Radar images of Titan taken in 2013 by Cassini show a twelve-mile patch appear in one of the moon’s methane lakes, then disappear.

The mysteries of science: Radar images of Titan taken in 2013 by Cassini show a twelve-mile patch appear in one of the moon’s methane lakes, then disappear.

They really don’t know what this patch is.

Prior to the July 2013 observation, that region of Ligeia Mare had been completely devoid of features, including waves. Titan’s seasons change on a longer time scale than Earth’s. The moon’s northern hemisphere is transitioning from spring to summer. The astronomers think the strange feature may result from changing seasons.

In light of the changes, Hofgartner and the other authors speculate on four reasons for this phenomenon:

  • Northern hemisphere winds may be kicking up and forming waves on Ligeia Mare. The radar imaging system might see the waves as a kind of “ghost” island.
  • Gases may push out from the sea floor of Ligeia Mare, rising to the surface as bubbles.
  • Sunken solids formed by a wintry freeze could become buoyant with the onset of warmer temperatures during the late Titan spring.
  • Ligeia Mare has suspended solids, which are neither sunken nor floating, but act like silt in a terrestrial delta.

“Likely, several different processes – such as wind, rain and tides – might affect the methane and ethane lakes on Titan,” [says Hofgarnter]

It is very important to remember that Titan is a very alien planet to the Earth. While some features, its methane lakes, have a superficial resemblance to lakes on Earth, the materials and environment are completely different. For example, on Earth the only thing that generally floats on water is ice, so that when winter arrives the surface freezes while the water below remains liquid. On Titan, if the methane freezes the ice will sink.

Scientists have found that Saturn’s hexagon-shaped jet stream is deeply rooted and that its rotation might be revealing the planet’s rotation as well.

Scientists have found that Saturn’s hexagon-shaped jet stream is deeply rooted and that its rotation might be revealing the planet’s rotation as well.

Due to the tilt of approximately 27º of the planet Saturn, its polar atmosphere undergoes intense seasonable variations with long polar nights lasting over seven years, followed by a long period of 23 years of variable illumination. However, the seasonal variations do not affect the hexagon and its jet stream at all, so both are part of an extensive wave, deeply rooted in Saturn’s atmosphere. The UPV/EHU researchers suggest that the hexagon and its stream are the manifestation of a “Rossby wave” similar to those that form in the mid-latitudes of the earth. On our planet the jet stream meanders from west to east and brings, associated with it, the system of areas of low pressure and anticyclones which we have been seeing regularly on weather maps.

On Saturn, a hydrogen gas planet, ten times the size of the Earth, cold in its upper clouds, without a solid surface, and with an atmosphere as deep as that of an ocean, “the hexagonal wavy motion of the jet stream is expected to be propagated vertically and reveal to us aspects of the planet’s hidden atmosphere,” pointed out Agustín Sánchez-Lavega, Head of the Planetary Sciences research group. “The movement of the hexagon could therefore be linked to the depths of Saturn, and the rotation period of this structure, which, as we have been able to ascertain, is 10 hours, 39 minutes and 23 seconds, could be that of the planet itself,” he added. Saturn is the only planet in the Solar System whose rotation period is not yet known.

Is a natural rain of diamonds occurring on Jupiter and Saturn? Two scientists say yes!

Is a natural rain of diamonds occurring on Jupiter and Saturn? Two scientists say yes!

In their scenario, lightning zaps molecules of methane in the upper atmospheres of Saturn and Jupiter, liberating carbon atoms. These atoms then stick onto each other, forming larger particles of carbon soot, which the Cassini spacecraft may have spotted in dark storm clouds on Saturn3. As the soot particles slowly float down through ever-denser layers of gaseous and liquid hydrogen towards the planets’ rocky cores, they experience ever greater pressures and temperatures. The soot is compressed into graphite, and then into solid diamonds before reaching a temperature of about 8,000 °C, when the diamond melts, forming liquid diamond raindrops, they say. Inside Saturn, the conditions are right for diamond ‘hail’ to form, beginning at a depth of about 6,000 kilometres into the atmosphere and extending for another 30,000 km below that, says Baines. He estimates that Saturn may harbour about 10 million tonnes of diamond produced this way, with most of it made up of rocks no bigger than a millimetre and perhaps some chunks spanning 10 centimeters.

But don’t invest your money yet in a diamond gathering expedition. This is only a theory, which many scientists dispute.

Cassini has found hints of activity coming from the Saturn moon Dione.

Cassini has found hints of activity coming from the Saturn moon Dione.

The spacecraft’s magnetometer has detected a faint particle stream coming from the moon, and images showed evidence for a possible liquid or slushy layer under its rock-hard ice crust. Other Cassini images have also revealed ancient, inactive fractures at Dione similar to those seen at Enceladus that currently spray water ice and organic particles.

Scientists have released the first topo map of Titan.

Scientists have released the first topo map of Titan.

Whereas Earth’s tallest mountain towers nearly 9 kilometers above sea level, Titan’s topographic variations are mild: Its highest point is just half a kilometer above the mean and its lowest just 1.7 kilometers below.

Overall the detail here is not very great. None of the instruments on Cassini can see anything smaller than a half kilometer, about 1,500 feet, so the data doesn’t really show us the rough details. Moreover, the best data is spotty, as it has been accumulated by about a hundred Cassini fly-bys, rather than systematically by an orbiting spacecraft.

New data suggests that the icy crust of Titan is twice as thick as previously estimated.

New data suggests that the icy crust of Titan is twice as thick as previously estimated.

“The picture of Titan that we get has an icy, rocky core with a radius of a little over 2,000 kilometers, an ocean somewhere in the range of 225 to 300 kilometers thick and an ice layer that is 200 kilometers thick,” [said Howard Zebker of Stanford University]. Previous models of Titan’s structure estimated the icy crust to be approximately 100 kilometers thick.

This means that the methane lakes and rivers of Titan are flowing across a bedrock of ice, which at the cold temperatures there would be as solid as rock is here on Earth.

Data of the tidal fluxes on Titan by the Cassini spacecraft now suggest that there is a liquid ocean below Titan’s icy crust.

Data of the tidal fluxes on Titan by the Cassini spacecraft now suggest that there is a liquid ocean below Titan’s icy crust.

The team’s analyses suggest that the surface of the moon can rise and fall by up to 10 metres during each orbit, says Iess. That degree of warpage suggests that Titan’s interior is relatively deformable, the team reports today in Science1. Several models of the moon’s internal structure suggest such flexibility — including a model in which the moon is solid but soft and squishy throughout. But the researchers contend that the most likely model of Titan is one in which an icy shell dozens of kilometres thick floats atop a global ocean. The team’s findings, together with the results of previous studies, hint that Titan’s ocean may lie no more than 100 km below the moon’s surface.

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