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01/13/2006 12:29:06 PM · #26 |
does light being sucked into a black hole travel faster than the native speed of light?
Edit: And wouldn't the "speed of light" change slightly depending on it's environemt? would light in the vacuum of space travel at the same speed through water? Maple Syrup?
Message edited by author 2006-01-13 12:31:35. |
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01/13/2006 12:48:28 PM · #27 |
Originally posted by Megatherian:
does light being sucked into a black hole travel faster than the native speed of light?
Edit: And wouldn't the "speed of light" change slightly depending on it's environemt? would light in the vacuum of space travel at the same speed through water? Maple Syrup? |
First I think light being sucked into a black hole does travel faster, thus the "black" from which no light can escape.
Second it is my understanding that even the thickest Maple syrup cannot slow down the speed of light. It merely filters and absorbs a portion of the light.
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01/13/2006 12:49:28 PM · #28 |
Originally posted by Megatherian:
does light being sucked into a black hole travel faster than the native speed of light?
Edit: And wouldn't the "speed of light" change slightly depending on it's environemt? would light in the vacuum of space travel at the same speed through water? Maple Syrup? |
The "speed of light" (Einstein's constant "c") is a theoretical maximum and is only attained in a complete vacuum. For reference, the speed of light traveling through a fiber-optical cable is 30% slower than Einstein's constant.
On the larger issue, this from Wikipedia:
"Constant velocity from all reference frames
It is important to realise that the speed of light is not a "speed limit" in the conventional sense. An observer chasing a beam of light will measure it moving away from him at the same speed as a stationary observer. This leads to some unusual consequences for velocities.
Most individuals are accustomed to the addition rule of velocities: if two cars approach each other from opposite directions, each travelling at a speed of 50 kilometres per hour (31 miles per hour), one expects that each car will perceive the other as approaching at a combined speed of 50 + 50 = 100 km/h (62 mph) to a very high degree of accuracy.
At velocities at or approaching the speed of light, however, it becomes clear from experimental results that this rule does not apply. Two spaceships approaching each other, each travelling at 90% the speed of light relative to some third observer between them, do not perceive each other as approaching at 90% + 90% = 180% the speed of light; instead they each perceive the other as approaching at slightly less than 99.5% the speed of light.
This last result is given by the Einstein velocity addition formula:
u = {v + w \over 1 + v w / c^2} \,\! (garbled equation in this forum)
where v and w are the speeds of the spaceships as observed by the third observer, and u is the speed of either space ship as observed by the other.
Contrary to one's usual intuitions, regardless of the speed at which one observer is moving relative to another observer, both will measure the speed of an incoming light beam as the same constant value, the speed of light."
Robt. |
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01/13/2006 01:57:19 PM · #29 |
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 |
I tried it a few minutes ago and it worked all right for me. You have to make sure that your batteries are fully charged and that you are switched to e-TTL mode.
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01/13/2006 02:05:26 PM · #30 |
Originally posted by Bear_Music:
Contrary to one's usual intuitions, regardless of the speed at which one observer is moving relative to another observer, both will measure the speed of an incoming light beam as the same constant value, the speed of light."
Robt. |
Finally, someone with a grasp of actual physics. :)
For the rest of you, I highly recommend Brian Greene's 'The Elegant Universe' and 'The Fabric of the Cosmos' for a good layman's introduction to modern physics. It should clear up your misconceptions.
Physics is not intuitive.
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01/13/2006 02:13:01 PM · #31 |
An interesting question in more ways than one. If you take the picture in the direction you are traveling no, you would not even see the flash because you are traveling the speed of light so in theory your are equal the speed of the flash.
Second interesting question that you didn't ask, "is it possible to take a picture at the speed of light" assuming your taking a picture out of the space craft. You would have to have a shutter speed of 1/183000 of a second just to begin to get anything in focus.
And third is the speed of light the fastest thing in our universe? The debate has be no in the last few years. Gravity seems to out speed light, thus black holes. If gravity was slower that light the light could escape. Goggle quantum physics about gravity vs. (SoL) speed of light. |
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01/13/2006 03:03:31 PM · #32 |
Originally posted by Mousie:
Physics is not intuitive. |
But it does have a sense of humor - thus ludicrous speed.
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01/13/2006 03:20:21 PM · #33 |
The speed of light is not affected by the source of light. Even if the flash is travelling at the speed of light, the light being emitted from the flash will still be the same speed (ie speed of light). If you were photographing something inside the spacecraft, then yes you would succeed, as the relative speed of the subject will be the same to you. If you were taking a pic of something outside, then by the time the light hits the subject and returns to you, you would have moved forward. Assume light travels at 2m/s. Assume your subject is 2m away. When you shoot, light will strike the subject in one second, and come back in one second. But in those two seconds, you would have moved 4m away, or to the side. If you were travelling towards the subject, you would have crossed it. Away from the subject, and the light will never reach you cause you would already have outrun it. It will always be 6m away from you, coming towards you but never reaching you, cause you are travelling at the speed of light. At a larger scale (actualy speed of light), things will be a little different, but will follow the same principle.
