What is Modified Newtonian Dynamics (MOND)? скачать в хорошем качестве

What is Modified Newtonian Dynamics (MOND)?

Modified Newtonian Dynamics (MOND) is a theoretical framework proposed as an alternative to the standard Newtonian dynamics and the need for dark matter to explain certain astronomical observations. The concept of MOND was introduced by physicist Mordehai Milgrom in the early 1980s. MOND suggests a modification to the law of gravity at low accelerations, where it deviates from the predictions of standard Newtonian physics. Key features and principles of Modified Newtonian Dynamics include: Acceleration-Dependent Modification: MOND proposes that Newtonian dynamics, which works well at larger scales, breaks down at very low accelerations. Instead of relying on dark matter to explain the observed gravitational effects, MOND introduces a modification to the law of gravity that becomes significant at these low accelerations. Critical Acceleration: In MOND, there is a specific acceleration scale known as the "critical acceleration." Below this critical acceleration, the gravitational force is hypothesized to become stronger than predicted by Newton's laws. Above this acceleration, standard Newtonian dynamics is assumed to hold. Galactic Rotation Curves: MOND was originally proposed to address the observed rotation curves of galaxies. According to standard Newtonian dynamics, the outer regions of galaxies should rotate more slowly than is observed based on the visible matter alone. MOND attempts to explain this discrepancy without invoking the presence of unseen dark matter. Cosmological Implications: While MOND was initially developed to address galactic rotation curves, it has been extended to cosmological scales to account for observations related to galaxy clusters and large-scale structures. However, MOND faces challenges in providing a comprehensive explanation for all cosmological observations. Alternatives to Dark Matter: MOND is considered an alternative hypothesis to the existence of dark matter, which is an as-yet-undetected form of matter believed to make up a significant portion of the total mass in the universe. MOND suggests that the observed gravitational effects attributed to dark matter can be explained by modifying the laws of gravity. Challenges and Criticisms: While MOND has had some success in explaining certain observations, it faces challenges and criticisms. Critics argue that MOND lacks a fundamental theoretical foundation and that it is less successful in explaining a wide range of observations compared to the dark matter paradigm. It's important to note that the debate between modified gravity theories like MOND and the dark matter paradigm is ongoing within the scientific community. Observations from various astrophysical scales continue to be studied to test the validity of these competing theories and to further our understanding of the nature of gravity and the mass content of the universe.