I noticed this on arxiv today. It is by a legitimate academic researcher and it MAY be reasonable for all I know. I can't judge. She is at the UNC-Chapel Hill department of Physics and Astronomy. But my initial impression is weirdness. I would like to be able to go to sleep tonight confident that it is OK to ignore this paper. Anybody want to dispose of it? http://arxiv.org/abs/gr-qc/0609006 The Arrow of Time Forbids a Positive Cosmological Constant [itex]\Lambda[/itex] Laura Mersini-Houghton 6 pages "Motivated by the mounting evidence for dark energy, here we explore the consequences of a fundamental cosmological constant [itex]\Lambda[/itex] for our universe. We show that when the gravitational entropy of a pure DeSitter state ultimately wins over matter, then the thermodynamic arrow of time in our universe must reverse in scales of order a Hubble time. This phenomenon arises from the gravitational instabilities that develop during a DeSitter epoch and turn catastrophic. A reversed arrow of time is clearly in disagreement with observations. Thus we are led to conclude: Nature forbids a fundamental [itex]\Lambda[/itex]. Or else general relativity must be modified in the IR regime when [itex]\Lambda[/itex] dominates the expansion of the Universe."