The discovery of a rare meteorite, NWA 12774, in the Sahara Desert has revealed a lost moon-sized world from the dawn of the solar system. This ancient protoplanet, potentially as large as the moon or even Mars, once orbited the young Sun before a violent collision shattered it into pieces. The angrite meteorite, one of only 68 known in the world, has long puzzled scientists due to its unusual composition, lacking silicon dioxide, or silica, a key ingredient in terrestrial planets. However, a closer examination of NWA 12774 has provided groundbreaking insights.
Aaron Bell, an assistant research professor at the University of Colorado Boulder, and his team identified clinopyroxene, a mineral typically found in Earth's crust and mantle, with exceptionally high levels of aluminum. This discovery suggests the meteorite formed under intense pressure deep within a larger body, requiring at least 17.5 kilobars of pressure, far exceeding the pressure at the bottom of the Mariana Trench. Such extreme conditions could not have existed inside a small asteroid, indicating a much larger parent body.
The sharp edges and delicate chemical features of the crystals within NWA 12774 further support this interpretation. These details would have been erased over time if the crystals had formed deep inside a massive world, suggesting they formed relatively close to the surface of the parent body. The researchers estimate the original world may have exceeded 1,800 kilometers in radius, comparable to the Earth's moon and potentially approaching the scale of Mars.
This discovery challenges our understanding of planetary formation. The materials that formed the angrite parent body are fundamentally different from those of Earth and Mars, pointing to a distinct evolutionary path. The possibility that this ancient world was destroyed during a major collision in the early solar system and its fragments became part of other rocky planets, including Earth, raises intriguing questions about the diversity of planetary formation.
In my opinion, this finding highlights the importance of thorough scientific exploration. With many meteorites sitting in drawers waiting to be studied, there may be more protoplanets waiting to be discovered, offering further insights into the early history of our solar system. This discovery not only expands our knowledge of planetary formation but also serves as a reminder of the vast mysteries that still exist in our cosmic neighborhood.
