How Big Is the Sun's Core and How Much Hydrogen

Q5: Define apparent brightness and absolute brightness.

Q6: What is first-generation energy?

Q7: A cloud of interstellar gas and dust

Q8: The Sun is composed primarily of hydrogen

Q9: A _ is a large volume of

Q11: Within a star, gravity pulls particles inward,

Q12: The process of absorption, emission, and convection

Q13: Describe sunspots.

Q14: _ are comparatively cool, dark regions on

Q15: The _ brightness of a star decreases