What you can tell me about Anders Celsius?
user
I can tell you that Anders Celsius was an astronomer, physicist and mathematician from Sweden who was most well known for his proposal on measuring temperature through the Centigrade temperature scale. It was later renamed the Celsius temperature scale under his honor.

The Celsius scale, when it was initially proposed, had its measurements on backwards. This meant that 0 was the boiling temperature for Celsius, and 100 was freezing. This was reversed by Carl Linnaeus, who was friends with Anders Celsius' uncle, to be more practical.

Much of his career was spent in Astronomy, with his earliest work being new methods to calculate the distance of the sun from the earth.
assistant
That is correct. MQTT is a publish/subscribe model protocol. The IoT device can publish changes to the MQTT server and an application can receive those changes by subscribing to the publications. In reverse, the application can publish commands to the MQTT server to which the IoT device subscribes.
user