Rocks older than 4.03 billion years could shed light on Earth's earliest geological history, but they're incredibly rare.
The vast majority of research has failed to show any link between thimerosal and autism or other neurological issues.
Hamill had to dig deep to justify the actions of his iconic character in Rian Johnson's 'Star Wars: The Last Jedi.'
The closest galactic relative to the Milky Way helped astronomers discover dark matter in the 1960's.