Magellan 's Synthetic Aperture Radar allows the spacecraft to photograph details as small as 120 meters across. Magellan 's computers can take in 36 million bits of data each second. In fact, the spacecraft has already sent back more data on Venus alone than had been acquired in total from all previous space missions, to all of the planets. Unlike Earth, Venus' heavy atmosphere and lack of liquid water or ice keep the planet's surface from eroding substantially. Unique kinds of impact craters Magellan has sent back beautiful images of impact craters on Venus, formed when large meteors plummeted through the planet's atmosphere and struck the ground.
Smaller meteors burn up completely in the thick Venusian air.
The collision utterly vaporizes the incoming object and the surrounding ground. Surface material is blasted out, forming a crater, and lava trapped miles below the ground can be released. On Venus, the atmosphere is so thick that the material thrown out by the impact doesn't fly very far, but the surface temperature is so hot that it stays molten, and oozes away from the crater. Thus the craters on Venus look different from those on any other planet. One way to tell the age of Venus' surface is to count the number of impact craters.