Titan By Christopher Barber Physics 1040 Elementary Astronomy

Introduction to Titan • Titan is one of numerous satellites that orbit the planet Saturn. Titan is also the largest of Saturn’s moons as well as being the second largest moon in our solar system (after Jupiter's moon Ganymede. ) • Titan is unique compared to other moons in our solar system due to the fact it has such a thick atmosphere. In fact, if Titan was orbiting around the sun and not around Saturn it would probably be considered a planet instead.

Who discovered Titan? • • • Titan was first discovered by Dutch astronomer Christiaan Huygens. (born April 14, 1629 -died July 8, 1695) He had been at the time observing the true shape of Saturn’s rings when he found Titan was also the first of Saturn’s moons to be discovered at the time. Huygens only found Titan because of the use of a refracting telescope. With a telescope that Christiaan and his brother, Constantijn Huygens Jr. had designed. To name some of his other notable astrological discoveries, he was the first person to correctly indentify the shapes of Saturn’s rings as well as being the first person to sketch and publish an image of the Orion Nebula.

How did Titan gets it’s name? • Titan, first designated as Saturn VI received it’s name after John Herschel (son of William Herschel, discoverer of the two Saturn moons Mimas and Enceladus) so name Saturn VI in his 1847 publication “Results of Astronomical Observations Made at the Cape of Good Hope”. It was by his suggestion that the names of Saturn’s Satellites be named after the mythological Titans, sisters, and brothers of Cronos, the Greek. • As an interesting side note the name Titan comes from Greek Mythology. The Titans were the son’s of Ouranos and Gaia. According to myth, the Titans are the ancestors of the human race. The Titans were known to have devoured the limbs of Dionysus, the son of Zeus furious, struck the Titans down with lightning. The fire then burned them to ashes, and from the ashes man was formed.

What is Titan’s composition like? • Titan's atmosphere is approximately 90% Nitrogen, and 10% other molecules such as methane, argon, and other hydrogen compounds. These chemicals is what gives Titan its reddish color and is what causes it to haven an extremely thick atmosphere. So thick in fact, that it hides its surface from view. • These chemicals come from evaporation, sublimation, and (what is only theoretical right now) volcanic activity. Thus making Titan the only moon that a substantial greenhouse effect. • Although because it’s so away from the sun, Titan’s surface temperature is pretty frigid (-180°C). Which makes the inside of Titan mostly different phases of ice and water. • Then deeper inside Titan, there are heavier, rocky and metal elements that form the core, such as silicates and iron.

Nasa’s Cassini Equinox Mission • On October 15, 1997, Nasa collaborated with ESA (European Space Agency) and launched the Cassini-Huygens to study Saturn and it's moons. The “Cassini” is the robotic mother ship spacecraft that holds the “Huygens, ” an ESA probe designed to record data and transmit it back to Earth. • The “Cassini” finally reached Saturn's orbit after a long journey on July 1, 2004. It took until January 14, 2005 to reach Titan. This was the first landing ever accomplished in the outer Solar system. Nasa extended the mission and renamed it the Cassini Equinox Mission. • The Cassini Equinox mission had several objectives involving the study of Titan. Here are three of them. 1. Study the dynamic behavior of Saturn's atmosphere at cloud level 2. Study the time variability of Titan's clouds and hazes. 3. Characterize Titan's surface on a regional scale. •

Cassini Equinox Mission Cont. • On October 27, 2004, the Cassini had its first flyby of Titan. It was able to send 4 gigabytes of pictures and information to earth. With this scientists were able to get a better understanding of the surface of Titan. • Cassini obtained radar pictures of Titan. These pictures show lakes of methane in Titan's polar regions. (This was the first discovery of any currently-existing lakes anywhere besides Earth. ) The lakes ranged in size from one kilometer to one-hundred kilometers across. • Titan, it was discovered, had icy mountains and valleys possibly made from icy volcanoes and methane rains. • The surface it turned out had a hard exterior but also had a “squishy” layer just below the crust. • Rounded boulders of ice were also discovered to be littering Titan’s surface.

pictures of Titan’s methane Lakes pictures of Titan’s rugged surface of mountains and valleys Actual picture from the Huygens probe of the icy Boulders on Titan’s surface

Recent Research • • • Scientist has also discovered fog over the lakes and lake effect clouds. This suggested to them that the lakes liquid methane may evaporate and enter the atmosphere. Much like water does on Earth. Then appearances of new lakes at the south pole showed that Titan's clouds most likely produced cold methane rain over the poles. The equatorial regions on Titan have been dry, with only vast expanses of rippling dune. . In National Geographic's March, 2011 Issue there is an article on the rains of Titan. New evidence has been brought to attention to support the idea of methane rain on Titan. According to the article recent research has shown that Titan’s rain is made of liquid methane which is a substance found on Earth as well as the main ingredient in natural gas. This is just the latest evidence, but it also shows that Titan most likely has a “methane cycle” much like earth’s water cycle.

Recent Research Continued • • • In September NASA’s Cassini Spacecraft saw a massive cloud form near Titan's equator. Scientist’s had never seen anything like this before. Images showed that a huge stretch of the dune’s had darkened before the cloud appeared. (Approximately 1, 200 miles x 80 miles. ) Two weeks later, the dunes began to lighten. According to scientists; “The most likely conclusion is, that the clouds dumped methane rain that is starting to slowly evaporate. ” The dunes slowly returning to their brightness strongly suggests evaporation of some liquid, presumably methane.

Titan vs. Earth • Just like on Earth, seasonal changes bring unsettled weather on Titan. Causing surprising amounts of erosion leading to surprising amounts of geology. • The composition of Titan's atmosphere is very close to the Earth's. Which is approximately 77% Nitrogen and has oxygen instead of argon or methane. • Pictures of Titan’s taken from the Cassin probe have shown river-like channels, mountainous terrain, and lakes. (although instead of water they are filled with liquid methane) • Titan also has a methane/ethane cycle resembling very closely the water cycle that we experience here on Earth. Titan (Middle)

Conclusion • In conclusion we have learned many things about Titan in recent years. • Titan is the largest of Saturn’s moons as well as being the second largest moon in our solar system • Titan is approximately 90% Nitrogen, and 10% other molecules such as methane. • The inside of Titan is mostly composed of different phases of ice and water. • There are heavier, rocky and metal elements that form the core, such as silicates and iron. • Scientists discovered methane lakes near Titans poles. This was the first discovery of any currently-existing lakes anywhere besides Earth. • They also discovered fog over the lakes and lake effect clouds. This suggested to them that the lakes liquid methane may evaporate and enter the atmosphere. • Titan is the only moon in the solar system with a substantial atmosphere.

References • http: //solarsystem. nasa. gov/planets/profile. cfm? Object=Titan • http: //en. wikipedia. org/wiki/Titan_(moon) • http: //inventors. about. com/library/inventors/bl_huygens. htm • hnews. nationalgeographic. com/news/2011/03/110317 -saturn-moon-titanapril-rain-spring-clouds-space-sciencettp: /// • http: //www. windows 2 universe. org/saturn/moons/titan_composition_overvie w. html • • http: //www. astrobio. net/pressrelease/1564/titan-versus-earth http: //www. nasa. gov/mission_pages/cassini/whycassini/cassini 20100923 b. ht ml • http: //saturn. jpl. nasa. gov/spacecraft/overview/ • http: //en. wikipedia. org/wiki/Cassini%E 2%80%93 Huygens