... Readily produced in nuclear reactions and particle collisions, they can easily pass completely through planet Earth without once interacting with any other particle. ... Recent photographs by the spacecraft Mars Global Surveyor, currently in orbit around Mars, show features unusual for Mars yet similar to a dried pond on Earth. ... The quake was the first ever recorded on the Sun, but only because astronomers have only recently figured out when and how to find them using the orbiting SOHO spacecraft...