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by archgoon 2471 days ago
It's 111 light years away. For all intents and purposes, that's a one way trip right there; irregardless of the rocket equation. Even at relativistic speeds, you can't come home anymore.
6 comments

Theoretically, you can. At 0.99c 111 light years take about 15 years of ship time to travel.
You can make the trip arbitrarily small from your perspective (in theory at least :) ). The issue is that by the time you've made it back home, it's 222 years later. Hence "you can't go home anymore". :)
If you put some money in an interest-bearing account you could at least buy a new home when you got back.
> If you put some money in an interest-bearing account you could at least buy a new home when you got back.

If you do it in a country that doesn't allow you to be declared legally dead when you are out of contact for a couple centuries, and if the institutions involved don't collapse, and if the interest on the account outpaces inflation, sure.

What percentage of the banks that were around 222 years ago have not failed?

From [0] we can see that there are 10 banks founded before 1700 and 24 from 1700 to 1800.

So it might not be that far fetched, assuming that the banks keep your accounts open after more than 100 years without use.

[0] https://en.wikipedia.org/wiki/List_of_oldest_banks_in_contin...

10 banks out of how many founded in 300 years?
As pointed out by other commenters: a non zero number have survived. A small investment made with many different institutions would substantially increase your chances of a massive return upon... return.
That's not the right question, though, because the expected rate of failure isn't constant throughout the lifetime of a bank. See, e.g., https://en.wikipedia.org/wiki/Lindy_effect

Seems like your best bet would be to park your money with several very old banks: https://en.wikipedia.org/wiki/List_of_oldest_banks_in_contin...

Also might want to think about purchasing bonds: https://en.wikipedia.org/wiki/List_of_oldest_banks_in_contin...

2nd link was supposed to be https://en.wikipedia.org/wiki/Perpetual_bond with information about a bond from 1648 with the issuer still paying annual interest.
Bitcoin! :)
What if they release Bitcoin 2.0 the year you leave?
Probably tiny?

Lloyds bank founded 1765

Barclays founded 1736

I doubt any banks in the new world are as old.

Berenberg Bank founded 1590 (429 years ago)
You know where I can find one of these interest-bearing accounts that can outpace housing cost inflation?
While not an interest bearing account, investing in an index fund of global stocks should outpace housing. Investing in a REIT should roughly keep pace with housing costs.
Better do it in different countries and in different currencies and hope none of them get confiscated or have hyperinflation.
Not if you have negative interest rates. I heard on the radio that some European banks want to introduce this.
Or maybe a meal at a nice restaurant?
Wait, is this correct? Doesn't 111 light-years mean even light takes 111 years to travel through? And light travels at 1c.
Light does not experience time at light speed - it is stuck in a static moment. So from our stationary perspective, light takes 111 years to come from a 111 light year distance, but from light's perspective it takes an instant.
Every time I think I’m closer to understanding matters of time and space...
Here's a quick analogy to help (loosely adapted from Brian Greene):

You're on a grass field, sitting on one of those riding lawnmower thingies, with a broken throttle. It's moving at a fixed speed of 1mph. You can't ever change its velocity. But you can steer it. If you are going precisely east-west, then it means you're not going north-south. The more you go north-south, the less you'll be going east-west. If you're going precisely north-south, it means you're not going east-west at all. One direction is traded against the other.

Pretty straightforward, right?

So here's the analogy: that grass field is a "dimension" in the same way that "spacetime" is a "dimension". The two "directions" of spacetime aren't "east-west" and "north-south", but "space" and "time". These are inherently traded against each other. The more you're moving through one, the less you're moving through the other.

So what about that constant-velocity rideable lawnmower? That's "c" -- the speed of light. You're always traveling at this velocity. If you are sitting still in space, then you are nonetheless moving through time. Your rate of movement through time is "c". But as soon as you start moving through space, it means you are moving less through time. This is exactly the same tradeoff as moving north-south vs. east-west. If you devote 100% of your "c" to moving in the direction of the "space" axis, then it means you're not moving on the "time" axis at all.

(This is basically all it means for something to be a "dimension": different axes that are traded against one another.)

This analogy can be used to understand quite precisely how movement relates to time dilation. (It also helped me understand e=mc^2. Why is "c" there? What does the speed of light have to do with the embodied energy of matter at rest? Answer: nothing is ever at rest; all static matter is moving through through time at the velocity of "c", and obviously that movement must have kinetic energy.) But it's not a completely perfect analogy. Weirder relativistic effects like length contraction and frame dragging need much weirder analogies.

I like this analogy, but I think an even bigger problem than distance contraction is that in fact the lawnmower can go east-west on one axis, but only towards the north on the other axis, towards the future, at least as far as we have observed in macroscopic systems.

