APOD: Northern Summer on Titan (2020 Jun 20)

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APOD: Northern Summer on Titan (2020 Jun 20)

Post by APOD Robot » Sat Jun 20, 2020 4:06 am

Image Northern Summer on Titan

Explanation: Today's solstice brings summer to planet Earth's northern hemisphere. But the northern summer solstice arrived for ringed planet Saturn over three years ago on May 24, 2017. Orbiting the gas giant, Saturn's moon Titan experiences the Saturnian seasons. Larger than inner planet Mercury, Titan was captured in this Cassini spacecraft image about two weeks after its northern summer began. The near-infrared view finds bright methane clouds drifting through Titan's dense, hazy atmosphere as seen from a distance of about 507,000 kilometers. Below the clouds, dark hydrocarbon lakes sprawl near its fully illuminated north pole.

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Re: APOD: Northern Summer on Titan (2020 Jun 20)

Post by orin stepanek » Sat Jun 20, 2020 11:26 am

You know; It looks possible that Titan may have continents! :mrgreen:
My Imagination may be getting carried away again! :shock: 🚀 🛸
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Re: APOD: Northern Summer on Titan (2020 Jun 20)

Post by Sa Ji Tario » Sat Jun 20, 2020 3:07 pm

On Earth we know that the mechanism of rain is: water vapor that gathers around a nucleus, then cohesion in the clouds and when the atmosphere does not support it, it is discharged in the rain. Ask, on Titan, is the mechanism the same? So what is the condensation core? Would methane and / or ethane act the same as water? or does everything work by super saturation?

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Re: APOD: Northern Summer on Titan (2020 Jun 20)

Post by BDanielMayfield » Sat Jun 20, 2020 4:50 pm

orin stepanek wrote: Sat Jun 20, 2020 11:26 am You know; It looks possible that Titan may have continents! :mrgreen:
My Imagination may be getting carried away again! :shock: 🚀 🛸 PIA21615TitanNorthSummer1024.jpg
wikipedia wrote:The surface of Titan has been described as "complex, fluid-processed, [and] geologically young".[70] Titan has been around since the Solar System's formation, but its surface is much younger, between 100 million and 1 billion years old. Geological processes may have reshaped Titan's surface.[71] Titan's atmosphere is twice as thick as Earth's, making it difficult for astronomical instruments to image its surface in the visible light spectrum.[72] The Cassini spacecraft used infrared instruments, radar altimetry and synthetic aperture radar (SAR) imaging to map portions of Titan during its close fly-bys. The first images revealed a diverse geology, with both rough and smooth areas. There are features that may be volcanic in origin, disgorging water mixed with ammonia onto the surface. There is also evidence that Titan's ice shell may be substantially rigid,[36][37] which would suggest little geologic activity.[73] There are also streaky features, some of them hundreds of kilometers in length, that appear to be caused by windblown particles.[74][75] Examination has also shown the surface to be relatively smooth; the few objects that seem to be impact craters appeared to have been filled in, perhaps by raining hydrocarbons or volcanoes. Radar altimetry suggests height variation is low, typically no more than 150 meters. Occasional elevation changes of 500 meters have been discovered and Titan has mountains that sometimes reach several hundred meters to more than 1 kilometer in height.[76] This may be compared to the much wider topological variations found on Earth and Mars, with Olympus Mons on Mars being 26 km above the surrounding plains, and Earth's Mauna Kea over 10 km above the ocean floor.

Titan's surface is marked by broad regions of bright and dark terrain. These include Xanadu, a large, reflective equatorial area about the size of Australia. It was first identified in infrared images from the Hubble Space Telescope in 1994, and later viewed by the Cassini spacecraft. The convoluted region is filled with hills and cut by valleys and chasms.[77] It is criss-crossed in places by dark lineaments—sinuous topographical features resembling ridges or crevices. These may represent tectonic activity, which would indicate that Xanadu is geologically young. Alternatively, the lineaments may be liquid-formed channels, suggesting old terrain that has been cut through by stream systems.[78] There are dark areas of similar size elsewhere on Titan, observed from the ground and by Cassini; at least one of these, Ligeia Mare, Titan's second-largest sea, is almost a pure methane sea.[79][80]
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Re: APOD: Northern Summer on Titan (2020 Jun 20)

Post by sillyworm 2 » Sun Jun 21, 2020 10:22 am

Such an interesting moon.What a diverse menagerie of Solar System objects! To see it all form from scratch!

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Post by neufer » Sun Jun 21, 2020 2:47 pm

https://en.wikipedia.org/wiki/Climate_of_Titan wrote:
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<<The findings of the Huygens probe indicate that Titan's atmosphere periodically rains liquid methane and other organic compounds onto the moon's surface. In October 2007, observers noted an increase in apparent opacity in the clouds above the equatorial Xanadu region, suggestive of "methane drizzle", though this was not direct evidence for rain. However, subsequent images of lakes in Titan's southern hemisphere taken over one year show that they are enlarged and filled by seasonal hydrocarbon rainfall. It is possible that areas of Titan's surface may be coated in a layer of tholins, but this has not been confirmed. The presence of rain indicates that Titan may be the only Solar System body besides Earth upon which rainbows could form. However, given the extreme opacity of the atmosphere to visible light, the vast majority of any rainbows would be visible only in the infrared.

The number of methane lakes visible near Titan's south pole is decidedly smaller than the number observed near the north pole. As the south pole is currently in summer and the north pole in winter, an emerging hypothesis is that methane rains onto the poles in winter and evaporates in summer. According to a paper by Tetsuya Tokano of the University of Cologne, cyclones driven by this evaporation and involving rain as well as gale-force winds of up to 20 m/s are expected to form over the large northern seas (Kraken Mare, Ligeia Mare, Punga Mare) only in the northern summer, lasting up to ten days. To date no waves have been observed on any of Titan's lakes; however, calculations suggest that, as the northern hemisphere, where most of the lakes reside, enters the long Titanean summer, wind speeds might increase to 3 km/h, levels sufficient to produce waves.>>
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