New Horizons' flyby of Arrokoth revealed it to be a contact binary formed by _______.
- Collisional fragmentation
- Gentle accretion in primordial disk
- Tidal disruption
- Volcanic resurfacing
Answer: Gentle accretion in primordial disk
Arrokoth's bilobate shape with aligned lobes indicates low-speed merger of two planetesimals in cold classical Kuiper Belt, preserving early solar system conditions.