As far as singular songs, these two are on regular rotation for me:
https://www.youtube.com/watch?v=q2x0TZmyuVk
https://www.youtube.com/watch?v=90aTb8X2tAw
https://www.youtube.com/watch?v=q2x0TZmyuVk
https://www.youtube.com/watch?v=90aTb8X2tAw
"For me, it is far better to grasp the Universe as it really is than to persist in delusion, however satisfying and reassuring." - Carl Sagan