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User: Framboise

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Comments · 164

  1. kW or kWh? on Bill Gates Endorses Water From Human Waste · · Score: 2

    From BG blog one can conclude that the author belongs to the category of people unclear about the difference between a quantity of energy and a rate of energy production. To his excuse the common poor choice of kWh instead of the SI J (Joule J, 1 kWh = 3.6 MJ) as energy unit is just making energy discussions more confusing.

     

  2. Mean and fluctuations on Linking Drought and Climate Change: Difficult To Do · · Score: 2, Informative

    The climate has always been a highly fluctuating system where extreme temperatures oscillate over seasons and location by, say typically +/-20K (Kelvin), around a mean value around 287K, slowly growing. In some countries the fluctuations are larger, in some others smaller. All the discussion about the human-induced warming is about the effect of changing this mean value by a couple of K (now +0.5K, in the next century by +2-4K). So even in the most pessimistic scenarios the warming remains in amplitude a small fraction of the typical annual fluctuations. No wonder that it will be difficult to prove that any extreme fluctuations will result from the warming.

  3. Re:Under US Jurisdiction? on Eric Schmidt: To Avoid NSA Spying, Keep Your Data In Google's Services · · Score: 4, Interesting

    Google is investing massively abroad, such as in Zurich, Switzerland, where privacy laws are especially strong. Expect that if US laws continue to have negative effects on Google income, the company is going to be more and more international.

  4. Xerox Alto on The Case For Flipping Your Monitor From Landscape to Portrait · · Score: 1

    Xerox Alto, one of the first PC (1973) had it!
    https://en.wikipedia.org/wiki/Xerox_Alto/

  5. Re:Only good news for science. on Berkeley Lab Builds World Record Tabletop-Size Particle Accelerator · · Score: 1

    Indeed low cost means more affordable devices for more labs, and new technology means possible expansion to bigger (then more exensive) such devices, allowing to explore new frontiers in physics.

  6. Real advantage on Who Needs NASA? Exoplanet Detected Using a DSLR · · Score: 2

    One cannot escape the fact that bigger apperture telescopes can record fainter
    stars, and/or perfom the photometry of bright stars with more precision than a simple camera.

    To detect exoplanets one needs both large samples of stars recorded as continuously as
    possible over several years and high precision photometry. Besides being cheap, the advantage
    of a small camera is than the field is larger. But with a larger telescope in space like Kepler one
    can target regions of the sky with density of stars optimal for the CCD/camera combination, and
    observe continuously for months with the same instruments, which is crucial for differential
    photometry. Thousands of amateurs worldwide detecting as many new exoplantes as Kepler
    would face the problem of coordinating the analysis of huge amounts of heterogeneous and
    incomplete data (due to day/night and weather interruptions in differently dark and transparent skies).

    The real question is wether crowdsourcing planet detection is cheaper for global economy at equal scientific return than with state sponsored research. Perhaps the most important benefit of such an
    activity is educational and promotional for research in general.

       

  7. The discussion is not on measuring continuous quantities
      but counting discrete objects. Physicists and mathematicians have indexed, say, vectors, starting with 1 for ages, except in recent times where sometimes they use 0 for very special reason (like chapter 0 in a book).

  8. Re:Assignement in Python on Ask Slashdot: What Are the Strangest Features of Various Programming Languages? · · Score: 1

    Observe that one needs two operators, memory copy, and "point to".
    What is wrong is to use only one symbol for the two, and change the meaning according to operator content.

  9. Assignement in Python on Ask Slashdot: What Are the Strangest Features of Various Programming Languages? · · Score: 2

    Assigning a number or a list in Python and many other languages (Julia) is a different operation. Such as

    >>> a = 2
    >>> b = a
    >>> a = 1
    >>> b
    2

    >>> a = [2]
    >>> b = a
    >>> a[0] = 1
    >>> b
    [1]

    Octave (Matlab) is more consistent on this point, every assignement is a memory copy.

