that must be it! dust stays the same size when you zoom out or in. Which means it gets larger as you zoom in, and smaller as you zoom out. In the video, when the earth gets smaller, i zoom out, which causes the photon torpedo to get larger in an attempt to remain the same size; however it doesn't zeem to be working.
Edit: ok this is how to recreate the glitch, it's not an exact process but bear with me.
1. Open Earth and moon simulation (anyone will work, this one's just simpler/easier)
2. Bombard Earth about 20-30 times with asteroids. impact marks on.
3. Alt-tab a few times, switch to other windows, do something in them
4. repeat step 2
5. fire photon torpedo
6. zoom in and out and look at glitch.