interplanetary-dust

Before dawn in a dark-sky location, a ghostly pyramid of light rises from the eastern horizon along the path of the zodiac. Ancient observers thought it was a meteorological phenomenon — moisture in the upper atmosphere catching the sun. It is not. It is sunlight scattered off trillions of interplanetary dust particles spread across the entire inner solar system, the ground-down debris of comets and asteroids, and it is far stranger than it looks. In 2021, a camera on NASA's Parker Solar Probe detected that this dust does not extend all the way to the Sun.