- #1
edpell
- 282
- 4
Are dark energy and the cosmological constant the same thing?
The cosmological constant is the simplest possible form of dark energy since it is constant in both space and time, and this leads to the current standard model of cosmology known as the Lambda-CDM model, which provides a good fit to many cosmological observations as of 2014.
Kkangliu said:No, there are not the same thing. the cosmological constant was firstly introduced by Albert Einstein in his theory general relativity to hold back gravity, so it is a negative force also know as lambda. After Hubble discovery that our universe is expanding, it imply that cosmological constant exist. Because if lambda don't exist, then due to the gravity, our universe should collapse not accelerate, by the way, according to the survey about 69% mass-energy in the universe are dark energy. and dark energy is a hypothetical form that explain whatever matter is responsible for the accelerating or expanding of the universe, in other words, cosmological constant is the expression of the dark energy
Dark energy is a hypothetical form of energy that is believed to be responsible for the observed accelerating expansion of the universe. It is different from the cosmological constant, which is a constant energy density that was introduced by Albert Einstein in his theory of general relativity to explain the observed static universe. Dark energy is a more recent concept and is not a constant, but rather a dynamic force that is thought to be driving the expansion of the universe.
Dark energy is not directly observable, but its existence is inferred through observations of the universe's expansion rate. In the late 1990s, astronomers discovered that the expansion of the universe is actually accelerating, which is in direct contrast to what was expected based on the effects of gravity. This acceleration is attributed to the presence of dark energy.
No, dark energy is not the only possible explanation for the accelerating expansion of the universe. Other theories, such as modified theories of gravity, have been proposed to explain the observed acceleration. However, dark energy is currently the most widely accepted explanation and is supported by the majority of observational data.
The cosmological constant is a theoretical concept that is used in Einstein's theory of general relativity to represent a constant energy density in empty space. Dark energy is a more general concept that encompasses the cosmological constant, as well as other forms of energy that may be responsible for the accelerating expansion of the universe.
At this time, dark energy cannot be directly measured or quantified. It is a theoretical concept that is inferred from the observed effects on the expansion of the universe. However, scientists continue to study and develop new methods for understanding and detecting dark energy in order to better understand its nature and properties.