[TheGrinningSkull]

(Original post by NYU2012)

(2) If for every step I take, that step is equal to half the distance of my previous step, will I ever reach my destination?

Depends on the distance to the destination and the length of the first step.

Simple geometric series.

(Original post by Guru Jason)
Did A level but your explanation is pretty clear. It does makes sense. It's not be a paradox then it seems.

If it helps as well, even though I see you've understood it, I usually like to think of looking at the fraction over 9.
So 1/9 is 0.1111111111111111...
2/9 = 0.22222222222222...
etc
8/9=0.888888888888888...
9/9 as a fraction we know is 1, but continuing the pattern, it's the same as 0.99999999999999999...

Just a way to remember it

[Mystic Creature]

(Original post by TheGrinningSkull)
A different timeline is created
A split in the timeline occurs.
You now can't return to your other timeline and are stuck in this new dimension.

Back to the future! Whooo

Yeah ive read about that..it's one of the solutions to the paradox, but still, fun to think about!

[HaNzY]

(Original post by IntelligentIdiot)
My favourite is the twins paradox.

According to Einstein, a moving clock runs slower than a stationary one.
t2=t1[1-(v^2/c^2)]^-0.5
Where t2 is the time measured by the 'stationary' observe and t1 is the time measured by the 'moving' one.
{To all physicsists, I know I am being ambiguous on my frame of refernces. Forgive me...I am trying to make it easier to understand.}

Suppose we can travel at 0.975c, where c is the speed of light (3.00X10^8).
Imagine there are two twin girls aged 18. One of them stays on earth and the other gets on a spaceship and whizzes around the galaxy at 0.975c for, according to the travelling twin, 15 years. Let 15 years =t1. When the travelling twin returns, the non-travelling twin will have aged by t2, where t2=t1[1-(0.975)^2]^-0.5. Hence t2=67.5. Which means the travelling twin is 33 but the one that stayed on earth would be a ripe old age of 82.5. Old enough to be her twins' mother. This is the reason why I think that I am going mad by studying A2 physics.

Can we actually send someone up in space to try this? lol or are we a little way off being able to do it? I like this paradox too!

[Mystic Creature]

(Original post by IntelligentIdiot)
My favourite is the twins paradox.

According to Einstein, a moving clock runs slower than a stationary one.
t2=t1[1-(v^2/c^2)]^-0.5
Where t2 is the time measured by the 'stationary' observe and t1 is the time measured by the 'moving' one.
{To all physicsists, I know I am being ambiguous on my frame of refernces. Forgive me...I am trying to make it easier to understand.}

Suppose we can travel at 0.975c, where c is the speed of light (3.00X10^8).
Imagine there are two twin girls aged 18. One of them stays on earth and the other gets on a spaceship and whizzes around the galaxy at 0.975c for, according to the travelling twin, 15 years. Let 15 years =t1. When the travelling twin returns, the non-travelling twin will have aged by t2, where t2=t1[1-(0.975)^2]^-0.5. Hence t2=67.5. Which means the travelling twin is 33 but the one that stayed on earth would be a ripe old age of 82.5. Old enough to be her twins' mother. This is the reason why I think that I am going mad by studying A2 physics.

Sounds interesting, but way too complicated for me. And I wanted to do a degree in physics. I guess that's out of the picture then

[Joinedup]

A party that comes 3rd in a general election having the power to decide who forms the next government

[geetar]

The words that come out of Boris Johnson's mouth.

[IntelligentIdiot]

(Original post by HaNzY)
Can we actually send someone up in space to try this? lol or are we a little way off being able to do it? I like this paradox too!

Not yet. To get close to the speed of light we need an almost infinite amount of energy. Interestingly, it is impossible to reach the speed of the light since we need an infinite amount of energy to exert an infinite force but technically it is possible to reach 0.9999(place as many 9s as you want here) times the speed of light.

[shezshez]

Intelligentidiot. Apt name.

[alexsasg]

The paradox of Postmodernity. Postmodernists reject all other theories on the basis that they are simply one version of the truth...but according to their own logic, they are just another version of the truth too.

[Time Tourist]

The Cretan who says that all Cretans are liars.

The least indefinable number.

'If this sentence is true, then Germany borders China'

The barber who shaves all and only those people in the village who do not shave themselves.

[IntelligentIdiot]

(Original post by shezshez)
Intelligentidiot. Apt name.

Ty. I try. I have a thing for oxymorons.

