lunar cathedral

Venus Just After Sunset
Credit & Copyright Tunç Tezel (TWAN)

Prometheus Rising Through Saturn’s F Ring

Saturn: Light, Dark, and Strange

Equinox and the Iron Sun

Earth and Moon from MESSENGER

Taken from a position as far away from Earth as Mercury.

Comanche Outcrop on Mars

Eclipse Shadow Cone Over Patagonia
Credit & Copyright Daniel Fischer (Cosmic Mirror)

Explanation: Sometimes, during a total eclipse of the Sun, a strange shadow of darkness can be seen stretching off into the distance. Called shadow cones, they are visible because the Earth’s atmosphere is not completely transparent, scattering sunlight and hence appearing blue during the day. Shadow cones are particularly dramatic for eclipses near the horizon, as geometry creates a long corridor of sun-blocked air. Visible above is a shadow cone caught during a sunset total solar eclipse visible last month from Patagonia, Argentina. The eclipsed Sun itself still appears bright around the edges of the Moon because of light from the surrounding corona. A few minutes later, the Moon began to move away from the Sun as both set behind distant Andes mountains.

Flowing Barchan Sand Dunes on Mars

Prometheus Creating Saturn Ring Streamers

Explanation: What’s causing those strange dark streaks in the rings of Saturn? Prometheus. Specifically, an orbital dance involving Saturn’s moon Prometheus keeps creating unusual light and dark streamers in the F-Ring of Saturn. Now Prometheus orbits Saturn just inside the thin F-ring, but ventures into its inner edge about every 15 hours. Prometheus’ gravity then pulls the closest ring particles toward the 80-km moon. The result is not only a stream of bright ring particles but also a dark ribbon where ring particles used to be. Since Prometheus orbits faster than the ring particles, the icy moon pulls out a new streamer every pass. Above, several streamers or kinks are visible at once. The above photograph was taken in June by the robotic Cassini Spacecraft orbiting Saturn. The oblong moon Prometheus is visible on the far left.

Four Planet Sunset
Credit & Copyright Jia Hao

Mercury, Venus, Mars, Saturn, and the star Regulus