Spacecraft that have been to Saturn and other planets

In the past only three probes have visited the ringed planet with the current mission being the Cassini-Huygens. There are no further plans to visit Saturn.

Pioneer 11 was the first spacecraft that was launched in May of 1973. The encounter of Jupiter was in December of 1974 and a visit of Saturn occurred in September of 1979. Contact was lost in November of 1995.

The most infamous of all probes, the Voyager series, was also designed to study the gas giants. Voyager 2 (launched before Voyager 1) was launched in August of 1977. The Jupiter flyby was in July 1979, the Saturn flyby was in August 1981, the Uranus flyby was in January 1986, and the Neptune flyby was in August 1989. The Voyager 2 has left the Solar System but is still in operation.

The Voyager 1 probe, launched in September of 1977, would only visit Jupiter and Saturn. The Voyager 2 probe was launched first after discovering the orbital positions of all four gas giants would allow the probes visit.Voyage 1 was launched as planned.

The Cassini-Huygens mission is a two part, joint venture with the European Space Agency. The mission consists of:
The Cassini orbiter
The Huygens probe

The Cassini orbiter is NASA's portion of the mission and it carried the ESA's Huygens probes to Titan.

The probe was launched on October 15, 1997 and arrived for orbital insertion on July 1, 2004. The Huygens probe was released on December 24, 2004 and descended Titan's atmosphere and landed on January 14, 2005.

The Ring discoverer

Many years later, in 1659, a Dutch astronomer named Christiaan Huygens solved the mystery of Saturn's "arms." Because of improved telescope optics, he correctly deduced that the "arms" were actually a ring system. Huygens also discovered Saturn's moon, Titan, and for this reason, the probe exploring Titan is named after him.

Christiaan Huygens

Robert Hooke was another early observer of the rings of Saturn, and noted the casting of shadows on the rings.

Robert Hooke

    Robert Hooke drawing of Saturn shadow(rings)

In 1675, Giovanni Domenico Cassini determined that Saturn's ring was composed of multiple smaller rings with gaps between them; the largest of these gaps was later named the Cassini Division. This division is a 4,800 km-wide region between the A ring and B ring.

Giovanni Domenico Cassini

        Giovanni Domenico Cassini drawing of Saturn ring

In 1787, Pierre-Simon Laplace suggested that the rings were composed of a large number of solid ringlets

Pierre-Simon Laplace

In 1859, James Clerk Maxwell demonstrated that the rings could not be solid or they would become unstable and break apart. He proposed that the rings must be composed of numerous small particles, all independently orbiting Saturn.

Sodia Kovalevskava found that Saturn's rings cannot be liquid ring-shaped bodies.

Maxwell's theory was proven to be valid in 1895 through spectroscopic studies of the rings carried out by James Keeler  of Allegheny Observatory and Aristarkh Belopolsky of Pulkovo Observatory.

References

The planets: National Geographic website: http://science.nationalgeographic.com/science/space/planets/

Space website:http://www.space.com/16080-solar-system-planets.html

Enchanted Learning website: http://www.enchantedlearning.com/subjects/astronomy/planets/

Fraser Cain Website: http://www.universetoday.com/15502/planets-in-the-solar-system/

About Saturn: Chris Jones websites: http://space-facts.com/saturn/

NASA website: http://solarsystem.nasa.gov/planets/profile.cfm?Object=Saturn


Uniques Features:Fraser Cain website: http://www.universetoday.com/15418/interesting-facts-about-saturn/


Who found Saturn?: Fraser Cain Website http://www.universetoday.com/15315/discovery-of-saturn/

The ring discoverer:
The First Professional Scientist: Robert Hooke and the Royal Society of London: http://books.google.com.my/books?id=tJu97S3BtGIC&pg=PA204&lpg=PA204&dq=robert+hooke+saturn+rings&source=bl&ots=fvehAumyIF&sig=dlfl1YOBghGn-yf-B2bhE6fpyi4&hl=en&sa=X&ei=Vqz2U4y9HNKfugTI3YHYBw&ved=0CGcQ6AEwDA#v=onepage&q=robert%20hooke%20saturn%20rings&f=false

http://www.kidsastronomy.com/saturn-rings.htm


http://moonphases.info/How-was-Saturns-rings-discovered.html

Saturn's Moons: Jet Propulasion Laboratory website: http://saturn.jpl.nasa.gov/science/moons/

NASA Website: http://solarsystem.nasa.gov/planets/profile.cfm?Display=Sats&Object=Saturn

Enchanted learning website:http://www.enchantedlearning.com/subjects/astronomy/planets/saturn/saturnmoons.shtml

Saturn's Rings: Jet Propulasion Laboratory website: http://saturn.jpl.nasa.gov/science/index.cfm?SciencePageID=55

http://www.space.com/23235-rings-of-saturn.html

http://csep10.phys.utk.edu/astr161/lect/saturn/rings.html

Spacecraft that have been to Saturn and other planets:

Fraser Cain Website: http://www.universetoday.com/15312/how-long-does-it-take-to-get-to-saturn/

NASA website: http://www.nasa.gov/mission_pages/cassini/main/#.U_bBc_mSwXg

Earth versus Saturn: National Aeronautics and Space Administration website: https://solarsystem.nasa.gov/planets/compchart.cfm?Object1=Saturn


Fraser Cain Website: http://www.universetoday.com/24161/saturn-compared-to-earth/

Earth versus Saturn

Comparison between Earth and Saturn.

