The way this describes two treefolk seeing each other both aging slower is the first time I've really understood how two parties relativistic effects are both able to see each other aging slower than themselves: the points at which they are seeing each other are not simultaneous.
The neighbor looks like it's aging more rapidly, not slower! Think if the neighbor tilts away from you, in the disk-by-disk play it will just look moving away disk by disk, the disks are elongated and the disks will end earlier.
And from the tilted neighbor's point of view it's similar.
Maybe it's easier to first think of two trees that both tilt away from each other.
The key observation is that there is no simultaneous. As in, an objective, observer independent, notion of simultaneous. Each observer carries its own notion of simultaneous and observers in different reference frames call different things simultaneous.
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The way this describes two treefolk seeing each other both aging slower is the first time I've really understood how two parties relativistic effects are both able to see each other aging slower than themselves: the points at which they are seeing each other are not simultaneous.
The neighbor looks like it's aging more rapidly, not slower! Think if the neighbor tilts away from you, in the disk-by-disk play it will just look moving away disk by disk, the disks are elongated and the disks will end earlier.
And from the tilted neighbor's point of view it's similar.
Maybe it's easier to first think of two trees that both tilt away from each other.
The key observation is that there is no simultaneous. As in, an objective, observer independent, notion of simultaneous. Each observer carries its own notion of simultaneous and observers in different reference frames call different things simultaneous.
Time is relative