So far, the planet has not been observed directly.
Views of the solar system, as astronomers announce there may be a ninth planet about 10 times bigger than Earth and...
A planet remarkably similar to Earth has been discovered in a "habitable zone" around a distant sun-like star.
The planet, which is about 60 percent bigger than Earth, is located 1,400 light years away
The New Horizons spacecraft is just days away from a historic fly-by past Pluto
The European Space Agency (ESA) landed a probe on a comet on Wednesday, a first in space exploration and the climax...