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Muc Much like that. It's a feasible possibility one could gather resources as they go but it would have to be of sufficient size for any manufacturing of those resources. As well as population growth. One could use the Oort cloud to hide in as their are lots of objects in the Oort cloud that escapes detection.

Like a customised self-gravitating body ~100+ km diameter built from carefully redirected small asteroids to put it into a path of ejection from the solar system? Internal thermal energy may be a viable long term energy source (or nuclear). Deep subterranean accommodation caverns should give reasonable protection from small collisions. Not sure I'd pick the lifestyle choice myself...

Could we not just make the world a little bigger and carry on as normal? Dig a hole into the centre of the earth and let off a nuclear bomb ( or an anti gravity device ?) so as to increase the radius of the planet to a suitable degree. The surface would expand and there would be endless opportunities for new resource exploitation and enough lebensraum for all. Those who don't like the idea could just sign up with Elon Musk.

If we're sticking to known physics a feasible possibility being the Alcubierre drive it's feasible if one can solve the solutions for reduced energy requirements and eliminate any need for negative mass. Theoretically this would address the collision scenario as the spacetime bubble would cause deflection. However it also in turn generates a greater problem that the bubble may also cause gamma ray production. One study I'm familiar with showed that even at 50 percent c. That gamma ray production could wipe out life on the planet it's leaving and arriving at. However I've only ever come across the one paper on it. Other than that I can't think of any viable means that isn't a 1 way trip. Which really negates curious visitations. Colonization would be far more likely than visitation in a 1 way trip scenario. Though one other possibility is some species that lives strictly in space however that would require am extremely large craft with a huge infrastructure for resource production

Solar sails feel a force of P/c, so you need ~3 x 10^9 watts to accelerate a 1 kg payload at 1g. And a point source of light will drop off as 1/r^2 Solar sails are not really maneuverable - it will get you from point A to B, but if you want to do other than straight-line motion it gets tough. No stopping off to gather raw materials. Such efforts require additional infrastructure which adds mass.

Rubber science, for sure. Except light sails, laser stations, the modes with external push. Again, maybe why Von Neuman devices could be more feasible - one the size of a beer can, with light sail wings. The physics is known, but I don't know how far the engineering will go. We are talking civs with massively elongated time frames, a hypothetical entity at this point. (shrug)

Agree that all such socially structured causes have deeper roots. If we can't fix dopamine rushes, maybe we could try some form of socialism and combine it with Green ideas. The Scandinavian Model seems to go that direction. And consuming less has reached the status of a fad in some wealthy countries, though it's really hard to say how far that will go. People who embrace Marie Kondo or home minimalism or Tiny Houses may not always stick with that. A minimalism that made community sharing its focus (as the Japanese fellow spoke of) would probably need a near-miraculous resurgence of the Counterculture in the US. I.e. Americans would be more motivated by framing it in terms of less housework, more disposable income, fewer time payments...

Everyone suffers somewhat, because under extreme regimes the truth is a casualty. And telling the truth becomes hazardous to your health. And even if you're an old quiet guy who just putters in his garden and reads pulp novels, you're not an island - you experience the weight that lies on everyone around you, the constant threat to anyone waving their freak flag, books vanishing from library shelves and stores, and so on.

I think we have to limit ourselves to known physics. If you extrapolate based on something new being discovered, all bets are off. Energy? No problem - we find out that over-unity is possible! Warp drive! Stable wormholes! Impervium! Mithril!

Technical analysis of this kind is useful IF we have reason to assume that a civilization millennia ahead of us still uses impulse rocketry for starfaring. So that assumption deserves scrutiny as well. Getting whacked by an interstellar proton does seem like a potentially serious problem, especially von Neuman machines with nanoscale engineering. Imagine a civ has molecule scale memory and you are stored as a miniature thumb drive aboard and after a thousand parsecs you're full of flipped bits or whatever. Woops, there goes third grade...there goes first kiss... Asimov. One S. Yes, hyperspace was a handy sci-fi workaround. Plenty of sci-fi writers took that route - Niven, Herbert, Heinlein, Clarke, et al. Such a story device is called rubber science . https://en.wikipedia.org/wiki/Rubber_science

That understanding is correct. The elephant your missing is that their are two categories (primarily) for cosmic rays. Primary and secondary. Primary cosmic rays are those sent from stellar objects like the Sun Secondary cosmic rays are those particles produced by the Primary rays interactions with our atmosphere. Neutrons are part of the secondary group. Part of that process includes mesons decays to that further allows leptons to form. Here is an examination of some of the different processes at different atmospheric levels https://pdg.lbl.gov/2019/reviews/rpp2019-rev-cosmic-rays.pdf

Cyclic universe models is one possible cause for our universe coming into existence. It does nothing to address how the first universe developed but for this thread your not concerned about that. This however doesn't really follow. The conditions of the BB according to mainstream physics was in a thermal equilibrium state. The extreme high temperature wouldn't even allow atoms to form. The four forces were in a state of thermal equilibrium. Once electroweak symmetry breaking occurs the 4 fources could separate. Gravity Em, weak and strong force. Particles could then drop out of thermal equilibrium. That's simply one process where it would be impossible for past information ideas etc would be literally obliterated even assuming such things could even survive the initial collapse of the previous universe.

Why did you think that?

Are you sure this is right? My understanding was neutrons are some of the secondary products produced when cosmic rays interact with atoms in the atmosphere.

The faster we achieve the political extreme's the faster the pendulum swings the other way, I just hope I don't have to suffer... 🙏

It's often mentioned that cosmic rays include non-charged subatomic particles like neutrons as part of their mix. This seems to contradict the two facts that an isolated neutron spontaneously decays within just 15 minutes and that the universe is awfully big. The only solution that springs to this mind is that extreme time dilation (due to near-lightspeed motion) hugely extends a neutron's normal existence, relatively speaking. Is this true? Or is this a classic instance of not seeing the elephant in the room? 🤥

Assimov was very careful to sepperate that from his hyperspace fiction.

The moon near the horizon seems bigger; this is known as the moon illusion. There is some debate as to the exact cause - there are several possible contributing factors. One is the difficulty in judging distance to things on the horizon - an object in the sky can be further away than those on the ground and still be visible. https://en.m.wikipedia.org/wiki/Moon_illusion

In rough terms it’s similar to a tsunami created by an earthquake - a sudden shift in a solid, and it pushes the fluid out of the way. The impulse creates a wave pulse. For something tearing, this is happening over and over, at a microscopic level.

Also, how much reaction mass do you need to carry? What is the payload? (At some point we get into the issue of how a craft survives hitting objects traveling near c)

Huxley was indeed prescient on the subject. Let's hope Nietsche was too.

Let's do it! Do what? All you've got ATM is, my bible is better than your scientific knowledge; I didn't think you liked that approach... Indeed. "God/alien's is the blanket we use to cover the unknowns and give it a shape." I think this was a quote from a roadie for the "Rolling Stones".

A bullet most definitely does make a noise as it flies through the air. Whether you hear it as a whizz or as a crack depends on whether it is sub- or supersonic as it passes. But in the case of paper and tape, you also have something else: a resonator. The surface of the paper or the tape will be made to move when the breaks take place and this will make a larger volume of air move.

I realize it's about fast motion, but then why doesn't a flying bullet squeal like crazy? That's fast motion too, what's the difference? The sudden movement of the tape, I read somewhere that the wave along the tape can move at supersonic speeds, but how does this all relate and cause this sound specifically?

If you think being 13.8 billion years old is "fresh and new", you have a curious conception of these terms.