You can hear sound effects from collissions in the alpha 7 preview here at 4:47.
And at 8:56 is how it sounds when sped up x4. 
https://www.youtube.com/watch?v=Ye9cwKa1144
Yes! My prayers have been answered. Sounds of collisions isn't what I was on my mind, exactly. However they are still cool. Also, when you add water on a planet, a splashing sound would be nice.
Oh, and can you guys record a video with higher quality? I do want to read the menu of the "powers" section. (Edit: Nevermind, it was a problem with my PC)
I'm so excited for Alpha7. Once again, good job!