Re: The fantasy of starships is no more realistic than magic

Steve Silverwood [KB6OJS] wrote:
> On Tue, 10 Feb 2026 18:44:24 +1100, Whisper <[email protected]>
> wrote:
>> As a wise man once said, a man's gotta know his limitations.  Not 
>> everything you can think up in sci fi fantasy can actually happen.  We 
>> will never get close to reaching another star system.
> 
> Quoting Clint Eastwood in this topic...?  Interesting.
> 
> The universe is a surprising thing.  Lots of things are possible if
> one has the dream.

Imagination is helpful, but not sufficient for progress.  There has to be
some connection to the real world.

> They're already experimenting with "transporters" (a la Star Trek),

"They" are not; that is a common misconception (because of the term used).
Quantum teleportation -- which is probably what you are alluding to -- is a
far cry from /Star Trek/'s transporters in many ways, including:

  1. only single elementary particles have been "teleported";

  2. a particle is *duplicated only* with regarding to one its properties
     because a particle that already existed at the destination is
     given that property;

  3. this has only been done with photons (AFAIK), not with stable particles
     with non-zero mass (out of which matter consists);

  4. the problem of not being able to determine certain properties of
     a particle simultaneously exactly ([Heisenberg] uncertainty principle)
     remains (in /Star Trek/, the Heisenberg compensators take care of that
     }8-)).

<https://en.wikipedia.org/w/index.php?title=Quantum_teleportation&oldid=1345660195>

> and it's entirely possible in my mind that eventually we'll "conquer
> physics" and come up with a practical way to make interplanetary space
> travel happen (beyond Earth, obviously, and hopefully beyond the Solar
> System).
One does not have to "conquer physics" for that, i.e. no new physics is
required, and no exotic possibilities of currently known physics (like warp
drive, or wormholes kept open by matter with negative energy) have to be
realized.

As for interstellar travel:

Andy Weir gives a pretty convincing example in his novel "Project Hail
Mary", of which a film adaptation of the same name (co-produced by and
starring Ryan Gosling, with Andy Weir advising) was recently released, of
how it could work.  (I have not read the novel yet, but I watched the movie;
certainly the latter is highly recommended if you are interested in science.)

I have calculated (you can even do that with a scientific desktop calculator
if you know the physics/maths and a mathematical trick) that, considering
special relativity, it would suffice for a spacecraft to accelerate from
relative rest with 9.8 m/s^2 (=~ 1 g_0; would provide artificial
gravitation, too) for ca. 91 standard days to achieve the speed 0.25 c.
Cruising at that speed to Proxima Centauri, ca. 4.25 light-years away (for a
pass-by, otherwise you have to decelerate for ca. 91 days, too) would take
only ca. 17 (Julian) years in the terrestrial rest frame (ca. 16.5 years for
the astronauts; so the "time dilation" at that speed is relatively benign,
and people will still remember the astronauts should they return the same way).

The main problem for using conventional propulsion is the propulsion system
(no spoilers here on how they solve it in the novel/movie; suffice it to say
that they still travel at subluminal speeds ;-)).  Radiation shielding
(light towards the front is blueshifted; ionizing radiation is
harmful/deadly), and deflection/evasion of interstellar dust (at large
relative speeds, even a relatively small object like a speck of dust has the
same kinetic energy as a hand grenade produces; this problem already exists
with space debris in orbit, and asteroid impacts) are other problems that
need to be solved.

-- 
PointedEars

Twitter: @PointedEars2
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