How Do We Discern Dark Matter from Dark Energy in the Universe?

[paweld]

How it's possible to discern dark matter from dark energy?
Why do we need both things? How we can tell so accuratelly that the universe
is made up 71.3% of dark energy and 27.4% of a combination of
dark matter and baryonic matter.
Thanks for answer.

 

[paweld]

I find it in wikipedia:

The total amount of matter in the universe (including baryons and dark matter), as measured by the CMB, accounts for only about 30% of the critical density.

How it's possible to determine amount of matter from these measurements.

 

[Chalnoth]

How it's possible to discern dark matter from dark energy?
Why do we need both things? How we can tell so accuratelly that the universe
is made up 71.3% of dark energy and 27.4% of a combination of
dark matter and baryonic matter.
Thanks for answer.

The behavior of the two is completely different.

Dark matter is a name for the missing matter we see in objects like galaxies and galaxy clusters. Basically, when we look at these objects, we find that most of the matter is in a non-visible component. Currently we've narrowed down the possibilities so that we're reasonably sure that dark matter is composed of some sort of massive particle that interacts only weakly with itself and with normal matter (somewhat like neutrinos, but neutrinos would have had too much kinetic energy when produced to explain our observations).

Dark energy, by contrast, is used to explain a very different sort of observation: the expansion of our universe after a few billion years ago has begun to accelerate. Right now it is much more speculative and open as to the possible explanations, but some of them have been eliminated, at least. Currently the prevailing explanations are some sort of modification of gravity at extremely large distances or an energy field that tends to stay constant or nearly constant in density as the universe expands.

 

[blandrew]

How it's possible to discern dark matter from dark energy?
Why do we need both things? How we can tell so accuratelly that the universe
is made up 71.3% of dark energy and 27.4% of a combination of
dark matter and baryonic matter.
Thanks for answer.

The 71.3% is the negative pressure energy that's required for the accelerating expansion model of the universe to be complete.

Although Einstein believed the universe to be static at the time, GR had flexibility to accommodate "Dark Energy" known as The Cosmological Constant.

Or so I believe.

 

[sardar]

I am glad to see that you are interested in understanding the concepts of dark matter and dark energy. These are two of the most intriguing and mysterious components of our universe.

Firstly, it is important to note that dark matter and dark energy are two distinct phenomena and cannot be discerned from each other. Dark matter is a type of matter that does not interact with light or any other form of electromagnetic radiation, making it invisible to our telescopes. It is believed to make up about 27.4% of the total mass and energy of the universe. On the other hand, dark energy is a mysterious force that is causing the expansion of the universe to accelerate. It is believed to make up about 71.3% of the total mass and energy of the universe.

So, how do we know that these two components exist if we cannot observe them directly? Scientists use a variety of methods to study the effects of dark matter and dark energy on the visible matter and energy in the universe. For example, the gravitational effects of dark matter can be observed on the motions of stars and galaxies. Additionally, the cosmic microwave background radiation, which is the leftover heat from the Big Bang, provides evidence for the existence of dark matter and dark energy.

Furthermore, scientists also use sophisticated mathematical models and simulations to study the behavior of dark matter and dark energy. By comparing these models with observations, we can determine the proportion of dark matter and dark energy in the universe.

It is important to have both dark matter and dark energy in our understanding of the universe because they play crucial roles in shaping the structure and evolution of the universe. Dark matter is responsible for holding galaxies and clusters of galaxies together, while dark energy is driving the expansion of the universe.

Lastly, the accuracy of the percentages you mentioned (71.3% dark energy, 27.4% dark matter and baryonic matter) is based on a combination of observational data and theoretical models. As our technology and understanding of the universe improve, these numbers may be refined, but for now, they provide the best explanation for the composition of the universe.

I hope this response has helped to clarify the concepts of dark matter and dark energy for you. As scientists, we are continuously studying and researching these phenomena to unravel the mysteries of our universe.