The Earth is bombarded by solar activity every second; this solar activity consists of charged particles and magnetic fields that connect the Sun to the space environment around Earth. We call it solar wind. The solar wind reacts with the Earth's magnetic field, creating the magnetosphere, which is shaped by different regions, each with different characteristics. The Cluster mission was launched to study the Earth's magnetosphere via four identical satellites with multiple instruments onboard. A key feature of the magnetosphere is plasma; to study plasma, we use the Velocity Distribution Function (VDF) to analyze ion distributions in velocity space. Vlasiator is a theory-based simulation of the magnetosphere built on VDF calculations. The goal of this thesis is to compare Cluster in-situ data with Vlasiator simulations to hopefully achieve a greater attraction for a larger audience. It was found that Cluster data for the CIS-CODIF instrument stopped working at some point during the mission for all but one spacecraft. Interesting results for the VDF show their importance in characterizing each region in the magnetosphere and how the solar wind affects them. We identified eight events between 2001 and 2021 that showed interesting previsions regarding the VDF. In the end, through the lens of esoteric data, similarities between Cluster and Vlasiator were found under selected solar wind conditions. These findings have helped solidify the importance of simulations such as Vlasiator in shaping a more prosperous future.