What is the reason for disappearance of hydrogen and helium from the early atmosphere? 

Solar activity can affect the Earth. The Sun constantly emits solar winds of charged particles. However, solar flares and prominences can erupt from the regions near sunspots and emit radiation from X-rays to radio waves. Coronal mass ejections can be observed from space with solar observatories like SOHO and TRACE. What protects the Earth from the effects of the Solar wind and proton storms due to solar flares (2 attempts)? 

Why do sunspots appear darker than their surroundings? 

What would you be most likely to find if you returned to the solar system in 10 billion years? A 

What happens within a contracting cloud in which gravity is stronger than pressure and temperature remains constant? 

Which of these colours of light passes most easily through interstellar clouds? 

What happens to the core of a high-mass star after it runs out of hydrogen? 

Looking

at the pattern on the diagram, decide how much dimmer the star with

brightness B = 1 at a distance d = 1 would look to us if it was placed

at the distance of d = 4?

After the helium flash in a low-mass star, the star’s luminosity 

Select all correct statements.