WHAT IS THE SILENCE IN HEAVEN?
Revelation chapters 4-7 present the first six of seven seals. The seventh seal is found in Revelation 8:1, “When He opened the seventh seal, there was silence in heaven for about half an hour”. This is followed by the Seven Trumpets, which are a series of disasters that fall upon the inhabitants of the earth.
Revelation has several sets of seven: The Seven Churches, Seven Seals, Seven Trumpets, Seven Thunders and Seven Last Plagues. A careful study shows that the seventh of each series of seven is the introduction or summary of the next section. For example, the seventh plague (Revelation 16:17-21) announces the fall of Babylon, and the next section (chapters 17-19:3) gives details about the identity, activities and fall of Babylon.
According to this pattern, “silence in heaven for about half an hour” is an introduction or summary of the Seven Trumpets, which take place during the “Time of Trouble”. The Time of Trouble is also called the “hour of trial which shall come upon the whole world, to test those who dwell on the earth” (Revelation 3:10). This implies that the Seven Trumpets, during which there is "silence in heaven for about half an hour, are the first half of the "Hour of Trial (the “Time of Trouble”). The second half are the Seven Last Plagues.
More specifically, the Time of Trouble or “hour of trial” is divided into two parts. The seventh seal mentions “half an hour”, and is followed by the seven trumpet plagues. During this period heaven is silent—“there was silence in heaven for about half an hour”. Apparently this is a period when God does not intervene, because in scripture, when God intervenes he no longer keeps silent.
“Our God shall come, and shall not keep silent; A fire shall devour before Him… He shall call to the heavens from above, and to the earth, that He may judge His people… But to the wicked God says:... These things you have done and I kept silent;… But I will rebuke you… Now consider this, you who forget God, lest I tear you in pieces, and there be none to deliver” (Psalms 50:3,4,16,21,22). “Behold, it is written before Me: I will not keep silence, but will repay— even repay into their bosom— your iniquities and the iniquities of your fathers together” (Isaiah 65:6,7).
In these verses we see a period of silence (“I kept silent”) in which God does not intervene , but during this time He gives the wicked an opportunity to “consider this, you who forget God, lest I tear you in pieces”. In other words, God sends a powerful warning and a call to repentance before he sends His judgments. This time of silence would correlate with the “half an hour”— the trumpet plagues. This is followed by the remainder of the “hour of trial” in which God “shall not keep silence, but will repay… your iniquities”— in other words, the time for repentance is over and God sends His judgments. This correlates with the Seven Last Plagues.
The following diagram illustrates the two parts of the “Hour of Trial” (also called the Time of Trouble and the Great Tribulation)
HOUR OF TRIAL (TIME OF TROUBLE)
SILENCE FOR HALF AN HOUR SHALL NOT KEEP SILENT
SEVEN TRUMPETS SEVEN LAST PLAGUES
This explanation is probably different than anything you have ever heard. For details and scriptural support see section 8:1 Silence in Heaven of The Book.
 See also Mic. 3:4-7