Astronomy | Astrophysics Answers

If you have infinite energy can you release infinite power forever by just releasing half of the remains energy each second?

Write down Friedman equation and sketch its solutions. Which one of these solutions correspond to the contracting universe ?

What is a quasar ? Sketch the spectrum of a quasar and describe its main characteristics.

Explain Hubble's scheme of galaxy classification. What is the type assigned to the Milky way galaxy ?

What is a black hole ? Derive an expression for Schwarzs child radius of a black hole on the basis of Newtonian mechanics and explain its significance.

What is a white dwarf star ? Explain, on physical basis the existence of an upper limit on the mass of a white dwarf star. What is this limiting value called ?

What is interstellar extinction ? How does it help in determining the composition of ISM ?

Draw a labelled H-R diagram. How does it help into estimating the size and mass of a star.

What is solar wind ? Explain, briefly, the reasons for its occurrence. How are the Van-Allen radiation belts formed ?

Assume that sun radiates like a black body of temperature T. Calculate T using Stefan-Boltzmann law. Take Q=5.67 x 10^-8 Wm^-2K^-4 and Lo=4 x 10^26 W.