1) If, by definition, no light can escape from a black hole, how are they detected? Describe two methods that have been used to detect black holes in as much detail as you can.2) Describe the stellar magnitude scale. Who developed it and how? What makes stellar magnitude unusual as a scale of brightness of stars? What is the difference between apparent and absolute magnitude?3) If one person cannot observe a single star go through its entire life span, how are astronomers able to determine the evolution (birth, life, and death) of stars?BRIEFLY identify the main stages that the following stars will go through AFTER they leave the main sequence (make sure to include what the final stage is).a) a star 2 times the mass of the Sunb) a star 8 times the mass of the Sunc) a star 20 times the mass of the Sun4) Start with a hypothetical hydrogen nucleus in the center of the Sun. Describe in as much detail as you can how that hydrogen nucleus contributes to the generation of the Suns energy. How does the energy that is created in the Suns core get out of the core and reach Earth?