Uranus orbits the sun on its side. Although the consensus is that the gas giant must have collided with something to make it this way, two researchers have modeled Uranus getting "wobbled" by a large moon, tugging it off axis.
Astronomers found Pluto's fifth moon 34 years after finding its first.
Planetary rings made of rock or silicates might be common in the Galaxy.
The fastest man-made object ever built crosses the orbit of Uranus today on its nearly decade-long odyssey to the dwarf planet Pluto.
Neptune and Uranus may possibly be hiding 4-billion year old clues to interplanetary homicide.
The only spacecraft to have visited Uranus was Voyager 2 in 1986. Now a team of scientists from Europe and the U.S. are planning a return mission to this bizarre planet.
Voyager 1, the spacecraft that launched on a tour of the solar in 1977, is getting ready to enter interplanetary space -- what a journey it's had!
As we approach the 164th anniversary of Neptune's discovery, there's another reason why we should celebrate this astronomical event: the gas giant is about to complete its first orbit since it was first spotted.