Understanding Dark Matter’s Gravitational Interaction: Attraction or Repulsion?

Dark matter is a mysterious substance that makes up a significant portion of the universe. It was coined to explain the gravitational forces needed to hold spinning galaxies together. The prevailing belief is that dark matter exerts attractive gravitational forces, much like how visible matter does. However, recent theories and observations are challenging this conventional wisdom and offer a more complex view of dark matter's behavior.

The Traditional View: Attraction

Initially, dark matter was proposed to fill the void and provide the necessary gravitational force to hold galaxies together. Based on this logic, it seemed logical that dark matter would also exert an attractive force towards other dark matter. This attractive force would ensure that dark matter does not form large conglomerations but rather remains dispersed throughout the universe.

New Theories and Observations: No Attraction or Repulsion

However, modern theories and observations suggest a more nuanced view. It is now believed that dark matter might not have any attractive or repulsive forces. In other words, one cloud or clump of dark matter could simply move without interacting with others. This movement is governed by the physics of space itself or its region, much like how stars and galaxies move according to gravitational forces.

Dark Matter and Pressure

One hypothesis suggests that dark matter repels each other at the center to create pressure through the expansion of space. This repulsion is limited to the critical point and initiates a chain reaction. This theory challenges the current understanding of dark matter and introduces a new dimension to its behavior in the universe.

The Cold Dark Matter Conjecture and Its Critics

Another theory suggests that dark matter is "cold," meaning it consists of massive, slow-moving particles. These particles, it is thought, would form clumps in orbit and eventually fall onto massive bodies. However, this theory is not widely accepted due to several observations and theoretical inconsistencies.

Some researchers argue that cold dark matter does not align with the observed distribution of dark matter in the universe. They propose a different model where dark matter particles are photons that radiate from ordinary massive matter. This hypothesis offers a more unified theory that can explain the observed phenomena without the need for slow-moving particles.

Conclusion

Understanding the nature of dark matter and its gravitational interactions is a complex and ongoing field of research. While the traditional view suggests that dark matter exerts attractive forces, modern theories and observations provide a more nuanced view. Whether dark matter attracts, repels, or simply moves independently according to the physics of the universe remains a fascinating and open question in astrophysics.

References

For further reading, please refer to the following sources:

NASA - Dark Matter Attraction Arxiv - New Models of Dark Matter Course Page - Dark Matter