Picture the Earth’s crust and you most probably think of dense, dry rock. You don’t imagine a goey, honey-like substance trickling down into the planet’s deep underbelly.

More Potential patches of Earth's ancient crust, sometimes called "sunken worlds," may have just been discovered deep within the mantle, thanks to a new way of mapping the inside of our planet ...

Similar deep-sea volcanoes found on Earth support microbial life that lives inside solid rock without sunlight and oxygen. Some of these microbes, called thermophiles, live at temperatures hot ...