This may not be a problem for some definitions of time, but for the notion of time which goes from past to future, I don't think the analogy holds very well.

So, actually, like, it's actually really intuitive I feel like:

From the perspective of an object accelerating, newtonian physics works totally intuitively. If you had a rocket that could accelerate at 1g indefinitely, you just go faster and faster and faster and you get to any destination you want (even far away!) pretty quickly. And it would be a rather comfortable trip! You'd have Earth-like gravity the whole way.

It's really only the observer's perspective that things get confusing. When an observer watches something accelerate, they see it never going faster than the speed of light, no matter how fast it "actually" goes.

The trick is time. Time for slow things passes faster than time for fast things. A clock on a very fast rocket ticks much more slowly than clocks on (relatively) stationary things. That's how the paradox is solved.

Let's say you wanted to visit the Andromeda galaxy, which is around 2,500,000 light years away. If you had a rocket that could travel at 1g indefinitely, you'd get there in a comfortable 29 years! However, observers on Earth would see the trip taking around 2,500,000 years.

If you'd like to play with these numbers yourself, feel free to check out this neat calculator (not made by me)

http://nathangeffen.webfactional.com/spacetravel/spacetravel...

There is nothing intuitive about relativity unless you understand the physics and math behind it. Intuition can only be as good as your knowledge and experience.
Go watch a Carlo Rovelli lecture on time and loop quantum gravity.

Time might not even exist in and of itself.

Just view light as like being in line at the DMV.
Yeah, the experience of time to travel a distance approaches zero as your speed approaches the speed of light. It's really crazy to think about.

It is worth adding for the sake of clarity that light has no perspective or frame of reference because photons are non-inertial.

>but from light's perspective it takes an instant.

And for that reason they don't experience distance either. So the term 'sun-kissed' isn't actually that far off...from the photon's perspective the sun IS giving you a kiss.

Super fun. Great one. Actual replying to save this thread so I can go back and check some of this out. Looks neat.
i'm pretty sure the assertions means that the 111 years needed would only age the traveler by 15 years
It takes 111 light years from our reference point to travel that distance. If photons could perceive things, it would not take them 111 years by their perception.
accelerating at 1G to the mid point, then decelerating at 1g, will mean you’ll get there in about 15.8 ship years, or 115 earth years.

Spend twice as long on boats though (32 years) and you can do about 10,000 light years.

A constant acceleration of 1g would cause the ship to hit c in about one ship year.
The ship will never hit c.
If the ship travels tens of billions of light years will it eventually be traveling away from it's starting point at greater than c due to the dark-energy expansion of space itself? Or will the ship just red-shift more and more but never disappear from an observer with a very good telescope who stayed home?

And what if you drove your ship straight into a super-massive black hole?

One theory of the far future (Big Rip) is eventually nearby galaxies will be receeding faster then light, then stars, planets, then even atoms.

There's a short story about the Big Rip

https://web.archive.org/web/20080725045740/http://www.solari...

So you can survive the trip but even if you come back home, it’s not home anymore? Imagine leaving 222 years ago and coming back now ...
When the French invade Fishguard, Wales in 1797 our hero Gruffyd Rhys Llewellyn goes to get help in the only place where help may be forthcoming. The Heavens!

I should make a kickstarter, but I am already in my jammies.

I'd like a pint of mead and a stout woman! /s
Many european cities would still exist and the mountains I grew up in front of too.

But granted, all people I know would be dead and some I could find in the history books maybe..

> and some I could find in the history books maybe..

Where you would also be, at that stage.

I would recommend reading Noumenon by Marina J. Lostetter if you'd like to scratch that theoretical itch playing out one specific way.
I mean that sounds pretty awesome if you invested your funds well. I'd definitely be willing to be the first person who did that.
Where can you invest that would still recognize those funds as yours after 222 years?
You'd have to form some kind of trust, the "Swizec is in space for 200 years trust" to handle your investments for you with a constitution that lays out how long it is expected for you to be gone.

You might come back to discover that after several generations without oversight your trust has invested in bombing children and enriching the fund managers. I dunno.

You still get in trouble I think. Have any political regimes been stable enough in the past 222 yaers for the trust to survive?

All of Europe has gone through multiple revolutions, USA was only 30 years old back then so you wouldn’t have considered it ... that leaves what, the UK? Any parts of Asia that survived since 1797?

It's been done actually. Ben Franklin established a trust that lasted over two hundred years by design.

https://www.nytimes.com/paidpost/franklin-templeton/investin...

