The Hidden Mass: Dark Matter’s Influence on the Milky Way скачать в хорошем качестве

The Hidden Mass: Dark Matter’s Influence on the Milky Way

#MilkyWay #GalacticRotation #DarkMatter #Astronomy #GalacticDynamics #NewtonianPhysics #DopplerEffect #CosmicMysteries In this video, we continue our exploration of the Milky Way by delving into its rotation and the intriguing discovery of dark matter. After examining the Milky Way’s spiral arms, we now ask a fundamental question: how fast is the Milky Way rotating? This inquiry takes us back to the foundational work of Isaac Newton and the heliocentric model proposed by Nicolaus Copernicus. Newton’s laws of motion and gravity allow us to understand the rotational dynamics of galaxies. By examining the rotation curves of the Milky Way, we notice something peculiar. Using Doppler shifts to measure the speed of gas clouds and stars, we observe that the inner parts of the galaxy rotate as if they are a solid body. However, the outer parts exhibit what is known as differential rotation, where the orbital speed remains roughly constant regardless of the distance from the galactic center. This behavior defies the expected Keplerian drop-off, where objects farther from the center should orbit more slowly. This discrepancy led astronomers to propose the existence of dark matter—an unseen and mysterious form of matter that exerts gravitational influence, accounting for the flat rotation curves observed in the Milky Way and other spiral galaxies. The only way to maintain a constant rotational speed at greater distances is for the mass of the galaxy to increase proportionally with the radius. This implies the presence of significant mass beyond the visible stars and gas. We utilize numerous methods to study dark matter, such as analyzing the rotation curves of external galaxies, looking for microlensing events, and observing gravitational lensing by galaxy clusters. These approaches collectively indicate that dark matter is ubiquitous, extending well beyond the luminous parts of galaxies. Evidence for dark matter extends beyond individual galaxies to galaxy clusters. Figures like Fritz Zwicky and Vera Rubin demonstrated that clusters of galaxies also require substantial amounts of dark matter to explain their dynamics. Observations of X-ray emitting gas within clusters, gravitational lensing, and the behavior of galaxy clusters during collisions support the notion that dark matter constitutes about 90% of the total mass in these systems. We explore the various candidates proposed for dark matter, such as MACHOs (massive compact halo objects) and WIMPs (weakly interacting massive particles), along with more exotic particles like axions and sterile neutrinos. While none of these candidates have been definitively detected, ongoing research continues to refine our understanding. The significance of dark matter reshapes our comprehension of the universe, indicating that most of the mass in the cosmos is non-luminous and interacts primarily through gravity. Understanding dark matter is critical for unraveling the full story of our galaxy and the broader universe. Join me in this deep dive into the mysteries of dark matter and the rotational dynamics of the Milky Way. We will explore the evidence, theories, and ongoing research that continues to push the boundaries of our knowledge in astronomy. 0:00 Introduction 0:01 The Link to Newton's Gravity 4:41 Circular Motion due to a Central Force 6:16 Circular Motion due to Gravity 7:16 Measuring Rotation Speed of Galaxies 8:54 The Rotation of the Galaxy's Disk 13:30 The Mass of the Milky Way Galaxy 16:56 Example: Milky Way 19:56 Dark Matter in the Milky Way 21:43 Rotation Curves of Other Galaxies 23:20 23% is Dark Matter 26:38 The Dark Matter of the Milky Way Galaxy 30:31 Dark Matter Halos 31:27 Dark Matter in Galaxy Clusters 38:45 The Musket Ball Cluster