Earth had 372-day year, 23-hour days 70 million years ago, study finds

Fossilized mollusc shells have provided a window into Earth's distant past, revealing that our planet once had a significantly different rotation and orbit. Around 70 million years ago, during the Cretaceous period, Earth completed 372 days in a year, with each day lasting approximately 23 hours and 31 minutes. This finding stems from detailed research into the growth patterns and structures within ancient shells.

The study, which examined the fossilized remains of a mollusc that lived for over nine years on a tropical seabed, also shed light on other ancient environmental conditions. Scientists observed evidence suggesting warmer ocean temperatures than present day. Furthermore, the research indicated a greater distance between the Earth and the Moon during this era.

An additional intriguing discovery from the analysis of the shells was evidence of photosymbiosis. This suggests that organisms living in the ancient oceans engaged in symbiotic relationships, likely involving algae or other photosynthetic organisms, contributing to the ecosystem's dynamics.