Densitet för titan
The geology of Titan encompasses the geological characteristics of Titan , the largest moon of Saturn. Titan's density of 1.
Titan - Wikiwand
The possibility of hydrocarbon seas on Titan was first suggested based on Voyager 1 and 2 data that showed Titan to have a thick atmosphere of approximately the correct temperature and composition to support them, but direct evidence was not obtained until when data from Hubble and other observations suggested the existence of liquid methane on Titan, either in disconnected pockets or on the scale of satellite-wide oceans, similar to water on Earth.
The Cassini mission confirmed the former hypothesis.
When the probe arrived in the Saturnian system in , it was hoped that hydrocarbon lakes or oceans would be detected from the sunlight reflected off their surface, but no specular reflections were initially observed. The equatorial lakes are probably " oases ", i. The strength of the reflection saturated the probe's receiver, indicating that the lake level did not vary by more than 3 mm implying either that surface winds were minimal, or the lake's hydrocarbon fluid is viscous.
On July 8, , Cassini's VIMS observed a specular reflection indicative of a smooth, mirror-like surface, off what today is called Jingpo Lacus , a lake in the north polar region shortly after the area emerged from 15 years of winter darkness. Specular reflections are indicative of a smooth, mirror-like surface, so the observation corroborated the inference of the presence of a large liquid body drawn from radar imaging.
Early radar measurements made in July and January indicated that Ontario Lacus was extremely shallow, with an average depth of 0. Ligeia Mare averages from 20 to 40 m 66 to ft in depth, while other parts of Ligeia did not register any radar reflection at all, indicating a depth of more than m ft. While only the second-largest of Titan's methane seas, Ligeia "contains enough liquid methane to fill three Lake Michigans ".
In May , Cassini' s radar altimeter observed Titan's Vid Flumina channels, defined as a drainage network connected to Titan's second-largest hydrocarbon sea, Ligeia Mare. Elevations of the liquid in these channels are at the same level as Ligeia Mare to within a vertical precision of about 0. Specular reflections are also observed in lower order tributaries elevated above the level of Ligeia Mare, consistent with drainage feeding into the main channel system.
Densiteten hos titan
This is likely the first direct evidence of the presence of liquid channels on Titan and the first observation of hundred-meter deep canyons on Titan. Vid Flumina canyons are thus drowned by the sea but there are a few isolated observations to attest to the presence of surface liquids standing at higher elevations. During six flybys of Titan from to , Cassini gathered radiometric tracking and optical navigation data from which investigators could roughly infer Titan's changing shape.
The team's analyzes suggest that Titan's surface can rise and fall by up to 10 metres during each orbit. That degree of warping suggests that Titan's interior is relatively deformable, and that the most likely model of Titan is one in which an icy shell dozens of kilometers thick floats atop a global ocean. In , Cassini found the first evidence of fluid-filled channels on Titan, in a series of deep, steep-sided canyons flowing into Ligeia Mare.
This network of canyons, dubbed Vid Flumina, ranges in depth from to m and has sides as steep as 40°. They are believed to have formed either by crustal uplifting, like Earth's Grand Canyon , a lowering of sea level, or perhaps a combination of the two. The depth of erosion suggests that liquid flows in this part of Titan are long-term features that persist for thousands of years. For example, a kilometre-wide 56 mi ring of bright, rough material known as Guabonito has been observed by Cassini.
Several other similar features have been observed in the dark Shangri-La and Aaru regions. Radar observed several circular features that may be craters in the bright region Xanadu during Cassini's April 30, , flyby of Titan. There is little evidence of formation of palimpsests through viscoelastic crustal relaxation, unlike on other large icy moons. Infill from various geological processes is one reason for Titan's relative deficiency of craters; atmospheric shielding also plays a role.
It is estimated that Titan's atmosphere reduces the number of craters on its surface by a factor of two. Xanadu has 2—9 times more craters than elsewhere.
Titan (Ti) - Grundämne nr 22 i Periodiska systemet
There are lower crater densities in areas of equatorial dunes and in the north polar region where hydrocarbon lakes and seas are most common. Pre- Cassini models of impact trajectories and angles suggest that where the impactor strikes the water ice crust, a small amount of ejecta remains as liquid water within the crater. It may persist as liquid for centuries or longer, sufficient for "the synthesis of simple precursor molecules to the origin of life".
Scientists have long speculated that conditions on Titan resemble those of early Earth, though at a much lower temperature.