Cosmic dust, often dismissed as a mere annoyance, is revealed to be a fundamental component of the universe's chemistry. It serves as a catalyst for the formation of hydrogen molecules (H2), which are vital for creating molecular clouds, the nurseries for stars. In the cold vacuum of space, hydrogen atoms adhere to dust grains, where they can bond and release energy, forming stable H2 molecules. Furthermore, dust grains can develop icy mantles consisting of compounds like water and carbon dioxide. These icy surfaces absorb ultraviolet radiation from stars, enabling complex organic chemistry to occur, which produces essential molecules such as amino acids and sugars. This chemistry mirrors processes occurring within living organisms, suggesting a cosmic connection to the origins of life. The findings underscore the importance of dust in the cosmic landscape, as it not only facilitates star and planet formation but also contributes to the very building blocks of life. The upcoming Part 4 promises to delve deeper into the implications of dust's role in the universe.