Confirmation of a Problem With Gravity Nobody Can Explain : S8 Tension

The video titled "Confirmation of a Problem With Gravity Nobody Can Explain: S8 Tension" by Anton Petrov, published on November 4, 2023, discusses a new problem in cosmology known as the S8 tension. This issue is similar to the previously known Hubble tension but causes different effects and currently lacks an explanation. Key points from the video include: 1. **Hubble Tension Background**: The video starts with a review of the Hubble tension, which relates to the expansion of the universe. In the 1990s, scientists realized the universe was expanding and accelerating, leading to the discovery of dark energy. However, measurements of the Hubble constant in the last decade have shown different values, indicating that the universe's acceleration rate is not constant and lacks a clear explanation. 2. **S8 Tension Discovery**: Recent simulations and observations have confirmed the existence of S8 tension. This phenomenon is related to the clumpiness of matter in the universe, specifically how matter forms larger and more dense objects like galaxies, clusters, and superclusters. The clumpiness of nearby galaxies has been accurately calculated, but there's a discrepancy when compared to the clumpiness measured from the cosmic microwave background (CMB) from 13.8 billion years ago. 3. **Implications and Problems**: The higher clumpiness in the early universe, as indicated by CMB measurements, presents a major problem. It suggests that the standard model of physics might need major restructuring, potentially altering our understanding of gravity. 4. **Potential Explanations and Theories**: The video explores several theories and potential explanations, such as changes in dark energy over time, the impact of galactic winds, or biases in calculations. However, none of these have provided a sufficient explanation for the S8 tension. 5. **Flamingo Simulation**: A significant part of the video discusses the Flamingo simulation, one of the most complex simulations of the universe, which attempted to resolve the S8 tension. Despite its complexity, the simulation did not provide a clear explanation for the discrepancy in clumpiness. 6. **Cosmological Implications**: The S8 tension, along with the Hubble tension, indicates that our current cosmological model might be incomplete or incorrect. This could lead to significant changes in our understanding of the universe. 7. **Future Research and Discoveries**: The video concludes by suggesting that these tensions in cosmology could lead to new discoveries, similar to how the discovery of dark energy reshaped our understanding of the universe in the 1990s. In summary, the video discusses the S8 tension, a new cosmological problem related to the clumpiness of matter in the universe, which challenges current scientific understanding and models.