Question

How does nuclear fusion change over time as the sun ages?

A) The rate of nuclear fusion increases as the sun ages.
B) The rate of nuclear fusion decreases as the sun ages.
C) The type of nuclear fusion reactions occurring in the sun changes as it ages.
D) The sun's nuclear fusion remains constant throughout its lifespan.
E) The sun's nuclear fusion gradually stops as it ages.

Answer 1

The rate of nuclear fusion in the Sun increases over time as the temperature and density in its core rise, leading to more frequent proton interactions and more energy production.

Step-by-step explanation:

As the Sun ages, the rate of nuclear fusion it undergoes undergoes changes due to various factors. In the Sun's core, hydrogen nuclei (¹H) are fused into helium (⁴He), releasing significant amounts of energy through the proton-proton cycle. Over time, as helium accumulates in the center of the star, the density and temperature of the inner region slowly increase. This rise in temperature and density causes each proton to acquire more motion energy on average, making it more likely to interact with other protons, thus increasing the rate of fusion. Therefore, the rate of fusion in the Sun increases as it ages, with the rate going up roughly as the temperature to the fourth power.