I'm wondering if it is that simple. Does the observer needs to have a "consciousness" ? Is a photon colliding with an atom is consider as the observer, or is it the scientist that lighted up the atom which is the observer ?

If we takes Schrödinger cats, when does the measure happen ? When the sensor detect the radioactive particle ? When the cat realize its death ? When the box is open ? When someone actually looks inside the box ?

That's true questions, I'm trying to understand quantum physics since years, but the sources I find are either too simple ("The cat is both dead and alive, It means there are parallel universe !), either too complicated (directly jump to equations).