Macbook pro reverts to original yosemite wallpaper after airplane ride

Dear apple community,

I brought my mac on an airplane trip. The landing was quite unpleasant.

When I logged onto my macbook , the desktop has reverted to the original yosemite wallpaper(you get this wallpaper the first time you use your mac). Other than that, no other problems discovered yet.

I verified disk and there is no problem as well. Is this physical damage that the macbook cannot detect?

Macbook pro 13 inch mid 2012 (with cd-drive)

Yosemite 10.10.5