The 'heartbeat' of Earth's ice ages is way more complicated than we thought, featuring weird 'forbidden' patterns that shouldn't exist.
April 13, 2026
Original Paper
Beyond the 100-kyr and 41-kyr dichotomy: ~76-kyr and ~52-kyr signals and forbidden periodicities
EarthArXiv · 10.31223/X5419D
The Takeaway
Textbooks usually say ice ages happen every 41,000 or 100,000 years. This research found hidden, middle-ground cycles that prove Earth's climate responds to planetary orbits in ways we previously thought were impossible.
From the abstract
While the Mid-Pleistocene Transition (MPT) is often described as a shift from 41-kyr to $\sim$100-kyr glacial cycles, this binary perspective fails to capture the nuanced spectral evolution of Quaternary climate. Applying wavelet-based spectral analysis to benthic d18O records, we identify previously underappreciated signals－~52 kyr before 1.2 Ma and ~76 kyr thereafter－marking the MPT's onset. Insolation analysis reveals these timescales primarily correspond to integer multiples (n) of the local