If We Had No Moon

The Earth has a large moon, making it unique in the inner solar system. Mercury and Venus have no moons, and Mars has only two small asteroid-sized objects orbiting it. In this essay, the father of the SMART-1 lunar mission, Bernard Foing of the European Space Agency, looks at the effect the Moon has had [...]

Four Terrifying Theories in Astronomy

Galileo may have been threatened with the rack during the Inquisition almost 400 years ago, but—relatively speaking—that was hardly terrifying. Whether the Earth went around the Sun (as Copernicus, Galileo and Newton thought) or vice versa (in the old model of Ptolemy or Aristotle), Galileo’s Universe was still a placid place. But these days, astronomers [...]