TITAN UNVEILED

Courtesy European Southern Observatory

Titan is 5,150 km in diameter, orbits Saturn at a mean distance of 1,221,830 km, and has equal orbital and rotational periods of 15.9454 earth days. Indeed Titan, Saturn's brightest moon, is of magnitude +8.28 and can be seen in small telescopes as it orbits the ringed planet.

Astronomer Christiaan Huygens discovered Titan in 1655 through one of his unusual 7-meter aerial telescopes. This consisted of the main objective lens placed at the top of a tall pole, attached to which was a 7 meter length of rope held by the observer, connected to the telescope's eyepiece. Sometime earlier Huygens had viewed the planet's rings that appeared to be two orbs attached either side of the planet, and became the first astronomer to identify the ring system for what they are. It was therefore quite an achievement to also discover the planet's largest moon, Titan.

Titan was thought to be the largest satellite in the solar system until recently, when it was recognized that estimates of its size had included its thick atmosphere. Titan's solid surface is slightly smaller than that of Ganymede, the largest of Jupiter's satellites.

The moon is also in synchronous rotation since Titan's day or axial rotation is the same as its orbital period around Saturn. Another oddity is Titan's orange smog-like atmosphere of hydrocarbons such as Methane, Ethane and Butane that almost entirely covers the moon. Titan's surface temperature of -178° centigrade is also quite close to the triple point of Methane, which means that this element can be in all three states together (Sold, Liquid or Gas) as the temperature fluctuates.

European astronomers using the Infrared Space Observatory have now confirmed that not only is water vapor (H2O) present in Titan's atmosphere, it exists in the atmospheres of all 4 gas giant planets.


Courtesy of the ESA

The Hubble Space telescope and European Southern Observatory took a series of images of Titan recently, which appears to show the surface features below the moon's atmosphere, that have now been confirmed as genuine by JPL/NASA scientists using images taken by the Cassini probe in July 2004.

The solid surface of Titan is surrounded by an atmosphere consisting mostly of molecular nitrogen with small amounts of methane, ethane, and other hydrocarbons. This thick, opaque atmosphere normally prevents the surface from being seen in visible light, although some surface detail has been observed via the European Southern Observatory, Hubble Space Telescope, and Cassini probe using infrared light.

As to the surface features themselves (whether they are cratered plains, upland mountains or deep valleys) these remains a mystery until the Huygens probe attached to the Cassini Huygens spacecraft now in orbit around Saturn, separates from its mother ship and moves with ever increasing speed towards Titan. The lander will then enter the moon's atmosphere and begin making meteorological measurements during its decent to the moon's mysterious surface. We don't know whether the Huygens probe will touch down on solid land, which now seems likely, or splash down onto a cryogenic ocean of Methane. :huh:

We know that the Mass of Titan is 2¼ times greater than that of the Earth's (Mass (Earth = 1) 2.2590e-02), while the moon's escape velocity is 2.65 km/second. It has now been calculated that if an ocean of some kind does exist on Titan, then its waves would be quite high and the liquid would flow very slowly indeed with the consistency of thick oil.

Like the mysterious dark markings on Mars that once haunted the astronomer Percival Lowell, shadowy features and mysterious markings appear to stain the surface of puzzling Titan.
Sixteen Cassini narrow angle camera images were used to produce the surface map shown here. From analysis of maps such as this, it is easy to discern the characteristics of a moon's surface. The equatorial region (30 degrees south to 30 degrees north latitude) is crossed by dark markings, although they are less prominent over the bright region named "Xanadu," located near longitude 90 degrees.

JPL scientists now believe some of the brighter, round markings might be recent impact craters, including a bright feature with rays apparently extending from it near longitude 130 degrees on the leading hemisphere of Titan.


Image Credit:
NASA/JPL/Space Science Institute

These mapped images were taken through the methane "window" at 938 nanometers with a polarizing filter. This combination was designed specifically to reduce the obscuration by atmospheric haze.

Cassini's second Titan flyby will take place on 13 December. A targeting maneuver to point the Huygens probe in the right trajectory ready for its release from its mother ship will happen on 9 December, followed by mother-ship separation on Christmas Eve 24 December. The small ellipse on the map shows the site of Huygens landing area.

What do you think the newly found black surface areas are? I am puzzled at the moment as to whether mountain building or past volcanism happened on Titan due to its low cryogenic surface temperture of -178 degrees (The opposite conditions that today exist on the planet Venus). I would appreciate your opinions on this subject everyone being a hot topic at the moment. :huh:

[Copyright Notice: The photos displayed here are reproduced with permission for noncommercial purposes, providing reference was made to the space agency's concerned.]

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Richard Pearson
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taikonaut

Yeah, well, what goes up must come down, somewhere, most of the time. :unsure:

I'm guessing it wasn't a practical joke, some engineers ex-girlfreinds mothers place?

Too bad, not good PR in any country.

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