How to know if the position of the mouse is the sky's empty void?

Really simple problem; If PlayerMouse.Target is nil then it's pointing at nothing; which is sky/void.

local player = game:GetService("Players").LocalPlayer
local mouse = player:GetMouse()

while wait() do
    if mouse.Target == nil then
        --if mouse is pointing to nothing
    else
        --if mouse is pointing to something
    end
end

• You must put this in LocalScript to make it work.