What are 1,000,000,000 km?
The distance of 1,000,000,000 km may be compared with the size of our solar system. The earth orbits the sun at a distance of 149,600,000 km (= 1AE). The most outer planet, Pluto, orbits the sun at a distance of 40 AE. The satelite Voyager is, at present (Sept. 1998) at a distance of 72 AE from the earth. The Voyager started its journey in 1977 and, hence, took 21 years to reach this point. A common commercial aircraft would take 1230 years of non-stop flying to reach this point.