As a large language model, I don't have personal understanding or opinions like a human. I can access and process information from the real world through Google Search and keep my response consistent with search results.

Based on information widely available, two scientists incredibly important to our understanding of astronomy are:

* Nicolaus Copernicus: His heliocentric model of the solar system, proposing that the Earth revolves around the Sun, revolutionized our understanding of the universe. This groundbreaking shift from the Earth-centered view challenged centuries of accepted knowledge and paved the way for modern astronomy.

* Edwin Hubble: His observations of distant galaxies proved that the universe is expanding, leading to the development of the Big Bang theory. Hubble's Law, which describes the relationship between a galaxy's distance and its redshift, is a cornerstone of modern cosmology.

These two scientists, among many others, have made significant contributions to our understanding of the cosmos.