THE giant planets Uranus and Neptune may have formed much closer to the Sun
than where they are today, a new computer model reveals. It shows how they could
have been catapulted outwards to their present locations on the fringes of the
Solar System after close encounters with the embryonic Jupiter.
Planetary scientists have long been baffled by the origins of Uranus and
Neptune. At their present locations, the disc of dust and gas from which the
planets formed 4.6 billion years ago would have been too slow-moving and
rarefied to generate such large bodies. Uranus and Neptune are 15…