Althought, if you were travelling that fast, mass would tend to infinity, and you will never be able to take any kind of photographs. And you would be producing a doppler shift color (red or blue), which would require you to set custom white balance ;-)
So take care and enjoy your space flight. |
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01/13/2006 03:30:51 PM · #34 |
Just wanted to clear something regarding gravity and light. Gravity is a dent in space/time. It follows the rules of physics, and thus cannot be faster than light (even considering that gravity is carried by 'gravitons' as in string theory). Imagine a piece of cloth tightly held in a horizontal positin. Now if you place a solid object on it, it will roll to the center and stay there, creating a 'dent' in the fabric. That is gravity. Light, and other objects will bend towards it travelling on the cloth. The sun bends lights. Planets bend light too.
A black hole if formed when a star more tha three solar masses collapses on itself when the fusion reactions in it are not creating enough energy to counter gravity. The gravity over powers the mass and it collapses on itself. Thus it forms a blackhole. Light is also sucked into it, but energy is conserved. Blackholes radiate energy what is known as Hawking's Radiation. That is how we 'see' them in the x-ray spectrum. A region at the border of the blackhole is not strong enough to pull light in, but not weak enough to let it escape. That is known as the 'Event Horizon'. |
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01/13/2006 07:01:29 PM · #35 |
Ignite, you're kinda off the track there...
The speed of light relative to an individual (ignoring the medium through which it travels) is a constant, at all times, no matter how fast they are moving (up to the speed of light, of course). Even if you are moving at nearly the speed of light through space, you will still percieve light flying away from and towards you and your flashlight at the speed of light. Here's why.
You can think of your absolute velocity as not just movement through the three spatial dimensions, but through time as well. If you increase your velocity in any one dimension, you decrease your velocity in the three remaining dimensions. This relative change in velocities is your acceleration. The effect of this is that, as you come closer and closer to travelling through spatial dimensions at the speed of light, you are actually travelling through time more slowly! To a theorhetical outside observer it would appear that the light is flying away from you at a much slower speed than the speed of light, but to you, since you are travelling through time so slowly, everything seems normal. The cosmological constant is basically the combined maximum speed of your travel through up/down, left/right, back/forth, AND time. As far as you're concerned, the light that you bounce off a passing planet will get back to you exactly as fast as it would have if you were not moving at all, no matter what that planet's relative speed.
In effect, we are ALL travelling at the speed of light AT ALL TIMES. It just happens to be through time instead of space, if we are sitting 'still'. :)
The moral of the story is to run around a lot, you will age infinitesimally slower than everyone else, and preserve your good looks.
Message edited by author 2006-01-13 19:09:01.
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01/14/2006 08:24:54 AM · #36 |
I agree, that for an observer on earth, someone travelling at the speed of light and coming back after 20 years will not have aged. But we are talking about 'everything' in space. There are no relative observers on earth measuring your speed/time in space at light-speed travel.
I think by the time we get to travel at that speeds, Canon would have come out with a space camera which would allow us to take pics at speeds of light ;-) Maybe a Canon Space Rebel !!! |
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01/14/2006 12:54:52 PM · #37 |
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01/14/2006 03:30:39 PM · #38 |
This thread has been brought to you by the letter Q, the number 3 and the colour Blue.
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01/14/2006 03:57:15 PM · #39 |
Originally posted by NathanW:
42 |
After running the question through my computer over the course of several years I have come to the conclusion that 42 was a rounded off number and the the real answer is actually 41.999999989256373552873837723625526674377473773672377437838772377278348777673478873736737737487848854885858834767366772878819199399383771.
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01/14/2006 11:22:23 PM · #40 |
Originally posted by NathanW:
42 |
And the question was? |
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01/15/2006 12:04:33 AM · #41 |
Originally posted by gjumi:
Originally posted by NathanW:
42 |
And the question was? |
You don't know? The meaning of life.
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01/15/2006 12:45:56 AM · #42 |
Originally posted by nsbca7:
Originally posted by gjumi:
Originally posted by NathanW:
42 |
And the question was? |
You don't know? The meaning of life. |
O man, I feel so depresed, with a brain the size of a planet and this guy telling me things that I know. I'd better go and push myself and the goat from this cliff and get over with it; I'm bored to death, more than this guy...
I know that 42 is the answer to life, the Universe and everything - what's the question?
Signed:
depressed Marvin |
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01/15/2006 01:06:03 AM · #43 |
Originally posted by gjumi:
Originally posted by nsbca7:
Originally posted by gjumi:
Originally posted by NathanW:
42 |
And the question was? |
You don't know? The meaning of life. |
O man, I feel so depresed, with a brain the size of a planet and this guy telling me things that I know. I'd better go and push myself and the goat from this cliff and get over with it; I'm bored to death, more than this guy...
I know that 42 is the answer to life, the Universe and everything - what's the question?
Signed:
depressed Marvin |
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?
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