One of the natural wonders of planet Earth,
the Grand Canyon
in the American southwest stretches across
The digitally stacked sequence reveals the canyon's
layers of sedimentary rock in bright moonlight.
Exposed sedimentary rock layers range in age from about
200 million to 2 billion years old, a
window to history on a
A recent study has found evidence that the canyon itself
may have been carved by erosion as much as 70 million years ago.
With the camera fixed to a tripod while
each star above carves a graceful arc through the night sky.
The concentric arcs are centered on the north celestial
pole, the extension of Earth's rotation axis into space, presently
near the bright star Polaris.