Consequences of a Universe without Dark Matter or Dark Energy

Introduction to Dark Matter and Dark Energy

Throughout the history of astronomy, two mysterious components of the universe have puzzled scientists: dark matter and dark energy. They both contribute to the structure and expansion of the universe. If these components were to vanish, the cosmos as we know it might face dramatic changes. Let's explore what would happen to our universe if either dark matter or dark energy were to disappear.

Dark Matter’s Absence and Its Impact on the Universe

If dark matter were to suddenly vanish, the structure of the universe would undergo fundamental transformations. Dark matter is believed to hold galaxies together, forming the elaborate spirals and shapes we observe in the night sky. If it were replaced by normal matter, the night sky might transform into a different, less visually stunning configuration. Imagine long strings of visible matter connecting galaxies, forming a cosmic web reminiscent of a spider's nest.

According to Einstein, space, time, and gravity are inextricably linked to matter. When matter vanishes, so too does space and time. Einstein's theory of general relativity posits that time and space, and thus gravity, have no separate existence from matter. If dark matter were to vanish, these fundamental aspects of the universe could also change, leading to significant alterations in cosmic dynamics.

Dark Energy’s Role and Future Forecasts

While dark matter holds galaxies together, dark energy drives the accelerated expansion of the universe. As time progresses, the distribution of matter becomes more sparse due to the expansion of the universe. However, dark energy remains constant, maintaining a consistent density throughout the cosmos. This means that as the universe expands, the proportion of dark energy relative to matter decreases, ultimately leading to a domination of dark energy in the future.

The current ratio of dark energy to matter is 68:32. In the next 10-11 billion years, as the linear scale of the universe doubles, the density of matter will decrease to 1/4, while the density of dark energy will increase to 4/4.25 or 94% of the mass-energy density. Another doubling of the linear scale will result in dark energy comprising over 99% of the mass-energy content of the universe.

The 'Sea' of Photons and the Four States of the Universe

The universe is essentially a vast 'sea' of photons, which exist in four distinct states: the ground state (vacuum), free state (electromagnetic waves), plasma state, and matter state. These four states interact with one another, shaping the fundamental nature of the universe.

Conclusion

The presence of dark matter and dark energy is not just theoretical; they are essential components that define the structure and evolution of our universe. The disappearance of either would result in dramatic and unforeseen changes. Understanding these components and their role in the cosmos is crucial for our comprehension of the universe's past, present, and future.