An object that is in free fall seems to be

An object that is in free fall seems to be weightless, even though the
usual force of gravity is acting on it. 

If the falling object happens to be a person, then every part of him is
falling at the same rate, so none of his internal organs are pressing
against anything like they normally do, and he has no sensation of weight. 

If a bathroom scale happens to be falling with him and he places it under
his feet, it won't read anything, since the scale and the person are both
falling at the same rate.

Efficiency is an act of doing something

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.