Light from the sun -> sharp shadows. Light from Earth -> blurry shadows. That's because the sun is almost a 'point' light source because it's far away, and Ear

Light from the sun -> sharp shadows. Light from Earth -> blurry shadows. That's because the sun is almost a 'point' light source because it's far away, and Earth is 'area' light source because it's close by. Also it depends how far the shadow source is from the shadow target.