6.2 KiB
Find the way to the ship
-
Author: u/hoja_nasredin Dai-Gurren Brigade*
-
URL: https://www.reddit.com/r/rational/comments/3lfstv/find_the_way_to_the_ship/
-
Score: 0
-
Created: 2015-09-18T14:49:27
Post:
So I was thinking of writing a story (probably will never write it but it is still fun to think about it)
You are a 16 years girl with a knife. You entered an alien ship and embarked to an unknown world.
On this rocky world with hostile fauna you lost the rest of the group of aliens due to an animal attack.
Aliens will take off in 7 days.
You are somehwere 1 day away from the landing site.
Aliens will not search for you.
How do you find your way to the ship?
Comments:
u/Sagebrysh [+3] Rank 7 Pragmatist (7 hours later)
Lets just do some quick mental arithmetic. For the sake of ease, I'm going to put myself in the girl in question's place and use my own approximate physical attributes.
The average person walks at a rate of 3.1 Mph. Assuming I spent one day walking to reach my current location, the ship should be roughly 30 miles away. If I drew a line outward from the centre of the ship to myself, I could visualize the uncertainty of my position as a circle on the ground with a radius of 30 miles, alien ship located at the centre.
Now, I personally would probably do okay in such a situation since I have a very strong sense of direction and how to retrace my steps. Plus my alien landing party probably left some evidence of their passage on the the terrain so I could retrace my steps by following the path I took previously.
But lets say I can't do that. Lets say I get knocked out or something when leaving the ship and come to 30 miles away with no idea how I got there or which direction the ship is in.
I can still probably figure this out. As long as I have enough resources to not have to waste time foraging, and don't get attacked by another animal, I should be able to do it.
Okay, so if I draw a 30 mile line out from myself, and use that line to define the radius of a new circle, I know that the ship will be somewhere along the edge of that circle.
So lets do some math!
C=π302
gives me a circumference of 188 miles. With an average human walking speed of 3.1 mph, I could cover the entire circumference in 60 hours. If I do nothing but walk: don't sleep, don't eat, don't stop to pee, I could cover the ground. That might be beyond the normal human levels of endurance though, so assuming I did 10 hours a day, it would take me 6 days.
That's cutting it a bit close, but it still lets me cover all the ground of the circle with a day to spare (which I will need, because I still have to walk in a straight line from my starting point 30 miles to the circle's line before I can start walking in anyway!)
Assuming I can follow the line despite terrain (no small task!) I would find the ship before they left. If I ran into a body of water I couldn't cross, then I could use that to cut time off my search, since I would probably remember if the ship had landed in a lake.
I can use math again to figure out how far I have to go to get back onto the line once I start following the cost, based on the angle that I intersect the coast at.
Now how am I going to possibly walk a circle 60 miles around without getting lost? Well the sun should be a good navigation tool. Knowing the rough time of day, and where the sun is at that time would pretty easily let me figure out directionality.
For a lot of this though? The terrain may very well be the biggest factor, and it isn't described at all. In a desert, or on a savannah or otherwise mostly open, flat land? You walk outwards in a wide spiral until you spot the ship on the horizon. This trick would work much less effectively in mountainous terrain where ridges and valleys break up the landscape and block line of sight. In places like that, getting to the nearest high ground to afford yourself a view would be the best plan.
In somewhere like a forest or jungle, it would be very tricky, since people tend to have a poor track record at navigating when they can't see a horizon line. There's a phenomena called hiker deja vu where people literally walk in circles, and its not really well studied enough to be able to actively compensate for that with conscious effort.
Other things like how big the ship is are going to also make a pretty huge difference. Is it the size of a bus or the size of a modern aircraft carrier? How tall is it while it's sitting on the ground? What did the place it landed look like? My best bet to finding my way back would probably be by using large reference features like mountains that I saw upon landing, and orienting myself with respect to them. Example: when the ship landed, there was a mountain with a glacier cap to my south. That mountain is now to my southwest, so I should travel east to get back to the ship.
The scenario presented is entirely blank though, without more details, the answer is pretty much going to be "it depends."
u/xamueljones [+2] My arch-enemy is entropy (12 hours later)
Applauds loudly
I had the exact same idea of walking out in a spiral versus walking directly to the imaginary circle and walking along the circumference. However, you had a more through plan and accounted for various potential details of varying environment. If I ever have to go in the wilderness or some other harsh environment, can you come with me?
u/want_to_want [+2] (2 hours later)
The description seems too vague. I would try to find water first, then get to high ground to look around. If either of these steps failed, I would lose the challenge and probably die.
u/Geminii27 [+1] (2 hours later)
Will the aliens follow a signal to you, or will they simply take off in seven days whether or not you are on board?
Is your memory good enough to recall details of the area around the landing site, the approximate time of day (assuming it was not night) that you left the site, and/or any constellations (if it was night)?
Do any of the local terrain features match those visible from the landing site (mountains etc)?