Small Dark Matter Particle Size Illustration
This illustration and its companion are intended to demonstrate the implications of various sizes of dark matter particles. The analogy compares dark matter particles to the people gathered in Times Square. In this image, the people are relatively small and, therefore, can congregate relatively close to one another. In the situation of dark matter, this would mean that astronomers would expect that dark matter would be confined to relatively small areas if the particles were smallish.
(Credit: MIT/J.Arabadjis et al.)

Larger Dark Matter Particle Size Illustration
In this view, the particles (people) are bigger than the other illustration. It is shown that as the size of the people grows, they are forced to scatter farther out into Times Square using this analogy. If this were the case in the universe, then astronomers would expect that dark matter would be spread out over a larger area than if the particles were smaller in size.
(Credit: MIT/J.Arabadjis et al.)

Chandra X-ray Image with Scale Bar
Scale bar = 50 arcsec
Credit: NASA/MIT/J.Arabadjis et al.