Given the task definition and input, reply with output. In this task, we ask you to elaborate the sentence without changing its general meaning. You can do so by explaining further the input sentence, using more precise wording, adding qualifiers and auxiliary information etc.

The subsolar point on a planet is when its sun looks like it is directly overhead ( in zenith ) .

The subsolar point on a planet is the point at which its sun is perceived to be directly overhead ( at the zenith ) ; that is , where the sun 's rays strike the planet exactly perpendicular to its surface .