Major craters and other features of the moon that I would like you to learn are Mare Imbrium, Serenetatis and Crisium, and craters: (from young to old) Tycho (500 million years), Copernicus (1.1 billion years), Eratosthenes (3.2 billion years), and Archimedes and Plato. The latter two were form between the Imbrium impact (3.85 billion years) and the subsequent flooding of basins that continued until 3.2 billion years. Their floors are flooded; others such as ghost craters were almost entire inundated by the basalt.
Eratosthenes is clearly older than Copernicus because all its rays have faded. Tycho is the youngest large crater judging form its extensive ray system. The rays are bright because of "gardening" of soil by a swarm of small projectiles ejected at the time of impact; dirt has been turned over and is therefore brighter but with time the fresh dirt also darkens due to sunlight.
The superposition of features can be used to date them relative to one another: from the oldest to the youngest:
Volcanic eruptions have injected sulfur and fluorine into the atmosphere which has combined with carbon, hydrogen, and oxygen to produce some of the most corrosive liquids known by chemists. Suspended in its atmosphere at a height of 50 km are droplets of sulfuric, hydrochloric( HCl) hydrofloric (HF) and fluorosulfuric acids. The latter, especially, dissolves lead, tin, and most rocks. Below the layer of acid droplets it is a clear, hot, and dense atmosphere.
The greenhouse effect is produced by a layer of gas (the so-called green house gasses that are carbin dioxide, water vapor, and methane) that is transparent to visible light and opaque to infrared light. Ordinary glass has the same properties, hence cars heat up during the summer when light enters through their windshields. Energy enters as visible light, but is trapped when it is transformed to infrared light.
We hope such is not the fate of the earth as we pour more and more carbon dioxide into our atmosphere. Venus, bright and beautiful from a distance, shines brilliantly in the sky as a dreadful warning to us about misusing our planet.
The surface of the planet is dominated by volcanic features. There are very few impact craters, although many must have been formed in the past during times of intense bombardment. Their evidence must have been erased by volcanic activity. There are no impact craters smaller than 10 km on Venus; meteorites that would have produced them would have been burned up in passing through its thick atmosphere.
The remaining 15% of the surface area of Venus is composes of highlands, such as Ishtar Terra and Aphrodite Terra. Ishtar contains the hightest mountain on Venus, Maxell Mons which rises some 12 km above the lowland plains. Ishtar also contains Lakshmi planum, Cleopatra, Sacajawewa, and Colette.
Our knowledge of Venus comes from radar mapping by Pioneer in 1979 and Magellan in 1990-3. The first glimpses we had of its surface were from the Soview Venera space craft which landed on its surface in 1983-84, and functioned only briefly before being destroyed.