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Ria Nieyli: About c and the speed of light
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Sibyyl
Garoun Investment Bank
Gallente Federation
#1 - 2014-06-19 22:50:05 UTC
Ria,

Wanted to start a discussion in reference to your post here:
Ria Nieyli wrote:
Kijo Rikki wrote:
Where lT = length of topic and tF = trolls for idea and tA = trolls againt idea:

lT = (tF*tA)c^2

c, of course, is the speed of light.


The speed of light can be rather unimpressive at times.


This quote from the article seems poignant:
Quote:
Such an exotic medium can be engineered to slow a light beam 20 million-fold from 186,282 miles a second to a pokey 38 miles an hour.


I wanted to write down what I understand, and I hope some of the smarter posters will respond (James, I am looking at you).

-Often "speed of light" is meant to refer to the speed of a group of photons (which may or may not be c, not individual photons (always c). I think it's disingenuous to claim "we slowed light down".. instead it's more accurate to say "we slowed down the observed speed of a group of photons).

-If photons travel through a medium and are absorbed in transit, and then "spit" out later, the absorption will correlate to elevated electron energy levels which may not propagate at c, however, the transit of photons as photons always occur at c

-If photons are refracted in a medium, then they will bounce around at c through the medium, and their observed speed as a group will be less than c

It doesn't appear to me that Ria's linked experiment changes anything about the speed of light. Is this a correct statement?

Joffy Aulx-Gao for CSM. Fix links and OGB. Ban stabs from plexes. Fulfill karmic justice.
Doreen Kaundur
#2 - 2014-06-20 01:00:24 UTC
Usually when people speak of light speed, it is the speed through empty space. Not through any medium.

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Riyria Twinpeaks
Perkone
Caldari State
#3 - 2014-06-20 04:33:50 UTC
I found this interesting with regards to light "slowing down" in materials.
Aspalis
Federal Navy Academy
Gallente Federation
#4 - 2014-06-20 08:17:20 UTC
Slightly offtopic: In astronomy, light speed serves more as a ruling stock for how far light travels given time.

Light travels 299,792,458 m/s. It takes eight seconds for light from our Sun (Sol) to reach us here on Earth. The closest star to us is Proxima Centauri at 4.24 light-years, meaning that we see the light from Proxima Centauri as it were 4.24 years ago. The farthest object from us is the proto-galaxy UDFj-39546284 at 13.42 billion light-years.

Marcus Gord: "Aspalis is an onion. Many layers, each one makes you cry."
Mizhir
Devara Biotech
#5 - 2014-06-20 08:20:57 UTC
For a disk shaped object with the radius 'Z' and thickness 'A' the volume is:

V = Pi*Z*Z*A Lol

❤️️💛💚💙💜
Aspalis
Federal Navy Academy
Gallente Federation
#6 - 2014-06-20 08:25:08 UTC
Mizhir wrote:
For a disk shaped object with the radius 'Z' and thickness 'A' the volume is:

V = Pi*Z*Z*A Lol


GET OUT YOU NERD!

Marcus Gord: "Aspalis is an onion. Many layers, each one makes you cry."
Mizhir
Devara Biotech
#7 - 2014-06-20 08:28:48 UTC
Aspalis wrote:
Mizhir wrote:
For a disk shaped object with the radius 'Z' and thickness 'A' the volume is:

V = Pi*Z*Z*A Lol


GET OUT YOU NERD!


Sorry. I didn't order extra onion for my pizza

❤️️💛💚💙💜
Ria Nieyli
Nieyli Enterprises
When Fleets Collide
#8 - 2014-06-20 16:56:41 UTC
Sibyyl wrote:
Ria,

Wanted to start a discussion in reference to your post here:
Ria Nieyli wrote:
Kijo Rikki wrote:
Where lT = length of topic and tF = trolls for idea and tA = trolls againt idea:

lT = (tF*tA)c^2

c, of course, is the speed of light.


The speed of light can be rather unimpressive at times.


This quote from the article seems poignant:
Quote:
Such an exotic medium can be engineered to slow a light beam 20 million-fold from 186,282 miles a second to a pokey 38 miles an hour.


I wanted to write down what I understand, and I hope some of the smarter posters will respond (James, I am looking at you).

-Often "speed of light" is meant to refer to the speed of a group of photons (which may or may not be c, not individual photons (always c). I think it's disingenuous to claim "we slowed light down".. instead it's more accurate to say "we slowed down the observed speed of a group of photons).

