ABSTRACT
We all know about the Earth being a planet in Space. In fact, we know a bit more
about where it is in Space: it is in the Solar System, which in turn is on one of the
outer arms of the swirl of the Milky Way galaxy (the band of light that we can see
across the night sky, if we don’t live in cities, anyway). And the Milky Way is one of
a huge number of galaxies in the Universe.
