Well over a million such fractures occur around the world each year, the study estimated.

If the temperature difference is very large, fracture can occur.

A fracture occurs when there is a break in one or more of the bones.

And so the crack runs through the material until total fracture occurs.

About 1.5 million fractures occur each year due to osteoporosis.

This fracture occurs in patients who have fallen from a height.

When such a fracture occurs, a traditional hip replacement is done instead.

A person is often not aware that they have osteoporosis until a fracture occurs.

Then why did the fractures only - or more frequently - occur during that precise time period?

Optical methods in trying to explain why these fractures occur, have not been very successful.