Although we like to think we know everything - and technology has advanced so much we practically have the answer to everything we don't know at our fingertips - there are still plenty of mysteries left to solve.
How did they build Stonehenge? What's the purpose of the pyramids? Is there a God? We don't know the answer to any of things for certain, but we might be one step closer to figuring out one of the biggest ones of all - what is the hum that emanates from deep inside the Earth?
That our planet has a hum isn't news in itself - that's been known to scientists for a long time. But now, and for the first time, researchers have used seismic instruments at the bottom of the ocean to actually capture it.
Using 57 seismometer stations located in the Indian Ocean east of Madagascar, researchers gathered data between 2012 and 2013 and used technology to remove interference from things like ocean infragravity waves - which sound awesome - currents and electronic glitches.
They also corrected for the signal generated by any earthquakes. What they were left with is a recording of the Earth's natural vibration - which apparently peaks at several frequencies between 2.9 and 4.5 millihetrz.
What that means is the vibrations are approximately 10,000 times smaller than the lower threshold of the human ear, which is 20 hertz.
It means that this successful attempt to capture the Earth's hum is especially significant. It also comes after decades of trying to do so. The first attempt was made in 1959, but it was in 1998 that scientists finally proved it existed.
Hundreds attempts have since been made but - until now - all had used seismometers on land, rather than in the murky depths of the ocean where who knows what kind of crazy creatures exist.
But we're getting off track. The fact that the hum has been detected at the bottom of the ocean suggests that it's present all across the planet. Given that 70 percent of the Earth is covered with water, that makes sense.
Now that the sound has been captured, the next step is to work out what the hell it is. Scientists have come up with many theories over the years, whether that's atmospheric disturbances or ocean waves moving across the sea floor.
Personally, we think it might be Cthulhu growling at us all, but we kind of hope it isn't.
Featured Image Credit: PA