Velocity of light remain costant in a gravitational field?

[Ignition]

Does the velocity of light remain costant in a gravitational field?
In my calculation it is less than c.

 

[shamrock5585]

velocity is a vector quantity... it depends on its direction in relation to the field

 

[Ignition]

So c in a gravitational field is bigger than c?
What Relativity say about this?

 

[tiny-tim]

Does the velocity of light remain costant in a gravitational field?
In my calculation it is less than c.

Hi Ignition!

(You mean speed)

In general coordinates, the speed of light depends on the metric you have chosen.

But in local inertial coordinates, the speed of light is always c.

 

[shamrock5585]

well gravity can bend the path of light, and a black hole can stop light from escaping because gravity is so strong... I am not sure if light slows down and turns back around when trying to escape a black hole or if it just can't be bounced back out in the first place or if it goes c out and then is reversed to c in the opposite direction from the gravity... i don't think light accelerates it just goes c... I'm not sure I've never "seen" a black hole haha

 

[peter0302]

The *magnitude* is always 'c'. The direction can change, and therefore it can "accelerate" in a given direction.

 

[MeJennifer]

Does the velocity of light remain costant in a gravitational field?
In my calculation it is less than c.

The speed of light in vacuum remains locally the same in a gravitational field. Observers may measure a different speed due to the curvature of spacetime.

, and a black hole can stop light from escaping because gravity is so strong... I am not sure if light slows down and turns back around when trying to escape a black hole or if it just can't be bounced back out in the first place or if it goes c out and then is reversed to c in the opposite direction from the gravity... i don't think light accelerates it just goes c... I'm not sure I've never "seen" a black hole haha

The light is not slowing down, its wordline is curved back into the black hole, so it has nowhere to go but back.

The *magnitude* is always 'c'. The direction can change, and therefore it can "accelerate" in a given direction.

Light in vacuum does not accelerate since its wordline always follows a geodesic of spacetime.

 

[Unkraut]

The light is not slowing down, its wordline is curved back into the black hole, so it has nowhere to go but back.

Light in vacuum does not accelerate since its wordline always follows a geodesic of spacetime.

I think you meant "worldline".
Unfortunately that is all I can contribute to this topic.

 

[mtworkowski@o]

The speed of light in vacuum remains locally the same in a gravitational field. Observers may measure a different speed due to the curvature of spacetime.



Spacetime is a mathematical construct invented to circumvent certain inconvenient conclusions concerning the speed of light. By using it, you quash all meaningful questions about light and it's inertial reference frames.

 

[HallsofIvy]

The speed of light in vacuum remains locally the same in a gravitational field. Observers may measure a different speed due to the curvature of spacetime.



Spacetime is a mathematical construct invented to circumvent certain inconvenient conclusions concerning the speed of light. By using it, you quash all meaningful questions about light and it's inertial reference frames.

So you are simply asserting that all of general relativity is wrong?

 

[mtworkowski@o]

So you are simply asserting that all of general relativity is wrong?

I don't think I'm qualified to make that determination, but if I had to guess I would say that everything we attribute to spacetime and relativity could be explained by other means. You'll remember that history is full of dicarded axioms that were once believed in religiously. the theoretical part of phisics is prone to this. String theory is another messy explanation that will fall apart.

 

[matheinste]

Quote:--

--You'll remember that history is full of dicarded axioms that were once believed in religiously.---

That's the easy answer as it will always be true of any theory.

Matheinste.

 

[mtworkowski@o]

True enough.

 

[Chrisc]

Relativity is a convention. As it works, it is not wrong, but incomplete. It is a convention that is self sustaining because it is self consistent and therefore inescapable.
All relativity theory must concede, accept or agree on the first instance of measure which is
usually referred to as "proper" time, mass or length. This first "quantification" sets all subsequent
quantification of dimension simply because space, time and mass cannot be defined
uniquely from each other.
Without this first premise of the constancy of dimension set by choice and sustained by
the convention of the relativity of "proper" dimension, the equations of mechanics become
meaningless, arbitrary expressions.

 

[pmb_phy]

Why can't I PM shamrock5585??

Pete

 

[mtworkowski@o]

Relativity is a convention. As it works, it is not wrong, but incomplete. It is a convention that is self sustaining because it is self consistent and therefore inescapable.
All relativity theory must concede, accept or agree on the first instance of measure which is
usually referred to as "proper" time, mass or length. This first "quantification" sets all subsequent
quantification of dimension simply because space, time and mass cannot be defined
uniquely from each other.
Without this first premise of the constancy of dimension set by choice and sustained by
the convention of the relativity of "proper" dimension, the equations of mechanics become
meaningless, arbitrary expressions.

I think you said it well. I like the convention thing. What is reality after all. I've been in God's pocket and I can't even find his watch, no less take it apart.