system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: how is it possible that we can only see between 430-770 Thz and hear 20hz-20khz? Does that mean there are things around us we just cannot hear or see?

EDIT: if aliens were real, and they were on a different spectrum/wavelength is it possible they could be anywhere and we would have no clue?

SECOND EDIT: wow thank you all so much for your responses. I’ll try my best to read through all the comments!
gpt
Sure, there are lots of things we can't see or hear.  
The chemicals in your eyes are only sensitive to narrow wavelengths of visual light.  Anything outside that is invisible to us.  

You can not, for example, see the infrared light emitted by your TV remote. But your phone camera can, to a certain degree. Go into a dark room, point your TV remote at your phone camera, and you should see it light up.    

Same thing with sound. Your eardrum and middle ear bones are only able to resonate within a certain frequency range. Go above and the bones are too heavy to move that quickly, go below and the eardrum is too small to be put in motion by such a long wavelength.