Revelation 8:1
This verse is talking about the first part of the great tribulation. It is a period of time that is equal to 2300 days. This happened in the year 1988. The period ended in 1994. During that time no one was being saved. This is the silence part. You see when a single person is saved there is joy in heaven with the angels, but during the first part of the great tribulation no one was being saved. Also the church ended at this time as well. God gave all churches up to Satan to prepare them for judgement. In 1994, people began to be saved again, this was the next Jubilee year, and the Holy spirit began pouring out again.
Revelation 12:3-4
The red dragon is a picture of satan. When we look at the crowns on the head, we understand that Satan is viewed not as the traditional view on Tom and Jerry, but infact looks just like Jesus. This was a picture of Israel who were suppose to be God's people but rejected him. So they have the appearance of something great, but in fact are just a false representation of God. Of course the child was Jesus whom he wanted to destroy.
Revelation 12:7-11
Michael is a picture of Jesus, the definition of Michael is "one who is like GOD", so in this set of verses, it was describing what happened at the cross. Up until that point Satan had access to heaven, and appered to be winning because people have died from day one. However when Jesus rose from the dead, he gave Satan a death blow. Death no longer had dominion over our life. At this point Satan was cast out of Heaven. He was sent down to the Earth to continue his work.