Selena Gutierrez


Were you wondering who discovered Saturn? Well, nobody knows. Here’s the problem. Saturn is one of the 5 planets that you can see with the unaided eye. In fact, if you’re seeing a bright star in the sky, there’s a good chance it’s Saturn. It takes a telescope to see the rings, but anybody can find Saturn, even in a bright city.

So perhaps a better question might be to ask, when did astronomers realize that Saturn was a planet? The ancient astronomers believed in the geocentric model of the Universe. The Earth was at the center of the Universe, and everything else orbited around it in crystal shells: the Sun, the Moon, the planets and the stars. One problem with this model was the strange movements of the planets. They would sometimes slow down, stop and even travel backwards in the sky. And to explain this, astronomers had to create elaborate models for the planets where the orbited inside spheres within spheres.

Anyway, this model was turned on its ear by Nicolaus Copernicus in the 1500s. He placed the Sun at the center of the Solar System, and had all the planets orbiting around it. This nicely explained the strange movements of the planets. They weren’t going backwards, it was just a change in perspective, since the Earth is also going around the Sun.

The first person to actually look at Saturn in a telescope was Galileo. He saw a strange oval-shaped planet. He thought the planet might have ears, or two small balls on either side. Later observations showed that these were actually Saturn’s grand ring system. Galileo also discovered Saturn’s moon Titan.

Better observations of Saturn by Giovanni Cassini turned up 4 additional moons of Saturn, as well a division in the rings that would later be named after him: the Cassini division.

But it wouldn’t be until 1979 that the first spacecraft flew past Saturn. NASA’s Pioneer 11 spacecraft made the journey, getting within 20,000 km of the planet’s cloud tops. This was followed by the Voyager spacecraft, and eventually NASA’s Cassini spacecraft that’s orbiting the planet today. All of our best images of Saturn were sent back by orbiting spacecraft.

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Saturn is sometimes called "The Jewel of the Solar System." It is a planet that is nothing like our own. Humans have been gazing up at Saturn for a long time. They have been wondering about it for thousands of years.

  • Saturn is huge. It is the second largest planet in our Solar System. Jupiter is the only planet that is bigger.
  • You cannot stand on Saturn. It is not like Earth. Saturn is made mostly of gases. It has a lot of helium. This is the same kind of gas that you put in balloons.

  • Its beautiful rings are not solid. They are made up of bits of ice, dust and rock.

  • Some of these bits are as small as grains of sand. Some are much larger than tall buildings. Some are up to a kilometer (more than half-a-mile) across.

  • The rings are huge but thin. The main rings could almost go from Earth to the moon. Yet, they are less than a kilometer thick.

  • Other planets have rings. Saturn's rings are the only ones that can be seen from Earth. All you need is a small telescope.

  • Saturn could float in water because it is mostly made of gas. (Earth is made of rocks and stuff.)

  • It is very windy on Saturn. Winds around the equator can be 1,800 kilometers per hour. That's 1,118 miles per hour! On Earth, the fastest winds "only" get to about 400 kilometers per hour. That's only about 250 miles per hour.

  • Saturn goes around the Sun very slowly. A year on Saturn is more than 29 Earth years.

  • Saturn spins on its axis very fast. A day on Saturn is 10 hours and 14 minutes.

  • The Ringed Planet is so far away from the Sun that it receives much less sunlight than we do here on Earth. Yes, the Sun looks smaller from there.
  • The day Saturday was named after Saturn.
  • Saturn has 62 confirmed moons of which 9 are waiting to be officially named


The Ringed Planet

Saturn was the most distant of the five planets known to the ancients. In 1610, Italian astronomer Galileo Galilei was the first to gaze at Saturn through a telescope. To his surprise, he saw a pair of objects on either side of the planet. He sketched them as separate spheres and wrote that Saturn appeared to be triple-bodied. In 1659, Dutch astronomer Christiaan Huygens, using a more powerful telescope than Galileo's, proposed that Saturn was surrounded by a thin, flat ring.

In 1675, Italian-born astronomer Jean-Dominique Cassini discovered a "division" between what are now called the A and B rings. It is now known that the gravitational influence of Saturn's moon Mimas is responsible for the Cassini Division, which is 3,000 miles (4,800 kilometers) wide.

Like Jupiter, Saturn is made mostly of hydrogen and helium. Its volume is 755 times greater than that of Earth. Winds in the upper atmosphere reach 1,600 feet (500 meters) per second in the equatorial region. (In contrast, the strongest hurricane-force winds on Earth top out at about 360 feet, or 110 meters, per second.) These superfast winds, combined with heat rising from within the planet's interior, cause the yellow and gold bands visible in the atmosphere.

Saturn's ring system is the most extensive and complex in the solar system, extending hundreds of thousands of kilometers from the planet. In the early 1980s, NASA's two Voyager spacecraft revealed that Saturn's rings are made mostly of water ice. They also found "braided" rings, ringlets, and "spokes," dark features in the rings that circle the planet at different rates from that of the surrounding ring material. Material in the rings ranges in size from a few micrometers to several tens of meters. Two of Saturn's small moons orbit within gaps in the main rings.

Many Moons

Saturn has 62 known natural satellites, or moons, and there are probably many more waiting to be discovered. Saturn's largest satellite, Titan, is a bit bigger than the planet Mercury. (Titan is the second-largest moon in the solar system; only Jupiter's moon Ganymede is bigger.) Titan is shrouded in a thick, nitrogen-rich atmosphere that might be similar to what Earth's was like long ago. Further study of this moon promises to reveal much about planetary formation and, perhaps, about the early days of Earth. Saturn also has many smaller "icy" satellites. From Enceladus, which shows evidence of recent (and ongoing) surface changes, to Iapetus, with one hemisphere darker than asphalt and the other as bright as snow, each of Saturn's satellites is unique.

Though Saturn's magnetic field is not as huge as Jupiter's, it is still 578 times as powerful as Earth's. Saturn, the rings, and many of the satellites lie totally within Saturn's enormous magnetosphere, the region of space in which the behavior of electrically charged particles is influenced more by Saturn's magnetic field than by the solar wind. Hubble Space Telescope images show that Saturn's polar regions have aurorae similar to Earth's. Aurorae occur when charged particles spiral into a planet's atmosphere along magnetic field lines.

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