X-ray images of the Sun generally show the 

Which of these things poses the greatest hazard to communication satellites? 

Which of these groups of particles has the greatest mass?

What would stars be like if hydrogen had the smallest mass per nuclear particle? 

Out of globular and open clusters, which are typically older? 

What slows down the contraction of a star-forming cloud when it makes a protostar? 

Use the simulation and decide if it is easier to measure parallax angle for stars that are further away or closer to the Earth. 

https://newt.phys.unsw.edu.au/share02/sims/parallax/parallaxEffect.html

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?

Which kinds of stars are most common in a newly formed star cluster? 

Run the simulation for all clusters provided in the selection options and decide which cluster is the youngest. 

https://newt.phys.unsw.edu.au/share02/sims/star-cluster/