There are many differences between Earth and Saturn. Firstly, Earth is the third planet from the Sun whereas Saturn is the sixth planet. Secondly, Saturn is much bigger than Earth. Saturn’s equatorial diameter is 120,536 km, which is about 9.5 times bigger than that of Earth.

Moreover,Saturn’s surface area is 83 times that of Earth. When comparing Earth and Saturn, the former is the densest planet of the two. Furthermore, Earth is the only place in the Solar system where life is seen. Earth is also the only planet that has liquid water in it. Amazingly, Earth has only one moon whereas Saturn has more moons. Next, unlike earth, Saturn has beautiful rings round it. When it comes to fast rotation Saturn won it all as, Saturn takes about 30 long years to go round the Sun once. In rotation, Earth takes more time. While earth takes 24 hours, Saturn takes about 10 Hours and 32 minutes to make one rotation.

Saturn's Moons

Saturn has 18 known moons. It is possible that Cassini will discover more. Saturn's moons range in size from smaller than an asteroid to larger than the planet Mercury. More moons of greater variety orbit Saturn than any other planet. They are listed first is Atlas, Calypso, Dione, Enceladus, Epimetheus, Helene, Hyperion, Iapetus, Janus, Mimas, Pan, Pandora, Phoebe, Prometheus, Rhea, Telesto, Tethys, and Titan.

All these moons (plus any new ones found) will be studied by Cassini, but the most extensive study will be the Huygens probe on Titan.

Titan: The only Saturn moon that has ever had a probe land on it: Huygens, a lander carried to the hazy world by the spacecraft Cassini. Titan’s “Earth-like processes” and thick atmosphere are among the things that make this world stand out to scientists. Ethane and methane rains from the atmosphere and flows on the surface.

A fish-eye view of Titan’s surface from the European Space Agency’s Huygens lander in January 2005. Credit: ESA/NASA/JPL/University of Arizona

Enceladus: An extremely reflective moon because it is made up of water ice. It’s also quite cold at minus 330 degrees Fahrenheit (minus 201 degrees Celsius). The moon has at least five different kinds of terrain, a “young” geological surface of less than 100 million years, and a possible liquid interior. The moon is also known for its ice plumes. 

Rhea: Rhea has at least two major sections: bright craters with craters larger than 25 miles (40 kilometers), and a second section with smaller craters. “This difference may indicate there was a major resurfacing event some time in Rhea’s history,” NASA stated. 

Mimas: Some people jokingly call it a “Death Star” because of the crater in its surface that resembles the machine from the Star Wars universe. The 88-mile (140-kilometer) Herschel Crater is about a third the diameter of the moon itself. The huge impact also could have created fractures (chasmata) on the moon’s opposing side. There are in fact craters throughout the moon’s small surface, making it among the most pockmarked in the Solar System. 

A view of Saturn’s moon Mimas from the Cassini spacecraft. Credit: NASA/JPL/Space Science Institute

Pan: Considered a “shepherd satellite” as it orbits within the Encke Gap of Saturn’s A ring and keeps the gap from being filled in with ring material. Its motions also make stripes (“wakes”) in the rings on either side of it. Pictures obtained at a distance show it looks something like a walnut.

Tethys: An airless moon that has a huge impact crater (called Odyssey Crater, 250 miles or 400 kilometers in diameter) — about two-fifths of Tethys’ diameter. It also has a large valley called Ithaca Chasma, which is 62 miles (100 kilometers) wide.

Dione: A moon that appears to have spun about 180 degrees, perhaps due to a large impact. It’s covered in canyons, cracking and craters and is coated from dust in the E-ring that originally came from Enceladus.

Saturn Rings

The Rings



Saturn's rings are the most distinctive feature of the planet. At one time, astronomers believed that the rings were uniform, but they now know that is not the case. Saturn's rings are actually composed of a collection of particles that range in size from a grain of sand to a car. The rings are comprised of ice and rock particles. The rings are divided into 7 major ring divisions and possess intricate structure and complex gravitational interactions.

The origin of Saturn's rings is a mystery. Scientists hope that data from Cassini will shed some light on the issue. In addition, understanding the origin of Saturn's rings may help scientists also understand the origin of the Solar System. Saturn and its ring system are thought to be similar to the setup of the early Solar System.

Who found Saturn?

Galileo Galilei was the first to observe Saturn with a telescope in 1610. Because of the crudeness of his telescope, he couldn't determine what the rings were. He incorrectly guessed that there were two large moons on either side of Saturn. Two years later when he viewed Saturn again, the "moons" had disappeared. We know now this is because Galileo was viewing the rings edge-on so that they were invisible, but at the time it was very confusing to Galileo. After another two years, Galileo viewed Saturn again and found that the "moons" had returned. He concluded that the rings were "arms" of some sort.

Galileo & his drawings 

Top drawing: Galileo's drawing of Saturn, 1610 

Bottom drawing: Galileo's drawing of Saturn, 1616 

A few years after Huygens' discoveries, an Italian-French astronomer by the name of Jean- Dominique Cassini discovered 4 other major moons of Saturn: Iapetus, Rhea, Tethys, and Dione. In 1675, Cassini discovered a narrow gap that splits Saturn's ring system into two parts, and the gap has since been known as the "Cassini Division." Because of his numerous contributions to our knowledge about the planet Saturn, Cassini was chosen as the name of the spacecraft flying to Saturn.

Jean-Dominique Cassini

Other major discoveries came later. During the 19th century, J.E. Keeler showed that the ring system is not a uniform sheet but actually comprised of small particles. Most recently, the Voyager spacecrafts (visiting in 1980-81) made discoveries about the composition and interaction of the rings.