-If photons travel through a medium and are absorbed in transit, and then "spit" out later, the absorption will correlate to elevated electron energy levels which may not propagate at c, however, the transit of photons as photons always occur at c

-If photons are refracted in a medium, then they will bounce around at c through the medium, and their observed speed as a group will be less than c

It doesn't appear to me that Ria's linked experiment changes anything about the speed of light. Is this a correct statement?


Phase velocity
Cherenkov radiation
Eurydia Vespasian
Storm Hunters
#9 - 2014-06-20 18:06:03 UTC
i have not much add so i'll just use this formula as my mathematic contribution.
Kijo Rikki
Killboard Padding Services
#10 - 2014-06-20 18:25:32 UTC
Aspalis wrote:
Slightly offtopic: In astronomy, light speed serves more as a ruling stock for how far light travels given time.

Light travels 299,792,458 m/s. It takes eight seconds for light from our Sun (Sol) to reach us here on Earth. The closest star to us is Proxima Centauri at 4.24 light-years, meaning that we see the light from Proxima Centauri as it were 4.24 years ago. The farthest object from us is the proto-galaxy UDFj-39546284 at 13.42 billion light-years.


Minutes :(

You make a valid point, good Sir or Madam. 
Aspalis
Federal Navy Academy
Gallente Federation
#11 - 2014-06-21 12:18:20 UTC
Kijo Rikki wrote:
Aspalis wrote:
Slightly offtopic: In astronomy, light speed serves more as a ruling stock for how far light travels given time.

Light travels 299,792,458 m/s. It takes eight seconds for light from our Sun (Sol) to reach us here on Earth. The closest star to us is Proxima Centauri at 4.24 light-years, meaning that we see the light from Proxima Centauri as it were 4.24 years ago. The farthest object from us is the proto-galaxy UDFj-39546284 at 13.42 billion light-years.


Minutes :(


Sorry! Cry Can I get away with that I had yet to get my first cup of coffee?

Thank you for correcting me though.

Marcus Gord: "Aspalis is an onion. Many layers, each one makes you cry."
Grimpak
Aliastra
Gallente Federation
#12 - 2014-06-21 13:11:52 UTC
wait, is this thread about the speed of light in ideal conditions (absolute vacuum)?

what's there to argue anyways?

[img]http://eve-files.com/sig/grimpak[/img]

[quote]The more I know about humans, the more I love animals.[/quote] ain't that right
Kijo Rikki
Killboard Padding Services
#13 - 2014-06-21 16:03:05 UTC
Aspalis wrote:
Kijo Rikki wrote:
Aspalis wrote:
Slightly offtopic: In astronomy, light speed serves more as a ruling stock for how far light travels given time.

Light travels 299,792,458 m/s. It takes eight seconds for light from our Sun (Sol) to reach us here on Earth. The closest star to us is Proxima Centauri at 4.24 light-years, meaning that we see the light from Proxima Centauri as it were 4.24 years ago. The farthest object from us is the proto-galaxy UDFj-39546284 at 13.42 billion light-years.


Minutes :(


Sorry! Cry Can I get away with that I had yet to get my first cup of coffee?

Thank you for correcting me though.


Of course! I can even edit my post and we can pretend like this never happened!

To Grimpak, no. The argument is about the speed of light through various mediums other than a vacuum, particularly the one in the article that claims to slow light down to 38 miles per hour. There are some interesting things being discussed here concerning phase velocity and group velocity that I don't quite understand yet even with the picture on the wiki page. But I can accept that these things happen, now....

My only question is what happens to the light once it returns to a vacuum? Does it maintain it's current speed? Or does it somehow return to c?

You make a valid point, good Sir or Madam. 
Grimpak
Aliastra
Gallente Federation
#14 - 2014-06-21 16:20:18 UTC
Kijo Rikki wrote:
My only question is what happens to the light once it returns to a vacuum? Does it maintain it's current speed? Or does it somehow return to c?



well, off-the-knee logic would dictate that for increasing speed, you would need more energy. unless photons manage to keep their energy while transversing a more dense medium.

[img]http://eve-files.com/sig/grimpak[/img]

[quote]The more I know about humans, the more I love animals.[/quote] ain't that right
Bagrat Skalski
Koinuun Kotei
#15 - 2014-06-21 20:18:23 UTC  |  Edited by: Bagrat Skalski
Grimpak wrote:
Kijo Rikki wrote:
My only question is what happens to the light once it returns to a vacuum? Does it maintain it's current speed? Or does it somehow return to c?



well, off-the-knee logic would dictate that for increasing speed, you would need more energy. unless photons manage to keep their energy while transversing a more dense medium.


The portion of energy is absorbed. The rest is just what it is, an energy, and goes with the speed of light.

http://en.wikipedia.org/wiki/Absorption_%28electromagnetic_radiation%29

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