London: It seems that the evolution of
Uranus may have been more violent than previously perceived.
A new study has suggested that the planet may have
been batted back and forth between Jupiter and Saturn before
being flung out to its present location.
Previous modelling has shown that Jupiter and Saturn
moved out of their initial orbits in the early solar system,
scattering nearby objects. In some simulations, this led to
Uranus crossing the path of Saturn, which could then have
flung it towards Jupiter, which lobbed it back to Saturn.
The process might have happened three times before
Uranus was finally ejected beyond Saturn, to where it now
resides. Hurling Uranus would have caused Jupiter and Saturn
to recoil, further shifting their orbits.
New simulations led by Alessandro Morbidelli of the
C?te d`Azur Observatory in France suggest this pinball game,
which would have lasted 100,000 years, fits with observations,
the `New Scientist` reported.
In an alternate scenario, Jupiter and Saturn moved
to their orbits over 5 million years by simply flinging away
space rocks, but this would have visibly scarred the asteroid
belt, say astronomers.
"The evolution of the giant planets has been more
violent than we thought," Morbidelli said.
The findings are to be published in an upcoming
edition of the `Astronomical Journal`.