Who was the inspiration for Cuthbert Calculus in the Tintin series?

The inspiration for Cuthbert Calculus, the absent-minded professor in the Tintin series, was Auguste Picard. Auguste Picard was a Swiss-Belgian physicist and explorer who was the first person to reach the stratosphere in a pressurized cabin. His achievements in the field of exploration and science, along with his eccentricity, made him a suitable inspiration for the character Cuthbert Calculus, known for his brilliant inventions and forgetful nature.