the.com/oceanfloor
Earth's basement, better mapped on Mars than under our own waves.
means The submerged bottom surface of the ocean, including its plains, trenches, ridges, and volcanic mountains.
from Plain English compound joining ocean (from Greek Okeanos, the river encircling the world) with floor, the surface you stand on, here flipped miles below the surface you can't.
Mostly unmappedOver 80 percent never surveyed in detail.
Deepest pointMariana Trench plunges nearly 11 kilometers down.
Always newMid-ocean ridges constantly birth fresh crust.
Dark worldSunlight quits around 1000 meters deep.