Could an ‘Earth-like’ planet be hiding in our solar system’s outer reaches?
Astronomers are racing to explain peculiar orbits of faraway objects at the edge of our solar system.
NASA may have unknowingly found and killed alien life on Mars 50 years ago, scientist claims
After landing on the Red Planet in 1976, NASA's Viking landers may have sampled tiny, dry-resistant life-forms hiding inside Martian rocks
Mysterious Earth-sized planet could be hiding in plain sight in our Solar System
If such a planet exists, researchers say it would have a mass about 1.5 to...3 times that of Earth!