PTE Reading

Multiple Choice, Single Answer

PTE · Multiple Choice, Single Answer

Read the passage and answer the question.

When you stand in warm afternoon sunlight, the light reaching your skin may seem instant, but its story is far older. Energy released by nuclear reactions deep in the Sun's core does not fly straight out. The core is so dense that each particle of light travels only a tiny distance before colliding with surrounding matter and changing direction. Through countless such collisions, energy zigzags slowly outward, taking on average tens of thousands of years to reach the Sun's surface. Once it finally escapes into open space, however, that light crosses the great distance to Earth in only about eight minutes.

Why does energy take so long to move from the Sun's core to its surface?

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