Noah's Arc.
If you want living beings to cross the vast, incomprehensible
distances of space, you need to build an arc.
A mere "Ship" won't do. There's no such thing as storage, not
for a trip that long. You need to something large enough for
a breeding population, something that can be maintained,
REBUILT, even as the population it hosts produces everything
it needs -- food, clothing, medicine, entertainment...
We can't build a machine that would last long enough to
cross our galaxy. We could send a chunk of metal there,
ballistically. We could work out direction, speed, how much of
a push we'd need to give it... maybe we could even work where
to point it in order to slow it down once it arrived. But we can't
built a computer that would last the trip. We can't build
transmitters, receivers, cameras...
At 10% the speed of light, it would take over 1 million years to
cross the galaxy.
And, no, we can't just built a probe that 3D prints it's own
replacement parts. If that were possible we could just build
the computers out of the same materials as the 3D printers
and be done with it!
As if you want to send a machine across even our galaxy,
never mind that vast stretches between galaxies, you need
an arc. You need a viable breeding population. You need a
manufacturing base. You need agriculture. You need some
goddamn people (aliens) to keep the goddamn thing
running!
This would be less important with machines -- sending
robots, say -- but still important.
Now, what would the inhabitants of our ark do once they
got there? Well. That's a subject for a different day...
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