What is the relationship between mass and weight in terms of formula

Mass is a measure of the amount of matter contained by an object, while weight is a measure of the gravitational pull on an object. As the gravitational force exerted by Earth is the constant upon which mass is calculated, the values of an object's mass and weight on Earth are approximately equal depending on geographic location. 

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.