Path: ...!eternal-september.org!feeder2.eternal-september.org!i2pn.org!i2pn2.org!.POSTED!not-for-mail
From: hitlong@yahoo.com (gharnagel)
Newsgroups: sci.physics.relativity
Subject: Re: Want to prove =?UTF-8?B?RT1tY8KyPyBVbml2ZXJzaXR5IGxhYnMgc2hvdWxkIHRy?=
 =?UTF-8?B?eSB0aGlzIQ==?=
Date: Tue, 19 Nov 2024 18:04:04 +0000
Organization: novaBBS
Message-ID: <98a0a1fbdc93a5fcc108882d99718764@www.novabbs.com>
References: <b00a0cb305a96b0e83d493ad2d2e03e8@www.novabbs.com> <539bca7a863c9e1f086b696841672e9f@www.novabbs.com> <911616334030d9ca343f54c18680f6f5@www.novabbs.com> <3d6b6b0e383c52f684c7a8cb660769de@www.novabbs.com> <da49ba83e2cbe407a10520cb3500ecb4@www.novabbs.com> <09a3723c6a91a9057fde1d506b7324e5@www.novabbs.com> <52ca2bd6b9ef00cd1e4bcf41d07bddff@www.novabbs.com> <b4fc9fb3e70f2a247e9d61f4930b948d@www.novabbs.com> <b016c45516f7bd7ef740c1c6c6183266@www.novabbs.com> <9687d391072c6f5d19d3e4cad9e944ba@www.novabbs.com> <01685fa9d16c8f15a4b8fd63f5b42ed2@www.novabbs.com> <b6c06d66a1d5da3a239a49ba5f903e2e@www.novabbs.com> <3cccb55b7c7c451a385b8aad5aac6516@www.novabbs.com> <cfcd6e742c4f3c2f8a5f69d4db75206f@www.novabbs.com> <d793169808c9c1e887527df5f967c216@www.novabbs.com>
MIME-Version: 1.0
Content-Type: text/plain; charset=utf-8; format=flowed
Content-Transfer-Encoding: 8bit
Injection-Info: i2pn2.org;
	logging-data="3229282"; mail-complaints-to="usenet@i2pn2.org";
	posting-account="TRF929uvrTGZYJLF+N3tVBXNVfr/PeoSjsJ9hd5hWzo";
User-Agent: Rocksolid Light
X-Rslight-Site: $2y$10$u2BoyHtnDQkbb5ES1plFSOv/rkacI1THxWtEo.H3FJnd.Hr/be3AS
X-Spam-Checker-Version: SpamAssassin 4.0.0
X-Rslight-Posting-User: cefb4c33981645a229d345bae7bb8942e6b32c35
Bytes: 3747
Lines: 50

On Tue, 19 Nov 2024 16:41:15 +0000, ProkaryoticCaspaseHomolog wrote:
>
> On Tue, 19 Nov 2024 16:06:10 +0000, gharnagel wrote:
> >
> > On Tue, 19 Nov 2024 9:41:32 +0000, ProkaryoticCaspaseHomolog wrote:
> > >
> > > Nope. Physics limits their application.
> > > You can achieve 99.999% reflectivity only at one specific angle
> > > (which is dependent on the mirror design). If the mirror reflects
> > > 99.999% of light normal to the surface, it won't reflect 99.999% of
> > > the light at other angles.
> >
> > Exactly.  I didn't realize how complex the LIGO optical train was,
> > nor the "power recycling" concept:
> >
> > https://arxiv.org/pdf/1105.0305
> >
> > I'm still quite certain, however, that when you throw 750 kW
> > into a 10 cm ball with walls that are 0.999999 reflective,
> > the losses will, as you say, cause serious problems.
> >
> > For one, that's a loss of 0.75 W/bounce, and bounces will happen
> > c/0.1 = 3x10^9 times per second -- IF one could supply the power
> > to keep it operating.  In which case, the whole thing would make
> > a beautiful incendiary display.  With only 5 W input to drive
> > the system, however, it would heat up to about 300 C, according
> > to my radiation slide rule.
>
> No. Your loss per bounce calculation is off.
> Think conservation of energy.

Prok, Prok, Prok!  Did you not read the above sentence that begins
with "-- IF"?

> At steady state, 5 W input equals 5 W output, which is not
> incendiary.
>
> It _is_ warm enough, however, that the whole shebang needs to be
> run in ultra-high vacuum to avoid convective effects.

The 300 degree temperature rise I calculated was under such
condition, based upon 300 cm^2 of surface area radiating with
no convection.

The point is, though, that with 3x10^9 bounces/second, it would
take much less than a second to whittle 5 W down to nothing:
1E5 bounces: 0.905Po
1E6 bounces: 0.368Po
2E6 bounces: 0.135Po
3E6 bounces: 0.050Po (in the first msec)
4E6 bounces: 0.018Po