Astro Glossary

Sagittarius, the Archer

Sagittarius is one of the most interesting regions of the sky. The center of our Milky Way galaxy lies inside Sagittarius, about 26,000 light-years away. The constellation also contains several globular clusters — tightly packed collections of hundreds of thousands of stars. Its brightest stars form the shape of a teapot, and the constellation slides low across the southern sky of summer.

Sandy Wood

Saturn

The sixth planet from the Sun in the solar system. Saturn orbits the Sun at an average distance of 9.5 AU. The planet has a mass 95.2 times the mass of Earth and a radius 9.45 times the radius of Earth. Saturn is a gas planet and has no solid surface. It is made of hydrogen, helium, ammonia, and methane. Saturn is most famous for its beautiful ring system. In addition to the rings, the planet has 62 known moons, the largest of which is Titan.

Saturn's Atmosphere

The sixth planet from the Sun in the solar system. Saturn orbits the Sun at an average distance of 9.5 AU. The planet has a mass 95.2 times the mass of Earth and a radius 9.45 times the radius of Earth. Saturn is a gas planet and has no solid surface. It is made of hydrogen, helium, ammonia, and methane. Saturn is most famous for its beautiful ring system. In addition to the rings, the planet has 47 known moons, the largest of which is Titan.

Saturn's Moons

Saturn has 62 known moons as of April 2009, the largest of which is Titan. Other major moons include Enceladus, Iapetus, and Mimas, the so-called “Death Star moon.”

Saturn's Rings

Thousands of individual rings make up Saturn’s ring system. Some rings are made of small bits of frozen water, others contain tiny grains of dust, and still others are a mixture of the two. In all, the rings are only a few hundred feet thick.

Scandinavian Skylore

Science

Scorpius, the Scorpion

Three bright stars form the “head” of Scorpius, the celestial scorpion, while its tail curves away below it in the southern sky of summer. The brightest star in Scorpius is Antares, which is in the middle of the scorpion’s curving body. If you placed this brilliant red star at the center of our own solar system, it would swallow Mercury, Venus, Earth, and Mars, and almost reach Jupiter.

Scutum, the Shield