BBC2’s flagship science programme, Horizon, dedicated yesterday’s episode to “Secrets of the Solar System”. The programme explained how the discovery and understanding of exoplanets had led directly to improvements in our understanding of our own Solar System.

Whereas traditionally our Solar System has been regarded as a static array of planets, which formed early after our star’s birth, about 4 billion years ago, and which since then have merely cycled through their orbits, we now understand that planets can radically change their orbits by interacting with each other and with the proto-planetary disk from which they formed.

A major part of this picture has been developed through understanding “hot Jupiters”, a class of planets which is now dominated by WASP discoveries. In particular the finding of hot Jupiters in retrograde orbits around their star was based largely on WASP planets, starting with WASP-17b.

Yesterday’s programme, on prime-time BBC television, featured a 20-minute discussion of hot Jupiters which was anchored around an observation of WASP-84b using the Telescopio Nazionale Galileo on La Palma.

Telescopio Nazionale Galileo

WASP-84b is a WASP-South planet that was announced in a 2014 paper led by Keele University postdoc David Anderson. The finding of an aligned orbit for this planet, announced in a 2015 follow-up paper which was also led by Anderson, is evidence that this particular hot Jupiter migrated inwards by interaction with the proto-planetary disk, and not by a close encounter with another large planet.

Thus the BBC’s Horizon showed how WASP discoveries are having a direct impact on our understanding of our Solar System, and thus of the origin of our own Earth. The audience for the programme was 2.03 million in the UK, and Horizon programmes are re-broadcast worldwide.