The stubbornly high levels of mercury in tuna had to do with ocean mixing, which is churning up mercury that’s lurked for decades in the ocean’s depths. Still, the complexities of that process ...

Here are some of the most amazing discoveries about Mercury to date and why they’re important. Mercury is metal Mercury’s large, mostly iron core explains why the planet is so dense.

A table of the chemical elements arranged in order of atomic number, usually in rows, so that elements with similar atomic structure (and hence similar chemical properties) appear in vertical columns.

Using data from NASA's MESSENGER spacecraft, scientists have determined that the solar system's tiniest planet, Mercury, hides a not-so-tiny secret: a 10-mile-thick mantle of diamond.