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Comment by wch | Hacker News Reader

On human scales, the time dimension is much "bigger" than the space dimensions...

This is really interesting, and it made me wonder how to convert between space and time. I mean, one meter up is equivalent in magnitude to one meter forward, is equivalent to one meter to the right. Is _c_ the conversion between space and time? In other words, is 300 million meters equivalent in magnitude to one second of time?

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This is right, yes. The distance (aka interval) formula for the flat 4D spacetime is

  dist^2 = (c * seconds)^2 - meters^2

So to compensate increase in 1 second you indeed need _c_ ~= 3e8 meters.

It is bigger only because you travel slowly in the spacial dimensions. You always travel thorugh spacetime with a constant speed (the speed of light). What happens is that you're usually going with 460 m/s (as Earth revolves around the Sun) and this is not really comparable to your `t` speed in the x/y/z/t coordinate system. So when you are still your speed is something like 230/230/0/299.791.998.

Or a meter is equivalent to the time that light needs to travel 1 meter.

Correct, the speed of light is the conversion factor

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