Unveiling Cosmic Secrets: Dark Energy

Published by on November 13, 2023

In the grandness of space, a recent study with the eROSITA X-ray telescope has revealed new insights into how our universe functions by exploring the fabric of space and time. The extended Roentgen Survey with an Imaging Telescope Array (eROSITA) X-ray, is essentially a space-based observatory designed to survey the sky in X-rays (Eppinga, 2023). Through this, the energetic universe can be captured (Figure 1). By focusing on galaxy clusters, scientists have discovered that dark energy appears to be uniformly distributed in space, constant in time (Maximilian, 2023).

Figure 1: X-ray (top row) and optical pseudo-colour (bottom row) images of three low-mass clusters identified in Final Equatorial-Depth Survey (eFEDS) survey data. The highest redshift cluster comes from a time when the Universe was approximately 10 billion years younger than today. The cluster galaxies in that case (farthest left cluster) are clearly much redder than the galaxies in the other two clusters. These galaxy clusters were used to determine the extent of dark matter across space and time (Eppinga, 2023).

This cosmic exploration traces its roots to the 1920s, when Edwin Hubble’s observations unveiled the expanding universe. In 1998, scientists further found that not only is it expanding, but actually accelerating. To explain this cosmic acceleration, scientists coined the term “dark energy”. Dark energy is a mysterious force, seemingly pushing celestial bodies apart through an anti-gravity effect (NASA, 2024). 

With the help of the eROSITA X-ray telescope, a team led by I-Non Chiu from National Cheng Kung University, alongside Ludwig Maximilian University (LMU) astrophysicists Matthias Klein, Sebastian Bocquet and Joe Mohr, delved into the mysteries of dark energy (Maximilian, 2023). To explore the mysteries of dark energy, they focused on galaxy clusters, which are massive congregations of galaxies (Maximilian, 2023). Dark energy’s influence disrupts the gravitational pull, impacting the formation of massive cosmic structures like galaxy clusters. The eROSITa Final Equatorial-Depth Survey (eFEDS) identified around 500 galaxy clusters (Eppinga, 2023). Tracking the number of these clusters over time would provide valuable insights into the nature of dark energy (Maximilian, 2023).

In pursuit of understanding the secrets of dark energy, the team utilized the eFEDS data and collaborated with the Hyper Suprime-Cam Subaru Strategic Program. This collaboration enabled a more thorough understanding of galaxy clusters, including precise measurements of their masses. The result of this groundbreaking research revealed that dark energy accounts for 76% of the universe’s total energy density (Eppinga, 2023). By meticulously merging these datasets, scientists have broadened our view of the cosmos and enhanced our understanding of the cosmic dynamics at play. Moreover, the calculations derived from this study suggested that the energy density of dark energy exhibits a uniform distribution in space and remains constant throughout the cosmic timeline (Thabet, 2014).

This uniformity solidifies dark energy’s dominance in the cosmic energy landscape and challenges previous notions of spatial variability. These empirical insights broaden our understanding of space and underscore the need for continued exploration of dark energy. The data prompts further questions, pushing us to delve deeper into the fundamental forces shaping our universe.

The insights from the eROSITA X-ray telescope not only deepens our cosmic understanding but also has practical implications for the future. A comprehensive grasp of dark energy’s properties, such as its uniform distribution in space and constancy over time, provides a solid foundation for future advancements in cosmology and astrophysics.

References

Eppinga, A., 2023. Unravelling the Enigma of Dark Energy with eROSITA X-Ray Telescope. Innovation Origins, [online] Available at: <https://innovationorigins.com/en/unravelling-the-enigma-of-dark-energy-with-erosita-x-ray-telescope/> [Accessed: 13 November 2023]

Maximilian, L., 2023. Study using X-Ray telescope indicates that dark energy is uniformly distributed in space and time, [online] Available at: <https://phys.org/news/2023-05-x-ray-telescope-dark-energy-uniformly.html> [Accessed: 13 November 2023]

NASA, 2024. Building Blocks. [online] NASA. Available at: <https://science.nasa.gov/universe/overview/building-blocks/> [Accessed 27 March 2024].

Thabet, M., 2014. The Understanding and Calculation of ‘Dark Energy and Dark Matter’. Available at SSRN 2447616. p.1-42. https://doi.org/10.2139/ssrn.2447616.