Accelerate progress in our three core enterprises — Explore Worlds, Find Life, and Defend Earth. You can support the entire fund, or designate a core enterprise of your choice.
Mercury "spider" Almost at the center of the gigantic Caloris basin on Mercury is this 40-kilometer (25-mile) impact crater, witting on top of a radiating spray of troughs. Are the troughs related to the crater? Or did the crater happen to form by a "bull's-eye" impact on the center of these radial fractures? NASA / JHUAPL / CIW