A good question. And I think there is a clue in 'the windows of heaven'
[KVJ] of 7:11 and 8:2. According to Strong, the word 'window' is
translated from 'arubba' (699) which is the feminine participle passive of
'arab' (693) which means 'to lurk' and which is translated to English in
the KJV as 'to lie in ambush.' 'Arubba' means 'lattice' or by implication:
'window,' 'dove-cot,' 'chimney' or 'sluce.' These seemingly unrelated
meanings may be tied together by the meaning of the root word -- 'to lurk.'
A latticed window can be lurked behind. A dove-cot has pidgen holes for
the birds to 'lurk' in. A chimney has aperatures for 'lurking' smoke to
escape through. And, a sluce has doors with water 'lurking' behind.
So, when we look at the phrase 'windows of heaven' the idea of something
lurking in the heavens seems appropriate. Unlike the stars and planets,
asteroids are largely invisible to the naked eye, even up to the point of
entry into the atmosphere, thus they could be thought of as lurking in
space waiting to crash in ambush to the earth.
The phrases 'the windows of heaven were opened' (7:11) and 'the windows of
heaven were stopped' (8:2) could be refering to the onset and the
subsequent suspension of an ambush by asteroids which had been lurking in
space. And thus a possible Biblical explanation of the astroblems.