Up is relative to the fiduciary observer.
What I find curious is that 'up' is actually 'down'.
The image on your retina, that gets sent to your brain, is 'upside down'. The brain 'flips' the image, so as not to confuse the owner.
Up and down is actually related to the pull of gravity (another thing we don't quite understand), and has nothing to do with any particular 'direction'.
Let's say there are 60 billion people on the planet. If they all point straight up, they are pointing in 60 billion different directions.