RE: Sol-like system discovered...SETI new directions?

From: Paul Grant (shade999@optonline.net)
Date: Sat Jul 12 2003 - 11:54:09 MDT

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    On Fri, Jul 11, 2003 at 11:48:51PM -0400, Paul Grant wrote:
    > That is *very* expensive relative to the manipulation of photons
    > (which effectively have very low masses [based on E = mc^2]).
    >
    > Me: Depends on how you do it :) no doubt an elegant solution is just
    > waiting to be found :) At this point, I wouldn't say its impossible,
    > or even improbable :) Just that more data is needed :) In any event,

    > it certainly is worth examining, if nothing else for the questions it
    > would raise....

    So, any ideas for this research program? In what ways can we generate
    gravitons (if working within the particle physics framework)?

    Me: For me personally, a thorough examination of gravity from an
    engineering perspective... The first of which is to be
    able to differentiate strong existing stellar gravitational signatures.
    Another would be the effects of gravity in manufacturing
    small-scale structures, or how it affects particularly sensitive physics
    experiments (thus necessitating the development
    of a robust senstive gravity sensor with a quick rebound period
    inbetween sampling). Than there's the really interesting stuff;
    orienting an experiment in a fairly uniform gravitational field, and
    messing around with it using a smaller amplitude (if you will)
    generator and measuring how much you can modulate a large gravitation
    wave with a smaller one (in practice), and see if it matches
    up with current transmitter construction techniques (algorithmically
    speaking)... To be quite honest, there's tons of avenues...
    But before I'ld rush off to do all these things, I'ld like to think of a
    series of specific experiments that cover the (possible)
    analogues between gravity and other phenomena... You know, make sure
    they're either like, or not like... Nail down some concrete facts.

    IMHO, trying to rapidly graph the gravitational forces in play within a
    small plane would be my first attempt...
    Then add time, and see how the gravitational field changes with respect
    to time :)

    In the GR field framework the issue would be to make strong gravity
    waves without having a large energy tensor. Maybe that can happen if one
    already has a big (complex) gravitational field where small inputs can
    be amplified by tapping energy or curvature already existing in the
    system. IMHO this sounds less unlikely than the previous approach, but
    still not particularly promising.

    <grin> see my second post :) I'm not interested in (at least for this
    project) generating huge amounts of energy; I'm interested in applying
    a small amount of energy at the right point in space, at the right point
    in time... Pretty much the major benefit, and hindrance, is the global
    reach of gravity; I'ld be extremely interested in say, a directed
    gravitational pulse...

    > Another really interesting question, which just occurred to me, is:
    > does gravity reflect? are their materials which absorb/rebuff
    > gravity... or is it all simply a matter of constructive/destructive
    > interference sans reflection?

    Static gravity fields do not seem to reflect/refract, but there are
    indeed some weird goings on for dynamic strong fields. Look at
    http://archive.ncsa.uiuc.edu/SCMS/DigLib/text/astro/Gravitational-Wave-B
    lack-Hole-Hobill.html
    for example, which shows some nontrivial "refractions" of a gravity
    wave.

    In general (no no pun intended) you need to learn more about general
    relativity in order to say something constructive about gravity. It is
    not the simple force we usually assume. Check out the links at
    http://math.ucr.edu/home/baez/relativity.html I especially like Greg
    Egan's tutorial
    http://gregegan.customer.netspace.net.au/FOUNDATIONS/index.html and the
    FAQ at http://www2.corepower.com:8080/~relfaq/relativity.html (which has
    a nice treatment of the speed of gravity issue)

    Me:

    Grin :) Agreed [regarding I need to learn alot more] :)
    I'm hoping to study Physics @ berkeley within a year :)
    A nice long review of the literature being published
    is in the works... I'm planning on taking my time to get
    the most out of my degrees.

    omard-out



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