Swirling spirals at the north pole of Mars

February 3, 2017
Perspective view of Mars north polar ice cap. Credit: ESA/DLR/FU Berlin; NASA MGS MOLA Science Team

A new mosaic from ESA's Mars Express shows off the Red Planet's north polar ice cap and its distinctive dark spiralling troughs.

The mosaic was generated from 32 individual orbit 'strips' captured between 2004 and 2010, and covers an area of around a million square kilometres.

The ice cap is a permanent fixture, but in the winter season – as it is now in early 2017 – temperatures are cold enough for around 30 percent of the carbon dioxide in the planet's atmosphere to precipitate onto the cap, adding a seasonal layer up to a metre thick.

During the warmer summer months most of the ice turns directly into gas and escapes into the atmosphere, leaving behind the water-ice layers.

Strong winds are thought to have played an important role in shaping the ice cap over time, blowing from the elevated centre towards its lower edges and twisted by the same Coriolis force that causes hurricanes to spiral on Earth.

One particularly prominent feature is a 500 km-long, 2 km-deep trench that almost cuts the cap in two.

The plunging canyon, known as Chasma Boreale, is thought to be a relatively old feature, forming before the ice–dust spiral features, and seemingly growing deeper as new ice deposits built up around it.

Mars north polar ice cap in context. Credit: NASA MGS MOLA Science Team

Subsurface investigations by radar instruments onboard Mars Express and NASA's Mars Reconnaissance Orbiter revealed that the ice cap is made up of many individual layers of ice and dust extending to a depth of around 2 km.

This presents a valuable record for the nature of how the planet's climate has changed as its tilt and orbit varied over hundreds of thousands of years.

Colour mosaic of Mars north polar ice cap. Credit: European Space Agency

Perspective view of Chasma Boreale. Credit: ESA/DLR/FU Berlin; NASA MGS MOLA Science Team

Explore further: Image: Frost build-up near Mars north pole

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Slaterdom
not rated yet Feb 10, 2017
These swirls are made directly from the centripetal vortex made by the magnetics north pole, the vortex runs clockwise, we see a similar effect on the north of saturn, but here it is seen in the geology. the shape compresses matter into a hexagon, but in geology its harder to see. its all magnetism, same for every plan et or moon, we see similar features based on the magnetic vortex of the north pole..... or south pole
jonesdave
5 / 5 (3) Feb 10, 2017
These swirls are made directly from the centripetal vortex made by the magnetics north pole, the vortex runs clockwise, we see a similar effect on the north of saturn, but here it is seen in the geology. the shape compresses matter into a hexagon, but in geology its harder to see. its all magnetism, same for every plan et or moon, we see similar features based on the magnetic vortex of the north pole..... or south pole


Except that Mars doesn't have an intrinsic magnetic field! You'll only find one, as at Venus and at comets, above the atmosphere, as the interplanetary magnetic field, carried by the solar wind, piles up against the atmosphere, and drapes around the planet. It won't affect anything at the surface.

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