Ten thousand world systems

I keep pondering over the below questions and thought of posting it here. 1. Is the physical universe(the one we observe with stars, galaxies, black holes etc) contained in the 31 planes of existence or the other way around? 2. A "ten thousand world systems" imply that there are other universes besides ours, which gives support to the multiverse hypothesis in science? 3. Are there ten thousand of world systems or infinite of them? Just trying to ponder if its infinite, then imagine the probability of being born as a human and able to understand dhamma, that is mind blowing. That also goes to show the sheer magnitude of samsara.