Explainer: What is a rock?
The definition is caught between a rock and a hard place.
Credit: Jodie Griggs / Getty Images.
Everyone is familiar with rocks. It’s hard not to be. They’re everywhere – we walk on them, skip them across ponds, dig them out of our gardens, and stare appreciatively at them as they form mountains and canyons.
So, we all know what a rock actually
is, right?
Turns out rocks are pretty hard to define
The definition of a rock is a bit woolly, often contradictory, and hard to pin down – even for geologists.
In the broadest sense, a rock is a collection of other things. Officially, it is a collection of one or more types of minerals, held together in a solid mass.
The
Archaeopteryx was a birdlike dinosaur that likely had to get a running start to take flight. It lived during the Jurassic Period. Stocktrek Images/Getty Images/Stocktrek Images
It all began with a single feather. On Sept. 30, 1861, the German paleontologist Christian Erich Hermann von Meyer published his description of a jaw-dropping new find. Fossil feathers were unheard of at the time, yet somebody had pulled one out of a limestone quarry near Solnhofen, Bavaria.
Von Meyer named the animal it belonged to
Archaeopteryx lithographica. His choice was apt; the first part of that name (i.e.,
Archaeopteryx) means ancient wing.