Ash from Mt. Pinatubo: NASA space-shuttle photograph, STS046-105-034, 08/08/92, 70 mm format. High-oblique view of Earth's horizon at sunrise over the Pacific. The upper blue layer results for molecular scattering of light. Middle gray and reddish-gray bands represent suspended ash and sulfuric acid particles from the eruption of Mt. Pinatubo in June, 1991. The lowest red layer marks the lower stratosphere.