>Today: SPHEREx analysis of 3I/ATLAS likely places diameter at 28.6mi instead of 7mi
>t. Avi Loeb
A 28.6mi 50/50 ice water/silicate object sublimated from 2.5au to 0.8au produces 300,000 0.25mi fragments. ~0.1% to 1% of objects are likely to strike, so 300 to 3,000 fragments.
At a velocity of 66km/s when passing within a MOID < 0.015au, each object has a force of ~26,627 megatons TNT. 8m to 80m megaton TNT impact likely. Affected zone leaves 300 to 3,000 14 to 20 km wide craters spread across 7% to 70% of Mars. Planet-wide bombardment possible with a scarred area of 150,000 km2 to 3,000,000 km2. Secondary craters likely affecting 100% of Mars Surface, ejecta rays visible by amateur astronomers, regolith churning.
Potential permanent thickening of atmosphere by 10%. Sunlight reduction could reduce temperatures by 5 to 50 degrees celcius. Paradoxically, the impact heat could trigger a greenhouse effect, leading to transient lakes and hydrothermal systems.
>This event has never been detected in the history of the Solar system. The closest "analogy" known is Shoemaker-Levy 9, but scaled up x270 more energetic with a x143 affected zone.