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01/13/2006 07:41:12 AM · #1 |
If I'm in a spacecraft travelling at the speed of light and I took a photo for a challenge entry would the flash work?
Steve |
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01/13/2006 07:43:31 AM · #2 |
| I think the real questions is, would you make the challenge deadline? ;) |
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01/13/2006 07:44:58 AM · #3 |
Originally posted by Tallbloke:
If I'm in a spacecraft travelling at the speed of light and I took a photo for a challenge entry would the flash work?
Steve |
It depends on which direction you were pointing it. The bigger question is would the camera record the image you see or what was there 20 years ago.
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01/13/2006 07:45:50 AM · #4 |
Originally posted by Tallbloke:
If I'm in a spacecraft travelling at the speed of light and I took a photo for a challenge entry would the flash work?
Steve |
If you are travelling away from your intended subject at the speed of light, no, your flash will NOT work. Your flash will seemingly stand as a ball of light, motionless in the air. Now, if you are travelling toward your subject at the speed of light, yes, your flash will, in essence, be twice as strong.
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01/13/2006 07:49:15 AM · #5 |
Originally posted by Tallbloke:
If I'm in a spacecraft travelling at the speed of light and I took a photo for a challenge entry would the flash work?
Steve |
if you are in the spacecraft, yes it would |
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01/13/2006 07:54:35 AM · #6 |
| I'm thinking that the electrons emitted from your flash unit would cause your spacecraft to deccelerate and consequently allow the flash to work as it should. |
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01/13/2006 07:57:12 AM · #7 |
If you put instant coffee in a microwave oven...will you go back in time?
Steve Wright the comedian used to do a whole set of jokes on questions like that...
Message edited by author 2006-01-13 07:58:13. |
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01/13/2006 07:57:21 AM · #8 |
Originally posted by dpaull:
...your flash will, in essence, be twice as strong. |
Twice as strong? Can light travel twice the speed of light? Or would it just sit like a "ball of light" in the flash?
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01/13/2006 08:02:33 AM · #9 |
If you drop a slice of buttered bread...
But what if you glued a slice of buttered bread butter side up to the back of a cat and dropped him off the roof. Would he still land on his feet?
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01/13/2006 08:08:40 AM · #10 |
Originally posted by nsbca7:
Originally posted by dpaull:
...your flash will, in essence, be twice as strong. |
Twice as strong? Can light travel twice the speed of light? Or would it just sit like a "ball of light" in the flash? |
Good point, yes, in that case, it will sit as a ball of light IN the flash and never leave...no one would even see it.
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01/13/2006 08:28:45 AM · #11 |
boink
Message edited by author 2006-01-13 08:29:30.
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01/13/2006 08:28:47 AM · #12 |
Originally posted by Tallbloke:
If I'm in a spacecraft travelling at the speed of light... |
What would you use for headlights on this spacecraft? And what happens when you accelerate past the speed of light? Do you go plaid?
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01/13/2006 08:48:28 AM · #13 |
Originally posted by dpaull:
Originally posted by nsbca7:
Originally posted by dpaull:
...your flash will, in essence, be twice as strong. |
Twice as strong? Can light travel twice the speed of light? Or would it just sit like a "ball of light" in the flash? |
Good point, yes, in that case, it will sit as a ball of light IN the flash and never leave...no one would even see it. |
Until you stopped. Then everything (like the flash, the light from the headlights, your dentures) would continue on ahead of you unchecked and still at the speed of light.
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01/13/2006 09:07:46 AM · #14 |
Originally posted by nsbca7:
If you drop a slice of buttered bread...
But what if you glued a slice of buttered bread butter side up to the back of a cat and dropped him off the roof. Would he still land on his feet? |
actually it would spin just above the floor in an endless motion. Once used by Egyptions to create electricity but inablity to feed cat caused irregular rotation and proved to be cat-istropic. ;p
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01/13/2006 09:29:10 AM · #15 |
Originally posted by nsbca7:
Originally posted by Tallbloke:
If I'm in a spacecraft travelling at the speed of light... |
What would you use for headlights on this spacecraft? And what happens when you accelerate past the speed of light? Do you go plaid? |
omg! Battaglia made me laugh!!!!
*faint*
Must be those new rules. lol
My head is spinning from this thread people - slow down. rofl
If you were traveling the speed of light, how would you get your hands up to lift your camera? HMMMMMM?
Your flash couldn't be twice as strong no.
But the sync would sure be off.
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01/13/2006 09:33:25 AM · #16 |
Super question! I would be v happy for anyone else to elaborate on or correct my basic understanding of the principles!
My understanding of special relativity is as follows.
The spacecraft could not actually travel at the speed of light (this would require an infinite amount of energy - energy/mass unification theory), so I will assume that we are just a fraction under the speed of light.
The flash would illuminate the inside of the spacecraft and appear to work normally to you, the photographer and passenger, because relative to the spaceship, you are not moving. The speed of light, relative to you, would appear to travel to and reflect from the insides of the spaceship normally.
To an outside observer, watching you go past and seeing you take the picture through the porthole, he would see the flash light arriving at his eyes at the speed of light. However, relative to him, the spaceship would look significantly shorter than its length at rest. To the outside observer, the photographer on the spaceship would be moving very very slowly, almost fixed in time.
