Liquid water could slosh beneath the frigid moon's icy shell.
Neptune, the other blue planet, is the eighth planet in our solar system. Neptune is an ice giant.
Voyager 1's rocket only had 3.5 seconds of fuel left when it sent the probe on its way 35 years ago.
This computer generated montage shows Neptune as it would appear from a spacecraft approaching Triton, Neptune's largest moon in this space wallpaper.
This week we saw debris from space shuttle Columbia found after eight years, launched a five-year mission to Jupiter and discovered potential dwarf planets.
Planetary scientist Alan Stern has been fighting for Pluto's planethood ever since the icy body was demoted to "dwarf planet" in 2006. He lays out the case for Pluto at SPACE.com.
The planet Neptune, eighth planet from the Sun in Earth’s solar system, is the fourth largest planet in diameter and third largest in mass. Neptune was named after the Roman God of the seas.
Astronomers searching for planets beyond our solar system could increase their odds of success by scrutinizing the dusty disks ringing faraway stars, a new study suggests.
A cache of 14 large space rocks beyond Neptune was recently discovered by astronomers searching through the archives of the Hubble Space Telescope.
Astronomers have discovered a new asteroid in a region of Neptune's orbit where no previous object was known to exist – a so-called gravitational "dead zone."
New measurements of Neptune's atmosphere from a European space telescope suggest that a comet may have impacted the outer-most planet in our solar system approximately two centuries ago.
A small space rock that orbits the sun from out beyond Neptune is almost completely coated in water ice, according to a new study.