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Most small asteroids are just piles of rubble in space, held together by gravity and weak molecular forces. Even the slight touch of sunlight can cause them to break up. Now we know exactly how different-shaped asteroids crumble, which might help us if one ever heads straight for Earth.
Photons聽 carry a tiny amount of momentum, so when sunlight hits an asteroid it can send the space rock spinning, in what is known as the Yarkovsky鈥揙’Keefe鈥揜adzievskii鈥揚addack (YORP) effect.
鈥淭he magnitude of forces acting on these asteroids is like the weight of three grapes sitting on a mountain,鈥…
