Views from other commentaries
"The last seal having been broken open, the book of God's eternal plan of redemption is opened for the Lamb to read to the blessed ones in heaven. The half hour's silence contrasts with the previous jubilant songs of the great multitude, taken up by the angels" (Re 7:9-11). (Jamieson-Fausset-Brown Commentary:)
The vision [of the seventh seal] is not the silence in heaven, but what John saw. On this point some commentators make a mistake here. What he saw was the seven angels which stand before God; that is, the angels who act as his immediate ministering servants, to whom were given seven trumpets. (People's New Testament Commentary)
Seventh-day Adventists generally see the half hour in symbolic time where a "day" represents a literal year of 360 days. The silence is then for one week. After the songs in heaven all are seen to come with Christ to get the righteous resurrected and living and take them to their heavenly home. It takes them seven days to ascend. (Seventh-day Adventist Bible Commentary, vol. 7, p. 878.
The conclusion of this commentary is different from all of these.
description of the time of silence
The following quotation seems to best describe the time of silence. Here faithfulness is shown by humble heart searching. Then the last seal is broken. Satan’s last accusation is shown unjust and the righteous are eternally free! Here is the quotation:
“With anthems of celestial melody the holy angels, a vast, unnumbered throng, attend Him on His way. The firmament seems filled with radiant forms—‘ten thousand times ten thousand, and thousands of thousands.’ No human pen can portray the scene; no mortal mind is adequate to conceive its splendor. ‘His glory covered the heavens, and the earth was full of His praise. And His brightness was as the light.’ As the living cloud comes still nearer, every eye beholds the Prince of life. No crown of thorns now mars that sacred head; but a diadem of glory rests on His holy brow. His countenance outshines the dazzling brightness of the noonday sun. ‘And He hath on His vesture and on His thigh a name written, King of kings, and Lord of lords.’
“Before His presence ‘all faces are turned into paleness;’ upon the rejecters of God's mercy falls the terror of eternal despair. ‘The heart melteth, and the knees smite together, . . . and the faces of them all gather blackness.’ The righteous cry with trembling: ‘Who shall be able to stand?’ The angels' song is hushed, and there is a period of awful [awesome] silence. Then the voice of Jesus is heard, saying: ‘My grace is sufficient for you.’ The faces of the righteous are lighted up, and joy fills every heart. And the angels strike a note higher and sing again as they draw still nearer to the earth.
The King of kings descends upon the cloud, wrapped in flaming fire. The heavens are rolled together as a scroll, the earth trembles before Him, and every mountain and island is moved out of its place. ‘Our God shall come, and shall not keep silence: a fire shall devour before Him, and it shall be very tempestuous round about Him. He shall call to the heavens from above, and to the earth, that He may judge His people.’" (Ellen G. White, The Great Controversy, 1911, pp.640-642. Pacific Press, Nampa, ID.)