OT- An animated scene from "The Moon is a Harsh Mistress"

[a425couple]

An animated scene from "The Moon is a Harsh Mistress".

https://vimeo.com/359653317?fbclid=IwAR0CRK1o2-N3KJQQwzuVM-_HoiEGjCrcHGtwsd2RDzDnI7M6lh0h3VMjyn4

Operation Hard Rock
a 3:54 'vimeo'
Animation inspired by 'The moon Is A Harsh Mistress' by
Robert A. Heinlein. Commissioned by the late Bruce R.
'Spike' MacPhee, this is a monument to his patronage
of the Arts and a tribute to great Science Fiction.

I seem to recall, that someone, somewhere, was saying that
Heinlein's math was all wrong. And that throwing rocks at the
Earth would not cause the political rethinking he wrote that
it would. That these 'rocks' would not really be the
equal of military weapons that would force Earth to give
up rule.
Any thoughts?

[J. Clarke]

On Mon, 9 Aug 2021 09:37:56 -0700, a425couple <a425c...@hotmail.com>
wrote:

Really depends on how big they are, how accurately they can be aimed,
and how fast they can be produced. A ton of rock should be about a
50-ton yield--that's about 1.5 B-52s worth, all delivered on a point
target. Delivered directly on the hatch cover that would likely take
out a missile silo. Delivered to the financial district it would
likely be a good deal worse than 9/11. How many of those hits does it
take to drill a hole in Cheyenne Mountain? And how much payload can
the launcher shoot anyway?

A Bagger 293 can dig about 900 tons an hour. If that can be
efficiently turned into projectiles and delivered on a production line
basis, that's 45KT/hour of explosive yield delivered.

[Lynn McGuire]

I don't know about the math but this is not off-topic.

Lynn

[Dorothy J Heydt]

In article <serll...@news4.newsguy.com>,

a425couple <a425c...@hotmail.com> wrote:
>
>I seem to recall, that someone, somewhere, was saying that
>Heinlein's math was all wrong. And that throwing rocks at the
>Earth would not cause the political rethinking he wrote that
>it would. That these 'rocks' would not really be the
>equal of military weapons that would force Earth to give
>up rule.
>Any thoughts?

I think it may be a function of when he was writing what. In the
late forties he and Ginny covered the kitchen table with big
sheets of butcher paper, working out Hohmann orbits for _Space
Cadet_. I bet they got that right.

Later, as he got older, he may have gotten

(a) sloppier,

(b) more confident that anything he wrote would sell, never mind
the math,

(c) both.

--
Dorothy J. Heydt
Vallejo, California
djheydt at gmail dot com
Www.kithrup.com/~djheydt/

[J. Clarke]

On Mon, 9 Aug 2021 19:42:44 GMT, djh...@kithrup.com (Dorothy J Heydt)
wrote:

>In article <serll...@news4.newsguy.com>,
>a425couple <a425c...@hotmail.com> wrote:
>>
>>I seem to recall, that someone, somewhere, was saying that
>>Heinlein's math was all wrong. And that throwing rocks at the
>>Earth would not cause the political rethinking he wrote that
>>it would. That these 'rocks' would not really be the
>>equal of military weapons that would force Earth to give
>>up rule.
>>Any thoughts?
>
>I think it may be a function of when he was writing what. In the
>late forties he and Ginny covered the kitchen table with big
>sheets of butcher paper, working out Hohmann orbits for _Space
>Cadet_. I bet they got that right.
>
>Later, as he got older, he may have gotten
>
>(a) sloppier,
>
>(b) more confident that anything he wrote would sell, never mind
>the math,
>
>(c) both.

When he was younger he really didn't seem to understand
relativity--apparently at some point somebody explained it to him.

[Dorothy J Heydt]

In article <j443hghnm0i33e0ec...@4ax.com>,

Well, there's that conversation in _Farmer in the Sky_ in which
the chief engineer is trying to teach some kids some physics, and
somebody asks, "What would happen if the ship got up to ~95 percent
of c and then the Captain slammed on the drive and held it
there?"

And the chief answers, "Don't ask me things like that, kid, I'm
an engineer with hairy ears, not a mathematical physicist."

We must remember that Heinlein was trained to be an engineer at
Annapolis: a mechanical engineer, and not a physicist.

[J. Clarke]

On Mon, 9 Aug 2021 22:39:36 GMT, djh...@kithrup.com (Dorothy J Heydt)

However it's rather hard to get away from the rudiments on that
campus. Albert Michelson was a graduate and the original
Michelson-Morley experiment was performed there. Oh, and Heinlein
appears in a group photo in the fencing loft.

[Christian Weisgerber]

On 2021-08-09, J Clarke <jclarke...@gmail.com> wrote:

> When he was younger he really didn't seem to understand
> relativity

A common affliction of SF writers, back then even more so then
today.

At least we have mostly left behind the "if we accelerate hard
enough we'll break the lightspeed barrier, just like Yeager did"
thinking. Nowadays it's all magic hyperspace and wormholes--which
still does not address the fundamental problem of "relativity,
causality, FTL, pick any two".

Anyway, I can't claim to understand special relativity either (much
less general relativity). I just memorized a few scenarios.

Which brings me to something I have wanted to ask for some time:
The best introduction to special relativity that I ever read was
camouflaged as, of all things, a Star Trek (rec.arts.startrek?)
FAQ. I read it a long time ago, twenty years?, and have been unable
to find it again. Does anybody know what I'm talking about or even
have a copy?

--
Christian "naddy" Weisgerber na...@mips.inka.de

[a425couple]

On 8/9/2021 7:07 PM, Lynn McGuire wrote:
> On 8/9/2021 8:29 PM, pete...@gmail.com wrote:

>> We also have to think about the effect of the atmosphere. These rocks
>> are coming in at about 11 km/s. Could they survive passage?
>> Pt
>
> The steel cladding needed for the electromagnetic accelerator will
> protect the payload for quite a while.
> Lynn

Yes.
Also, If an object is going mostly horizontal, (as intended
for re-entry spacecraft) it is burning up and slowing down.
These 'warheads' would be mostly straight down.
"Whoosh Thud!!"