New answers tagged

0

There are indeed models for halos made of warm dark matter. The profiles will depend on exactly what the dark matter is and what its temperature is. I am no expert, but a starting point could be a paper by Vinas et al. (2012), who claim that the profiles are much flatter in the centre than those of CDM halos. http://arxiv.org/abs/1202.2860 Hot dark matter ...


3

For the first part of your question, @userLTK has already provided a very good explanation, and I believe that by introducing redshift, the second part of your question is also partially answered. I will try to expand a little on it, hoping that I have understood your question correctly. To start off, I'm going to go ahead and quote my own thesis (not yet ...


2

For any local map of galaxies, the relative velocity is slow enough as to be irrelevant. Andromeda and the Milky way are roughly 2.5 million light years apart and they are moving towards each other currently at about 1 light year every 2,270 years (based on 402,000 km/h). In the 2.5 million years that it takes for Andromeda's light to reach us, it's ...


9

Let me see if I can answer at least some of this. Yes, there is dark matter between galaxies. This is demonstrated by the fact that in galaxy groups and clusters, you need more dark matter than is found in the galaxies themselves to explain what's going on: in terms of why the groups or clusters are gravitationally bound in spite of the extreme velocities ...


4

The short answer to your question is no, there is not dark matter between galaxies, at least at any appreciable level. There is ordinary matter between galaxies, called the intergalactic medium (IGM). The IGM is an extremely dilute, hot gas that pervades the space between galaxies. The typical density of the IGM is about one hydrogen atom per cubic meter ...


1

No, "dark fluid" is not a synonym for dark matter. The Daily Mail article derives from a press release by the EPFL and an article in Science magazine, neither of which mention the word 'fluid'. We don't know what dark matter is yet. There are several theories. One of them compares dark matter to a fluid: Normally speaking, subatomic particles ...


-1

The Great Attractor at the heart of the Laniakea Supercluster meets the criteria. Light does not make for a good sign post. If I continually accelerate I am always changing reference frames but my perspective on the speed of light will always be the same. How can you tell what ABSOLUTE frame of reference an observers is in when the absolute signpost of ...



Top 50 recent answers are included