Is the Light Cone a Valid Representation of Light's Behavior?

In summary, the conversation discusses the concept of a light-cone in space-time diagrams, specifically how light-rays spread out isotropically in a cone shape when emitted from a source. The conversation also delves into the properties of the light-cone, such as the vertical axis representing time and the hypotenuse representing a pulse in space-time. The question of whether it is possible for the hypotenuse to be greater than the speed of light is also raised. There is also a discussion about the difference between a light cone in a space-time diagram and a light cone from an object emitting light. Ultimately, the conversation explores the relationship between the space-time interval and a pulse's world-line in relation to the light-cone.
  • #1
zarmewa
44
0
As smatter in the subject therefore I have the following confused questions about the light-cone.

As we all know that when a flash of light is released from source, light-rays spread out isotropically in space, tracing out a cone on a space-time diagram. As "light-cone" is expanded at the speed of light, and light emitted at the apex and moves on the surface of the cone, therefore, at any instant “t” say one light second, the radius, edge and the vertical axis of cone represent a right angle triangle in which

Vertical axis is the perpendicular of triangle; x = time

Radius of cone is the base of triangle; y = speed of light in one second

Edge of the cone is the hypotenuse of triangle; z = space-time diagram of a pulse in one second

Thus x2 + y2 = z2, where z > c, so is this possible?

The space-time interval is always zero between two events connected by a light speed path BUT the slant edge of cone which is GREATER than the speed of light "c" represents the true motion of a pulse [world line] in both space and time, therefore, isn’t time dilating even in a stationary light clock due to extra distance covered by a pulse in its world-line?
 
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  • #2
I don't think the Light Cone in a spacetime diagram is the same as a light cone from an object emitting light.
 
  • #3
zarmewa said:
Vertical axis is the perpendicular of triangle; x = time

Radius of cone is the base of triangle; y = speed of light in one second

Edge of the cone is the hypotenuse of triangle; z = space-time diagram of a pulse in one second

Thus x2 + y2 = z2, where z > c, so is this possible?
The hypotenuse you're describing doesn't represent the path of any particle or signal---its just some line that you're drawing. The length of that line is 'z', which is not a velocity (like the speed of light 'c').

zarmewa said:
The space-time interval is always zero between two events connected by a light speed path BUT the slant edge of cone which is GREATER than the speed of light "c" represents the true motion of a pulse [world line] in both space and time
The spacetime interval (ds) is zero along a null-like trajectory (i.e. light path); a 'pulse' would follow the same time of (45deg) null-trajectory----not a world-line (horizontal or vertical depending on how you're drawing your diagram).
 

Related to Is the Light Cone a Valid Representation of Light's Behavior?

1. What is a light cone?

A light cone is a graphical representation of the path that light takes through spacetime. It shows the past, present, and future positions of a flash of light emitted from a single event.

2. How does the concept of a light cone relate to relativity?

In relativity, the speed of light is considered to be a fundamental constant. This means that the shape of a light cone is always the same no matter the observer's frame of reference, as it is determined by the speed of light and the geometry of spacetime.

3. Can anything travel faster than light within a light cone?

No, according to Einstein's theory of relativity, nothing can travel faster than the speed of light. Anything within a light cone is limited by the speed of light, and anything outside of the light cone is considered to be traveling faster than light.

4. How do scientists use light cones in their research?

Light cones are used in various fields of science, including astronomy, physics, and cosmology. They help scientists understand the behavior of light and how it interacts with spacetime, as well as the effects of gravity and the expansion of the universe.

5. Can light cones be observed in real life?

Light cones cannot be physically observed, as they are a mathematical concept used to describe the behavior of light. However, they can be represented and studied through experiments and simulations using tools such as telescopes and computer models.

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