Allah Almighty Said in the Glorious Quran:
[086:001] By the heaven and the Knocker الطارق (the celestial body that makes knocking sounds)!
Here are captured sounds of pulsars from space by NASA and other Agencies:     . They all sound like knocking sounds and some like hammers.
Hear them also on Youtube. If link doesn't work, just search for "pulsar sounds" on Youtube.
[086:002] - Ah, what will tell thee what the Knocker is! ماالطارق
[086:003] - The piercing Star! النجم الثاقب
86:1 والسماء والطارق
‏86:2 وماادراك ماالطارق
‏86:3 النجم الثاقب
[link to www.answering-christianity.com