On 7/6/2025 10:23 PM, Lee Gleason wrote:

ÿ That have teleportation across stellar distances, but only to teleportation booths that have been first been transported to their destinations by conventional space travel on ships. I know I've read
several stories using this over the decades. but can't think of 'em
right now....some of the stories dealt with ships that could use the destination booth while in flight, simplifying crew changes and resupply over the long periods it would take to get to a destination. SOme
couldn't use the target booth until it was set up at the destination, complicating the long flight to it.

Sounds a bit like Lloyd Biggle Jr.'s novel "Watchers of the Dark"

pt

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On 07/07/2025 07.53, Stefan Ram wrote:

Lee Gleason <lee.gleason@comcast.net> wrote or quoted:

That have teleportation across stellar distances, but only to
teleportation booths that have been first been transported to their
destinations by conventional space travel on ships.

Transfer booths only working between fixed locations equipped with
booths exist in Larry Niven's Ringworld.

Booth-to-booth teleportation is shown in the "middle future" segment of Kuttner's _The Time Axis_. At one point, as the POV character is fleeing pursuit, he sees somebody who had apparently just come from another planet,
as snow is puddling on the floor behind him. (Off-hand, I don't recall
how he knew that it wasn't just from Earth's other hemisphere.) This
causes him to think briefly about the disease-spreading possibilities of transfer booths.

<https://www.isfdb.org/cgi-bin/title.cgi?5582>

--
Michael F. Stemper
There's no "me" in "team". There's no "us" in "team", either.


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On 07/07/2025 09.15, Ted Nolan <tednolan> wrote:

In article <104gjc9$gmu$2@reader1.panix.com>,
danny burstein <dannyb@panix.com> wrote:

In <md20hbFmrmjU1@mid.individual.net> ted@loft.tnolan.com (Ted Nolan
<tednolan>) writes:

In article <booths-20250707135221@ram.dialup.fu-berlin.de>,

Transfer booths only working between fixed locations equipped with
booths exist in Larry Niven's Ringworld.

I was thinking about that. Was there a reason given why they aren't
used off-planet? Maybe they are SPEOL only?

Also... they had to compensate for the differing potential
energies between receiving and transmission sites, as one
could be "traveling" (term used a bit loosely) a lot faster
and in a different direction, and altitude, etc., than
the other.

This would otherwise lead to potentially a hefty chunk of
heat being released at the receiving site.

(This was, iirc, a plot device in one of his stories).

It's bad enough when talking about locations on the
same planet, but if you're looking at space velocities
and energy wells, etc., it's mind boggling...

I think it's probably a handwave that it works on the planet then, as
the Earth is revolving, progressing on its orbit & drifting through
space with the spiral arm and whatnot.

The rotation of the Earth was mentioned as a problem; for changes in
either latitude or longitude. (It might even have been specifically
stated that if you stayed on the same line of longitude, and your
latitude only underwent a sign change, there was no problem.)

However, the motion of the Earth around the Sun, or the Sun around
Sag A*, or the Milky Way's headlong rush towards Andromeda would
not have been an issue.

Assume that the matter transmission is limited to C. Any place on Earth
is within 12,800 km of any other place. That works out to 22 usec
travel time. That's about 7e-13 of the Earth's orbital period.

Working in degrees, the angle of Earth's velocity then changes
by about 2.4e-10 degrees. Subtracting 30k/s at an angle of zero
from 30k/s at an angle of 2.4e-10 degrees gives a change in the
Earth's orbital velocity of about 1.3e-10 m/s. I think.

Since newer transfer booths were stated to have mechanisms that
could compensate for teleporting between low and high latitudes,
which could involve delta-vees of hundres of meters per second,
the change in orbital velocity would be trivial.

Similar arguments apply to the other motions.

--
Michael F. Stemper
What happens if you play John Cage's "4'33" at a slower tempo?

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"Michael F. Stemper" <michael.stemper@gmail.com> wrote or quoted:

The rotation of the Earth was mentioned as a problem; for changes in
either latitude or longitude. (It might even have been specifically
stated that if you stayed on the same line of longitude, and your
latitude only underwent a sign change, there was no problem.)

However, the motion of the Earth around the Sun, or the Sun around
Sag A*, or the Milky Way's headlong rush towards Andromeda would
not have been an issue.

You point out that some critical readers are a bit inconsistent
when they consider one kind of movement but overlook another.

That's fair, but those critiques mostly focus on side issues.
The main point is that instantaneous teleportation isn't
scientifically viable since every energy transfer we've seen
follows local causality and never exceeds the speed of light.

Like a lot of stuff in "science" fiction, teleporters are
really more like magic/fantasy than actual science. And once
you accept that kind of unscientific magic, there's no real
call to explain hitting a target with science.



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