ScienceMoon was born when Earth and Theia smooched 4.5 billion years ago Apollo rocks show a slightly different composition to similar objects on Earth. Lending an evidence of an impact 4.5 billion years ago between the Earth and a Mars-sized body called Theia.by James Maynard
ScienceEvidence of explosive volcanic activity on Mercury a surprise, may shed light on how the planet formedby Jim Algar