Headline, July 15 2022/ ''' '' MERCURY SHARDS MYSTERY '' '''


 MYSTERY '' '''


SHARDS OF MERCURY MAY BE SCATTERED ON EARTH. Mercury does not make sense. It is a bizarre hunk of rock, with a composition unlike that of its neighboring rocky planets.

''It's way too dense,'' said David Rothery, a planetary scientist at the Open University in England. Mercury's core is in fact most of the planet, and the part closest to the sun.

It lacks a thick mantle, like Earth's, around the core, and no one is quite sure why. One possibility is that the planet used to be much bigger - perhaps more than twice its current bulk. 

Billions of years ago, this fledgling proto-Mercury, or super Mercury, might have been hit by a large object that stripped away its outer layers and left the remnant we now see.

Previously, there was no direct evidence for that theory. But some researchers think they have found something. In work, presented at the Lunar and Planetary Science Conference in Houston in March, Camille Cartier, a planetary scientist at the University of Lorraine in France, and her colleagues said pieces of this proto-Mercury may be hiding in museums and other meteorite collections. Studying them could unlock the planet's mysteries.

According to the Meteoritical Society, nearly 70,000 meteorites have been gathered around the world from places as remote as the Sahara and Antarctica, finding their way into museums and other collections.

Most are from asteroids ejected from the belt between Mars and Jupiter, while more than 500 have been traced to the moon. More than 300 are from Mars.

Noticeably absent from these documentations are confirmed meteorites from our solar system's innermost planets, Venus and Mercury. It is typically hypothesized that it would be difficult, although not impossible, for detritus originating closer to the sun and caught in its gravity to make their way farther out into the solar system.

But a small number of meteorites collections contain a rare type of space rock called aubrites. Named after the village Aubres in France, where the first meteorite of this type was found in 1836, aubrites are pale in colour and contain small amounts of metal.

They are low in oxygen and seem to have formed in an ocean of magma. About 80 aubrite meteorites have been found on Earth.

Their composition seems to match scientific models of conditions on the planet Mercury in earlier days of the solar system. ''We have often said that aubrites are very good analogues for Mercury,'' Dr. Cartier said.

But scientists have stopped short of saying that they are actually pieces of Mercury, Klaus Keil, a scientist at the University of Hawaii at Manoa who died in February, argued that in 2010 that aubrites were more likely to have originated from other kind of asteroids than from something ejected from Mercury; some scientists have favored a group of asteroids called E-type asteroids in the belt beyond Mars.

Dr. Cartier, however, has another idea. What if aubrites originally came from Mercury?

Extending the hypothesis that a sizable object collided with a younger Mercury, Dr. Cartier said a large amount of material would have been thrown into space - about a third of planet's mass. A small amount of that debris would have been pushed by the solar wind into what is now the asteroid belt, forming the E-type asteroids.

There, the asteroids would have remained for billions of years. But eventually, she suggested some pieces were pushed toward Earth and fell to our planet as aubrite meteorites.

Low levels of nickel and cobalt found in aubrite match what we would expect from the proto-Mercury, Dr. Cartier said, and data from the NASA Messenger spacecraft, which orbited Mercury from 2011 to 2015, supports similarities between Mercury's composition and that of aubrites.

''I think aubrites are the shallowest portions of the mantle of a large proto-Mercury,'' Dr. Cartier said. ''This could resolve the origin of Mercury.''

The Honour and Serving of the Latest Global Operational Research and Publishing on Planetary Systems, continues. The World Students Society thanks author Jonathan O'Callaghan.

With respectful dedication to the Planetary Scientists and Researchers of the Universe, and then Students, Professors and Teachers of the world. See Ya all prepare and register for Great Global Elections on The World Students Society - for every subject in the world : wssciw.blogspot.com and Twitter - !E-WOW! - The Ecosystem 2011 :

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