We can interpret this amazing image of a forming solar system (HL Tauri, from the Alma array; ESO 2014).
Iron meteorites with #taenite and #kamacite domains forming a Widmanstätten pattern tell us that in systems like this or our own solar system:
–planetesimals had already formed and differentiated, while a heat source (decay of 26-Al) was still available.
–they were on the order of 100's of km in diameter, with enough rock to insulate the slowly-cooling core.
#MinCup25 Round 2 Match 7: It's high-pressure #kyanite against deep-space #taenite.
Vote: https://www.mineralcup.org/2025/vote/r2m07
Results: https://www.mineralcup.org/2025/results/r2m07
The solid-state diffusion of iron and nickel into #taenite and #kamacite domains forms the Widmanstätten pattern in iron meteorites. The growth of these domains has been calibrated with temperature.
The meteorite pictured (Tambo Quemado, Peru, type IIIB) suggests a cooling rate of 1.2 °C per million years; modelling suggests this occurred in a planetesimal ~ 200 km in radius (which was later disrupted and fragments of the core exposed to space) (Goldstein & Short, 1967).
#MinCup25 #Meteorite
#MinCup25 Round 1 Match 15 - It's a mineral found mostly in the farthest reaches of space vs one so common an exhaustive list of localities is nigh impossible as alloy #taenite faces off against clay #nontronite.
Vote: https://www.mineralcup.org/2025/vote/r1m15
Results: https://www.mineralcup.org/2025/results/r1m15
Hoba meteorite, the largest intact meteorite, weighing about 60 tons, that has been found on Earth. It was discovered in 1920 on a farm called Hoba West, located 19 km (12 miles) west of Grootfontein in northern Namibia. The Hoba meteorite dropped from the sky less than 80,000 years ago and has
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