Dark Energy and the Accelerating Universe: Challenges and Opportunities
DOI:
https://doi.org/10.61173/tzd36b79Keywords:
Dark energy, accelerating expansion, cosmological constant (Λ)Abstract
The authors of this article start from the observation of unexpected luminosity of type la supernovae in 1998 Supernova Cosmological Project to the classification of dark energy in the ΛCDM model, and finally to the modern theory of dark energy model, including Dynamical Dark Energy, Interacting Dark Energy theory and Holographic Dark Energy theory. The concept of cosmological constant is illustrated, leading to the introducing of the two main problems encountered when investigating dark energy, Fine-tuning and coincidence problems. As possible solutions to these cosmological problems, Holographic Dark Energy and Interacting Dark Energy are introduced as a supplement to the theory of Dynamical Dark Energy, all of which are trending theory with the potential to provide a consistent explanation and model for dark energy and simultaneously accelerating expansion of the universe. Space observation projects and existing theories are combined to illustrate possible future developments in dark energy theories which also link back to the Standard Model of physics, such as Quantum Gravity theory.
References
why the dark energy density is so small but nonzero, if Astronomical Society, 2010, 405(4): 2639–2650. any theory regarding OG wants to be consistent [14]. [2] Perlmutter, S., Supernovae, Dark Energy, and the
String theory tries to replace point-like particles in the Accelerating Universe, Physics Today, 2003, 56(4): 53–60. Standard Model of particle physics with a one-dimension- [3] Hu, W.; Dodelson, S., Cosmic Microwave Background al line called string and is a theory of QG [15]. It probes Anisotropies, Annual Review of Astronomy and Astrophysics,
a scale smaller than particle scales, stating that strings 2002, 40: 171–216. behave like particles when the scale grows larger. The vi- [4] Planck Collaboration (N. Aghanim et al.), Planck brational state of strings corresponds to graviton, a type of 2018 results. VI. Cosmological parameters, Astronomy &
quantum particle with gravitational energy. Since String Astrophysics, 2020, 641(A6): 1–67. theory combines gravitational force with other three fun- [5] Tripathi, A.; Sangwan, A.; Jassal, H. K., Dark energy damental forces, it is a candidate as Theory of Everything equation of state parameter and its evolution at low redshifts, that can describe everything inside the scope of Standard Journal of Cosmology and Astroparticle Physics, 2017, Model of physics. Therefore, String theory is still required 2017(06)012: 1–15. to solve Fine-tunning problem and the coincidence prob- [6] Padmanabhan, T., Cosmological constant—the weight of the
lem, if it wants to be consistent. vacuum, Physics Reports, 2003, 380: 235–320. [7] Weinberg, S., The Cosmological Constant Problem, Reviews
of Modern Physics, 1989, 61(1): 1–23. 6. Conclusion [8] Prat, J.; Hogan, C.; Chang, C.; Frieman, J., Vacuum Current understanding of the nature of dark energy is Energy Density Measured from Cosmological Data, Journal of
inadequate, even if the dark energy equation of state pa- Cosmology and Astroparticle Physics, 2022, 2022(06)015: 1–20. rameter is still under discussion and without finalized con- [9] Samaddar, A.; Singh, S. S., CPL-parametrized cosmic firmation. Additionally, no consistent theory existed can expansion in Galileon gravity: constraints from recent data,
solve Fine-tunning problem, the calculated value of dark arXiv, 2025, 2508.14392: 1–17. energy density 120 times larger than observed, and the [10] Wang, S.; Wang, Y.; Li, M., Holographic Dark Energy,
coincidence problem, the matter energy density parameter Physics Reports, 2017, 696: 1–57. being around of the same order of dark energy density pa- [11] van der Westhuizen, M. A.; Abebe, A., Interacting dark rameter. A correct and adequate understanding of the role energy from parameterizations: A revisit, Journal of Cosmology
that dark energy played in the evolution of the universe and Astroparticle Physics, 2024, 2024(01)048: 1–29. is lack; despite having already agreed that dark energy [12] Landim, R. G., Dark energy, scalar singlet dark matter and
drives the accelerating expansion of the universe. the Higgs portal, Modern Physics Letters A, 2018, 33(15): 1–10. As stated, the new observation results are expected to pro- [13] Kannan, R.; Garaldi, E.; Smith, A.; Pakmor, R.; Springel, vide important data to dark energy models, and hopefully, V.; Vogelsberger, M.; Hernquist, L., Introducing the THESAN a final dark energy model that is able to explain Fine-tun- project: radiation‑magnetohydrodynamic simulations of ning and the coincidence problem and is also consistent the epoch of reionization, Monthly Notices of the Royal
within the cross-investigation of different observation Astronomical Society, 2022, 511(3): 4005–4030. results. [14] Esposito, G., An introduction to quantum gravity, arXiv,
Therefore, the existence of dark energy plays a vital role 2011, 1108.3269: 1–58. in the evolution of the universe from the 1998 Supernova [15] Wray, K., An Introduction to String Theory, Preprint, 2011, Cosmological Project to the late-time Integrated Sachs- —: 1–324. Wolfe effect. It also links to the Theory of Everything as
Downloads
Published
Issue
Section
License
Copyright (c) 2025 by the authors.
This work is licensed under a Creative Commons Attribution 4.0 International License.
