Give three proofs that the earth is almost spherical in shape.
- Circumnavigation of the earth. When one sails or flies along a straight path without changing direction, he or she comes back to the starting point.
- The earth’s horizon appears spherical when observed from a high point.
- Rising and setting of the sun, since people living in the east see the sun earlier than those in the west.
- When a ship is approaching the land from the sea, an observer standing on a high cliff first sees the smoke, then the mast and finally the rest of the ship’s body.
- During the eclipse of the moon, (lunar eclipse), a spherical shadow of the earth is cast on the moon.
- All other planets are spherical, hence the Earth being a planet, is not an exception.
- Photographs of the earth taken from the space by satellites show that the earth has a spherical shape.