O Louis Moinet Astralis é um cronógrafo de carga manual, de roda de colunas, com função rattrapante e turbilhão.O mostrador contem fragmentos de meteoritos de Marte. Caixa de 46,5 mm, em ouro rosa para a versão Marte. Os outros modelos do conjunto são Mercúrio (também em ouro rosa), Sol (em ouro branco) e Lua (em ouro branco e diamantes). Estanque até 50 metros. Os quatro modelos vêm num estojo representando um planeta, obra do artista Jean-Yves Kervévan. O conjunto de quatro vem em caixas forradas a pele, e que fazem um conjunto entre si.
Até hoje, apenas 63 meteoritos encontrados na Terra foram identificados como sendo provenientes de Marte. A Louis Moinet tem uma colaboração exclusiva com Luc Labenne, o mais conhecido dos caçadores de meteoritos.
Entrevista com Luc Labenne
The distance between Mars and Earth is over 50 million kilometres. What is the path of a Martian meteorite before landing on Earth?
A Martian meteorite is a fragment of Mars ejected after impact from another a meteorite impact. To assess the age of the Martian rock, we first talk about the “formation age” on Mars. The impacts on the surface allows us to determine the “age of ejection” of the meteorite. The length of time between the rock leaving Mars and reaching Earth can vary from about 1 million years to 20 million years. The last bit of useful data is the “terrestrial age” of the meteorite ground, that is, the length of time it has been on Earth. These three dates allow us to obtain relatively precise information on the origin of the meteorite as well as the path it has taken before landing on Earth.
How can we be sure that a meteorite has come from Mars?
A first sample is taken and then sent to universities and scientists such as A. Irving (University of Washington, Departement of Earth and Space Sciences, Seattle, USA), an expert in Martian meteorites or R. Korotev (McDonnell Center for Space Sciences, Washington Univ., St. Louis, USA), an authority on lunar meteorites. When identifying a Martian meteorite, the first thing is to establish its composition. Analysis of gases contained in the bubbles of the minerals can be compared with the results of analyses gathered by probes from NASA’s pioneering Viking program to confirm the Martian origin of meteorites. This is the main thing we have to do. Identification is then confirmed by the oxygen isotopes of these analyses. Finally, the control of the «formation age» of the rock enables the final confirmation. In fact, Martian meteorites are relatively young, about a few hundred million years old compared to 4.5 billion years for non-planetary meteorites. To date, 63 Martian meteorites have officially been found on Earth. Most have been dedicated to science or exhibited in museums.
What is the importance of having Martian or lunar meteorites, from a scientific point of view?
For the Moon, for example, we have samples from the Apollo missions, but these relate only to the visible face of the Moon – for communication reasons (no radio signals), the mission was not able to explore the hidden side. There is therefore interest in whether the lunar meteorites originated from the visible or hidden side. After analysis, the moon rocks I have found on Earth were a lot different to those brought back by the Apollo mission, and this has given us other information about the composition of the lunar soil. In general, meteorites allow us a better understanding of the origins and formation of planets. It’s the same importance for Martian meteorites, to find out about their formation, but also to figure out if Mars could ever have supported life and/or has traces of water. Currently, no sample of rock has been brought back from Mars. Future missions are still on the drawing board for complexity and financial reasons. Curiosity is performing analyses but not bringing samples back. Martian meteorites can therefore make up for this by providing these samples. Until now, the Martian meteorites are essentially basalt (chunks of lava). Scientists hope to find sedimentary meteorites to obtain more information and perhaps prove the existence of life on Mars. This is also the reason why Curiosity landed in a crater: It’s a good place to find and analyse these sedimentary rocks.
Is the composition of a Martian meteorite very different from a terrestrial rock?
As previously stated, Martian meteorites found so far are mainly lava rocks so visually close to terrestrial basalt rocks. However, shock veins can be observed in meteorites, which do not exist in terrestrial rocks and this allows early identification in the field. But the main difference lies in the fact that the minerals in these rocks are partially melted due to the impact on Mars. Bubbles of gas specific to Mars are also present in these meteorites.
The meteorites that you find – for whom are they intended?
Primarily for scientists, then private collectors and museums. For lunar and Martian meteorites, most are intended for science due to their limited number, priority is given to research.
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