According to Mr. Siu two dimensions is a circle, three dimensions is a ball and four dimensions is a banana. I have never heard of anything more weird and misleading.
We know that space is four dimensional since Einstein came up with the General Theory of Relativity, but we cannot readily visualize the four dimensional space, we see only three dimensions, but we can observe some effects of the fourth dimension by the way light is bending around a massive object like a galaxy and we can measure how time is affected by the proximity of a mass by measuring the time difference between an atomic clock located on the earths surface and an atomic clock located on a satellite in space.
By definition, the fourth dimension of the universe is time, time can be measure in meters due to the constant velocity of light.
The distance of the fourth dimension is c * t, where
c = the speed of light in m/s, &
t = time in s, & m/s * s = m;
so time can be measured in meters like the other three space dimensions that we can readily visualize.
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