Remarkable migration of the solar system from the innermost Galactic
  disk; a wander, a wobble, and a climate catastrophe on the Earth
  Recent knowledge of Galactic dynamics suggests that stars radially move on
the disk when they encounter transient spiral arms that are naturally generated
during the process of disk formation. We argue that a large movement of the
solar system from the innermost disk over its lifetime is inferred from a
comparison of the solar composition with those of solar twins within the
Galactic chemical evolution framework. The implied metal-rich environment at
the Sun's birthplace and formation time is supported by measured silicon
isotopic ratios in presolar silicon carbide grains. We perform numerical
simulations of the dynamical evolution of disk stars in a Milky Way-like galaxy
to identify the lifetime trajectory of the solar system. We find that a solar
system born in the proximity of the Galactic bulge could travel to the current
locus by the effect of radial migration induced by several major encounters
with spiral arms. The frequent feature we identify is the repeated passages of
stars inside the same spiral arm owing to the wobble of stars traveling in and
out of the spiral arms. We predict that such episodes are evidenced in the
Earth's geological history as snowball Earth and that their occurrence times
are within our prediction. In particular, the stellar motion that vertically
oscillates during passages through spiral arms occasionally leads to a split
into two discrete passage episodes with an interval of several tens of Myr,
implying two relevant snowball Earth events that occurred in rapid succession
(~7.2 and 6.5 hundred Myr ago).
