• Ziggurat@jlai.lu
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    9 hours ago

    I know enough physics to say no Even inter-Stellar is out of our reach (without generation ship).

    We have zero reason to believe in an effective way to build wormhole, jump gates or anything similar. Even high energy cosmic rays have a limited range (due to collision with photons) which is a strong clue that there is no shortcut in space

    • mech@feddit.org
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      6 hours ago

      Fuck it, let’s assume we can build jump gates.
      Let’s say they’re just big enough to send a tiny unmanned drone through.
      I hop into my space ship and accelerate with a conventional engine to 86% of light speed.
      No violation of physics needed, just shitloads of energy.
      I fly to another star, which takes 10 years from earth’s point of view.
      Due to time dilation at 86% light speed, time in my space ship passes half as fast as on earth.
      If someone on earth had a strong enough telescope, they could look at a clock on my ship and see that it ticks half as fast as the clocks on earth.
      But in my frame of reference, earth moves away from me at 86% light speed.
      So if I look at earth through a telescope, I see that the clocks on earth tick half as fast as mine.
      There isn’t a universal time. Time is always relative to speed and this is no problem when the reference frames are separated.

      I arrive at the star, look through my telescope and see that 5 years have passed on earth.
      I activate a jump gate and send the drone through with a message. It arrives on earth instantly, 5 years after I left.
      But from their reference frame, they could see my clock ticking only half as fast as theirs.
      After earth’s 5 years, only 2.5 years have passed for the space ship they see.
      They activate their jump gate and send the drone back with a reply.
      It arrives instantly at the star, 7.5 years before my space ship gets there.

      This is why FTL travel isn’t and will never be possible. Even with tricks like jump gates or wormholes, it creates time paradoxes.

      • Canaconda@lemmy.ca
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        8 hours ago

        I think the closest we will come is detecting radio signals from another species. But like obviously 2 way communication would be almost impossible due to sheer distance.

        • UnspecificGravity@piefed.social
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          7 hours ago

          Sadly the universe is filled with enough random radio radiation that its unlikely any coherent signal is going to travel more than a few light years. With our current technology there could be an identical version of earth around the nearest star and we probably couldn’t detect it.

          • Canaconda@lemmy.ca
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            6 hours ago

            The signal isn’t destroy though. So one could argue that isolating it in the noise is doable with enough math.

            Obviously the real limit is still distance since we’d need a radio dish like the size of earths orbit or something to pick up a signal from 200LY away.

            • Hadriscus@jlai.lu
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              5 hours ago

              Probably with virtual telescopes, smaller receivers arrayed throughout the entire solar system, like EHT but biiiiiiiigger

    • balderdash@lemmy.zip
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      8 hours ago

      But doesn’t the generation ship / cryogenic technology make it possible (albeit very slow)?

      • Canaconda@lemmy.ca
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        8 hours ago

        In theory yes… but the oldest frozen specimen of humans we’ve found is only a few thousand years old. We don’t even know if long term cryogenic reanimation is possible.

        Assuming the ship travels at 10x our current capabilities we’re still looking at ~8,000 years to reach our closest stellar neighbour at only 5 lightyears away.

          • Canaconda@lemmy.ca
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            6 hours ago

            We’ll still run into the same assumption/problem; shelf life.

            Consider how memories work. Every time you remember something, your brain alters that memory slightly. Even looking at how the brain parses the data through several cortex (visual etc) implies that consciousness is potentially inseparable from the components of the brain. In this video about Cockatoo intelligence they speculate that birds brain anatomy causes them to think in ways that seem limited to us.

            Basically we don’t even know if its possible to preserve human consciousness for that long. Similar to cryogenics we have to question if reanimation is even fundamentally possible after centuries.

      • bluGill@fedia.io
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        8 hours ago

        Sort of - but there is no reason to think we will ever be able to make something that won’t break. Even intersellar is questionable just because the odds of the ship breaking in the time needed are too high.