  We prove Tsirelson's conjecture that any scaling limit of the critical planar
percolation is a black noise. Our theorems apply to a number of percolation
models, including site percolation on the triangular grid and any subsequential
scaling limit of bond percolation on the square grid. We also suggest a natural
construction for the scaling limit of planar percolation, and more generally of
any discrete planar model describing connectivity properties.