Taking a photograph of the observer from the spaceship, the observer would also look very thin and slow moving. This thinness would be reflected in the photograph.
If you took a photograph facing forwards, the flash would still take a photograph of the inside of the spaceship normally (though to the outside observer, this would be a very small distance and everything would look very slow moving). If you were taking a photograph of a stationary object in front of you, the flash would leave the camera at the speed of light and hit the object at the speed of light. The reflected image would hit the camera very shortly before you hit or passed the subject. Because you were travelling at nearly the speed of light, you would not have very much time to avoid the obstacle.
You would almost get some element of motion blur that would prevent you from scoring well!
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01/13/2006 09:38:17 AM · #17 |
This is just doing my head in!
So, in the original Star Wars, when Luke was practising his light saber in the ship, they were going at light speed, so what you're saying is that wouldn't work unless you pointed it in the direction you were going, or would you not see it at all? |
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01/13/2006 10:59:03 AM · #18 |
Originally posted by Makka:
This is just doing my head in!
So, in the original Star Wars, when Luke was practising his light saber in the ship, they were going at light speed, so what you're saying is that wouldn't work unless you pointed it in the direction you were going, or would you not see it at all? |
Relative to him, the light saber was not travelling at all. It would only look different to an external observer who was not travelling at light speed!
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01/13/2006 11:01:19 AM · #19 |
Originally posted by legalbeagle:
To an outside observer, watching you go past and seeing you take the picture through the porthole, he would see the flash light arriving at his eyes at the speed of light. However, relative to him, the spaceship would look significantly shorter than its length at rest. To the outside observer, the photographer on the spaceship would be moving very very slowly, almost fixed in time.
Taking a photograph of the observer from the spaceship, the observer would also look very thin and slow moving. This thinness would be reflected in the photograph.
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I don't really think you would be able to see an outside observer nor could they see you if you were going by at the speed of light. Perhaps a quick flash and then a series of sonic booms a few minutes later.
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01/13/2006 11:12:08 AM · #20 |
It is all a matter of scale.
If you replace "spaceship" with star, and assume it is travelling "past" you at high velocity a few light years away, you would have plenty of time to watch it go past (and in space there is no sound, let alone a boom!).
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01/13/2006 11:17:03 AM · #21 |
Originally posted by legalbeagle:
(and in space there is no sound, let alone a boom!). |
Ah, but you didn't say it was in space. You said it was going by an observer which could well be standing right down the road from you at this very moment and I started the sentence with the disclaimer "Perhaps"
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01/13/2006 11:38:28 AM · #22 |
If you were taking a photograph of a stationary object in front of you, the flash would leave the camera at the speed of light and hit the object at the speed of light. The reflected image would hit the camera very shortly before you hit or passed the subject. Because you were travelling at nearly the speed of light, you would not have very much time to avoid the obstacle.
You would almost get some element of motion blur that would prevent you from scoring well!
Loved this bit
:-)
I suppose the bit that bakes your noodle is the question that (as in an aircraft or orbit weightlesness) your perception of your speed is nil. If I throw a tennis ball down an aircraft passageway as it's travelling at 300mph, I haven't just thrown the ball 310mph but it did travel at 310mph relative to the ground!!
With the speed of light being absolute we can't use the same hypothesis though. If the spacecraft travels at the speed of light (or just under so as not to use all the energy in the universe and be infinitely massive)then the light that emits from my flash (Speedlite 430ex) can't go faster than the speed of light relative to anything.
I propse then that if the spaceship is travelling at slightly below the speed of light the the "ball" of light coming from my flash (which is not hindered by mass) would travel, naturally, at the speed of light and would appear to me in the spacecraft to be moving away from the flash unit very very slowly.
Since the light must bounce off the subject (a spinning toast cat, for example) then back to the camera CCD to be recorded, overexposure and camera shake would be serious problems.
Therefore I propose the forthcoming DP Challenge "take a pin sharp picture of a perpetual motion spinning toast cat while travelling at or near the speed of light" be abandoned.
I love Fridays
Steve
edit: brain melted
Message edited by author 2006-01-13 11:40:06. |
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01/13/2006 11:46:04 AM · #23 |
| if you are taking a pic in the direction you are traveling your flash is also going the same speed you are. when you fire the flash in the direction you are going the light from the flash will leave the flash at the speed of light pluse the speed you are traveling |
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01/13/2006 12:25:31 PM · #24 |
Originally posted by legalbeagle:
Super question! I would be v happy for anyone else to elaborate on or correct my basic understanding of the principles!
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Super answer! You said it all, now all you have to add is equations. Or, invent a super-hyper-uber-extremely-fast-shutter-speed camera, so that there's no blur for the picture. |
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01/13/2006 12:25:40 PM · #25 |
Originally posted by holdingtime:
if you are taking a pic in the direction you are traveling your flash is also going the same speed you are. when you fire the flash in the direction you are going the light from the flash will leave the flash at the speed of light pluse the speed you are traveling |
It can't do that for reasons that were just explained in the previous post. Light cannot travel faster then the speed of light no matter how fast it is going when emitted,
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