A meteorite recovered from the Saara desert offers the first definitive evidence of a lost world that existed in the early solar system. The fragment, known as NWA 12774, came from a planetary body that may have rivaled Lua in size. Pesquisadores of Universidade of Colorado on Boulder analyzed the rock and published the results this week.
The finding changes conceptions about the formation of rocky planets shortly after the emergence of Sol, 4.5 billion years ago. Cientistas classify the material as angrite, a rare type of volcanic rock among the oldest in the solar system.
Composição chemistry challenges previous assumptions
The NWA 12774 meteorite weighs about 454 grams and was found in 2019. Diferente of Terra and Marte, it contains little silica, the main component of sand and planetary crusts. Isso led experts to imagine, for decades, that angrites came from small asteroids.
Recent Análises changed this picture. Cristais of clinopyroxene inside the rock revealed high aluminum content. Tal composition only forms under extreme pressures. The researchers calculated minimum pressures of 17.5 kilobars. Isso exceeds the bottom pressure of Fossa and Marianas by 17 times.
- Pressure indicates formation at significant depths of a large body.
- Cristais preserve sharp edges and chemical patterns that would not withstand long periods in a planet’s hot interior.
- The parent body would need to have a radius greater than 1,800 kilometers to generate such conditions near the surface.
Esses details suggest a protoplanet substantially larger than an average asteroid.
Meteorito preserves traces of distinct evolutionary path
Aaron Bell, geoscientist at Universidade at Colorado at Boulder and lead author of the study, highlighted key differences. The materials that formed the parent body of angrite differ from the ingredients of Terra and Marte. Essa distinction points to a separate evolutionary trajectory in the first million years of the solar system.
Angritas are scarce. Of the more than 80,000 meteorites cataloged in Terra, only 68 belong to this class. Elas originated alongside the young Sol and serve as natural clocks because of radioactive elements. NWA 12774 formed more than 4.5 billion years ago.
The aluminum-rich mineral clinopyroxene worked as a pressure marker. Reconstruções indicate that the original body measured at least the size of Lua and could approach Marte in scale. Fragmentos like it survived violent collisions that shaped the young solar system.
Protoplanet’s Destino remains unclear
What happened to this ancient world is unclear. One hypothesis considers that it disintegrated in one of the frequent collisions of the time. Partes of the material would have been incorporated into other rocky bodies, including Terra.
Cientistas observe that meteorites stored in collections may hide more evidence of forgotten protoplanets. Estudos details of existing samples still yield surprises. NWA 12774 demonstrates how a single fragment reveals lost chapters of planetary history.
The research was published in the journal Earth and Planetary Science Letters. Equipes continues to scan other angritas for similar patterns.
Implicações for Understanding Planetary Formation
The finding reinforces that the early solar system was more dynamic and diverse than previously assumed. Diferentes bodies developed unique paths before collisions and accretions defined today’s planets. Dados from the meteorite helps refine models of planetary evolution.
Pesquisadores plan additional isotopic composition analyses. Resultados may clarify interactions between the protoplanet and other bodies. The material also provides opportunities to study high-pressure conditions inaccessible in terrestrial laboratories.
Especialistas emphasize the importance of preserving and analyzing rare meteorites. Cada sample carries information about processes that occurred billions of years ago. NWA 12774 turns a piece of rock from Saara into a window onto a vanished world.