Doodle vs Doodle: Copernicus and al-Tusi

by Salman Hameed

Perhaps, appropriately, Persian polymath Nasir al Din Tusi (1201-1274 CE) decided to have his birthday on February 19th, a day before Copernicus. Google then decided to have a Tusi doodle on the 18th, but kept it away from the non-Arab world. Here is Tusi doodle that appeared only on Arabic Google (tip from House of Wisdom):

So why care for Tusi? Well, like other natural philosophers of his time, he contributed to many different fields. He even waded in on idea of the development and evolution of species, including that of humans. But it is his Tusi-Couple that ended up changing the face of astronomy (he also formed the important Marageh Observatory in 1259 CE). Something very similar was used by Ibn al-Shatir in his geocentric model and Copernicus in his heliocentric model. Historians now believe that Copernicus must have known about the Tusi-Couple and adapted it for his model (for clarification, al-Tusi or Ibn al-Shatir did not place the Sun at the center of the solar system).

Here is the Tusi-Couple:

And on queue, February 19th was the 540th birthday of Copernicus. Here is the Google doodle for that:

Happy belated birthdays!