Something my scientist husband pointed out to me today:

http://www.nature.com/news/temporal-...istory-1.13141

Mind you, physicists are looking at this for various reasons other than what folks who hang around here might be interested in, but it does demonstrate something about the mutable nature of time and space and "the past". Just some food for thought. Also, this particular finding has to do with just hiding data, rather than erasing it, but if it's not visible, it's not visible...