If you can somehow accelerate/decelerate at a constant human-acceptable 1G, time dilation means almost anywhere is reachable in a human-lifetime.
That coincidence(?) could easily become false if we are accustomed to lower accelerations or lesser lifespans.
You think those time periods are large because you see a lot of numbers in the units you chose, or because it is much larger than your lifespan. But in the grand scheme a galaxy is nothing but a spec of dust, 10k years a blink of an eye.
There is no other natural velocity that I'm aware of that we could compare it to, but we can say that the speed of light is the fastest there is, so how can it be slow?
if we add more 9s, is it possible to reduce that number to within a human lifespan?
If you accelerate at 1g constantly for 1y you travel 0.5 light years. You do that for 10.5 years and you reach the center of the milky way. You do that for another 4 (~14 total) years and you are in the Andromeda galaxy, and you do that for another 10 years (~24 years total) and you reach what today is considered the edge of the observable universe.
By the time you get there you are basically traveling at a rounding error from C.
Can't we accelerate past 1G constantly? Or do we expend so much energy doing it that we can't realistically do it with today's technology?
Chemical rockets are currently the only thing that allow sustaining such accelerations briefly for human-size payloads, but the low exhaust velocity and exponential reaction mass requirement make sustaining it for days/months/years completely impossible.
You'd have to supply the energy externally (i.e. some sort of beam propulsion), but getting any significant fraction of g out of such a system (with human-sized payloads) seems unlikely within the next centuries, especially as the distance increases.
Or some form of ram scope, plenty of H everywhere, but those also have the issue of you collecting things while going at relativistic speeds.
Magic warp bubble tech is the bare minimum, and we're nowhere close to inventing that.
Increasing the acceleration a little bit more than that (eg to 1%) would make a difference.
Wouldn't that be only a few months on a decades-long journey at 1.01G vs 1G??
People always say that about speed of light stuff, but I don’t get it. Do you have any more examples of counterintuitive math?
Because what you’re describing is basically the equivalent to compound interest in finance. (e.g. investing $100 at 10% interest over 10 years results in $260)
- [pic](https://home.davidgoffredo.com/hackernews/proper-time-one-li...)
- [plot](https://home.davidgoffredo.com/hackernews/proper-time-one-li...)
1,000 seconds = ~0.01 days (~17 min)
1,000,000 seconds = ~11.57 days (~12 days)
1,000,000,000 seconds = ~11,574.07 days (~32 years)
1,000,000,000,000 seconds = ~11,574,074.07 days (~32k years)
Maybe it's just our human calendar/time unit rollercoaster (60*60*24*30*12) that's playing tricks on us here.
But it isn't intuitive, you're not used to numbers that big or that grow that fast.
Few things go from a million to a billion, especially when related to time.
At 99.999% of C, the Lorentz factor is ~223.6.
It grows pretty quickly as you add more 9s to the fraction. Every two additional 9s multiply the Lorentz factor by ~10.
So at 0.99999999999 c, it'd be ~223,607x.
2.5M years / 223,607 is: ~11 years
Of course this is all highly theoretical.