|by John Walker|
Doubling the exposure to half a second further enhances the streamers and some of the filamentary structure of the corona, particularly near the active region at the top right. The white light which predominates in the inner corona is principally due to light from the photosphere scattered by free electrons stripped from ionised atoms in the corona, where the temperature exceeds one million degrees Kelvin. In the outer corona, light scattered by interplanetary dust also contributes to the continuum emission. This dust pervades the solar system along the plane of the ecliptic to beyond the Earth's orbit and can be seen as the zodiacal light after sunset and before dawn (in a dark and transparent sky).