This would be a perfect project for students as a science fair entry, but the answer is pretty simple and depends on the time of day and the lunar phase.

Of course if you are seeing it in your daytime sky, someone located on the other side of the world will not see it in their sky at night. The special case would be near sunrise or sunset. For observers on opposite sides of the Earth at the same time, the only lunar phase that can be seen by both parties is the Full Moon. It would be on the horizon.

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