# 60 Second Adventures

This is very interesting series of small videos in which the authors are asking many puzzling questions and they're giving simple explanations. For example how could a humble tortoise beat the legendary Greek hero Achilles in a race?

Will time travel ever be possible? What would happen if a man went back in time to a date before his parents were born and kill his own grandfather?

With no grandfather one of the man's parents would never have been born and therefore the man himself would never have existed. So there would be nobody to go back in time and kill the grandfather in the first place.

Can a machine ever be truly called intelligent? If there was a hotel with an infinite number of rooms and an infinite number of guests what happens if someone new comes along looking for a place to stay? Is it true that the faster you travel through space the slower you move through time? Is it true that before you measure a particle, that particle is in a superposition of every possible state all at the same time?

An economy is a tricky thing to control and governments are always trying to figure out how to do it. Back in 1776 economist Adam Smith shocked everyone by saying that what government should actually do is just leave people alone to buy and sell freely among themselves. He suggested that if they just leave self-interested traders to compete with one another markets are guided for positive outcome as if by an invisible hand.

The English language begins with the phrase "Up yours Caesar" as the Romans leave Britain and a lot of Germanic tribes start flooding in, tribes such as the Angles and Saxons who together gave us the term Anglo-Saxons. The Romans left some very straight roads behind, but not much of their Latin language. The Anglo-Saxon vocabulary was much more useful.

Schrodinger takes the prize for best quote on quantum mechanics :)

Great series of short videos that summarise some complicated concepts in a simple introductory way. Also nice to hear the narration from David Mitchell ^_^

It is an enjoyable documentary. Much better and available on this site is "Sixty Symbols". My all-time favorite.

Great!!!!!!!!

Brilliant

What if you are travelling at the speed of light ..would your head lights still work????

Yes. The light would travel ahead of you at the speed of light relative to you. This is the basics of the theory of relativity.

I'm inclined to say NO. c + c = c and not 2c. light doesn't travel relative to you, light travels at light speed :) , do you like my explanation ?

No, because its wrong.

Just noticed you said c + c = c and not 2c. How can you justify proceeding with any argument when getting something this wrong.

One more thing. Lets suppose your theory is right and from your logic imagine that: We are in a car travelling at C - 1 mph, you are then to turn the headlights on and you would see light travel away from you at one mile per hour. Imagine this and use it to realise how your answer is incorrect, it is simply implausible.

"you couldn't be more wrong, you could try but you will fail". Ad hominems ? Really ? For calling you an ignorant ? Isn't that a fact ? You're backing up your poor arguments with information that clearly states that you're wrong. Have you even read the first couple of paragraphs in your link ? Here it is ( from YOUR link ) : "The speed of light is nonetheless invariant, the same for all observers." , also on the same page : "The speed of light in a vacuum is the same for all observers, regardless of their relative motion or of the motion of the light source."

The first sentence in my link states: "The speed of light in vacuum, commonly denoted c, is a universal physical constant ", which means that c + c is still c.

What do you have to say now ?

I believe the first one is flawed or poorly presented. Let's make some fair assumptions: the human is running at a mean speed of 5 m/s and has a distance of 100m to cover, that would take 20s. The tortoise 'runs' at 0.05 m/s and covers only the last 50m, that would take 1000s. Clearly the human overtakes the tortoise at some point. Easily resolved? YES!

I understand the idea that the runner always has to catch up smaller and smaller distances, but it just doesn't stand.

But, if the idea is presented differently, for instance: the human has to catch the tortoise (which is standing still), but is only allowed to cover half the distance between him and the tortoise, then things would get interesting in theory but also in practice. For example: distance is 100m; first only 50 meters are covered, then 25, then 12.5, then 6.25 and so on. No mater what the distance, there would still be a remaining half between them and he will never reach the tortoise; what ever distance remains to be covered, divided by 2 will never be 0, needed to reach the full 100m.

There you go: improvement !

v = car's speed. c = light speed. w = speed of light from the headlights

w = combined speed of v and c .

w = ( v + c ) / (1 + v*c/c*c ) . for car traveling at light speed v = c , then :

w = (c + c) / (1 + c*c/c*c) => w = 2c / 2 => w = c . (no surprise there)

meaning that w, the speed of the headlights is not 2c but still c , in other words : c (from headlights) plus c (of the car ) is still c.

This is confirmed by : "The speed of light .. is the same ..regardless ..of the motion of the light source."

If w = c then c + c = 2c. And therefore you suck at maths. Why do you continue this fight. Just google the question.

You just said the answer in your last paragraph meaning you agree with me. So well done, now please stop.

Velocities don't combine the same as apples or.. letters. Velocities accurately combine like this: V (v1,v2) = (v1+v2) / ( 1+ v1*v2/c*c )

Galilean transformation (is an approximation of the Lorenztian transformation) : 30 m/s + 30 m/s = 60 m/s (in the same direction of course)

The more accurate Lorenztian transformation: 30 m/s + 30 m/s = 59.9999999999994 m/s.

Upper limit - Lorenztian transformation - addition of speeds :

V( 299792458 m/s , 299792458 m/s ) = 299792458 m/s

Galilean transformation cannot be applied here.

You are a very very very very stupid person. Go read your novels and let others do physics !

I'm unsubscribing.

Again why incorrectly insult someone thats teaching you something you don't understand?

Turn on the lights and the light travels at the speed of light, as you have mentioned twice. I will no longer be responding.

Unsubscribing from what?

This is the velocity subtraction formula. Try it out. v = (w − u)/(1 − wu/c2)

I'm not a quantum physicist or something and reading formulas for something that hasn't been proved with factual evidence (car or light source is traveling on speed of light) is just boring.. I'll just use my plain imagination regarding this and then please tell me if my imagination is failing me.

in theory: the head lights will still work but it wouldn't be seen unless the source (car) will stop or decrease its speed from traveling at the speed of light.

Your imagination is alright, but I urge you to do the math, or else you're just a dilettante. I ended up losing the formatting (the 2 is an exponent) but the math is quite simple. You can learn how to do the velocity subtraction formula by typing it into youtube or google.

You're imagination is partially right and partially wrong, given the ambiguity as to who the observer is, which is very important.

work = force x distance

force = mass x acceleration

acceleration decreases as it approach the speed of light. if it reaches light speed though it would be zero. making force = to zero and so work too is equal to zero.

I didn't like this one. It was wishy-washy. But I am getting a kick out of the argument in the comments section. These dudes are getting their panties in a bunch over math. lol

Is that David Mitchell narrating?

Agree

Incredibly shallow and poor way of explaining very interesting topics. 0 stars out of 10.

Who is driving a car at light speed... and THEN turning the head lights on lol :P

You're all wrong

what i want to know is how the hell is a CAR traveling at light speed?it cant right? it has mass.

you would not be able to turn your car lights on because before you reached light speed your car would be crushed. right?