Re: Re: starship-design: Re: Re: debate

[kuo@bit.csc.lsu.edu (Isaac Kuo)]

Kelly St wrote:
>In a message dated 12/11/97 12:39:11 AM, kuo@bit.csc.lsu.edu wrote:

>>Conservation of energy has been around for longer than that, and the
>>physics of relativity did not invalidate most of the predictions
>>made by classical mechanics.

>Actually E=mC^2 did violate classical conservation of energy, since no one
>ever thought matter and energy were convertable.  No doubt similar
>'corrections' in our assumptions are ahead of us.

What you describe is really the result of two previously unknown
forces--the strong and weak forces.  In the absense of these,
"classical" conservation of energy is correct.

The principle of conservation of energy is, in and of itself, not
very predictive because you just don't know everywhere that energy
can be bound up.

General relativity is the one place where the principle of
conservation of energy really predicts something.  It predicts
that space is curved a certain amount by energy (this term is
not to be confused with "mass", because mass now exclusively
refers to rest mass).  That means all energy, not just the energy
we currently know how to use.

>>What relativity did was it explained a lot of phenomena which didn't
>>quite fit classical mechanics.

>>The critical difference between classical mechanics and general
>>relativity is that there were a lot of natural phenomena which
>>didn't fit classical mechanics, and there are NO phenomena (natural
>>or manmade) which don't fit general relativity.  We might observe
>>some phenomena which don't, but we've pushed the bounds to near
>>light velocities and haven't found anything inconsistent with it yet.

>Actually physisc is full of unexplain phenominon and unexplored energies and
>and conditions.  Masy we don't even have the equipment to look at yet.

Yes, there are unexplained phenomena all over the place.  However,
there are no observed phenomena (explained or otherwise) which are
inconsistent with general relativity.

Contrast this with classical mechanics, which had "explained"
observed phenomena which were contradictory (light having both
wavelike and particlelike properties)!

>>>Research into
>>>newer physics, capable of far greater power, performance, etc (zero point
>>>energy, inertia/mass damping, etc) has progressed to the degree that NASA is
>>>funding some conferences and studies on them.

>>We will always look for ways around what we know, and research into
>>zero point energy and cold fusion is very inexpensive to conduct.

>>That doesn't mean there's any credibility to any of it.

>True, but their was no credibility to relativity until it was tested.

You're right, but relativity has passed all its tests with flying
colors.

So far zero point energy research is having even less success than
early cold fusion research.

>>If you honestly think so, then why do you care at all about this
>>starship design list's concept?  According to your thinking, there
>>is no chance that anything we come up with will be anything even
>>remotely like what would be worth sending to the stars.

>True, in the same way the lunar systems designed by the british interplanetary
>society most of a century ago, or those designed by VonBraun in the '50's,
>bore little relation to to the apollo systems.  But it did show you could go
>to the moon with those technologies.

That's what I think we should be doing.  We aren't here to try and
come up with what we think will be the design of the first manned
interstellar missions.  That's hopeless.

What we should try to be doing is trying to find the best thing
possible using as conservative technology possible just as a
baseline to see if it's possible at all, and at what maximum cost.
(Improvements in science and technology will necessarily reduce
the mission cost, if our baseline uses only existing technology
at existing cost.)

>>The predictive power of general relativity is simply too much
>>better than what came before, and too heavily tested and confirmed
>>by hostile scientists, to put it on the same level as what came
>>before.

>  :)   Chavanist.  All ages think they found the ultimate truths, all are
>superceeded by their  succesors.

Yes, but it's important to recognize just how much better general
relativity is compared to anything that came before.  In many ways,
it's the most awesome scientific theory ever devised (so far).
Despite its radical and highly dubious (to scientists of the time)
concepts and masses of skeptical testing, it's stood the test of
time.  It combined high controversy over its concepts with a perfect
record in scientific observations.  It's all encompassing nature
allowed it to make predictions which could be tested in widely
disparate ways.  Einstein's said that when he found that general
relativity predicted the precession of Mercury, he _knew_ is was
correct.

>>>You gain increased range due to the larger virtual lens from the array.

>>NO YOU DO NOT!!!!!!!!

>>YOU DO NOT INCREASE RANGE BY EVEN A SINGLE MILLIMETER.

>>The larger virtual lens size is exactly counteracted by the reduced
>>efficiency.  In other words, if you get a spot which is 1/10 the
>>area, it will also have 1/10 the beam energy.  You haven't gained
>>anything.

>>OTOH, you have _lost_ 9/10's of the theoretical optimum beam (the
>>optimum beam is if the elements are bunched up shoulder to shoulder).

>>Kelly, try and comprehend this one fact, if nothing else.  The
>>widely spaced array gains you NOTHING.

>Thats was countered by oter on this board.  To put it blutly.  You need that
>size to focus at long ranges.  If you can't focus the beam, it dosn't matter
>how much of it you transmit.

No.  You are wrong.  To put it bluntly.

Look.  Just calculate the strength of the beam yourself using the
calculation of interference between in phase coherent beams.

Just do the calculation yourself.  Please.

Note: a beam does not suddenly disappear at a particular range.  It
continues to disperse in an asymptotically conical spread.  This
does mean it places a smaller amount of energy on a particular spot
size with distance.  That's the way physics works.
-- 
    _____     Isaac Kuo kuo@bit.csc.lsu.edu http://www.csc.lsu.edu/~kuo
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