Is there a relationship between dark matter and anti-matter?

In summary, the OGLE micro-lensing project initially searched for dark matter through massive compact objects, but has since found more success in discovering exoplanets. The MACHOs theory, which proposed dark matter as invisible 'normal matter', is now largely abandoned due to recent observations of the Universe. The CMB observations have further disproved this theory. Anti-matter is not related to dark matter and their properties are different, with dark matter having no electric charge. Further research is needed to fully understand the nature of dark matter.
  • #1
Dade Murphy
5
0
Hello,
I've been reading articles about the OGLE micro-lensing project, which started out looking to find dark matter as 'massive compact objects,' but now seems to have had more success finding exoplanets. Searching the forums here I couldn't find much recent discussion about theories of this sort, but a lot about the WIMP theory, which I understand is the most popular. Is it safe to say that the MACHOs theory is pretty well abandoned?

Thanks for your time,
 
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  • #2
As far as I know this theory is not as yet completely discounted, however the most recent observations of the contents of the Universe seem to suggest that there simply isn't enough density of invisible 'normal matter', such as neutron stars and brown dwarfs to account for dark matter phenomena.
 
  • #3
Dade Murphy said:
Hello,
I've been reading articles about the OGLE micro-lensing project, which started out looking to find dark matter as 'massive compact objects,' but now seems to have had more success finding exoplanets. Searching the forums here I couldn't find much recent discussion about theories of this sort, but a lot about the WIMP theory, which I understand is the most popular. Is it safe to say that the MACHOs theory is pretty well abandoned?

Thanks for your time,
Yes. CMB observations put the nail in that coffin, as the CMB was emitted before any compact objects would have formed, and the signature of dark matter in the CMB itself is very clear.
 
  • #4
Chalnoth said:
CMB observations put the nail in that coffin,
Ah, thanks for updating me on that, I didn't know that CMB had finally laid that one to rest.
 
  • #5
isn't dark matter just reflective matter just anti matter?
 
  • #6
dirty dan said:
isn't dark matter just reflective matter just anti matter?
No, antimatter is something completely different. It would be best to ask any followup questions in a new thread - but only after you've read some of the many dark-matter threads we already have.
 
  • #7
dirty dan said:
isn't dark matter just reflective matter just anti matter?
Anti-matter has all of the exact same properties of normal matter, except that its electric charge is opposite*. Dark matter has no electric charge at all, hence why it is dark. There's no reason to believe that normal matter and anti-matter are related in any sort of simple sense. There is surely a relationship between them, but chances are it's pretty complicated. It certainly involves physics we don't yet know.

* There's also a parity difference, but that is rarely relevant, and doesn't change the overall nature of the argument here.
 

1. What is dark matter?

Dark matter is a type of matter that makes up about 27% of the universe. It does not interact with light, which is why it is called "dark". Its existence is inferred through its gravitational effects on visible matter.

2. How is dark matter different from regular matter?

Dark matter is different from regular matter in several ways. It does not emit or absorb light, it does not interact with electromagnetic forces, and it does not form atoms. Regular matter, on the other hand, does all of these things.

3. How do scientists study dark matter?

Scientists study dark matter through indirect methods. This includes observing its gravitational effects on visible matter, studying the rotation of galaxies, and using particle accelerators to search for its hypothetical particles.

4. What is the current understanding of dark matter?

The current understanding of dark matter is that it is a non-baryonic, or non-atomic, form of matter that makes up a significant portion of the universe. It is believed to be a key component in the formation and evolution of galaxies.

5. Why is dark matter important?

Dark matter is important because it helps explain the structure and behavior of the universe. Without it, the observed movements of galaxies and the formation of large-scale structures could not be explained. Additionally, studying dark matter can also provide insights into the fundamental nature of the universe and the laws of physics.

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