Which of the following best explains why the Sun's luminosity gradually rises over billions of years?

A) Fusion gradually decreases the number of independent particles in the core, allowing gravity to compress and heat the core, which in turn increases the fusion rate and the Sun's luminosity.
B) Nuclear reactions in the Sun become more efficient with time, so that each fusion reaction releases more energy when the Sun is old than when it is young; this in turn raises the Sun's luminosity.
C) The Sun's core gradually expands with time, and this expansion means there is more room for energy to be generated and hence increases the Sun's luminosity.
D) The planets need more and more energy to maintain any life on them as time goes on, and therefore the Sun must bet hotter.


A

Physics & Space Science

You might also like to view...

Our current calendar is the______________ calendar

Fill in the blank(s) with correct word

Physics & Space Science

___________is the processing of an existing product into a material that can be used to make a new product.

Fill in the blank(s) with the appropriate word(s).

Physics & Space Science

What is the composition of the lunar regolith?

A. olivine and silicon dioxide B. silicon dioxide and anorthosite C. anorthosite and basalt D. basalt and olivine

Physics & Space Science

A string is attached to the ceiling. At the bottom of the string a rope of the same length as the string is attached. In the rope-string system, which of the following is the position of greatest tension? Assume the rope has more mass per unit length than the string

a. at the bottom of the rope b. at the top of the rope where it is attached to the string c. at the bottom of the string where it is attached to the rope d. at the top of the string

Physics & Space Science