  10. Re:Time to travel 11 light years on Astronomers Find What May Be the Closest Exoplanet So Far · · Score: 1

    Before embarking to such a trip you had better wait the confirmation of a planet around Alpha Centauri at 4.3 ly. Even if the already announced discovery turns out to be wrong, the probability that some planets exist in the Alpha Centauri system is large.

  11. Re:Another giant leap? on Researchers Find Evidence of How Higgs Particle Imparts Mass · · Score: 1

    The Higgs is not responsible for creating mass in general, just for the mass of particles included in the Standard Model. The Standard Model is incomplete since in this model the mass of neutrinos is zero. So the Higgs doesn't explain the mass of neutrinos.

  12. Neutrino temperature on The Big Bang's Last Great Prediction · · Score: 5, Interesting

    The orginal article keeps quoting the temperature of 1.96K as the neutrino background temperature, as found in most textbooks on the topic. This is a relic of the time people were assuming massless neutrinos. The confusion is maintained by people using the temperature as a synonym of energy. Actually the non-zero rest mass energy must be subtracted, providing the real kinetic energy of these particles (moving now at 100-1000 km/s) that would be exchanged with a super large thermometer (in view of the tiny interaction cross section). The effective neutrino temperature would then be measured in the milliKelvin range.

     

  13. The art of lying on Snowden Queries Putin On Live TV Regarding Russian Internet Surveillance · · Score: 1

    A good lier should not lie most of the time, otherwise one just needs to reverse the saying to know the truth with high probability.

    On that account Obama is smarted than Putin IMHO. He does lie, but in a less systematic manner.

     

  14. Re:He should get the Nobel Peace and War Prize on Edward Snowden and Laura Poitras Win Truth-Telling Award · · Score: 1

    The so-called "Peace" prize is indeed badly named. Other famous war makers, H-bomb creator, mass killing authors and terrorists got it:

    Yasser Arafat, Shimon Peres and Yitzhak Rabin (1994)
    Mohamed Anwar al-Sadat and Menachem Begin (1978)
    Andrei Dmitrievich Sakharov (1975)
    Henry A. Kissinger and Le Duc Tho (1973)

    So perhaps Edward Snowden and Laura Poitras have better not to be awarded
    the Nobel.

  15. Re:Power density? on Could Earth's Infrared Emissions Be a New Renewable Energy Source? · · Score: 1

    The total heat produced by radioactivity in Earth is 44.2 TW (Wikipedia).
    The total solar power received by Earth by the upper atmosphere is 174 PW (Wikipedia).
    This means 3937 more solar energy is received by Earth than produced by radioactivity in its interior.
    Furthermore geothermal energy is high entropy energy in regard of solar energy since the temperature difference between
    ground (~287K) and nearby space (>10K) (DT=277K) is much less than the temperature difference between
    sunlight (5778K) and ground (DT=5491K).

    In short the whole idea of converting Earth heat into electricity is completely inefficient in regard of solar energy.
    The only way to use efficiently geothermal energy is to find hot spots where it is concentrated by thousands with respect to average.

  16. Cyber war preparation on How the NSA Plans To Infect 'Millions' of Computers With Malware · · Score: 1

    Developing massive attack tools like that make a global cyber war more likely.
    As with the initial ICBM's the first one to strike may believe to win.
    Very dangerous, and foolish.

  17. Microsoft is on decline on Ask Slashdot: How Do I Change Tech Careers At 30? · · Score: 5, Insightful

    Think about the fate of dinosaurs that were replaced by smaller more agile mammals when difficult times came...

