This image from NASA’s Cassini spacecraft shows three moons — Rhea (top), Titan and Mimas (bottom). Titan appears fuzzy because we only see its cloud layers and light refracts within its atmosphere, extending the crescent. Image credit: NASA/JPL-Caltech/Space Science Institute.The three moons shown here — Titan (3,200 miles or 5,150 kilometres across), Mimas (246 miles or 396 kilometres across), and Rhea (949 miles or 1,527 kilometres across) — show marked contrasts. Titan, the largest moon in this image, appears fuzzy because we only see its cloud layers. And because Titan’s atmosphere refracts light around the moon, its crescent “wraps” just a little further around the moon than it would on an airless body. Rhea (upper left) appears rough because its icy surface is heavily cratered. And a close inspection of Mimas (centre bottom), though difficult to see at this scale, shows surface irregularities due to its own violent history.
This view looks toward the anti-Saturn hemisphere of Titan. North on Titan is up. The image was taken in visible light with the Cassini spacecraft narrow-angle camera on March 25, 2015.
The view was obtained at a distance of approximately 1.2 million miles (2.0 million kilometres) from Titan where the image scale is 75 miles (121 kilometres) per pixel. Mimas was 1.9 million miles (3.1 million kilometres) away with an image scale of 11.4 miles (18.4 kilometers) per pixel, while Rhea was 2.2 million miles (3.5 million kilometres) away with an image scale of 13.1 miles (21.1 kilometres) per pixel.
Saturn’s rings cast shadows on the planet’s cloud tops, providing a perfect backdrop for the brilliant sphere of the moon Enceladus in this image taken by NASA’s Cassini probe.
Three naked-eye planets – Mars, Jupiter and Saturn – grow in prominence in the dawn sky this month. If you wish to identify them for yourself, let the waning Moon be your celestial guide from 7–11 March. We also show you what to look for in binoculars and telescopes.
For lunar and planetary enthusiasts, the only naked-eye planet of the evening sky is distant and tiny Mars in the constellation of Taurus. But if you’re prepared to be an early riser, the dawn sky is where you’ll find two of the solar system’s heavyweights, Jupiter and Saturn, getting up close with the Moon on 27 and 29 March, respectively.
