Podcast: Planet 9, Apollo 9 and aurora adventures

In the latest episode of Radio Astronomy, the BBC Sky at Night Magazine team discuss the latest theories about Planet 9 with physicist Antranik Sefilian, plus there’s chat about aurora hunting and the achievements of Apollo 9.

"Just as the solar system is a few small planets in millions of kilometres of empty space, an atom is just a few electrons orbiting the tiny central atomic nucleus." Credit: NASA