It's impossible to say for sure who said "I figured out Earth is larger than most people thought" without more context. This is a very general statement, and many people throughout history have contributed to our understanding of Earth's size.

Here are some possibilities:

* Ancient Greek philosophers: Eratosthenes, in the 3rd century BC, famously calculated the circumference of the Earth with remarkable accuracy. He might have said something similar, though not in those exact words.

* Early explorers: Explorers like Christopher Columbus and Ferdinand Magellan contributed to our understanding of Earth's size and shape through their voyages of discovery.

* Modern scientists: Many scientists throughout history have contributed to our understanding of Earth's size and structure, from measuring its gravity to studying its internal composition.

To give you a more accurate answer, please provide more information, such as:

* When was this said?

* Who was the speaker?

* What was the context of the statement?

With more information, I can help you identify who might have said this.