Author Topic: Physics question - help needed (Read 3804 times)

kappa · « **Reply #15 on:** January 08, 2004, 10:12:23 AM »

Quote

Originally posted by Mini D
Seeing light as blue or red is not related to "the speed of light" but the wavelength of the light.

I've not heard of gravity effectively slowing light. I have heard of it bending the light's path... but not slowing it.

MiniD

yes, color shifts are frequency related...

It was just with in the last 2 years that a Australian physisit (i think) proved that gravity effected the speed of light.. That light did 'not' have a constant speed...

vorticon · « **Reply #16 on:** January 08, 2004, 10:14:53 AM »

Quote

Take the sun as an example, it revolves around the center of our galaxy at a modest 217 000 m/s. A photon, or ray of light if you will, that leaves the "front of the sun" (i e in the direction of movement) will have the speed 299 792 458 m/s, and not (as one might expect from the car example) 299 792 458 + 217 000. Meanwhile a photon leaving the back of the sun will ALSO have a speed of 299 792 458 m/s and not 299 792 458 - 217 000.

1. the sun isnt in the center of the galaxy...its somewhere on one of the "arms"
2. "back of the sun" doesnt really count because its on the other side...the light leaving it travels away from the earth...
3. the "front of the sun" light that we can see all travels at the same speed but i beleive the frequency changes due to the doppler effect (and thus multi coloured light)(dont know if this is true...but it seems to make sense to me right now...please correct me if im way off on this)

AKIron · « **Reply #17 on:** January 08, 2004, 10:16:55 AM »

Gravity is considered by most to be the curving of space. Light passing through strong gravity takes longer to go from point a to b because it is traveling further, not because it's speed has changed.

Dowding · « **Reply #18 on:** January 08, 2004, 10:22:16 AM »

The effect of gravity on light was to make it appear to change it's speed - what was in fact happening was a deviation in path, effectively making it 'slow down' due to an increase in distance travelled. In fact there was no decrease in speed.

That book was called 'Uncle Albert' something or something according to 'Uncle Albert'.

Also, the most important thing to remember is that everything is relative to the point of observation.

kappa · « **Reply #19 on:** January 08, 2004, 10:26:26 AM »

Quote

Originally posted by Dowding
The effect of gravity on light was to make it appear to change it's speed - what was in fact happening was a deviation in path, effectively making it 'slow down' due to an increase in distance travelled. In fact there was no decrease in speed.

That book was called 'Uncle Albert' something or something according to 'Uncle Albert'.

Also, the most important thing to remember is that everything is relative to the point of observation.

that is true but not entirely...... Gravity bending light was proven many many years ago during an eclipse of the Sun.. I cant remember what star it was they used, but it seemed to shift locations caused by the Sun's gravity...

I will find info on gravity 'changing' the speed of light.. it does happen and has been proven.... Dowding, you have a masters in physics and have read nothing of this? It was farly recent.......

Besides, if it couldnt, why cant light escape a black hole.. 8)

Nakhui · « **Reply #20 on:** January 08, 2004, 10:31:35 AM »

Quote

Originally posted by AKIron
Gravity is considered by most to be the curving of space. Light passing through strong gravity takes longer to go from point a to b because it is traveling further, not because it's speed has changed.

You're information is a little out of data, sir.

Here's a few articles about what has recently been discovered about the speed of light.
http://www.cbsnews.com/stories/2002/08/07/tech/main517850.shtml
http://www.abc.net.au/lateline/s347215.htm
http://www.space.com/scienceastronomy/generalscience/constant_changing_010815.html
http://www.icr.org/pubs/imp/imp-179.htm

You know since I went through school.... there's been at least 4 new elements discoverd (or should I say created... but we knew in theory where they belonged in the periodic chart)

Another interesting principle of science - "Knowledge is not constant."

What you learned yesterday isn't necessarily true today.

kappa · « **Reply #21 on:** January 08, 2004, 10:37:57 AM »

Well, not exactly how I remembered it.. But relative..

http://msnbc.msn.com/id/3077354/
http://abc.net.au/news/indepth/featureitems/light.htm

vorticon · « **Reply #22 on:** January 08, 2004, 10:38:47 AM »

Quote

Besides, if it couldnt, why cant light escape a black hole.. 8)

go to a soft mattress and put a heavy weight on it...roll a marble past the depression caused by the weight...

light cant escape the black hole because its not going fast enough to "swing" down the "steep slope"of the gravity well and "swing" back out...it hits the "steep" part and merely falls...

AKIron · « **Reply #23 on:** January 08, 2004, 10:48:39 AM »

Quote

Originally posted by Nakhui
You're information is a little out of data, sir.

Here's a few articles about what has recently been discovered about the speed of light.
http://www.cbsnews.com/stories/2002/08/07/tech/main517850.shtml
http://www.abc.net.au/lateline/s347215.htm
http://www.space.com/scienceastronomy/generalscience/constant_changing_010815.html
http://www.icr.org/pubs/imp/imp-179.htm

You know since I went through school.... there's been at least 4 new elements discoverd (or should I say created... but we knew in theory where they belonged in the periodic chart)

Another interesting principle of science - "Knowledge is not constant."

What you learned yesterday isn't necessarily true today.

Wow, interesting stuff. The last article speculates the rate of decay in the speed of light to be 38km/s per year. They further speculate that this may be as a result of change in the additional quantum level dimensions which make up space.

Way over my head but if these analysis are correct then it would seem that space and time are changing. If so, it may not be light that is changing but rather the medium in which it exists and is observed from.

majic · « **Reply #24 on:** January 08, 2004, 10:48:44 AM »

Quote

Originally posted by vorticon
go to a soft mattress and put a heavy weight on it...roll a marble past the depression caused by the weight...

light cant escape the black hole because its not going fast enough to "swing" down the "steep slope"of the gravity well and "swing" back out...it hits the "steep" part and merely falls...

Nice analogy.

Dowding · « **Reply #25 on:** January 08, 2004, 10:48:57 AM »

My degree is three and a half years old. I have avoided physics like the plague ever since - after 4 years I had had enough and went to work doing something completely unrelated. Actually, I haven't had anything to do with relativity for 5 and a half years, since after the second year I chose modules that concerned the semi-conductor industry; that being the area I was most interested in.

I'll scan my degree certificates if you still doubt I hold the qualification and I can email you my thesis on the photo-electric properties of poly-pyridine.

moot · « **Reply #26 on:** January 08, 2004, 12:24:53 PM »

Someone with a good memory of advanced physics should read what the guy I linked says, because he's basically refuting Einstein and Feynman (and Greene) etc.

Hortlund · « **Reply #27 on:** January 08, 2004, 01:40:59 PM »

Is the speed of light different in vaccum, water or air? Or is it the same irregardless of in what medium?

Yeager · « **Reply #28 on:** January 08, 2004, 01:48:12 PM »

The speed of light can be increased or decreased depending on applied variables.

I know this because there is nothing in the cosmos that is perfectly constant forever. Except the single creating force of all that is nature (aka GOD).

Otto · « **Reply #29 on:** January 08, 2004, 05:15:09 PM »

Hortland, it's the same everywhere. Think of the SOL as a type of boundry between the 'present' and the 'past'. One reason matter(you) can't go faster than the SOL is because if you did it would take you into the past (a big No-no). You are a three dimensional being that is moving at the SOL though Time. If you could out run that movement you wouldn't go into the future (it dosen't exist yet) but you would catch up with a past 'present'.

My little theory and a dime will get you a ride downtown on the bus so take it at face value:p