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The Earth's magnetic field protects us from solar activity, but the Moon and Mars are more exposed. The upcoming solar maximum is the perfect time to observe how our dynamic Sun affects its planets.
Reports from the Kepler mission have raised hopes for finding an Earth-like planet. Nevertheless, our Earth is probably unique — not just because of its distance from the Sun, but also because it has co-evolved with the life forms it has hosted.
The Late Ordovician period, ending 444 million years ago, was marked by the onset of glaciations. The expansion of non-vascular land plants accelerated chemical weathering and may have drawn down enough atmospheric carbon dioxide to trigger the growth of ice sheets.