  18. Re:Natural gas 3.5, solar electric 35 on Computing a Winner, Fusion a Loser In US Science Budget · · Score: 1

    Research funding must consider mid to long term planning, so one has to project somewhat in the future, say 2020. There are many such forecasts, but perhaps this one is interesting to quote in view of the origin (US DOE) http://www.telegraph.co.uk/finance/comment/ambroseevans_pritchard/10242882/Solar-power-to-trump-shale-helped-by-US-military.html/

    "The US Energy Department expects the cost of solar power to fall by 75pc between 2010 and 2020. By then average costs will have dropped to the $1 per watt for big solar farms, $1.25 for offices and $1.50 for homes, achieving the Holy Grail of grid parity with new coal and gas plants without further need for subsidies. "

  19. Fusion is a solved problem on Computing a Winner, Fusion a Loser In US Science Budget · · Score: 1

    It makes sense to cut in traditional fusion research. Indeed, by now it is clear that the best and cheapest practical fusion energy reactor for the foreseeable future has been found in the form the gravity stabilized fusion reactor called Sun. With declining costs solar panels already compete with conventional nuclear reactors. If the trend continue to ~2020 even coal and oil might be seen then as too expensive in regards of solar energy.

       

  20. Re:Single point of failure on Report: Space Elevators Are Feasible · · Score: 1

    > Sigh... your numbers are wrong, your science is wrong, and your concept is questionable.
    ?? You might read at least Wikipedia on the topic before looking like a pretentious person.

    > Let's start with the basics: GEO is 35,768 KM from the equator. You need twice that much, at most,
    No, for equal length ribbons on both sides of the GEO forces are unequal ! Gravity force decreases like 1/r^2 you know,
    and centrifugal force increases like r^1.

    > ribbon (not cable. Cable is dramatically less feasible and stupid besides).
    In the topic people have used the words cable, ribbon and tether, this is irrelevant to the problem of fragility, so I guess you are trolling.

    >No idea where you got 100,000 KM from..
    Ah, you don't know the Wikipedia article, which will give you a link to a book where you will find this value.
    But in more detail I did calculate the force on both sides (integrating along the radius) supposing a linear mass density decreasing
    linearly with the distance to GEO, with zero endpoint values. My result for the highest point is 98178 km from Earth center.

    This is probably enough food for a t... as you don't even deign to consider that a single cable/ribbon is a fragile concept.

  21. Single point of failure on Report: Space Elevators Are Feasible · · Score: 1

    A robust system should not totally break because of one point of failure. A single elevator is fragile because any natural (meteorite), man-made (space junk) or intentional (war) cause acting anywhere along the 100'000 km long cable can totally destroy it with dramatic consequences on Earth when parts of the cable impact the surface. The elevator design could be made more resistant by building a network of cables, not a single cable.

  22. Can a creationist explain me? on Watch Bill Nye and Ken Ham Clash Over Creationism Live · · Score: 1

    Why if the universe is ~6000 yr old virtually all the astronomical images returned since a century or so show objects at distances requiring more than 6000 yr for light to reach us?

    Why would the Creator be so deceptive to create 6000 yr ago in the most exquisite details images of the universe looking precisely 13.8 billions yr old, and this false impression would have been reserved just for us in the recent decades?

  23. Simpler, incinerate with common trash on Where Old Hard Disks (with Digital Secrets) Go To Die · · Score: 2

    My town has a huge incinerator for common trash that will bring any computer component well over 1000C: most computer component would be finely destroyed to atomic level. As a bonus the incinerator produces electricity.
    It would suffice to secure the transport to the incinerator and let heat finish the task.

  24. Neutrinos? on New Supernova Seen In Nearby Galaxy M82 · · Score: 5, Informative

    THE question I am sure many will think about is how many neutrinos will be detected.
    For supernova 1987a at 168'000 light years 24 neutrinos have been detected.
    At 12 mega light years M82 is 71 times further, which dilutes the neutrinos by a factor ~5000.
    So the answer is 0 neutrino if the detectors were the same as in 1987.
    I doubt that the present detectors have improved by a factor 1000 in the meanwhile,
    but I would be glad to be disproved.

  25. Forming accretion disks on Astronomers Discover When Galaxies Got Their Spirals · · Score: 2

    Retrospectively it could have been guessed long ago that disk galaxies need at least a few tens of rotation periods to look progressively like symmetric accretion disks in other astrophysical contexts (disks around black-holes, stars or planets). The difference between galaxies and smaller disks is mainly the number of rotations they could make, a few tens of rotations for spiral galaxies, millions or billions for smaller disks.