Although the full moon is bright enough for many people to read by at night, the moon's surface is rather dark. Only about 7% of the light from the Sun is reflected off the moon's surface (the moon has an albedo of 7%). So the moon is really not very bright at all - it probably couldn't begin to answer this week's question. The Earth's surface is also rather dark, not only because like the moon, the Earth's crust consists generally of dark rocks such as basalt, but because vegetation and water absorb much more light than they reflect. However, the Earth reflects about five times as much light as does the moon. The reason why is that clouds in the Earth's atmosphere reflect upwards of 70% of the incoming sunlight. In addition, snow and ice also reflect about 70% of the Sun's visible light. The combination of the reflectances of the rocks, oceans, vegetation, snow, ice, and clouds gives an average albedo for the Earth of about 35%. Venus also has clouds. Since the atmosphere of Venus is about 100 times more dense than the Earth's, its thick carbon dioxide clouds reflect 71% of the Sun's light.

Like the moon, Venus has phases. When Venus is farthest from the Earth, it is in its full phase and our view of it is blocked by the Sun. When Venus is closest to the Earth, we are facing the side that is not illuminated by the Sun. This is just like the new moon phase. However, when Venus is slightly farther away, and not in front of the Sun from our perspective, it is very bright even though only a portion of its surface is illuminated (it is in the crescent phase). So, Venus is brightest in the early morning just before sunrise or in the early evening just after sunset. Try looking at Venus with binoculars to see if you can see its crescent phase.