# Dark Matter as a condensation of photons in a space

• I
• ahmashojaeddin
In summary, the conversation discusses whether the relativistic mass of photons can act as dark matter due to their contribution to gravity. While photons do not have rest mass, their energy can still affect gravity. However, this contribution is negligible in the current epoch of the universe due to the expansion of space. Additionally, photons do not emit photons and can be observed, making them different from dark matter.
ahmashojaeddin
TL;DR Summary
could we think of DARK MATTER as condencation of photons in a space (eg. galactic space) that not yet escaped from that huge wide space due to limitaion of light speed?
if we assume each photon of light as a very very light piece of matter (by famous E = mc^2 and then: m = E / c^2) and sum up all photons that have been made from the creation time of a galaxy (also considering limitation of speed of light) and also photons that accidentally passing throw that galaxy (eg. coming from other galaxies), could we result that, relativistic mass of these photons can act as matter that can curve space-time and doing like DARK MATTER as they don't emmit photons and do not absorb or reflect them?

Astronuc, PeroK and weirdoguy
1) You can't use ##E=mc^2## for photons, since m stands for rest mass and photons have none. The full equation is ##E^2=(mc^2)^2+(pc)^2##, which for zero rest mass reduces to ##E=pc##, where p is momentum.
2) The energy of photons does contribute to gravity, similar to mass. But it's negligible at current epoch in the history of the universe, due to it diluting with the expansion of space faster than any other kind of energy. The only time when there was enough energy in photons in the universe to count for anything was back when the universe was still opaque to light. All the observation suggesting dark matter come from later epochs, and require behaviour different than that of light (such as forming localised overdensities).
3) Photons don't emit photons, but they are photons. Which means they are observable. A shining light bulb is not dark.

Astronuc

## 1. What is dark matter?

Dark matter is a type of matter that makes up about 85% of the total matter in the universe. Unlike regular matter, which is made up of atoms and can be seen and detected, dark matter does not interact with light and cannot be directly observed.

## 2. How is dark matter thought to be a condensation of photons in space?

According to some theories, dark matter is believed to be made up of particles called WIMPs (Weakly Interacting Massive Particles) which are thought to be a type of condensed photon. This means that they are formed from the energy of photons, which are particles of light, in a process called "photon condensation".

## 3. How does dark matter interact with regular matter?

Dark matter does not interact with regular matter through electromagnetic forces, which is why it cannot be seen or detected using traditional methods. However, it does interact with regular matter through gravity, which is how scientists are able to detect its presence.

## 4. What evidence supports the theory of dark matter as a condensation of photons in space?

One piece of evidence that supports this theory is the observation of gravitational lensing, where the gravity of a massive object bends the path of light passing by it. This effect can be explained by the presence of dark matter, which has a gravitational pull but does not interact with light.

## 5. How does the existence of dark matter impact our understanding of the universe?

The existence of dark matter is crucial in explaining the structure and evolution of the universe. Without it, the current theories and models of the universe would not accurately predict the observed behavior of galaxies and the large-scale structure of the universe. It also plays a role in the formation of galaxies and the distribution of matter in the universe.

• Astronomy and Astrophysics
Replies
13
Views
2K
• Astronomy and Astrophysics
Replies
4
Views
2K
• Beyond the Standard Models
Replies
12
Views
2K
• Astronomy and Astrophysics
Replies
4
Views
1K
• Astronomy and Astrophysics
Replies
2
Views
2K
• Cosmology
Replies
23
Views
1K
• Astronomy and Astrophysics
Replies
13
Views
1K
• Astronomy and Astrophysics
Replies
10
Views
4K
• Astronomy and Astrophysics
Replies
7
Views
2K
• Astronomy and Astrophysics
Replies
4
Views
1K