Wed. Sep 27th, 2023
What is Dark Energy?

Dark energy is a term that has been used in the field of astrophysics for many years. It is a mysterious force that is believed to be responsible for the accelerating expansion of the universe. Despite being one of the most studied phenomena in the field, it remains one of the least understood. In this article, we will provide a glossary of terms related to dark energy, starting with the basics of what it is and how it works.

What is Dark Energy?

Dark energy is a hypothetical form of energy that is believed to permeate all of space and is responsible for the accelerating expansion of the universe. It is thought to make up about 68% of the total energy density of the universe, with dark matter making up about 27% and normal matter making up the remaining 5%.

How Does Dark Energy Work?

The exact nature of dark energy is still unknown, but it is believed to be a property of space itself. As the universe expands, the amount of space between galaxies increases, and this causes the gravitational pull between them to weaken. Dark energy is thought to counteract this weakening by pushing galaxies apart, causing the expansion of the universe to accelerate.

What is the Cosmological Constant?

The cosmological constant is a term that was introduced by Albert Einstein in his theory of general relativity. It is a mathematical constant that represents the energy density of the vacuum of space. Einstein originally introduced the cosmological constant to counteract the gravitational attraction between matter in the universe and prevent it from collapsing. However, with the discovery of dark energy, the cosmological constant has been reinterpreted as a measure of the energy density of dark energy.

What is the Equation of State?

The equation of state is a mathematical relationship that describes the behavior of a substance under different conditions. In the case of dark energy, the equation of state describes how its energy density changes as the universe expands. The equation of state is an important parameter in understanding the nature of dark energy, as it can provide clues about the underlying physics that governs its behavior.

What is the Dark Energy Survey?

The Dark Energy Survey (DES) is a large-scale astronomical survey that aims to study the properties of dark energy and dark matter. The survey uses a 570-megapixel camera mounted on the Blanco Telescope in Chile to observe a large portion of the southern sky. The data collected by the survey is used to create a 3D map of the distribution of galaxies in the universe, which can be used to study the effects of dark energy on the expansion of the universe.


Dark energy remains one of the most intriguing and mysterious phenomena in the field of astrophysics. Despite decades of research, we still know very little about its nature and properties. However, with the help of advanced telescopes and astronomical surveys like the Dark Energy Survey, we are slowly unraveling the mysteries of this enigmatic force. By continuing to study dark energy, we may one day unlock the secrets of the universe and gain a deeper understanding of the fundamental laws that govern our existence.