Everything in space is moving constantly, and distances are variable and dynamic over wide ranges. Data are rounded to a maximum of 3 significant figures. In most cases, we have given average distances for simplicity's sake. For planets, we have given minimum distances - the closest the planets come to Earth over the course of their orbits. Other distances (termination shock, heliopause) are uncertain and estimates are given. Some distances, particularly the location of probes and other man-made spacecraft, are based on time-specific readings taken in February 2014. Travel times are based on travelling in a straight line - spacecraft rarely do this in practice. Asteroid and comet measurements are diameters. Distances are from Earth’s surface. Object sizes are not to scale.