1. What is the significance of understanding the characteristics of the earth?

The Earth is a rotating sphere that orbits the Sun. The axis of rotation of the Earth is at a constant tilt with respect to its orbit around the Sun, thus resulting in the change of seasons. Iron and oxygen make up 65% of the Earth's mass. The Earth also has gravity and magnetic force fields.

Neptune is the eighth planet from the sun. it was the first planet to get its existence predicted by  mathematical calculations  before it was actually seen through a telescope on sept. 23, 1846. irregularities in the orbit of  uranus  led french astronomer alexis bouvard to suggest that the gravitational pull from another celestial body might be responsible. german astronomer johann galle then relied on subsequent calculations to   spot neptune via telescope. previously, astronomer galileo galilei sketched the planet, but he mistook it for a star due to its slow motion. in accordance with all the other planets seen in the sky, this new world was given a name from greek and roman mythology — neptune, the roman god of the sea.