Photography in 4D World: Time & Space

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SUMMARY

The discussion centers on the dimensionality of photographs within the context of time as a dimension. It establishes that a photograph can be viewed as a (2+1)d object, where the two spatial dimensions correspond to the plane of the photo and the additional dimension represents time. The conversation contrasts Newtonian and relativistic perspectives, emphasizing that while time can be treated as a parameter or a dimension, a photograph remains a static representation of light captured at a specific moment. The implications of adding a temporal dimension are also explored, suggesting that this would transition the concept from a photograph to a dynamic medium like a TV screen.

PREREQUISITES
  • Understanding of dimensionality in physics, specifically (2+1)d and (3+1)d concepts.
  • Familiarity with Newtonian and relativistic physics principles.
  • Basic knowledge of how cameras capture images and the role of time in photography.
  • Conceptual grasp of light cones and their significance in relativity.
NEXT STEPS
  • Research the implications of time as a dimension in physics, focusing on relativity.
  • Explore the concept of light cones and their relevance to photography and imaging.
  • Investigate the differences between static images and dynamic representations like video.
  • Learn about the mathematical representation of (2+1)d and (3+1)d spaces in physics.
USEFUL FOR

This discussion is beneficial for physicists, photographers interested in the theoretical aspects of their craft, and anyone exploring the intersection of time, space, and visual representation in modern physics.

sonutabitha
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If time is a dimension, what would be the dimension of a photograph in such a space?
 
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Idealising the image as being one face of a physical piece of paper, it's a (2+1)d object, although there's nothing interesting about the time-like direction since (apart from any overall motion/deformation/damage/etc of the photograph) nothing changes.

Loosely, in Newtonian terms you regard a camera as mapping points (x,y,z) onto a plane (x,y) at a given time T-z/c (to allow for the finite speed of light) - it chooses a value of the time parameter and drops the z coordinate, in other words. In relativistic terms you'd regard it as taking points in the plane (x,y,z,T-z/c) and mapping them onto a plane (x,y) - so dropping the z and t coordinates. The only real difference is whether you regard time as a parameter or a dimension.
 
Ibix said:
Idealising the image as being one face of a physical piece of paper, it's a (2+1)d object, although there's nothing interesting about the time-like direction since (apart from any overall motion/deformation/damage/etc of the photograph) nothing changes.

Loosely, in Newtonian terms you regard a camera as mapping points (x,y,z) onto a plane (x,y) at a given time T-z/c (to allow for the finite speed of light) - it chooses a value of the time parameter and drops the z coordinate, in other words. In relativistic terms you'd regard it as taking points in the plane (x,y,z,T-z/c) and mapping them onto a plane (x,y) - so dropping the z and t coordinates. The only real difference is whether you regard time as a parameter or a dimension.
So are you saying that the photograph will be still 2 dimensional? I am considering time as a dimension not a parameter.
 
Objects are, in general, (3+1) dimensional. Idealising a photo as one surface of a piece of paper then it's (2+1) dimensional. There are two spacelike directions in the plane of the photo and it has extent in time. But the extent in time is boring because a photo is still only a recording of the light that struck it when it was exposed.

Why are you asking?
 
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sonutabitha said:
If time is a dimension, what would be the dimension of a photograph in such a space?

You are simply describing the world as it is now. Unless you add a temporal dimension into the photo, in which case you are describing a TV screen.
 
Algr said:
You are simply describing the world as it is now. Unless you add a temporal dimension into the photo, in which case you are describing a TV screen.
You need to be a bit careful about what you mean by "now" in relativity, which is why I answered as I did (at least at time of writing this thred is labeled A). In fact you are describing part of a null surface, the past light cone of the camera.

Otherwise, yes. Still curious in what context the OP wanted to know.
 

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