If you said that is the noise made by a fallen tin bowl or circular tin plate as it hits the floor, you're absolutely right! Sterling Archer demonstrates below:
Now imagine the same physics on a planetary scale:
I've offered to lecture the kids in the MIT Astrophysics program on this fascinating astral phenomenon but I haven't heard back yet on when they want me to present. I wonder what the delay is?
On a related note, some obscure hack named Steve Hawkin or Hawkings has left a number of rude messages on my voice mail. I'm strongly tempted to find out where this cheeky bugger lives and expose him for the quack he is. Such are the trials and tribulations of the upper intellectual elite of academia I suppose!
Hope your Friday's going as well as mine is!!! :)