Science Why does a gravitational lens sometimes create an Einstein Cross with four images and sometimes a circle?
Robotic Spaceflight, Science, Solar System How will the landings, takeoffs, and investigative explosions from the OSIRIS-REx and Hayabusa2 spacecraft alter the orbital paths of asteroids Bennu and Ryugu? Can these effects be equated to a duration of sunlight falling on each asteroid?
Science If our Sun is a typical star, and if most stars are surrounded by Oort clouds, why do these clouds not obscure our view of other stars?
Science Is the Moon’s rotation rate still slowing down? If so, will there come a time when the currently unseen 41 percent will be visible from Earth?
