Neptune is the fourth largest planet in our solar system and is known for its deep blue color and prominent dark spots. Research on Neptune focuses on understanding its atmosphere, weather patterns, and magnetic field. Scientists are also interested in studying its moons and rings to learn more about the planet's history and formation. Neptune's distant location and extreme cold temperatures pose challenges for exploration, but spacecraft like Voyager 2 and Hubble Space Telescope have provided valuable data to help unravel the mysteries of this icy giant.