A weaker magnetic field may have paved the way for marine life to go big
Decreased protection from cosmic radiation could have boosted oxygen levels in the atmosphere and oceans
![illustration of Earth’s magnetic field](https://i0.wp.com/www.sciencenews.org/wp-content/uploads/2024/05/050624_kk_magneticfield-life_feat.jpg?fit=1030%2C580&ssl=1)
Earth’s magnetic field buffers our planet against barrages of cosmic particles. It fluctuates in strength on timescales of thousands to millions of years. A weaker field in the past could have led to an explosion in the size of marine animals, a new study proposes.
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