Well, it’s only “little” when considering the ultralow frequencies involved. In fact, it’s a massive tune. It’s a world-wide phenomenon and probably as old (thus long) as the Earth itself. The article below summarizes years of research into a perpetual hum that has been detected in places such as Antarctica, Algeria and on the floor of the Indian Ocean:
I always had a gut feeling that there’s more to what our bodies need from Earth, other than oxygen, water and nutrition. This primordial vibration that permeates all life on this planet should probably be considered if we think about relocating to another planet. Unless this can be replicated somehow, there could be unforeseen consequences to us departing our world long-term.
The coming decades will clarify the relation between our body and certain facts about the environment on this planet, particularly previously-hidden “features” such as this humming. I’m going to keep my ears on the ground for more news about the Earth’s song. See what I did there?