[ExI] The Universe is big - really, really BIG.
Adam A. Ford
tech101 at gmail.com
Wed Jul 12 01:48:34 UTC 2023
Anders Sandberg and Stuart Armstrong wrote a paper 'Eternity in 6 hrs' -
tldr build a dyson swarm from the matter of a few large asteroids and use
it to thrust heaps of VN probes towards every solar system/energy source
within reach - and that reach is far. We don't know how much dust there is
btw galaxies, and galaxy clusters atm, so hard to model success rate.
Assume lots of redundant probes.
Here is my interview with Stuart on the topic:
Adam A. Ford
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On Wed, 12 Jul 2023 at 05:13, Brent Allsop via extropy-chat <
extropy-chat at lists.extropy.org> wrote:
> Wait, no.
> In 50 or so years, nobody will die. In other words, we will live, FOREVER.
> No problem spending a million or more years before we get somewhere, in
> that case, right?
> We've got to have something to fill up our eternal lives,don't we we?
> On Tue, Jul 11, 2023 at 12:51 PM BillK via extropy-chat <
> extropy-chat at lists.extropy.org> wrote:
>> On Tue, 11 Jul 2023 at 18:36, Adrian Tymes via extropy-chat
>> <extropy-chat at lists.extropy.org> wrote:
>> > Most interstellar ambitions are flat-out impossible without some form
>> of faster than light drive.
>> > What few theoretically possible ways we know of to achieve this, can
>> not be developed without the sort of mature outer space industry that seems
>> highly unlikely to happen without associated human colonization of
>> non-Earth bodies in our solar system.
>> > Therefore, to reach across the stars we must first seriously begin to
>> colonize the solar system.
>> > _______________________________________________
>> I asked the new Claude 2 LLM (that was just released today) about FTL
>> It was not very hopeful.
>> What are the problems facing travel at near light speed?
>> There are a few key challenges faced by travel at near light speed:
>> Energy requirements: As mentioned before, it takes an enormous amount
>> of energy to accelerate to a significant fraction of light speed due
>> to relativistic mass increase. Just getting a spacecraft to 90% the
>> speed of light would require energy outputs rivaling a star.
>> Conventional rockets won't cut it. New propulsion technology would be
>> Time dilation: A traveler moving at 90% the speed of light would
>> experience time dilated by a factor of about 2.3 compared to a
>> stationary observer. This means that a 10 year journey for the
>> traveler would mean over 20 years passed on Earth. Long journeys would
>> find the traveler returning to an aged earth.
>> Communication delays: Signals sent between a near-lightspeed traveler
>> and Earth would experience huge delays. A message sent from a ship
>> traveling at 99% light speed would take over 5 years to reach those on
>> Earth. Normal communication would be impossible.
>> Navigation hazards: Even small particles like dust grains would carry
>> enormous kinetic energy from a near-lightspeed ship's perspective.
>> Impacts with these particles would be seriously damaging. Detection
>> and avoidance of hazards would be critical.
>> Deadly radiation: Collisions with particles would also bathe the ship
>> in radiation. Shielding requirements would be extreme, adding more
>> mass and energy needs. The hazard increases as speed increases.
>> Required precision: Near light speed travel would require extremely
>> precise trajectory control and navigation. Even tiny errors in course
>> or speed could result in missing the destination completely.
>> Autonomous systems or AI may be needed.
>> While these challenges are daunting, some physicists think that
>> technology could one day make near-lightspeed travel possible. But it
>> would require major innovations in propulsion, materials, navigation
>> and more. Significant obstacles remain before we're zipping around at
>> 99% the cosmic speed limit.
>> What are the problems facing travel exceeding light speed?
>> Exceeding the speed of light poses both practical and fundamental
>> physics problems:
>> Infinite energy: As mentioned before, accelerating an object with mass
>> to speeds faster than light would require infinite energy due to
>> relativistic mass increasing to infinity at lightspeed. So some new
>> physics or loophole would be needed.
>> Violating causality: Faster than light travel would violate cause and
>> effect and allow time travel to the past according to relativity. Most
>> physicists think causality should remain inviolate. So the
>> implications of FTL travel for timelines would need to be resolved.
>> Time travel complexes: If FTL allows time travel, it also introduces
>> logical problems like the grandfather paradox where someone goes back
>> to change their own timeline. The implications and paradoxes of time
>> travel are complex.
>> Exotic matter: Many hypothetical FTL concepts like wormholes or warp
>> drives require large amounts of "exotic" matter with negative
>> mass/energy. But this exotic matter has not been shown to exist. It
>> may not be possible to obtain or produce.
>> Unknown side effects: The full effects of FTL travel are hard to
>> predict. But it's likely that traveling faster than causality would
>> have profound and possibly dangerous side effects. Think unstable
>> wormholes, time loops, quantum disruption, etc.
>> Lack of evidence: So far, there is no solid experimental evidence that
>> FTL travel is even possible. Many concepts are entirely theoretical.
>> So viable mechanisms for exceeding light speed remain speculative.
>> While FTL could offer tantalizing possibilities, it comes with
>> practical barriers and would require overturning much of known
>> physics. Most experts think exceeding light speed is highly improbable
>> given our current scientific knowledge. The problems and paradoxes may
>> simply be insurmountable. But the quest continues.
>> extropy-chat mailing list
>> extropy-chat at lists.extropy.org
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