Brian Cox Explains What Dark Matter Actually Is To Neil deGrasse Tyson

Brian Cox and Neil deGrasse Tyson break down how scientists know dark matter is real and why it is such an important part of modern cosmology. Brian explains that the evidence for dark matter does not come from just one observation. Scientists see its effects in multiple independent ways, including the structure of galaxies, the large-scale cosmic web, and the cosmic microwave background — the oldest light we can observe in the universe. The cosmic microwave background comes from roughly 380,000 years after the Big Bang, when the early universe had cooled enough for light to travel freely. That ancient light still carries information about what the universe was like at that time. Brian explains that before that light was released, the early universe was filled with hot plasma. Sound waves moved through that plasma, and those waves left measurable patterns behind. Scientists can study those patterns today and compare them with theoretical models. Dark matter plays a major role in making those models match what we actually observe. Brian describes how researchers can change the amount of dark matter in a model and immediately see the prediction shift away from the real data. If you reduce the amount too much, the model stops matching the universe we observe. That is one of the reasons physicists take dark matter so seriously. It is sometimes presented as if scientists simply invented dark matter because galaxy rotation did not make sense. But the evidence goes much further than that. Dark matter also appears in: galaxy formation the cosmic microwave background the cosmic web large-scale structure gravitational effects early-universe physics and precision cosmology Brian also explains why dark matter and dark energy are not the same thing. Dark matter appears to behave more like some kind of invisible matter or particle that affects gravity and structure. Dark energy is even more mysterious and is connected to the accelerated expansion of the universe. Scientists still do not know exactly what dark matter is, but multiple independent observations strongly suggest that something is there. This clip is a great explanation of how modern astrophysics works: scientists do not just make a theory and accept it. They build models, compare those models with real measurements, and see whether the predictions match the universe. Featuring Brian Cox and Neil deGrasse Tyson discussing dark matter, the Big Bang, the cosmic microwave background, galaxy formation, cosmology, astrophysics, and one of the biggest mysteries in modern physics. #BrianCox #NeilDeGrasseTyson #DarkMatter #DarkEnergy #BigBang #Cosmology #Astrophysics #Space #Universe #ScienceExplained More Clips: ‪@learnwhilelaughing‬​