I admit I have some bias here being British, and just assuming the banking system won’t go under. I think if I was actually going to execute on this I’d end up finding a bunch of countries with well-established trust law and spread it between them.
And how much time will it take a person to reach that speed at human-safe acceleration? And how much energy would it take?
It will take longer that people here have calculated. As you approach c the energy required to accelerate quickly rises. To reach c you need infinite energy.

Maintaining 1g of acceleration for a useful amount of time would require an extraordinary amount of propellant.

All of those estimates are tongue-in-cheek and are accurate if your energy expenditure is actually unlimited.

Just under a year at 1g (according to google. I'm on mobile and would have to derive from F = ma on paper to solve). Energy is variable. I'd assume energy isn't relevant, as it's currently impossible, so we're taking that for granted.

Not really that long.

Not a physicist, but I think it might not be that simple. From our point of view, a ship with constant 1g acceleration increases its speed by 9.8 m/s every second, but people on a ship moving at a significant fraction of c take more than one of our seconds to experience one of their seconds. During the time they experience one of their seconds, the speed increases more than 9.8 m/s, so they must experience greater than 1g acceleration. I haven't done the math but it would be interesting to work out how the acceleration in our reference frame needs to reduce to ensure constant acceleration in the ship's reference frame, and how long it would really take to reach .99c without squashing the passengers.
Err, that isn't a correct understanding of physics, I believe. The ship wouldn't need to reduce its output as it gets faster relative to some other object in the universe. It can happily keep accelerating at 9.8 m/s for as long as it likes (or has fuel). No passengers would get squashed.
If the ship's means of propulsion is set to impart a constant force, then I understand that the passengers could experience a constant acceleration indefinitely, but that constant acceleration would be with respect to the ship's reference frame, not ours. A constant acceleration of 1g in our reference frame would mean by definition that the speed reaches 2c in two years, which can't be right. Subject again to the disclaimer that I'm not a physicist and haven't done the math, the only outcome I can picture is that in our reference frame the speed asymptotically approaches c in some interesting way.
Isn't a second now officially defined as a single period of atomic decay of a certain atom (I think Cessium?)? So this theoretical near-lightspeed craft could adjust it's accelerators based on an onboard atomic clock that would not be based on seconds as we tend to perceive them, but on SI seconds. I assume these would be getting longer as velocity approached 1c. Unless radioactive decay is also affected by relativity (obviously I am not a scientist), in which case of course that wouldn't work.
One of the consequences of the theory of relativity is that there is no "absolute time". The atomic clock will perceive time just as you will–that is, slower than an inertial reference frame.
Length contraction is something outside observers would see; the people on the ship would see themselves as normal (and hence not be "squashed".)
This paper has some interesting ideas. They want to manufacture really tiny black holes (radii of "a few attometers") and use Hawking radiation (which is inversely related to mass) to drive the vehicle. The black hole serves as both engine and fuel tank.

https://arxiv.org/abs/0908.1803

I calculate it to take about a year, with 1 g acceleration, but don't take my word for it, am curious to compare with a more authoritative answer.
Which would put you in your 50s to 60s if all you did was go there and back.
Heck, I managed that without interstellar travel.
And? Seems unlikely that we would send a small number of people on a 30 year trip. Given 30 years in a tin can with little to do, I'd expect the age range on departure to be ~18+ (with some people knowingly making a one way trip), and the age range on arrival back at Earth to be 0+, due to new additions to the crew mid-flight.
We're talking about just escaping the surface gravity, not returning to Earth.
If you can get there from 111 light-years away, you can probably also solve the higher surface gravity. While the former problem is theoretically solvable in a straightforward way, both are impractical with our current understanding of physics and material science.
But that's assuming you're traveling at the speed of light, right? In reality it would take much much longer than 111 years.
The fastest man-made object: https://en.wikipedia.org/wiki/Parker_Solar_Probe

Travelling at that speed (0,00064c - no relativistic effects) would take ~170,000 years.

The fastest spacecraft humans have produced is the Parker Solar Probe which when it zips around the sun will reach 430,000 mph. At that speed it would take 173,000 years to reach this planet.
It is also the slowest spacecraft. Speed is relative. To get it going that 'fast' when close to the sun the other half of its orbit is correspondingly slower than earth. When launched it accelerated away from earth at speed, but from the perspective of the sun is was actually decelerating, and was moving much slower that it was when attached to the earth.
Great! , do that gravity assist a few more hundred times around the sun and we are there in 500 years.
You can't do a gravity assist around the sun once you've reached solar escape velocity, because you won't be visiting the sun again.

If we could pull that trick so easily, we already would have.

Well... you could wrap around another star, or two, and come back to this sun for another assist a la Rendezvous with Rama.
At 111 light-years, we need to create a vehicle that can sustain several generations.
regardless