  In coming years, the first truly Earth-like planets will be discovered
orbiting other stars, and the search for signs of life on these worlds will
begin. However, such observations will be hugely time-consuming and costly, and
so it will be important to determine which of those planets represent the best
prospects for life elsewhere. One of the key factors in such a decision will be
the climate variability of the planet in question - too chaotic a climate might
render a planet less promising as a target for our initial search for life
elsewhere.
  On the Earth, the climate of the last few million years has been dominated by
a series of glacial and interglacial periods, driven by periodic variations in
the Earth's orbital elements and axial tilt. These Milankovitch cycles are
driven by the gravitational influence of the other planets, and as such are
strongly dependent on the architecture of the Solar system.
  Here, we present the first results of a study investigating the influence of
the orbit of Jupiter on the Milankovitch cycles at Earth - a first step in
developing a means to characterise the nature of periodic climate change on
planets beyond our Solar system.
