# Re: Howlers

Andrew Stephenson <ames@xxxxxxxxxxxxxxxxxxx> wrote:

In article <1hwpq49.1251h8b1ku3jofN%spam@xxxxxxxxxxxxxxxxxxxx>
spam@xxxxxxxxxxxxxxxxxxxx "Jonathan L Cunningham" writes:

A jump has to violate conservation of angular momentum, too.

If you are moving, then your angular momentum about some point depends
on your distance from it. But you are movingn in every reference frame
except one.

Might be easier to think this one through in terms of degrees of
freedom (3x lateral, 3x rotational, 3x vibrational, &c) and what

I wasn't talking about rotational angular momentum, but angular
momentum about a fixed point (e.g. the sun).

And you can't conserve angular momentum by changing the rate of
rotation of the object which jumps, because in some frames of
reference it is not moving, so its rate of rotation should stay
unchanged, in other frames it *is* moving, so its rotation would
have to change.

E.g. if you teleport from the midnight side of Earth, to the noon
side, your ang. mom. wrt Earth is unchanged, but wrt the Sun (or
the Moon) it has changed. (Actually, you'd hit the ground at a couple of
the ground: the Earth is rotating.)

amounts of energy the body has stored in each. Working out good
hand-waving rules for what happens to kinetic energies (those 3x
lateral ones) is left as an exercise for the writer. I like the
way Larry Niven coped with it ("Flash Crowd" (?)), especially as
I thought of the same solution before seeing his story. (*zot*)

Yes, he has a murder story in that collection too, which depends
on heating/cooling if you 'port to a different altitude.

Potential energy, which I see as that stored in the relationship
between gravity wells and spatial deformations they cause, makes
for some amusing hand-waving too.

There isn't any way, AFAICT, to make the sums come out consistent,
even in a Newtonian universe, without violating conservation laws.

Taking *some* of the consequences does make good story fodder.

Jonathan

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