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  1. P

    Cooling of primary mirror

    If the humidity is low, then your water idea will promote faster cooling. Google "swamp cooler" to understand why. If humidity is high, then you will have the opposite effect.
  2. P

    Reflecting a laser with a mirror is there a limit to the power level?

    The military optical systems I've worked on all used beryllium. I've never worked on a telescope, but the optical design engineers who worked with me told me that the large telescope mirrors were also polished metal, but maybe not Be. We used it because it was the only material that met all...
  3. P

    Reflecting a laser with a mirror is there a limit to the power level?

    Some weapons already have countermeasures against LASERs. Many missles for example rotate in flight so the energy is absorbed over a much larger area.
  4. P

    Reflecting a laser with a mirror is there a limit to the power level?

    The glass just supports the film, but that is not how high end optical mirrors are made. If someone did this for real, I'd expect them to use a highly polished beryllium plate with a redlectivity of about 98%. Able to survive much more heat transfer, lower absorption, and easier to provide...
  5. P

    Does lightening cause a form of cavitation?

    Dragon is correct, that this cannot be cavitation the way we normally understand the term. But it is something similar. With such rapid heating of the air, you have very rapid expansion. That is followed by very rapid cooling and a collapse of the air back to something close to its original...
  6. P

    If lightning can destroy trees, how come that people survive it?

    All that is true, but trees are not always destroyed. A hot strike will explode a tree as you say, but a cool strike will set it on fire. We can survive a very small current thru the heart, or sometimes a very large current. In the band in between we are dead. They have different theories as...
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