The planet Neptune is incapable of supporting life as we know it, according to NASA. One major reason for this is because of the effective temperature, which is about minus 353 degrees Fahrenheit.
The atmosphere of Neptune is inhospitable to human life. The primary constituents are hydrogen, helium and methane. By comparison, the Earth's atmosphere is mostly nitrogen and oxygen.
Neptune is about 2.8 billion miles away from the sun, making it the farthest of the eight major planets. It takes about 165 Earth years for Neptune to make one complete revolution around the sun.
As of 2014, Voyager 2 is the only spacecraft that has visited Neptune.