APOD
Astronomy Picture of the Day
Discover the cosmos! Each day a different image or photograph of our fascinating universe is featured, along with a brief explanation written by a professional astronomer.
Grand Canyon Star Trails
Explanation: One of the natural wonders of planet Earth, the Grand Canyon in the American southwest stretches across this early evening skyscape . 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 geological timescale. 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 Earth rotates , 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 .
| Date | March 3, 2013 |
|---|---|
| Credit | Image Credit & Copyright: Babak Tafreshi ( TWAN ) |
| Authors & editors: | Robert Nemiroff (MTU) & Jerry Bonnell (UMCP) |
| A service of: |
ASD at NASA / GSFC, NASA Science Activation & Michigan Tech. U. |



