Looking at our ears on the sky - the giant radio telescopes that extend our studies of the Universe beyond the range of optical light.

One common thread in SF stories is the idea of precursor civilisations - ancient races that lived, died and passed out of general knowledge long before humanity took to the stars.

Will humanity find friendship in the stars, or are we merely a helpless child, crying in the wolf-infested forest.

Exploring megastructures - artificial structures on enormous scales - in SF.

World ships - planets which move under the deliberate control of their inhabitants or others - are a staple of science fiction. But how plausible are representations of world ships in SF, and why are they so popular?

A running theme in science fiction is the idea that alien races are willing and eager to talk to us, but this is not an assumption that has gone unchallenged in science fiction, or indeed in our wider culture.

Fermi’s Paradox - the lack of alien contact despite the a Universe that should be teeming with life - has excited the interest of scientists as well as philosophers, and some of the many possible solutions have been explored both by popular science writers and the writers of science fiction.

Interstellar comets are rare and unusual visitors - but while they're alien, are they result of intelligences beyond our Solar System? It is a premise that has formed part of the science fiction repertoire for many years.

The concept of a scanner - a remote sensing device that can identify evidence of life at a distance - is a common staple of science fiction. While some science fiction takes this to an extreme, it’s neither a new idea nor one that is entirely divorced from science fact.

If the laws of mathematics and science are the same everywhere in the Universe, then these might provide a key common ground for communication - as science fiction has explored.