Understanding the Curvature of Time: Exploring Perception and Experience

In summary: What we see as a 3-d curve is the projection onto 3 dimensions of the 4-d geodesic.In summary, the curvature of time is closely related to the curvature of space in the concept of curved spacetime. Objects in this type of space-time follow geodesics, which can be seen by throwing a ball and watching its path. The curvature of space-time affects how objects move and experience time, and is best understood as a combination of curved space and curved time. The Pythagorean Theorem does not hold in regions of curved spacetime, and the geodesic lies in the 4-dimensional space-time surface.
  • #1
Xeinstein
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We can all see what curvature of space looks like, just by throwing a ball and watching it follow the natural geodesic.

But what does curvature of time look like?

How do we experience it?

We typically experience the passage of time in what seems to be a forward linear manner. The forward part seems to be due to how our nervous system works, thus giving a chronological bias towards causality in our perception.

But if we can see how gravity curves space, then how do we percieve how it affects time?
 
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  • #2
Xeinstein said:
We can all see what curvature of space looks like, just by throwing a ball and watching it follow the natural geodesic.
Objects in GR don't generally follow geodesics in space, they follow geodesics in spacetime, usually the paths that minimize the proper time (although I gather it can maximize it in certain cases). I'm pretty sure a ball isn't following a geodesic in space when you throw it (unless you're in flat spacetime and the ball goes in a straight line).
 
  • #3
Xeinstein said:
We can all see what curvature of space looks like, just by throwing a ball and watching it follow the natural geodesic.
Sorry, that is not the curvature of space.

If you throw a ball into the air and then someone throws you into the air as well, you'll see the ball moving in a straight line relative to yourself (in the absence of air resistance, of course).

At least, that's what happens at first. If both objects remain in free-fall long enough, eventually the ball will start to change course slightly (or speed up or slow down), due to the fact that the acceleration due to gravity is not constant everywhere. Now that's the curvature of space-time.

You can't isolate the curvature of time from the curvature of space.
 
  • #4
Xeinstein said:
We can all see what curvature of space looks like, just by throwing a ball and watching it follow the natural geodesic.

No. The trajectory of the ball is mainly an effect of "curved time". Curved space produces only minor effects like orbit precession and additional light bending (doubling the amount caused by "curved time" alone). But note that "curved time" is not possible, without curved space, because you cannot have only one dimension of a manifold curved. So it's best to talk about curved spacetime.

Xeinstein said:
But what does curvature of time look like?
A nice visualization:
http://www.physics.ucla.edu/demoweb..._and_general_relativity/curved_spacetime.html
More visualization links:
https://www.physicsforums.com/showpost.php?p=1557122

Xeinstein said:
How do we experience it?
- Apples falling from trees.
- Clocks going faster on a mountain than in a valley.
 
  • #5
To say it another way, if the curvature of the ball's path were representative of the curvature of space, then space would be mighty curved right there, and we'd have thrown out Euclidean Geometry centuries ago. In other words, if that parabolic path represented a straight line in that region of space, then there's no way the Pythagorean Theorem would hold in that region.

As others have said, the geodesic lies in the 4-d space-time surface (manifold).
 

1. What is the curvature of time?

The curvature of time is a concept in physics that suggests time is not a linear progression, but rather a curved or warped dimension. This means that time can be affected by factors such as gravity and velocity, causing it to bend or stretch.

2. How does the curvature of time affect our perception and experience?

The curvature of time can have a significant impact on how we perceive and experience time. For example, time dilation, a phenomenon predicted by Einstein's theory of relativity, states that time moves slower in higher gravity or at faster speeds. This means that our perception of time can be altered depending on our surroundings and movements.

3. Is the curvature of time a proven concept?

While the concept of the curvature of time is supported by the theories of relativity and has been observed in experiments, it is still a theoretical concept and not yet fully proven. Scientists continue to study and explore the concept in order to gain a better understanding of the nature of time.

4. How does the curvature of time relate to time travel?

The concept of time travel is closely related to the curvature of time. The bending and warping of time can create the possibility of traveling through time, as seen in science fiction, although it is still a theoretical concept and has not been proven to be possible in reality.

5. What implications does the curvature of time have on our understanding of the universe?

The curvature of time is a fundamental aspect of our understanding of the universe and plays a crucial role in theories such as the Big Bang and the expansion of the universe. It also challenges our traditional perception of time as a constant and unchanging dimension, expanding our understanding of the complex nature of the universe.

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