Astronomy Picture of the Day

Explanation: Captured one night last May this eight frame mosaic starts on the left, down Northside Drive through Yosemite National Park. It ends thousands of light-years away though, as the arc of the Milky Way tracks toward the centre of our galaxy on the right, far beyond the park's rugged skyline. That night was still moonless when the storm clouds retreated, so the rocky faces of the surrounding mountains are lit by campfires and artifical lights. Yosemite Falls is at the left. The granite face of Half Dome juts above the far horizon, near the centre of the view. The remarkable flash above it is a bright meteor. Part of the annual Eta Aquarid meteor shower the colourful streak is moving up, its trail pointing directly back to the shower's radiant, low in Aquarius. This year's Eta Aquarids should peak in the moonless early morning hours of May 6 as the Earth sweeps through dust from the tail of Comet Halley.