November 17, 2000
This image taken from the Space Shuttle shows the Manicouagan Impact Crater in Quebec, Canada. The diameter of the rim is approximately 70 km (43 miles), and it's estimated to be about 212 million years old. It's perhaps the largest and oldest of the preserved impact craters visible from space. The light colored band defining the crater rim is an annular lake that formed when impact-brecciated rock was eroded by glaciation and subsequently filled with water when the ice melted. In this wintertime view, the annular lake is ice covered. Note the radial drainage pattern of streams draining into the crater. Meteor showers, such as the Leonids, which may be visible after midnight (Saturday morning), rarely ever result in impact craters. Nearly all of Earth's existing large impact craters (more than a km in diameter) were produced from asteroids or planetesimals that smashed into the Earth more than 40,000 years ago.