What is the most important factor that makes it hard to directly study the centre of our own Milky Way galaxy? Select one alternative:
O A. The super-hot gas and rapidly moving stars found at the centre of the galaxy move in such complex ways it is difficult to understand what we see.
O B. Our view of the galactic centre in visible light is blocked by dark matter in the plane of the galaxy.
O C. Light from the galactic centre is absorbed by the super-massive black hole that is found there.
O D. The galactic centre is so far away it is difficult to see the details, even in big telescopes.
O E. Our view of the galactic centre in visible light is blocked by dust lying in the plane of the galaxy.
