What Processes Shape Planetary Surfaces?
ES2708  Laboratory Earth

The processes that shape planetary surfaces occur either very slowly, requiring long periods of observation, or very infrequently, meaning that you have to be looking at the right time and place to see them happen at all.

Ideally, we'd like to be able to observe planetary surfaces continuously over long periods of time and in a reasonable amount of detail. Assuming we could do it safely, it would also be great to send scientists to study other planets, but the cost would be truly astronomical! A more affordable approach is to send robotic spacecraft to study the planets and send data back to Earthbound scientists for analysis.

Earth—a living laboratory

  !   Click the image of Earth to see a list of all the solar system exploration missions to date. As you scroll down the list, notice when the first successful mission to each planet occurred.

1. What was the first mission to explore a planet other than Earth or the moon? When did this occur, and which planet did it visit?

Much of the information we receive from space probes is indirect. Scientists must make inferences—educated guesses—about surface processes based on the limited information available. Fortunately, we can safely and economically study one planet in detail—Earth. By understanding the processes that shape our planet, scientists can make better inferences about the processes at work on other planets.

2. How can a surface feature tell you about a surface process? Give an example.

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