Tragedy of the Light Year Train: Locomotion Explosion

Computer Science Level 5

Scientists have built a train between worlds.
It goes so fast it'll make you hurl.
It stretches all the way to Alpha Centauri to Earth.
Don't even ask how much it's worth.

"What is its length?", you do beseech.
The train has 1 100 \frac{1}{100} light years of reach.
This here train can sure vamoose:
It's 1.5 1.5 light years from Earth to its caboose.

The whole track is 4.2 4.2 light years long.
Everyone's boarding so come along.
Suddenly, something's gone wrong:

The front and back cars simultaneously explode.
They casted into space their loads.
Both ends burst and turned to stars.
The tragedy was seen afar.

10000 10000 witnesses along the track existed.
Their distances from Earth are listed. (light years)

Nothing so horrid has ever been seen in locomotion.
How many years does it take for the average witness to see both explosions?

Details and assumptions:

  • Each distance is separated by a new line.

  • Round your answer to the nearest hundredth.

  • The list of distances can be found here .


The answer is 0.88.

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Brock Brown by Brock Brown , 25, USA

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1 solution

Beakal Tiliksew
Oct 18, 2015 
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total=0
time=0
for item in text:
    total+=1
    if item <=1.5:
        time+=1.51-item
    elif 1.5 < item < 1.51:
        time+=max(1.51-item, item-1.5)
    else:
        time+=item-1.5

print time/total

What will be the average time if the train was moving at relativistic speed?

3 Helpful 0 Interesting 0 Brilliant 0 Confused

@Brock Brown great problem but it is a little problematic if you take SR into account. We could come up with a reference frame where the two explosions take place at the same time. Also due to the relativity of simultaneity the witnesses do not observe the explosions to be simultaneous unless the train is moving at a very slow speed with relation to them. The clocks at the front of the train will lag by the ones at the back by V ( 0.01 c ) c 2 \frac{V (0.01c) }{c^2} where V V is the speed of the train relative to whatever reference frame the witnesses are in. It gets even more complicated if you consider time dilation effects on each observer .

Thaddeus Abiy - 5 years, 7 months ago

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