1) The Voyager 2 spacecraft in 1989.
2) The Hubble Space telescope.
3) Earth based methods, especially spectroscopy.
No humans have visited the planet Neptune.
Neptune is a gas giant, so it is uninhabitable to humans.
No. There is no oxygen in Neptune's atmosphere
neptune is a huge gas giant. it has winds reaching up to 159 miles per hour. it is the 8th planet from the sun.
Neptune is a planet.
Planet Neptune is the eighth planet from the sun.
Neptune is an outer planet. It is the outermost planet in the solar system.
It may be possible in the future, but today we are not able to travel that far.
Neptune's vision is blue and it is the 8th planet. There is Neptune because it is a planet.
Neptune is the eighth and furthest planet from the Sun.
There are many websites on the internet that contain information on the plant Neptune. Some such websites would be Wikipedia, and National Geographic.
Neptune is the eighth planet from the sunneptuneNeptune.