Aristarchus of Samos, a Greek astronomer who lived in the 3rd century BC, is famous for proposing that the Earth revolves around the Sun, a revolutionary idea for his time.

Here's what we know about his views on the universe:

* Heliosentrism: Aristarchus is credited with being the first to propose a heliocentric model of the solar system, where the Sun is at the center and the Earth revolves around it. This contradicted the prevailing geocentric model, which placed Earth at the center.

* Relative Sizes: He made the first attempt to calculate the relative sizes of the Sun and Moon, and the distances between them. While his calculations were not accurate, they were significant for being the first to attempt such measurements.

* The Universe is Vast: He also believed the universe was much larger than was commonly thought, suggesting that the stars were very distant.

However, it's crucial to note:

* Limited Evidence: Aristarchus's heliocentric model was not widely accepted in his time. There was little observational evidence to support it, and the prevailing geocentric model was more aligned with the common sense observations of the day.

* Lost Writings: Unfortunately, most of Aristarchus's writings have been lost, and we only know about his ideas from secondary sources.

In summary, Aristarchus of Samos was a visionary thinker who dared to challenge the accepted view of the universe. His heliocentric model, though ahead of its time, paved the way for future astronomers to understand the true nature of our solar system.