Tree-like channel networks resemble drainage networks, suggesting water was once at or near the surface. There are some impact craters, but far fewer than the Moon, Mercury, or even Mars. Vast dark portions of the radar images indicate smooth plains, likely lava. Distinct lava flows are visible, as are many volcanoes. Bright fault lines crisscross the surface.
Some roundish features appear to have both volcanic and deformation characteristics.
Some large regions are intensely deformed. These are often high-standing, and so are reminiscent of mountain ranges on Earth. Earth Earth is strikingly different from its cousins. The presence of water in the atmosphere, oceans, lakes, rivers, and glaciers dominates the appearance of our planet. Weathering and erosion due to the presence of water quickly wear down landforms.