astronoy discussion#######

Discuss the causes, characteristics, and major features  of black holes.  Explain why the concept of a black hole does or doesn’t seem reasonable to you and provide some rationale for your views?     i need two paragraph for this discussion. and need two differen answer for this question.




1.     Describe a planetary nebula and its cause?



2.     What would the major impact on Earth be if the Earth remained in its present orbit and our Sun was 50% more massive than it is now?



3.   Under certain circumstances a white dwarf will go type Ia supernova becoming much brighter for a short period of time. What special circumstance is required for this event to occur? 



4.     Why is a large mass required to have a type II supernova event?



5.     If our Sun maintained its current mass, but suddenly collapsed and became a block hole, how would Earth’s orbit be affected?