The Milky Way Over Glacier Point

Yosemite has the darkest sky most American visitors ever see. Polly had heard this from Tomas. She wanted to see for herself.

She waited out the afternoon at Glacier Point, an overlook 970 metres above the valley floor. A small crowd was there for the sunset. Polly perched on the railing.

The sun went down behind the Sierra ridge. Half Dome, across the valley, caught the last red light on its face and held it for twenty seconds. Then the red was gone. The crowd clapped softly.

A park astronomer in a brown vest set up a small telescope. He gave a talk while the sky grew darker. He explained that most American cities have lost the Milky Way to streetlights. But in Yosemite, on a clear night, you can still see what humans have seen here for thousands of years.

The first stars came out one at a time. By full dark, the Milky Way was a band of pale light running across the sky. It was broken by dark patches where dust clouds blocked the stars behind them. The biggest dark patch was called the Great Rift. Polly could see it clearly.

The astronomer pointed the telescope at a small smudge near Sagittarius. "This is the centre of our galaxy," he said. "The supermassive black hole at its heart is twenty-six thousand light years away."

A visitor looked through the eyepiece, then stepped back. The astronomer tilted the telescope so Polly could see in too. Through the eyepiece was a dense cluster of stars and dust.

Twenty-six thousand years ago, the light leaving that cluster had started its trip to this telescope. Polly looked for a long time.