# Is there an intrinsic speed of time? [closed]

If time and speed is relative, then we could double the speed of every particle in the universe, as this increases the clocks rate we shouldnt be able to tell any difference.

But my question is, in this new scenario, when two cars collide with double speed, why dont they make much more impact? They now have 4 times the kinetic energy, how is that canceled out?

If this doesnt cancel out, then time isnt relative and there is an intrinsic speed of time?

## closed as unclear what you're asking by Emilio Pisanty, knzhou, Dale, David Z♦May 26 at 16:34

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• Why the downvote? Perhaps you didnt comprehend the question – TROLLHUNTER May 26 at 14:35
• Yes, it is unclear what you are asking. – Feynmans Out for Grumpy Cat May 26 at 14:37
• What is unclear to you? Its complicated, not unclear. – TROLLHUNTER May 26 at 14:39
• Well, what do you mean by the speed of time? – Feynmans Out for Grumpy Cat May 26 at 14:41
• Imagine two universe besides each other, then one can physically move twice as fast as the other. Can you detect which universe you are in? – TROLLHUNTER May 26 at 14:47

The point is that if you do this, not every physical quantity changes in the same way. For example, you know the length of a stick in meters wouldn't double, because you're not changing the unit of length. Energy has units of $$\text{kg} \, \text{m}^2 / \text{s}^2$$, so we expect it to quadruple, so there's no issue here.
For a simpler version of this "paradox", you might note that changing your distance unit from yards to feet will only triple your height in the new units, but it will make land areas $$9$$ times larger. This does not mean that real estate is now magically $$9$$ times cheaper.
• @TROLLHUNTER The point is that time is a dimensionful quantity. So you need to choose a unit. The "dimensionless prefactor" you seem to be referring to is just the conversion factor between different units which you are free to choose, i.e., you are free to choose the unit of time. For example, with the dimensionless prefactor of $60$ you can switch between minutes and hours and make things move $60$ times faster or slower in a numerical sense. This is not called the "relativity" of time in an SR or GR sense. This is just a change of units. – Feynmans Out for Grumpy Cat May 26 at 15:26