[llacerta]

"There was only one catch and that was Catch-22, which specified that concern for one's own safety in the face of dangers that were real and immediate was the process of a rational mind. Orr was crazy and could be grounded. All he had to do was ask; and as soon as he did, he would no longer be crazy and would have to fly more missions. Orr would be crazy to fly more missions and sane if he didn't, but if he was sane he had to fly them. If he flew them he was crazy and didn't have to; but if he didn't want to he was sane and had to."

I love Catch-22.

[ANIGAV]

(Original post by llacerta)
"There was only one catch and that was Catch-22, which specified that concern for one's own safety in the face of dangers that were real and immediate was the process of a rational mind. Orr was crazy and could be grounded. All he had to do was ask; and as soon as he did, he would no longer be crazy and would have to fly more missions. Orr would be crazy to fly more missions and sane if he didn't, but if he was sane he had to fly them. If he flew them he was crazy and didn't have to; but if he didn't want to he was sane and had to."

I love Catch-22.

What is Catch-22? I keep hearing that name.

[llacerta]

(Original post by ANIGAV)
What is Catch-22? I keep hearing that name.

It's a book by Joseph Heller. It's...strange, but once you get into it, it can be very funny in a sort of satirical way. I also found it quite unnerving. Definitely worth a read if you can get your hands on a copy!

[ANIGAV]

(Original post by llacerta)
It's a book by Joseph Heller. It's...strange, but once you get into it, it can be very funny in a sort of satirical way. I also found it quite unnerving. Definitely worth a read if you can get your hands on a copy!

LOL sounds worth reading.

[HaNzY]

(Original post by IntelligentIdiot)
Not yet. To get close to the speed of light we need an almost infinite amount of energy. Interestingly, it is impossible to reach the speed of the light since we need an infinite amount of energy to exert an infinite force but technically it is possible to reach 0.9999(place as many 9s as you want here) times the speed of light.

Out of curiosity, how close have we been to the speed of light? I mean particle acceleration speeds as I am aware this is probably the fastest we have achieved.

In theory, what you say is possible...hence this implies we can travel forward in 'Earth time' so someone travelling for a good few years could come back and see the future lol and live in the future, however they would never be able to get back in time.

And hang on a sec...you say we can get to 0.9999...recurring the speed of light, earlier someone proved this = 1. Therefore...? I understand that we need infinite energy to get to the speed of light though.

And as another question because I'm so curious and love this sort of thing, if we could get to the speed of light, what would happen? Would we be stationary in time? And if we went faster than the speed of light we would go back in time? I am assuming that faster than the speed of light doesn't exist though? But why??

I always wanted to do physics, my childhood dream was to be an astronaut rather than the conventional vet or teacher lol, but I don't like lightbulb and electric physics lol only space stuff and interesting things like this topic!

[Retrodiction]

(Original post by ANIGAV)
Let's all try to share abit of knowledge so that we can all grow. What is your favourite paradox? it can be anything from maths to physics to philosophy itself.

Also please try to give a very brief explanation of the paradox if you understand it.

I start;


Video: http://youtu.be/aH2fpmxMV4Q

Correct me or any other user if the explanation of the paradox is wrong.

But the universe could just be infinite space rather than infinite stars? It's possible that there's only a cluster of stars within an infinity of space, and we're in it.

[117r]

(Original post by HaNzY)
Can we actually send someone up in space to try this? lol or are we a little way off being able to do it? I like this paradox too!

Well no, not quite, although it has been tested several ways, such as firing odd particles round accelerators and looking at the rates of decay.

As for the paradox itself, it's not so much a paradox as a meaningless question. It only seems like a paradox because the understanding that we have of time is essentially wrong, or at least only applicable to slow speeds. In reality, the concept of time running at different speeds for different people doesn't create a paradox since if you were to actually meet with the person travelling at near the speed of light, there would be some form of acceleration involved, which would disrupt things.

Sorry for confusing explanation, it's probably wrong and certainly very vague. If you are interested in this sort of stuff I'd like to recommend A Very Short Introduction to Relativity. Very clear explanations there.

[Joe_250]

(Original post by chickenonsteroids)
On opposite day... is it actually opposite day or not?

I tried to pos you but it is opposite day, so I negged you.
(Actually its just because I'm using a touchscreen and my fingers are too big). Sorry.

[ckingalt]

(Original post by NYU2012)
(1) This statement is false.

(2) If for every step I take, that step is equal to half the distance of my previous step, will I ever reach my destination?

(Original post by 117r)
Is 2 really a paradox? It has an answer: you will never reach the destination...

You can reach the original destination if you change your destination to a point twice as far but along the same path. However, you will never reach your second destination unless....