u/Rumpunstiltskin

I am planning an event with some thrown projectiles, I am considering printing PHA spheres in vase mode (0.4mm thick) and filling them with native seeds and soil as a lightweight projectile that will break down easily - have any studies been done on PHA breaking down in a natural environment?

The area is a wet forest, so I imagine it would be a good environment to break down in. I would try to make the prints as easily broken down as possible.

My other options are linen sacks, but these would likely take longer to break down.

Are there any things I can do to assist the breakdown? the spheres will be 2 parts and slide together, so they are likely to come apart into hemispheres anyway on impact.

I am wondering if human eyes have seen everything there is to see on earth. I am speaking only about dry land - but shallow coastline could be an interesting extension.

If I were to go out exploring, what are the chances that I would be standing/looking at something never before seen by human eyes? I obviously don't expect to see a mountain range that has escaped anyone's notice etc, but what about a tree? Is there a tree nobody has seen? A spot nobody has stood?

It keeps me up at night.

Edit;
To clarify "Seen" is equivalent to a human being within detailed visual range, ~50ft
Let's clarify this further and insist that the location is reachable by normal means (i.e walking/swimming/light climbing e.g trad climbing, but not extreme ice climbing or mountain faces.)

I mean throughout human history insofar as that can be estimated.