There Are No Superclusters

Ethan Siegel at Starts With a Bang has a nice post on superclusters of galaxies. You can also leave comments at the synopsis on Science Blogs.

The basic idea of the post is that while people often talk about superclusters, they don’t really exist as structures in the universe. Much like constellations, they might be a convenient way to talk about what we see in the sky but have no existence outside our own minds. This is because superclusters are so large that in the context of an accelerating, dark energy dominated universe, they probably can’t be gravitationally bound.


Boulder Flooding: One Year Later

This week marks one year since the major flooding along the Front Range due to a storm that’s been estimated as a nearly one in a thousand year rainfall event. This year has been quite wet but there haven’t been any major storms like the one last year.

In the city of Boulder, most of the obvious damage has been repaired. Some trails remain closed, and some of the bridges across  Boulder Creek are still out but otherwise you don’t see much damage in town. In more rural areas, the damage still hasn’t been fixed. Construction on US 36 past Lyons was still going on this summer, and there are undoubtedly a number of houses in the mountains that haven’t been rebuilt.