Light elements like hydrogen and helium form a large percentage of the outer planets and Sun is made up primarily of hydrogen. Why are these elements nearly absent from the inner planets?
A) It is a mystery that has never been solved by science.
B) Hydrogen and helium have all been bound up by chemical reactions on the inner planets and are held in rock.
C) The Sun captured all of the hydrogen during its formation.
D) These light elements are blown away from the inner planets by the solar wind.

Question

Quizplus · Accepted Answer

The solar wind blows hydrogen and helium away from the inner planets, making these elements nearly absent from them. This is why the outer planets, which are farther from the Sun, have a higher concentration of these light elements.

Light Elements Like Hydrogen and Helium Form a Large Percentage