Mystery of Titan's moving 'island': Giant mass 58 THOUSAND football fields in size rises and sinks on Saturn's moon

Home »Mystery of Titan's moving 'island': Giant mass 58 THOUSAND football fields in size rises and sinks on Saturn's moon

Mystery of Titan's moving 'island': Giant mass 58 THOUSAND football fields in size rises and sinks on Saturn's moon

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Astronomers have been left baffled by the rise and subsequent fall of a huge feature in a sea on Saturn's moon Titan.

In July 2012 a giant feature 100 square miles (260 square kilometres) in area - roughly the area of 58,000 football fields - is seen surfacing from under the liquid before partially disappearing again.

No definitive explanation is yet apparent but it could be a surface wave, rising bubbles or even a solid object just below the surface.

In this series of images from the Cassini spacecraft the giant object 100 square miles (260 square kilometres) in size is seen rising out of one of Titan's largest seas before disappearing again. In the latest image on the right the object still seems to be partially submerged beneath the surface

The feature was spotted by Nasa's Cassini spacecraft, which is currently in orbit around the Saturnian system.

It was spotted in Ligeia Mare, one of the largest seas on Titan, and was observed by Cassini's radar experiment.

In images from 10 July 2012 to 21 August 2014 the feature is shown rising and then falling below the surface.

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TITAN: SATURN'S LARGEST MOON

With its thick atmosphere and organic-rich chemistry, Titan resembles a frozen version of Earth several billion years ago, before life began pumping oxygen into our atmosphere.

Because Titan is smaller than Earth, its gravity doesn't hold onto its gaseous envelope as tightly, so the atmosphere extends 370 miles (595 kilometres) into space.

As on Earth, the climate is driven mostly by changes in the amount of sunlight that comes with the seasons, although the seasons on Titan are about seven Earth years long.

Titan's 'water' is liquid methane, CH4, better known on Earth as natural gas. Regular Earth-water, H2O, would be frozen solid on Titan where the surface temperature is -180°C (-292°F).

With Titan's low gravity and dense atmosphere, methane raindrops could grow twice as large as Earth's raindrops. As well as this, they would fall more slowly, drifting down like snowflakes.

But scientists think it rains perhaps only every few decades.

A comparison image from 26 April 2007 shows how no similar feature was previously spotted in that region.

The mysterious feature appears bright in the radar images, suggesting it has a somewhat similar composition to the land nearby in the image.

This supports one theory that it may be a solid structure - potentially an island - that surfaced from under the liquid before sinking again for an unknown reason.

The dark area in the image is the liquid hydrocarbon sea on Titan's surface, while the bright area is land.

Scientists on the radar team are confident that the feature is not an artifact - or flaw - in their data.

They have also ruled out the possibility of it being due to evaporation, as the nearby shoreline has not changed much.

Several theories currently exist including surface waves, rising bubbles, floating solids, solids suspended just below the surface or 'something more exotic' according to Nasa.

When asked for further comment by MailOnline the agency was yet to respond.

A comparison image from 26 April 2007 (left) shows how no similar feature was previously spotted in that region. The feature was spotted by Nasa's Cassini spacecraft, which is currently in orbit around the Saturnian system. On the right is an image of Titan in orbit around Saturn

The feature was spotted in Ligeia Mare (shown), one of the largest seas on Titan, and was observed by Cassini's radar experiment. Several theories currently exist including surface waves, rising bubbles, floating solids, solids suspended just below the surface or 'something more exotic' according to Nasa

The appearance of the feature may also be due to changing seasons on Titan, with summer drawing near in the moon's northern hemisphere.

Monitoring these changes is a major goal of Cassini's current extended mission.

'Science loves a mystery, and with this enigmatic feature, we have a thrilling example of ongoing change on Titan,' said Dr Stephen Wall, the deputy team lead of Cassini's radar team, based at Nasa's Jet Propulsion Laboratory in Pasadena, California.

'We're hopeful that we'll be able to continue watching the changes unfold and gain insights about what's going on in that alien sea.'

TECTONIC ACTIVITY SPOTTED ON JUPITER'S MOON EUROPA

It's not just Titan that is thought to have an active surface; earlier this month scientists found the first sign of geologic activity on a solar system world other than Earth - Europa.

Experts from the University of Idaho and the Johns Hopkins University, Maryland, say Europa could be more Earth-like than experts imagined.

The latest find appears to solve a puzzle that has perplexed planetary scientists. It shows where old crust was destroyed and how the icy crust is expanding.

Many parts of Europa's surface show evidence of extension, where wide bands - up to tens of miles wide - formed as the surface ripped apart, and fresh icy material from the underlying shell moved into the newly created gap, a process akin to terrestrial seafloor spreading, according to the study published in the journal Nature Geoscience.

Europa's surface is considered to be relatively young at between 40 and 90 millions of years old, which can perhaps now be explained by plate tectonics.

It has been a decade since Cassini entered orbit around Saturn (illustration shown). In June the Cassini mission celebrated 10 years of exploring the planet, its rings and moons. It arrived for a four-year mission but has since been continuously extended, although it will almost certainly end in 2017

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