Has the mystery of the 'alien' marks on Ceres been solved? Bright spots on the dwarf planet's surface may be WATER ICE

A series of strange 'alien' marks on the surface of the dwarf planet Ceres have intrigued scientists since they were first spotted earlier this year.

But now experts think the mysterious bright spots on the distant world may be water ice.

They believe one crater in particular contains evidence for frozen water, which creates a hazy cloud of ice or dust particles.

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Scientists believe they have solved the mystery of Cere's 'alien' bright spots (pictured), claiming they may be ice. This image of the Occator crater in false colours shows the differences in the surface composition

Ceres is the largest object in the asteroid belt, which lies between the orbits of Mars and Jupiter.

It measures approximately 590 miles (950km) in diameter, making it the largest of the minor planets within the orbit of Neptune and a fascinating world for scientists to investigate.

Water vapour has previously been found close to Ceres, raising interest in the dwarf planet's composition and life cycle. 

Water vapour has previously been found close to Ceres, raising interest in this dwarf planet's composition and life cycle. A The Occator crater is shown in 3D, including several bright spots

The images were taken with the aid of the camera system aboard Nasa’s Dawn space probe (illustrated) from a distance of 2,750 miles (4,425km)

Andreas Nathues led a team at the Max Planck Institute for Solar System Research in Goettingen, Germany, which used data obtained from the Framing Camera on board the Dawn spacecraft to make detailed observations of the surface of Ceres.

They discovered that although the surface of the dwarf planet is black like asphalt, more than 130 bright spots can be seen.

These spots range in brightness from that of concrete to the levels of light reflected from 'ocean ice' and are mostly associated with impact craters, according to the study, published in Nature.

Spectral measurements suggest that these bright areas are likely to be composed of hydrated magnesium sulphates - an inorganic salt containing magnesium, sulphur and oxygen, which is an ingredient in Epsom salt on Earth- although other compositions are also possible.

Examining the floor of the crater Occator, which is about 56 miles (90km) wide and two-and-a-half miles (4km deep) they found it contains a central pit covered by bright material.

They discovered that although the surface of the dwarf planet is black like asphalt, more than 130 bright spots can be seen. Mosaic of the surface is shown above. The Occator crater is shown top left, Oxo crater, top right and bottom, a typical crater without signs of ice

This material displays evidence for water-ice sublimation - when a material changes from a solid to a gas - resulting in haze clouds, which are probably made up of ice or dust particles and originate from inside the crater.

The experts note they appear during the day and disappear at night.

The results imply that Ceres is the first known large body in the main asteroid belt to 'display comet-like sublimation activity - or creating jets of icy particles.

It marks a U-turn, since scientists said in April, the spots were likely not ice.

The Dawn spacecraft is currently making a seven-week long dive towards Ceres, where it will orbit 235 miles (380km) above the surface - the closest it has yet been to the dwarf planet.

Experts have previously said the bright spots could be ice, salt deposits, volcanic flows or geysers.

WHERE DID CERES COME FROM? MINERAL SUGGEST OUTER SOLAR SYSTEM 

The dwarf planet may have formed in the outer Solar System, based upon the identification of specific minerals on the surface of Ceres.

Recently, water vapour was reported around Ceres and although measurements obtained from telescope data indicate several minerals exist on the dwarf planet’s surface, they could not be identified until now.

In this artistic impression, two different hypotheses regarding the formation of Ceres are presented: In the first image, Ceres formed in the main belt and ammonia was incorporated from the external zones of the Solar System. In the second, Ceres itself was formed in the external zones of the Solar System, including ammonia in its formation process, and then migrated to the main belt

Maria Cristina De Sanctis and colleagues from Osservatorio Astronomico di Roma (INAF) in Rome detected ammoniated phyllosilicates - sheet silicate minerals - on the dwarf planet, according to the study in Nature.

The results suggest that ammonia, incorporated into the planet either as organic matter or as ice, may have reacted with Ceres’ clays during its formation.

Ammonia ice is stable only at the cold temperatures of the outer Solar System, suggesting that either Ceres formed there before reaching the main asteroid belt, or that pebble-sized objects were transported from that region and incorporated into the main asteroid belt. 

When sunlight reaches the Occator crater, a kind of haze of dust and evaporating water forms there. This haze can only be discovered by looking at it laterally, as has been done here

One theory says the spots are salt flats that are reflecting sunlight, left on the surface by saltwater or by other chemical reactions, while another possibility is that they are cryovolcanoes - volcanoes that are shooting out water or ice.

The Dawn spacecraft has spent almost eight years travelling to Ceres after being launched in 2007.

In September, a stunning 3D flyover of Ceres revealed the dwarf planet's mysterious bright spots in the most detail to date.

It also highlighted a prominent mountain with bright streaks on its steep slopes. The peak's shape has been likened to a cone or a pyramid, and it appears to be about four miles (6km) high.

This means the mountain has about the same elevation as Mount McKinley in Denali National Park, Alaska, the highest point in North America.