Proportion of energy compared to mass in universe

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SUMMARY

The discussion centers on the relationship between energy and mass in the universe, specifically addressing the concepts of dark matter and dark energy. It clarifies that dark matter and dark energy are distinct entities, not different forms of the same substance, and emphasizes that in cosmology, both are treated as "mass-energy." The conversation highlights that while total energy in the universe remains constant, its forms evolve from high entropy to low entropy, with dark energy driving the accelerated expansion of the universe. Key equations in cosmology utilize energy density to describe all constituents, including thermal energy.

PREREQUISITES
  • Understanding of mass-energy equivalence as described by Einstein's equation E=mc².
  • Familiarity with cosmological concepts such as dark matter and dark energy.
  • Knowledge of energy density and its role in the universe's evolution.
  • Basic grasp of entropy and its implications in thermodynamics and cosmology.
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  • Research the implications of dark energy on cosmic expansion and its role in the universe's future.
  • Explore the concept of energy density in cosmology and its mathematical formulations.
  • Study the differences between dark matter and dark energy, including their properties and effects on the universe.
  • Investigate the theories surrounding the evolution of the universe from the Big Bang to its current state.
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Astronomers, physicists, cosmologists, and anyone interested in understanding the fundamental principles governing the universe's structure and evolution.

auntio
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In Wikipedia article dark matter, there is a picture that shows us the proportion of matter and energy in the current universe - CMB.

It seems to suggest there is nothing that exists as energy form except dark energy - which we are yet to see - and every observable exists as matter forms.

Is this correct interpretation?

Of course, I know that matter's mass can be converted into energy by Einstein's basic and famous equation.

If every observable exists as matter, is energy always converted to matter after being converted into energy from matter?

Thanks.
 
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there is a picture that shows us the proportion of matter and energy in the current universe - CMB.
The names "Dark Energy" and "Dark Matter" seem to imply that both are essentially the same, one in the form of energy and the other in the form of "matter".
That's not true, they are just - unfortunate, btw - names. Both things have nothing in common, and they are certailny not different form of the same substance.
One does not discern "matter" and "energy" in cosmology. Both are called "mass-energy" in the Wiki article you cited.
The relevant equations all work with "energy density" for all constituents of the universe, which includes e.g. thermal energy.
 
Is this correct interpretation?

no...for a better overall perspective see this brief discussion:



I forget where I got the following..maybe from post in these forums:

These few paragraphs provide a brief overview of how energy is believed to evolve from beginning to end. A most basic fact is that the universe evolves: We do not live in a static cosmos. Total energy in the universe is constant, but its form is steadily evolving from a low entropy to a high entropy form. All forms of energy, such as matter, fission, fusion, and kinetic and potential energy are precisely offset by the negative gravitational potential of everything. All energy is contained either in matter or force fields and the theoretical Higgs field which imparts mass to certain particles (as protons, neutrons and electrons).


The universe not only expands but the expansion is accelerating. All appears to have started from a bang, perhaps infinite, perhaps finite, depending on the model of your choice, but the universe began from a very high energy, high temperature, unstable state.
It evolves towards a more stable lower temperature state and might eventually reach absolute zero in the big bang model. Inflationary energy created exponential expansion just after the big bang and such energy decays into radiation via quantum mechanical processes. Cyclic models reflect repeated expansions and contractions powered by the endless cycling of energy between gravity, forms of dark energy, kinetic and potential energy.

In the beginning it’s believed most energy was in the form of heat radiation and inflationary (vacuum) energy from which space, time, and matter evolved. As the universe expands, the total vacuum energy increases and its repulsive nature causes space to expand even faster…in a run away exponential expansion. In the big bang model, dark energy powers an accelerated expansion after 9B years as it over powers the gravitational attraction of matter. [we are in this phase currently]

Matter energy density decreases as volume grows and matter spreads out; while radiation energy density not only decreases but its wavelength is stretched further by expansion depleting its energy faster, so radiation density falls faster than the energy density of matter. Dark matter energy density remains nearly constant. Dark matter dominated the past; dark energy will dominate the future.
 

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