April 26: Saturn

It was on this date in 1514 that Copernicus made his first observations of Saturn. Here are some things you may not know about the planet with rings:

1. Saturn is the sixth planet from the Sun and the second-largest in the Solar System, after Jupiter. It is the most distant of the five planets easily visible to the naked eye from Earth, (the other four being Mercury, Venus, Mars and Jupiter) and hence has been observed since ancient times.
2. The rings, however, aren't visible to the naked eye and so nobody knew they existed before the invention of the Telescope. Galileo was the first to see them in 1610, and even he mistook the rings for moons. The rings extend from 6,630 km to 120,700 km from Saturn's equator, and are about 20 meters thick. They are composed of 93% water ice and 7% amorphous carbon. The rings are thin enough to disappear to observers on Earth at certain points in the planet's rotation. This happens about every 15 Earth years. They are made up of particles ranging in size from specks of dust up to 10m.
3. Saturn has 62 known moons, 53 of which have been named. Scientists believe there are also hundreds of "moonlets", larger bodies within the ring system. The largest moon is Titan, which accounts for 90% of everything orbiting Saturn, including the rings. Another major moon is Enceladus, which has a similar chemical makeup to comets, and could have microbial life.
4. It takes Saturn 10,759 Earth days (29 1⁄2 years), to orbit the Sun.
5. Wind speeds on Saturn can reach 1,800 km/h (500 m/s), higher than on Jupiter, but not as high as those on Neptune. At the poles of Saturn, there are permanent storms raging. The one at the north pole is hexagonal in shape. The sides of the hexagon are about 13,800 km (8,600 mi) long, longer than the diameter of the Earth. There are also huge storms which happen fairly regularly during the planet's northern hemisphere's summer solstice, about once every 30 earth years.
6. Saturn is the only planet of the Solar System which is less dense than Water—about 30% less.
7. Saturn is named after the Roman god of agriculture. Its astronomical symbol (♄) represents the god's sickle and is known as the "crescent below the cross".
8. Saturn is a gas giant, but it is thought to have a core of iron–nickel and rock surrounded by a deep layer of metallic hydrogen, an intermediate layer of liquid hydrogen and liquid Helium, and a gaseous outer layer made up of 96.3% molecular hydrogen and 3.25% helium. The upper atmosphere contains ammonia crystals, which give the planet its yellowish hue.
9. Saturn's Surface area is equivalent to 83.703 Earths and its volume equivalent to 763.59 Earths.
10. In astrology, Saturn is associated with precision, ethics, purpose, career, authority, stability, karma, boundaries, anxiety, practicality, reality, and time. The Saturn Return (when the planet arrives back at the point in the zodiac where it was when the person was born) is said to mark significant events in life.