Main HN discussion is here:<p><a href="https://news.ycombinator.com/item?id=12702759" rel="nofollow">https://news.ycombinator.com/item?id=12702759</a><p>Incidentally, it is interesting to see how many folks uniformly have the same misconception that dark matter is only about explaining galactic rotation curves. Obviously it's not at all surprising or troubling that laymen aren't experts, but the mistaken information is really far from random.
To answer questions:<p>1) We still need dark matter. This mostly focuses on small satellite galaxies. Not galactic rotation, galaxy cluster interaction, or light lending though Galaxy Clusters.<p>2) The main interesting tidbit is that it seems the density of Galaxies in the Universe has changed sharply in the past 1billion years. Which may lend more data points to Dark Energy/Inflation models.
We build a bigger, better telescope. Soon... "Observable universe contains 100x more galaxies than previously thought"<p>Downvote me all you want, I've seen the predicted amount of galaxies in the universe increase by factors of 10 and 100 time and time again over the years. This is not the first time our scientists' best guess has increased by a factor of 10 and it won't be the last.
Plot twist: they don't actually exist; it's like looking into the sparkles in car paint under a constantly changing POV and direction of light.