A giant planet lurking at the outskirts of the solar system could explain the odd orbits of far-flung hunks of icy debris . If the planet exists, its average distance from the sun would be between 500 and 600 times Earth’s distance.Signs of ancient life
Mounds of minerals discovered in Greenland appear to have been deposited by clusters of microbes 3.7 billion years ago. If so, these stromatolites represent the oldest fossilized evidence of life on Earth.
Lucy’s big fall
A controversial study claims that Lucy, the most famous fossil in the study of human evolution, died after falling from high up in a tree . The autopsy supports the hypothesis that Australopithecus afarensis split its time between the ground and the trees.
Nucleus with no charge
Researchers have spotted signs of a “tetraneutron,” an atomic nucleus with four neutrons but no protons. If confirmed, this first-of-its-kind nucleus might be explained by a new, interneutron force.
