Speed of light?

Right. Yes.




Ahhh, i see! the train's speed approaching him is 120mph/400,000,000m/s because he is travelling at 60 mph / 200,000,000m/s and that + the other trains speed will make the speed of approach from the two trains raise to 120mph/400,000,000m/s!

the way i show my understanding may be puzzling but i think i got it now

Interesting

I'm currently in a BTEC NAtional diploma L3 in ICT and Computing.

I think i might go onto univursity but i am very tempted just to jump into a job after.

Right, right.

BUT.

The guy on the train calculates that the other train is moving towards him at about 250,000,000 m/s, not 400,000,000 m/s!

Crazy, isn't it?

The first thing that ever came to my mind when I found out that nothing can go faster than the speed of light was this:

"Well, what if I'm a train going at the speed of light minus 5 mph, then a ride my bike inside the train at 10 mph? That puts me at 5 mph OVER the speed of light!"

I thought I was brilliant.

Alas, when you're going that fast, measurements (and therefore reality) distort so much, the number NEVER works out to be over the speed of light.

Yes that is abit crazy, why the hell would he read it as 250,000,000 ?????????? that seems so random.


But that theory that you go 5mph over the speed of light... is... incorrect lol. im not sure how many MPH there is in 300,000,000m/s. But if we just say for example there is 200,000,000mph = light speed

surely this would make your bike be travelling 199,999,990 mph slower than the train? lol.


*i know 200,000,000mph is not the speed of light, if i knew the correct measurements i would adjust my example but it still makes sense*

you ARE travelling faster than the trains speed AWAY from speed of light, but actual speed of the train compared to the bike, the train is VERY VERY VERY fast compared to it.

250,000,000 ??? - this would ONLY work if the trains where infact travelling at this speed... thus making the calculation of the man standing on the railtrack indeed 500,000,000 m/s... where did 250,000,000 come from out of all this? lol how puzzling

Let's assume that the speed of light is exactly 300,000,000 m/s.

My "brilliant" idea was this:
Imagine yourself in a train car going 299,999,999 m/s. You are in that train car with a bicycle. You pedal your bicycle towards the front of the train at 300,000,004 m/s, this breaking the speed of light.

Alas, that doesn't work.

No.

If two trains are each going 60 mph, and headed straight for each other, a person in one train will measure the second train as moving 120 mph relative to him.

However:

If two trains are each going 200,000,000 m/s, and headed straight for each other, a person in one train will measure the second train as moving at 250,000,000 m/s relative to him.


See the difference? We'd *expect* the answer in the second one to be 400,000,000, but it's not, thanks to relativity.

Ohh, i understand you.... wait, hmmm

that does seem quite brilliant.... why doesen't that work?? - if you had a railway track going out into space, and there was a train travelling at 2,999,999 m/s and you rode your bike at 5 mph in the train going from carriage to carriage, u've broken the speed of light barrier as you are travelling toward something in space at the speed of light... well, until you reach the end of the train that is!

y woulden't that work?

Crazy, isn't it?

The guy who measured the train at 299,999,999 m/s will only measure you on your bike at around 299,999,999.01 m/s.

The reason is quite complex. Suffice to say, when traveling at great speeds, lengths appear to contract and time appears to grow longer, influencing your measurements. The net effect is that no matter how fast two objects appear to be moving relative to each other, you will never measure any one of them as exceeding the speed of light.

If you want a more in-depth discussion of these effects presented in a way that's accessible to someone without a physics background, I suggest these books:

Inside Relativity by Mook and Vargish
A Brief History of Time by Hawking

Hmmm, i c its a shame you could of became famous lol.

Perhaps if you had a HUGE train, travelling at 299,999,999 m/s. and have another train inside the train travelling at 200,000,000 m/s+

it would move up the train and gain enough 0.1's to reach speed of light?? or would it also be seen as 299,999,999.01m/s?

I will have a look for these books in my local store

I can't be bothered to do the calculations right now, but it would probably be more like 299,999,999.6 m/s.

A train going 299,999,999 m/s inside another train that is going 299,999,999 m/s inside another train going 299,999,999 m/s will still only be measured at like 299,999,999.99 m/s (assuming the speed of light is exactly 300,000,000 m/s)

+ thanks for your time in explaining these things to me you could of just left me in confusion but im greatful you explained and simplified aspects well

Damn it. LOL

I see why now you say speed of light is impossible.

ahh why coulden't god make the world more simplified eh, a pedal bike riding at 300,000,004 m/s, wow, lol, and i'll be watching you and other great minds of earth on pedal bikes inside trains running tests lol.