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Other Discussion Boards => Science & Alternative Science => Topic started by: spanner34.5 on January 26, 2015, 11:04:29 AM

Title: Speed of light is variable.
Post by: spanner34.5 on January 26, 2015, 11:04:29 AM
Speed of light is not always 'c'.

Interesting development into the theory of all sorts.

http://www.bbc.co.uk/news/uk-scotland-30949979

http://www.bbc.co.uk/news/uk-scotland-glasgow-west-30944584

http://www.thejournal.ie/speed-of-light-slow-1900175-Jan2015/
Title: Re: Speed of light is variable.
Post by: Thork on January 26, 2015, 02:15:40 PM
I told everybody this 2 months ago. But now the BBC says so ...

http://forum.tfes.org/index.php?topic=2142.0

I am better than all the scientists.  :-B
Title: Re: Speed of light is variable.
Post by: Rama Set on January 26, 2015, 02:32:24 PM
Slowing down a photon is not news, but I am interested to know why it remained at that speed.  I tweeted NDT for insight.
Title: Re: Speed of light is variable.
Post by: Thork on January 26, 2015, 03:28:16 PM
Slowing down a photon is not news, but I am interested to know why it remained at that speed.
Would acceleration not require additional energy that is not present in the system?
Title: Re: Speed of light is variable.
Post by: Rama Set on January 26, 2015, 04:13:50 PM
Slowing down a photon is not news, but I am interested to know why it remained at that speed.
Would acceleration not require additional energy that is not present in the system?

The theory says that photons are massless and are required to travel at c.  I am pretty sure, but will double check now, that a photon, upon exiting a refractive medium, goes back up to cv.
Title: Re: Speed of light is variable.
Post by: Ghost of V on January 26, 2015, 06:53:30 PM
This is very interesting. The repercussions of this could be profound.
Title: Re: Speed of light is variable.
Post by: Rama Set on January 26, 2015, 08:05:23 PM
Slowing down a photon is not news, but I am interested to know why it remained at that speed.
Would acceleration not require additional energy that is not present in the system?

The theory says that photons are massless and are required to travel at c.  I am pretty sure, but will double check now, that a photon, upon exiting a refractive medium, goes back up to cv.

So the apparent change in velocity of a photon through a refractive medium is due to a delay created by a photon being absorbed and re-emitted by a particle in the medium.

Apparently this news story is not the entire story and in fact there is no ground-shaking discovery here:

http://www.reddit.com/r/science/comments/2tdgts/scientist_slow_the_speed_of_light_in_free_space/

http://www.sciencemag.org/content/early/2015/01/21/science.aaa3035

I will keep an eye on this, but we have to wait a little longer for ftl travel I guess.
Title: Re: Speed of light is variable.
Post by: Pete Svarrior on January 27, 2015, 10:51:47 AM
I mean, I had to check. its c, right? Its a constant. 299,792,457m/s
Why would you remind us of your blatant displays of ignorance?
Title: Re: Speed of light is variable.
Post by: Rama Set on January 27, 2015, 02:02:30 PM
I feel like your post is the one doing the reminding.
Title: Re: Speed of light is variable.
Post by: Pete Svarrior on January 27, 2015, 02:22:43 PM
I feel like your post is the one doing the reminding.
Well, he did deliberately link to the thread. Of course, I amplified the effect, but that stikes me as much less counter-intuitive.

I would argue that it makes more sense for me to maliciously mock others than it does for Thork to link to stuff that makes him look like an idiot and yet claim that it somehow helps his case.
Title: Re: Speed of light is variable.
Post by: Rama Set on January 27, 2015, 04:40:08 PM
I would argue that it makes more sense for me to maliciously mock others than it does for Thork to link to stuff that makes him look like an idiot and yet claim that it somehow helps his case.

You make a good point, but then again... Thork.
Title: Re: Speed of light is variable.
Post by: Fortuna on February 05, 2015, 12:41:21 AM
If photons are massless, then why are they affected by gravity?
Title: Re: Speed of light is variable.
Post by: Rushy on February 05, 2015, 12:45:55 AM
If photons are massless, then why are they affected by gravity?

Mass has nothing to do with gravity. It just so happens that mass correlates with energy and the energy itself spurs gravity. Photons have energy, therefore they have gravity. Newton's gravity equation is still useful for most gravity calculations, but the equation itself is not theoretically sound and it falls apart when relativistic or quantum physics comes into play.

Most high school curriculums still deem Newton's equation as "good enough" but using it for precise calculations is a Very Bad Idea.
Title: Re: Speed of light is variable.
Post by: Lord Dave on February 05, 2015, 01:06:21 AM
If photons are massless, then why are they affected by gravity?

Mass has nothing to do with gravity. It just so happens that mass correlates with energy and the energy itself spurs gravity. Photons have energy, therefore they have gravity. Newton's gravity equation is still useful for most gravity calculations, but the equation itself is not theoretically sound and it falls apart when relativistic or quantum physics comes into play.

Most high school curriculums still deem Newton's equation as "good enough" but using it for precise calculations is a Very Bad Idea.
I thought photons weren't affected by gravity so much as they followed the curve of space, which is distorted in strong gravity.
Title: Re: Speed of light is variable.
Post by: Rushy on February 05, 2015, 01:17:16 AM
I thought photons weren't affected by gravity so much as they followed the curve of space, which is distorted in strong gravity.

That's one way to think about it, but there isn't a functional difference between saying it is gravity or space distortion, since gravity is literally interpreted as space distortion.