Curious inquiry about exotic matter

[sozme]

Forgive me for being a lay person, I am a medical student and the only physics I've ever had was non-calculus based 200-level. Anyway, I was reading the "wormhole" faqs page from Dr. Rodrigo's webpage via UCal-Irvine: http://www.webfilesuci.org/WormholeFAQ.html

How realistic is it to suppose that exotic matter exists?

Its existence isn’t as far fetched as you might at first think. Four arguments for its likely existence are: 1) The ordinary electromagnetic field is infinitesimally close to being exotic. 2) Quantum effects are known to create negative-energy densities. 3) Something is causing the expansion of the universe to accelerate. Cosmologists have recently speculated that it might be cosmic exotic matter (which they call “phantom energy” or “superquintessence”). 4) Formerly sacrosanct energy conditions have been dying off for the last few decades. Why not a couple more?

I was wondering what your comments might be, in particular about #3. For one, is the theorized dark matter really "exotic" and why must this be so?

 

[Bill_K]

I was wondering what your comments might be, in particular about #3. For one, is the theorized dark matter really "exotic" and why must this be so?

Sounds to me like you're confusing exotic matter, dark matter and dark energy, which are all three different.

 

[sozme]

Sounds to me like you're confusing exotic matter, dark matter and dark energy, which are all three different.

Is dark matter not responsible for the acceleration of expansion via strong negative pressure?

 

[Bill_K]

Is dark matter not responsible for the acceleration of expansion via strong negative pressure?

Nope, that's dark energy. Did you read the Wikipedia articles I pointed to?

 

[pmacias]

Thank you for your question about exotic matter. I am always happy to see someone curious about a topic that may be outside of their field of study. To answer your question, I will provide some background information on exotic matter and address each of the arguments mentioned.

Exotic matter, also known as negative mass or negative energy matter, is a theoretical form of matter that has negative energy density and violates the usual energy conditions of general relativity. It is considered “exotic” because it does not behave like the matter we are familiar with in our everyday lives. As you mentioned, there are several arguments for its existence, and I will address each of them.

1) The ordinary electromagnetic field is infinitesimally close to being exotic.

This argument is based on the fact that the energy density of the electromagnetic field can be negative in certain scenarios. However, this negative energy density is very small and does not violate the energy conditions of general relativity. Therefore, it is not considered true exotic matter.

2) Quantum effects are known to create negative-energy densities.

This is true, and it has been observed in various quantum systems. However, these negative-energy densities are also very small and do not violate energy conditions. Therefore, they are not considered true exotic matter either.

3) Something is causing the expansion of the universe to accelerate.

This is a very interesting argument, as it suggests that exotic matter may be responsible for the acceleration of the universe’s expansion. However, this is still a speculative idea and has not been confirmed by any observations. Additionally, there are other proposed explanations for the acceleration, such as dark energy, which is a form of energy that permeates all of space and is not considered exotic matter.

4) Formerly sacrosanct energy conditions have been dying off for the last few decades. Why not a couple more?

Energy conditions are fundamental principles in general relativity that govern how energy and matter behave in the universe. While some energy conditions have been found to be violated in certain scenarios, this does not necessarily mean that exotic matter exists. It could also mean that our understanding of these energy conditions is incomplete.

In regards to your question about dark matter, it is not considered exotic matter. Dark matter is a form of matter that does not interact with light, making it difficult to observe. It is believed to make up a significant portion of the mass in the universe, but its exact nature is still unknown.

In conclusion, while there are