Ellen's fascinated by dark matter, that mysterious stuff astronomers think might compose more than 70% of the universe, so I'm sure she'll be interested in this RedNova report on a new effort to measure dark matter on an intergalactic scale. By studying a very large and very distant galatic cluster, astronomers are able to use gravitational lensing to make a more accurate study of the dark matter within the system. I was most impressed by this:

Despite its distance of 4.5 thousand million light-years (about one third of the look-back time to the Big Bang) from Earth, this massive cluster is wide enough to equal the angular size of the full Moon.

If that doesn't make you feel small then you're not paying attention.