Rethinking Gravity: Unveiling Dark Matter and Dark Energy Secrets

"The cosmos is within us. We are made of star-stuff. We are a way for the universe to know itself." - Carl Sagan

 The Mystery of Dark Matter and Dark Energy: An Amateur Astronomer’s Journey

Introduction

In the last week, while reading, I came across an interesting thought: if we changed the theory of gravity as proposed by Newton, it would no longer be required to explain dark matter. This came as an astounding realization to me. Suddenly, I realized that because of one theory and one assumption, we are dealing with an unexplainable anomaly. We are doing more and more experiments, but the explanation for dark matter is just not within grasp.

 Newton's Theory of Gravity

Newton's theory of gravity has been a cornerstone of physics for centuries. It explains how objects attract each other with a force that is proportional to their masses and inversely proportional to the square of the distance between them. This theory has helped us understand the motion of planets, the behavior of falling objects, and much more.

The Challenge of Dark Matter

Dark matter is an elusive substance that makes up about 26.8% of the universe's mass-energy content. It does not emit, absorb, or reflect light (electromagnetic radiation) , making it invisible and detectable only through its gravitational effects. So, why is dark matter such a big deal?

In the standard Lambda-CDM model of cosmology, the mass–energy content of the universe is 5% ordinary matter, 26.8% dark matter, and 68.2% dark energy. Thus, dark matter constitutes 85% of the total mass, while dark energy and dark matter constitute 95% of the total mass–energy content.

Evidence for Dark Matter

The first real evidence for dark matter came in 1933, when Caltech’s Fritz Zwicky used the Mount Wilson Observatory to measure the visible mass of a cluster of galaxies and found that it was much too small to prevent the galaxies from escaping the gravitational pull of the cluster. Something else, concluded Zwicky, was acting like glue to hold clusters of galaxies together. He named the substance "dunkle Materie," or dark matter in German.

In the 1970s, Vera Rubin and Kent Ford measured the rotation speeds of individual galaxies and found evidence that, like Zwicky’s galaxy cluster, dark matter was keeping the galaxies from flying apart. Other evidence throughout the years has confirmed the existence of dark matter and shown how abundant it is in the universe. In fact, dark matter is about five times more common than normal matter.

Gravitational Lensing and Dark Matter

Gravitational lensing provides a powerful tool to map the distribution of dark matter. Lensing occurs when the alignment between the massive object (lens) and the background light source is very close. It can create multiple images, arcs, or even a complete ring of the background source, known as an Einstein ring.

The Mystery of Dark Energy

Dark energy is just the name that astronomers gave to the mysterious "something" that is causing the universe to expand at an accelerated rate. Dark energy has been described by some as having the effect of a negative pressure that is pushing space outward. The two cosmology projects (the Supernova Cosmology Project and the High-Z Supernova Search) contributed immensely to this platform by studying the red shift in distant supernovae.

An Amateur Astronomer's Perspective

I am an amateur astronomer, and by reading and arranging these thought processes, I am contributing to my own learning, which is the most important objective of such blogs. The mysteries of dark matter and dark energy are vast and intriguing. They challenge our understanding of the universe and push us to explore new theories and ideas.

Conclusion

The exploration of dark matter and dark energy is a journey that continues to captivate scientists and enthusiasts alike. By questioning long-standing theories and examining new evidence, we can expand our knowledge of the cosmos. As an amateur astronomer, I am excited to be a part of this journey, learning and sharing insights along the way.

This blog aims to provide a simple yet comprehensive overview of dark matter and dark energy, making it accessible to young readers and curious minds. The wonders of the universe are within reach, and together, we can continue to explore and understand the mysteries that lie beyond.