Earth

As long ago as 340 BC the Greek philosophe Aristotle .On the heaven s was able to put forward two good arguments for beleiving that the eartjh was a round sphere rather than a flat place .First he realised that eclips of the moon were caused by the earth comimg between sun and the moon.The earth's shadow on the moon always round ,which would be true only if the earth was spherical.Second the Greeks knew ffrom their travels that the North star appeared lower in the sky when viewed in the south than it did in more northerly regions (since the North star lies over the north pole,it appears to
be directly above on the observer at the north pole but to some one looking from the equateor.it appears to lie just at the horizon.