Physics brain-bender

[Spaded]

I couldn't sleep last night so I thought of what an object might look like if it could travel faster than light. I came up with a solution, only to come up with a totally different and more sensible solution a few minutes later.

Lets say that there is a ball traveling towards you at 2x the speed of light. At time zero, the ball is one light-second away from your head. At 0.5 seconds, the ball stops by the side of your head (not right in front of your face, or you would only see the ball). What do you see during the whole second?

Big disclaimer: I know that nothing can approach the speed of light, and I know that if it did exceed it, it would be going back in time like the hypothetical tachyon, but just ignore that...

[Rev. Good Will]

I don't know if the human eye would refresh fast enough to view it moving.

[MelchyBeau]

can you see 2.99*10^8 meters away?

Lets look at the Lorentz Transformation.

so we get L/(sqrt[1-(4c^2/c^2)]) = L/(sqrt[1-4]) = L/(sqrt(-3))

It is imaginary, you won't see anything

Melch

[daryn]

by the time it takes for the light to leave your eye, bounce off the object, and come back to your eye, it's gone baby.

[Patrick del Poker Grande]

I'm pretty sure this one sucks. Next.

[Spaded]

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can you see 2.99*10^8 meters away?

[/ QUOTE ]
The sun is 93 million miles away. It takes light more than a second to reach our eyes, so yes I can see that far. Can you see stars?

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It is imaginary, you won't see anything

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And that is why I said to ignore the fact that objects cannot approach the speed of light.

Think outside the box of equations, this isnt a physics quiz, just a concept. And yes, you can see something. As I said, the object stops moving beside your head.

[Spaded]

Here's the answer in white if you are interested

<font color="white"> The moment the object stops beside you, you see the object. Then you also see a ghost image of the object moving backwards towards the original position it was at at time zero, giving the illusion of two balls; one is stationary beside you, the other is moving backward. You did not see the object as it was approaching you because it was moving faster than the speed of light, but when it stopped, the light reflected by the object while it was traveling reaches your eye, giving the illusion that the object simply appeared in front of you, and shot an image of itself to its original position.</font>

That's it! No formulas or anything, just fun conceptual BS /images/graemlins/smile.gif Now go give your physics professor a hug.

[MelchyBeau]

I meant an object the size of a ball.

We can't ignore physics to figure out a physics problem.

Melch

[PairTheBoard]

You would first see the ball appearing from out of nowhere beside your head. Over the next half second you would then see an image of the ball apparently travelling backwards to it's point of origin 1 light second away.

PairTheBoard

[Spaded]

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We can't ignore physics to figure out a physics problem.


[/ QUOTE ]

Who said it was a physics problem? Its just a lark.

[Quaalude]

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We can't ignore physics to figure out a physics problem.


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Who said it was a physics problem?

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Umm, the subject line?

And just to nitpick, most anything can approach the speed of light, it just can't reach the speed of light... that whole infinite energy thing and all that.

[kevyk]

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The sun is 93 million miles away. It takes light more than a second to reach our eyes...

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This is more like 8 light- minutes

c~=186,000 miles/sec.