Author Question: How many moons is Pluto known to have? A) none B) three C) one D) four E) ... (Read 59 times)

shenderson6 · **on:** Jul 27, 2018

How many moons is Pluto known to have?

A) none B) three C) one D) four E) two

Question 2

Why does conversion of its core to iron have to mark the end of a star's life? Which stars can end up with iron cores?

What will be an ideal response?

phuda · **Reply #1 on:** Jul 27, 2018

Answer to Question 1

B

Answer to Question 2

Stars with a total mass of 8 solar masses or more may form iron cores. The formation of an iron core ends the normal life of a star because iron cannot be fused into heavier elements and produce energy, as previous fusion reactions have done. In order to fuse iron, energy must be provided. The star, at this point in its evolution, has finally run out of energy sources in its core. This disrupts the hydrostatic equilibrium of the star; the inward pressure of gravity takes over and the star collapses and then explodes as a Type II supernova.