Analog Science Fiction and Fact - June 2013

THE ALTERNATE VIEW Jeffery D. Kooistra
ON THE SUCKING OUT OF INERTIA
So I was minding my own business, getting
ready to hang Christmas lights in
early December, when I checked my
Facebook account before going outside
and found an email from Rajnar Vajra. He
was writing a story for an anthology and
wanted to ask me a physics question, or
more precisely, a “super-science physics”
question. Here’s how he put it: “So here’s my
question: assuming some miraculous device
that can temporarily remove a person’s inertial
potential, and considering all net forces,
if said person jumped off a building, how fast
would they fall?”
Actually, Rajnar had already thought this
over, but wanted me to think it over as well
to see if I would independently come to the
same conclusion he had, which he did not
provide me with in the email.
The most dramatic and vivid memory I
have of a device that “sucks out inertia”
comes from Heinlein’s Methuselah’s Children.
Therein, Lazarus Long’s long-lived
“families,” in an attempt to escape persecution
on Earth, steal an enormous generationtype,
slower-than-light starship. Prior to this
theft, Lazarus had discussed with his genius
friend Andy “Slipstick” Libby the possibility
of developing a “space drive” to aid in their
escape. This Libby accomplished. It fit inside
a satchel. Heinlein described how it looked
thusly: “Assembled from odd bits of other
equipment, looking more like the product of
a boy’s workshop than the output of a scientist’s
laboratory, the gadget which Libby referred
to as a ‘space drive’ underwent
Lazarus’ critical examination. Against the polished
sophisticated perfection of the control
room it looked uncouth, pathetic, ridiculously
inadequate.”
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A few sentences later he says it’s a “giddy
little cat’s-cradle of apparatus.”
This is typical of Heinlein when describing
something entirely made up—he makes the
reader do the heavy lifting of envisioning it.
It is up to you to decide what an uncouth, pathetic,
cat’s-cradley thing looks like.
For the next several pages the starship is
taken on a trajectory very near the sun, the
idea being that Libby’s machine will be
turned on, the inertia in the ship will go
away, and the Sun’s light and wind will instantly
accelerate the ship to near light
speed. Bear in mind that they don’t as yet
even know for sure if the drive will work—
but then comes that inevitable moment
when they’re going to find out that it does.
Or die.
The scene is as follows:
“(Lazarus) poked a thumb at Libby’s uncouth-looking
‘space drive.’ ‘You say that all
you have to do is to hook up that one connection?’
‘That is what is intended. Attach that one
lead to any portion of the mass that is to be
affected.’
Andy hooked it up.
‘Go ahead,’ urged Lazarus. ‘Push the button,
throw the switch, cut the beam. Make it
march.’
‘I have,’ Libby insisted. ‘Look at the Sun.’
‘Huh? Oh!’
The great circle of blackness, which had
marked the position of the Sun on the starspeckled
stellarium, was shrinking rapidly. In
a dozen heartbeats it lost half its diameter;
twenty seconds later it had dwindled to a
quarter of its original width.”
No doubt about it, that’s exciting stuff! I