind lost a large amount of wealth.

  9. Units were chosen for the conclusion? on Brookings Study Calls Solar, Wind Power the Most Expensive Fossil Alternatives · · Score: 1

    Can't be bothered to read TFA, and got a life-threatening yawn scanning the overly complicated rebuttal.

    Dollars of carbon offsets vs. megawatts of installed capacity is mostly a measure of the average capacity factor during operation, possibly adjusted by the fossil fuels needed for maintenance but that is way beyond this level of analysis.

    Capacity factor is something like 20% for solar (5 full sun hours most days), 40% for wind in a favorable location, 95% for nuclear until something bad happens In the end if they all have the same cost per installed MW then nuclear wins. If solar had 5x less installed cost then it wins, similarly for wind at 2.5 less.

  10. I'm happy here in North Carolina on New Map Fingers Future Hot Spots For U.S. Earthquakes · · Score: 1

    where the state legislature is not afraid to make suh environmental dangers illegal.

  11. Re:Christmas is coming early this year on TSA Prohibits Taking Discharged Electronic Devices Onto Planes · · Score: 5, Insightful

    Such a bomb could well house a small battery for detonation, big enough to also power the device for a short time for the trigger swipe. Rejecting devices that don't work is absolute insanity.

  12. Re:Engineering win on Elon Musk's Solar City Is Ramping Up Solar Panel Production · · Score: 1

    But no net energy that way, just pointless multiplication of PV panels. If you want a energy return equal to the energy that went into making the first panel, the first 5 years is a loss - all it does is produce a panel. If you produce no more panels after that it takes another 5 years to recover the energy you could have used 10 years earlier to do something useful. Only after that is net energy. Some of the net energy can be used as a new source of useful energy, the rest to produce more panels and ultimately as the energy source to develop a Dyson sphere. When you stop building panels, it's all net energy.

  13. Re:Engineering win on Elon Musk's Solar City Is Ramping Up Solar Panel Production · · Score: 1

    Energy Return on Energy Invested (EROEI) of PV can be 3-4 in favorable cases but the rate of return is also important if you want to multiply the resource. If energy parity for the first panel takes 5 years then its output could produce a second panel in another 5 years. So for 10 years you get no net energy, after which you can tap some of the output for other uses while still continuing to add panels at an accelerating rate. Doesn't matter if you start with 10 or 10 billion, there is still no net energy for 10 years. Starting with a large number could cause energy shortages and social unrest which could end the sustainable growth entirely.

    Yes, we should have started 20 years ago.

  14. Re:This always ends well.... on South African Schools To Go Textbook Free · · Score: 2

    As always, there is plenty of free and superior course material. The real graft is at whatever level can issue the mandate that the latest and priciest must be used. Nothing but the best for our children, etc.

  15. Re:Philip K Dick on High Frequency Trading and Finance's Race To Irrelevance · · Score: 1

    "The Penultimate Truth" http://en.wikipedia.org/wiki/T...

  16. Does anyone look at ads anyway? on Google Foresees Ads On Your Refrigerator, Thermostat, and Glasses · · Score: 1

    I have script and ad blocks and bogus host file entries to speed up browsing but can honestly say I don't pay attention to ads when they get through, When looking for something to buy I do the search and find it hard to believe unsolicited ads bring in any customers.

    Are there really people who click through and buy something because an ad says they need it?

  17. Re:The image formation process is still the same on How To Build a Quantum Telescope · · Score: 1

    That's the infinite plane wave approximation for lattices of infinite extent. Scattered spherical waves from finite objects will result in some energy passing through the aperture for every spatial frequency. Although it could be difficult to sort out which frequencies are contributing (aliasing). Analysis of the through focal series can do that, also changing the convergence of incident illumination.

    But if the source is known to be two points, accurate measurement of the spacing between the resulting PSFs is limited only by signal to noise.

  18. Re:The image formation process is still the same on How To Build a Quantum Telescope · · Score: 3, Insightful

    Yes, and what's more diffraction causes no fundamental limit to resolution, it just happens to be the distance between the first zeroes of an interference function. For two point sources of equal intensity that leads to an easily seen contrast difference of around 25% but trained observers can detect 5%. On electronic displays the contrast can be cranked up arbitrarily.

    The fundamental limit to resolution is signal-to-nose.

  19. Technocracy Study Guide on Ask Slashdot: What Essays and Short Stories Should Be In a Course On Futurism? · · Score: 1

    http://www.technocracy.org/stu...

    Written mostly during the 1930s by M. King Hubbert of peak oil infamy. Describes a sustainable society directed by science instead of wishful thinking.

  20. Re:Can someone explain this theft? on Mt. Gox Shuts Down: Collapse Should Come As No Surprise · · Score: 1

    Isn't the history of a bitcoin included in the block chain? And the stolen bitcoins identifiable?

    If so whoever tries to use one risks being traced, moreover the recipient could be considered as knowingly accepting stolen goods..

    Sort of like the haul from a bank robbery having an indelible "This money stolen from Bank X" printed on every bill.

  21. Re:Please no? on Fixing Broken Links With the Internet Archive · · Score: 1

    Presumably the wayback redirect would tell you the page does not exist, but the he last time it could be loaded, this was the content. What's wrong with that?

  22. Re:idle time on Ask Slashdot: What's the Most Often-Run Piece of Code -- Ever? · · Score: 1

    The idle loop is alive and well in embedded systems. In some cases energy use is minimized by using a slow clock chosen for some small fraction of idle time, in others by sleeping between bursts of fast processing.

    x86 idle power reduction under unix started sometime in the late 1990s
    https://blogs.oracle.com/bholler/entry/the_most_executed_code_in

    Other OS starting using it around 2000
    http://en.wikipedia.org/wiki/System_Idle_Process

    Thus seti@home launched in 1999 could legitimately claim it made use of otherwise wasted CPU cycles on the Mac and Windows 95 clients.

  23. Re:idle time on Ask Slashdot: What's the Most Often-Run Piece of Code -- Ever? · · Score: 1

    On modern operating systems the idle loop is never coded in a high level language. It is painstakingly optimized in assembly language, for maximum speed.

  24. Re:9.1 on Windows 9 Already? Apparently, Yes. · · Score: 1

    And a wireless mouse under the covers.

  25. Re:Greeks had that on Why We Think There's a Multiverse, Not Just Our Universe · · Score: 1

    Another advantage not mentioned in the wiki article was that someone could hold an office only once. That meant when some crises occurred there were probably several people immediately at hand who had previous experience directing public policy.