Distribution and proportion of dark matter in galaxies

In summary, dark matter is a type of matter that cannot be directly observed but makes up about 85% of the total matter in the universe and is crucial to the formation and evolution of galaxies. Its distribution in galaxies is determined through methods such as gravitational lensing and simulations, and varies among different galaxies. The distribution of dark matter also greatly influences the overall structure of galaxies, providing the necessary gravitational pull and shaping features such as spiral arms and halos. The most widely accepted theory about the nature of dark matter is the Cold Dark Matter model, but other theories propose it could be composed of exotic particles like WIMPs or Axions.
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I read that the distribution and proportion of dark matter to regular matter is different for regular-size galaxies and dwarf galaxies. Could you guys elaborate on that?
 
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  • #2
the theory is that dark matter could cover 99 percent of our universe, but today i don't think we know much about it relative to regular matter.
 
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I thought it covered 96%
 
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It could be a lot less depending on how innaccurate our theories are.

We don't really know for sure how gravity works on larger scales.
 
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Yes, that is correct. The distribution and proportion of dark matter in galaxies can vary greatly depending on the size and type of galaxy. Regular-size galaxies, like our own Milky Way, tend to have a higher proportion of dark matter compared to regular matter. In fact, it is estimated that about 85% of the matter in our galaxy is dark matter. On the other hand, dwarf galaxies, which are much smaller in size, have a lower proportion of dark matter. This difference in proportion can be attributed to the fact that dwarf galaxies have less gravitational pull and therefore do not require as much dark matter to maintain their structure.

In terms of distribution, dark matter is believed to be more concentrated towards the center of regular-size galaxies, while in dwarf galaxies it is more spread out. This is due to the fact that regular-size galaxies have a stronger gravitational pull, causing dark matter to be pulled towards the center. In contrast, dwarf galaxies have weaker gravitational pull and therefore dark matter is not as tightly clustered.

It is important to note that the distribution and proportion of dark matter in galaxies is still not fully understood and remains a subject of ongoing research. Scientists are using various methods, such as gravitational lensing and galaxy rotation curves, to study and better understand the properties of dark matter in different types of galaxies.
 
  • #6


I can confirm that the distribution and proportion of dark matter in galaxies is a topic of ongoing research and discussion in the scientific community. It is believed that dark matter makes up about 85% of the total matter in the universe, while regular matter (such as stars and gas) makes up the remaining 15%.

In terms of distribution, dark matter is thought to be more concentrated towards the center of galaxies, while regular matter is more spread out throughout the galaxy. This is due to the fact that dark matter does not interact with light or other forms of electromagnetic radiation, making it difficult to detect and map its exact distribution.

Additionally, the proportion of dark matter to regular matter is believed to be different for regular-size galaxies and dwarf galaxies. Dwarf galaxies are smaller and less massive than regular-size galaxies, and therefore have a higher proportion of dark matter to regular matter. This is because dark matter is thought to play a crucial role in the formation and evolution of galaxies, and smaller galaxies have less regular matter to counterbalance the gravitational effects of dark matter.

However, the exact distribution and proportion of dark matter in galaxies is still a topic of ongoing research and debate, and further studies and observations are needed to fully understand this mysterious component of our universe.
 

1. What is dark matter and why is it important in galaxies?

Dark matter is a type of matter that cannot be directly observed because it does not interact with light. However, it makes up about 85% of the total matter in the universe and plays a crucial role in the formation and evolution of galaxies.

2. How is the distribution of dark matter determined in galaxies?

The distribution of dark matter in galaxies is determined through various methods, such as gravitational lensing, rotation curves, and simulations. These methods allow scientists to infer the presence and distribution of dark matter based on its gravitational effects on visible matter.

3. Are there variations in the proportion of dark matter in different galaxies?

Yes, the proportion of dark matter in galaxies can vary. Some galaxies have a higher percentage of dark matter compared to visible matter, while others have a lower proportion. This is due to factors such as the mass and size of the galaxy, as well as its environment.

4. How does the distribution of dark matter affect the overall structure of galaxies?

The distribution of dark matter has a significant impact on the overall structure of galaxies. It provides the gravitational pull necessary to hold galaxies together and influences the formation of structures such as spiral arms and galactic halos.

5. What are some current theories about the nature of dark matter?

There are several theories about the nature of dark matter, but the most widely accepted one is the Cold Dark Matter (CDM) model. This theory suggests that dark matter is made up of unknown particles that move slowly, or "coldly," compared to the speed of light. Other theories propose that dark matter could be composed of exotic particles, such as Weakly Interacting Massive Particles (WIMPs) or Axions.

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