Post your favourite paradoxes

[RogerMexico]

Where did everyone read the sweet new article announcing time goes backwards as you exceed the speed of light? Last I checked, it simply meant that you move faster than the appearance of something happening. If someone paints a giant middle finger on the side of a planet one light year away, and you travel back to Earth instantly, then yes, you have a year to wait until the light radiating off the planet tells you to fuck yourself. That doesn't mean you've traveled back in time. It simply means that light can be pretty slow in the cosmic scheme, and you shouldn't assume the shit you're seeing isn't old news.

Also, there are existing physical phenomena that exceed the speed of light. Einstein's ideas about that whole thing are now viewed in the scientific community as at least partially fucked. Quantum entanglement, for example: where two particles share the fate of outside forces acted upon them, instanteously, despite any kind of spatial separation. Change the spin of one photon on Earth, for example, and its partner's spin one light-year away (on the planet with the giant middle finger) will change simultaneously.

[Bob (SRB)]

Yeah I know according to the theory of relativity you would need an infinte mass and and an infinte amount of energy to reach the speed of light. But these new advances in quantum mechanics could possibly disprove that whole theory. Also, if one were able to change their composition into a wave they would be able to exceed the speed of light. And if one were to travel via a wormhole they could reach places instantaneously, where it would take light years to reach. If someone were just able to invent a quantum computer, concepts like time travel wouldn't be so far off.

[Rion.]

If time travel was invented, wouldn't we already know about it since we'd have been visited by those who invented it in the future?

(It's late, I may be talking crap if this makes no sense inform me tomorrow thanks)

[Abatis]

Out of the loop?

If time travel was invented, wouldn't we already know about it since we'd have been visited by those who invented it in the future?

(It's late, I may be talking crap if this makes no sense inform me tomorrow thanks)

You haven't been told? We were visted by time travelers in '87 and Japenese scientists are going to discover time travel in 2032... If only they had told us how we discovered it...

[iKillburger]

how do you know we aren't already moving at the speed of light. Is speed not just a relative motion between 2 objects. How do you know which object is going the speed of ligh. i.e. if you make a boat go 10000000 mph how do you know you didnt slow it down that much in relation to the rest of the universe. WHere is the frame of reference??

[Saturn V]

All this FTL talk reminded me of the Einstein-Podolsky-Rosen paradox dealing with quantum entanglement.

As for traveling backwards in time, that may or may not depend on the existence of CTC's (closed time-like curves). Time travel in to the past may also violate conservation energy laws.

E = mc^2/sqrt(1 - v^2/c^2)

As something with rest mass approaches the speed of light, the energy approaches infinity. And even if you approach 99% the speed of light, you're still a long way from reaching the speed of light (as the speed of light is the same for all observers regardless of their speed). This doesn't say that FTL is impossible, however (just impossible using classical mechanics, I guess).

As someone mentioned earlier, I don't believe time travel into the past to be possible in my lifetime (or at least affordable in my lifetime) because I haven't been visited by my future self telling me to invest in Microsoft.

Fuck, my head hurts. :crying:

Edit:
I did some math for fun. If you travel at .9c for 10 seconds, about 22 seconds will have elapsed for all other observers.

[Jeansi]

If you move with the speed of light, light will still pass you with the speed of light.

[Volny]

really?

Wikipedia quote:

The Monty Hall problem is a riddle in elementary probability that arose from the American game show Let's Make a Deal with host Monty Hall. In spite of being an elementary problem, it is notorious for being the subject of controversy about both the statement of the problem and the correct answer.

The problem is as follows: At the end of the show, a player is shown three doors. Behind one of them, there's a prize for him to keep, while the other two contain goats (signifying no prize to be won). Although the show host knows what is behind each door, of course the player does not. After the player makes a first choice, Monty opens one of the two other doors, revealing a goat. He then offers the player the option to either stick with the initial choice or switch to the other closed door. Should the player switch?

The answer is that the chances of getting the prize increase substantially if he switches. Wrap your mind around that ;P

I really dont get this - I dont see reason why switching has got higher value than staying. After revealing the goat he has 1/2 chance of win - independently on his first choice so stay or switch are both same value.
Did i make mistake?

[Verthanthi]

Yes, but Monty Hall is DEFINATELY not a paradox.

[Azhran]

I really dont get this - I dont see reason why switching has got higher value than staying. After revealing the goat he has 1/2 chance of win - independently on his first choice so stay or switch are both same value.
Did i make mistake?

The chance of it not being the one you picked the first time is 2/3, and this stays the same even if the host opens one of the doors.

[Volny]

The chance of it not being the one you picked the first time is 2/3, and this stays the same even if the host opens one of the doors.

But same chance remains for 2nd unopened doors - it was 1/3 too. By opening the doors both chances changes to 1/2 so why switch the doors?

[Vykromond]

how do you know we aren't already moving at the speed of light. Is speed not just a relative motion between 2 objects. How do you know which object is going the speed of ligh. i.e. if you make a boat go 10000000 mph how do you know you didnt slow it down that much in relation to the rest of the universe. WHere is the frame of reference??

NO
NO
NO
NO
NO
NO
NO
NO
NO
NO
NO
NO
NO
NO
NO
NO
NO

[Azhran]

But same chance remains for 2nd unopened doors - it was 1/3 too. By opening the doors both chances changes to 1/2 so why switch the doors?

Because it doesn't change to 1/2, it's still 1/3 and 2/3s.

[RogerMexico]

how do you know we aren't already moving at the speed of light. Is speed not just a relative motion between 2 objects. How do you know which object is going the speed of ligh. i.e. if you make a boat go 10000000 mph how do you know you didnt slow it down that much in relation to the rest of the universe. WHere is the frame of reference??

The frame of reference is light reaching us from the stars in our universe moving in different directions, but outward from a central point. If several bodies scatter (with small variations) from one point, you can gather enough information from the bodies moving near and far -- toward and away from you -- to get a rough idea of where you're headed and how fast.

Also, I know it's just a hypothetical, but I have to know: out of all the possible vehicles you've chosen for which to peruse and tour space, at ungodly speeds no less (not sure why this part matters especially), why'd you pick a boat? I would have picked a hammock.

And if you're committed to a boat, might I recommend these flossy digs:



Second star to the right and straight on till morning, Homey. You'll be there in no time at that rate.

[NaiLed]

Where did everyone read the sweet new article announcing time goes backwards as you exceed the speed of light? Last I checked, it simply meant that you move faster than the appearance of something happening. If someone paints a giant middle finger on the side of a planet one light year away, and you travel back to Earth instantly, then yes, you have a year to wait until the light radiating off the planet tells you to fuck yourself. That doesn't mean you've traveled back in time. It simply means that light can be pretty slow in the cosmic scheme, and you shouldn't assume the shit you're seeing isn't old news.

Also, there are existing physical phenomena that exceed the speed of light. Einstein's ideas about that whole thing are now viewed in the scientific community as at least partially fucked. Quantum entanglement, for example: where two particles share the fate of outside forces acted upon them, instanteously, despite any kind of spatial separation. Change the spin of one photon on Earth, for example, and its partner's spin one light-year away (on the planet with the giant middle finger) will change simultaneously.

Yeah, interesting stuff.

The phenomena that excel the speed of light are called tacheons. I think that scientists only theroise that they exist too (I may be wrong)