I Is the Cosmic Void Between Galaxies Truly Empty?

[Mohd Abdullah]

Hey guys,

Regarding the cosmic void between galaxies, is it really empty? If you read articles from pop science sources mostly said "cosmic voids are devoid of matter", "there are full of dark matter", etc.

Thoughts?

 

[phinds]

Hey guys,

Regarding the cosmic void between galaxies, is it really empty? If you read articles from pop science sources mostly said "cosmic voids are devoid of matter", "there are full of dark matter", etc.

Thoughts?

Well, "empty" gets to be a bit more complicated than you might think, as witnessed by the many hundreds of threads on this forum discussing just that.

Basically it is "empty" by human standards but not really. First and foremost there is a huge amount of radiation passing through it plus neutrinos and the odd dust particle here and there.

EDIT: also, NEVER take pop-science seriously.

 

[Drakkith]

Cosmic voids are not completely empty, they just contain a much lower density of matter and dark matter than other areas of the universe (such as around galaxy clusters).

 

[SleepDeprived]

Well I am just going to be happy I don't care. :-).

But seriously while we are on this topic, strictly in technical term, the void doesn't mean cosmic dust, radiation, or dark matter or anything like that. There are supposed to be this Higgs field and who knows what else that we have not discovered. I mean how does gravity wave travel? If indeed gravity waves have been detected, this empty space at least will have some type of gravity field or whatever that is.

 

[Drakkith]

Well I am just going to be happy I don't care. :-).

But seriously while we are on this topic, strictly in technical term, the void doesn't mean cosmic dust, radiation, or dark matter or anything like that. There are supposed to be this Higgs field and who knows what else that we have not discovered. I mean how does gravity wave travel? If indeed gravity waves have been detected, this empty space at least will have some type of gravity field or whatever that is.

Void in this context simply means that the density of matter and dark matter across a very wide area of space is much lower than average. Remember, context matters!

 

[lifeonmercury]

What about the space being created all the time between galaxies. Does that space have any atoms in it?

 

[Drakkith]

What about the space being created all the time between galaxies. Does that space have any atoms in it?

Space is not being "created". The distance between unbound objects is simply increasing over time. (that's a subtle but important distinction)
Also, no, expansion does not create new matter.