What are the factors that affect the speed of light?

[Rohan Sahuji]

What makes light travel so fast?

 

[tiny-tim]

Hi Rohan!

Light is made of photons, and photons have no mass.

So photons can travel at the maximum possible speed.

 

[RocketSci5KN]

A more interesting question is why light travels at the speed it does, and not faster or slower? Why does zero mass give us exactly 'c' in vacuum?

 

[Dr Lots-o'watts]

A more interesting question is why light travels at the speed it does, and not faster or slower? Why does zero mass give us exactly 'c' in vacuum?

Why don't you reverse that question? i.e.:

Q: Why did the Universe evolve such that all massive bodies around us have the velocities we measure?
A: Because the speed of light is finite.

 

[Drakkith]

Why don't you reverse that question? i.e.:

Q: Why did the Universe evolve such that all massive bodies around us have the velocities we measure?
A: Because the speed of light is finite.

Touche...

 

[Radrook]

Why does light travel at all and what keeps it going? I fail to see any propulsion system.

 

[tiny-tim]

Why does light travel at all and what keeps it going? I fail to see any propulsion system.

uhhh?

Newton's first law … anything on which no forces act, moves at the same velocity forever

 

[RocketSci5KN]

Why don't you reverse that question? i.e.:

Q: Why did the Universe evolve such that all massive bodies around us have the velocities we measure?
A: Because the speed of light is finite.

My question is why light has the velocity we measure, 'c', and not a higher or lower value...

 

[inline]

My question is why light has the velocity we measure, 'c', and not a higher or lower value...

The 'c' value is a fundamental property of our Universe. Maybe another universes with different values of c, h and G exist.

 

[Drakkith]

My question is why light has the velocity we measure, 'c', and not a higher or lower value...

As said above, it's simply a constant of the universe. It does no good to ask why we have this constant, as it's just the way it is.

 

[lpetrich]

Why does c have the value it does? My answer is: relative to what?

Its value is fixed by the geometry of space-time, and in a lot of theoretical work, it is set equal to 1. One relates time and space values in familiar units by using a value of c in them as a units factor. Thus, 1 m ~ 3 nanoseconds.

 

[Chronos]

The speed of light is due to the properties of permeability and permissivity of space. These are derived from the Maxwell equations.

 

[RocketSci5KN]

I understand that 'c' is exactly 299,792,458 metres per second or can be expressed as c = 1/√ε0μ0, (two other universal constants), but I was hoping for a more satisfying answer other than 'its the way it is'. The proton mass was a constant, and just the way it is, until QED showed a way to calculate the value. Anything similar for 'calculating' what c should be for a massless particle yet without using circular logic?

 

[inline]

'c' can be expressed as c = 1/√ε0μ0, (two other universal constants)

Are you troll? By defenition $$\mu_0 = 4\pi \cdot 10^{-7} Gn\cdot m,\ \epsilon = c^2/\mu_0$$ and not universal constants.
'c' is just a natural unit of speed.

 

[Drakkith]

I understand that 'c' is exactly 299,792,458 metres per second or can be expressed as c = 1/√ε0μ0, (two other universal constants), but I was hoping for a more satisfying answer other than 'its the way it is'. The proton mass was a constant, and just the way it is, until QED showed a way to calculate the value. Anything similar for 'calculating' what c should be for a massless particle yet without using circular logic?

Proton mass isn't a constant just like the mass of the Earth isn't a constant. Some of the physical constants are: the speed of light in vacuum c, the gravitational constant G, Planck's constant h, the electric constant ε0, and the elementary charge e.

I don't know of a way of calculating why c is c, sorry. Perhaps someone else does.

 

[bobalazs]

whats really interesting concept to me, is what i read in wikipedia under keyword faster-than-light.
according to this-...In other words, any travel that is faster-than-light will be seen as traveling backwards in time in some other...
I connected the imagery with something similar to the workings of the mind.
When we remember something, we often see images of the thought.
Since our brains work with electrics and light, is it possible that those thoughts are faster than light, or is this just incomprehensible nonsense?

 

[Drakkith]

whats really interesting concept to me, is what i read in wikipedia under keyword faster-than-light.
according to this-...In other words, any travel that is faster-than-light will be seen as traveling backwards in time in some other...
I connected the imagery with something similar to the workings of the mind.
When we remember something, we often see images of the thought.
Since our brains work with electrics and light, is it possible that those thoughts are faster than light, or is this just incomprehensible nonsense?

Our brains work on electrical and chemical signals I believe. And no, we aren't remembering things faster than light.

 

[Nakisima]

Thoughts could never be faster than light. Brain signals are electricity, which are forced electrons, which have a mass of 1. Photons that make up light have zero mass as expressed previously. More mass = Reduced Speed Capabilities.

Plus we're on earth, not in a vacuum.