6 ms·
Even at .99c, everything interesting is years, decades, centuries, and millennia apart. All interstellar solutions include maintenance over millennia. Once you'
by thechao 2y ago
Even at .99c, everything interesting is years, decades, centuries, and millennia apart. All interstellar solutions include maintenance over millennia. Once you're doing that, relativistic velocity is just a hazard, not a boon. If we do conquer interstellar travel it'll probably be at 1% c. The factor of 10-20x scale won't matter to such long lived civilizations.
- weberer 2y agoFrom the perspective of someone on the ground, yes. But due to time dilation, it could be just a few days for the people on the ship.
- Sanzig 2y agoAt .99c, the Lorentz factor is only about 7, so 1 year of ship time for 7 years of earth time.
- brandall10 2y ago.99c only dilates time by a factor of 7, so one year of time passed on a vehicle would yield ~7 light years. Heck, you have to get better than 5 nines to even compress a year into a day, .9999963c, which would take a freakish amount of energy to accelerate a KG to (3.3 × 10^19 J).
- Retric 2y agoOn top of this at 1g it takes ~1 year accelerating to that speed and another year decelerating. So even the nearest star is going to be a multi year subjective journey or a really unpleasant trip.
- llm_trw 2y agoThis is assuming that you have to be conscious during the trip. Antimatter storage is a lot more scifi than human hibernation.
- skissane 2y agoThe problem with human hibernation is that it is almost impossible to ethically test. What medical ethics board is going to approve a research project "put healthy experimental subject in coma for 5 years, observe what they are like when they wake up?" Reminds me of https://en.wikipedia.org/wiki/Deep_sleep_therapy https://en.wikipedia.org/wiki/Deep_sleep_therapy and https://en.wikipedia.org/wiki/Chelmsford_Royal_Commission https://en.wikipedia.org/wiki/Chelmsford_Royal_Commission I think this is an example of a technology which, if it is ever developed, is most likely to be developed by some kind of totalitarian regime which has no ethical qualms about human experimentation.
- zardo 2y agoThat's not really how hibernation works in mammals, they have to raise their body temperature and come out of hibernation every couple weeks, the leading theory is this is to (ironically) catch up on sleep. Inducing torpor would have major medical uses in surgical and emergency medicine, it's not just useful for passing the time.
- jaybrendansmith 2y agoHeinlein story time! Door into Summer https://en.wikipedia.org/wiki/The_Door_into_Summer https://en.wikipedia.org/wiki/The_Door_into_Summer Protagonist signs their life away for a 'cold sleep' that will allow them to wake up many years later. Tech is iffy. They do it because they are desperate, and the interest gained over time should make them rich (doesn't happen of course).
- sungho_ 2y agoPeople with incurable diseases or just strange individuals can volunteer for such experiments. After that, if they write about their experiences, it could be featured first on Hacker News.
- Retric 2y agoI think the opposite is true. We do know how to inefficiently create and store antimatter, we don’t have any idea how to cause human hibernation. To me getting two dozen of orders of magnitude better at something is clearly hard, but that still beats trying to do something we don’t have a clue how to start. For human hibernation step 1 is probably serious genetic engineering and there’s going to be other steps.
- dietr1ch 2y agoDamn, c is too big for traveling with compressed enough time for cheap, yet too small to make communication within the earth be pretty much instantaneous (like getting 1ms roundtrip latency everywhere).
- jamiek88 2y agoRight? I’ve often thought this. Light is both frustratingly fast and frustratingly slow at the same time.
- dullcrisp 2y agoIt’s not that light is too fast it’s that space is too big.
- rossjudson 2y agoThe problem is that we don't live long enough. We're fireflies.
- dietr1ch 2y agoIdk, given how things are going I'll take 45yrs over 10^6yrs
- polishdude20 2y agoIsn't this a pointless goal anyways since any spaceship we'd have capable of getting to any meaningful percentage of c would get destroyed by any small amounts of matter or gas it bumps into on the way.
- BriggyDwiggs42 2y agoSeems reasonable might have some way of dealing with that when they’re able to accelerate sizable objects to multiple percents c.
- vlovich123 2y agoMy understanding is that space is so big and empty that the odds of you actually hitting anything is quite small.
- forgetfreeman 2y agoI'd imagine that simply interacting with stray hydrogen atoms faffing about in interstellar space would cause significant damage over time?
- TheSpiceIsLife 2y agoSounds about right. In the interstellar medium, matter is primarily in molecular form and reaches number densities of 10^12 molecules (mostly composed of) hydrogen, then helium, oxygen, nitrogen) per cubic meter (1 trillion molecules per cubic meter).[1] So, what, about a picogram per cubic meter. If your ship has a cross-sectional area of one square meter, and Alpha Centauri is 40,000,000,000,000 meters away [2] (and you thought it was a long way to the shop if you want a Chiko Roll), you’ll have to manage with 2.62^23 tonnes of mostly hydrogen in the way. The interstellar medium is also about 1% dust, so about 2.6^21 tonnes of solid matter. Someone check my mass maths. 1. https://en.m.wikipedia.org/wiki/Interstellar_medium https://en.m.wikipedia.org/wiki/Interstellar_medium 2. Google Search AI Overview
- thrance 2y agoWith a ship that accelerates at a constant 1G, you can go pretty much anywhere in the universe in less than 50 (subjective) years [1]. And when I say anywhere, I mean anywhere. [1] https://www.reddit.com/r/dataisbeautiful/comments/s4tbry/oc_space_travel_with_constant_acceleration/ https://www.reddit.com/r/dataisbeautiful/comments/s4tbry/oc_...
- diggan 2y agoMaybe I'm mistaken, but that graph would be for passing by places, as it doesn't include the time it would take to slow down from that constant acceleration, if you want to actually visit any other places than your zipping spaceship.
- creato 2y agoThe title of the graph says it is for accelerating half way, then decelerating the other half
- aardvark179 2y agoThis comes up every time this sort of thing is discussed on HN. Sustained 1 g acceleration takes a staggering amount of fuel, and carrying enough to slow down again makes it even worse.
- thrance 2y agoIt's definitely sci-fi for now, but we can always imagine some far out way to store energy much more densely than antimatter. A huge amount of photons orbiting a micro black hole on its Schwarzschild radius, would only weigh as much as the black hole and let you store a potentially infinite amount of energy.
- aardvark179 2y agoNo, they would have as much mass as the black hole plus the energy of the photons (they still distort spacetime and exert a gravitational force, and have inertial mass) and you still have to move that mass with you. You may have increased your fuel density, but you haven’t reduced its mass compared to antimattter, and you still have not dodged the relativistic rocket equation.
- dehrmann 2y agoSo it's only worthwhile to do big excursions if participants self-fund it or we missed something about relativity and faster-than-light travel. Funding it would be like the Roman empire telling us a small boat will land in Genoa in 2025 that spent the last two millennia traveling the world and collecting data with the best tools of the first century.
- thechao 2y agoYep. Interstellar space is pretty famously big.
- anothername12 2y agoYou just won't believe how vastly, hugely, mind-bogglingly big it is. I mean, you may think it's a long way down the road to the chemist's, but that's just peanuts to space.
- wombatpm 2y agoSpace is big. Space is dark. It’s never hard to find a place to park - Burma Shave