[wch]

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?

[lostmsu]

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.

[edem]

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.

[scotty79]

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

[Misdicorl]

Correct, the speed of light is the conversion factor