You would imagine that one big project is enough for Marina Abramovic to tackle at a time; but quite the contrary. “512 Hours” is the new performance work opening today in London’s Serpentine Gallery. The title is obvious, named for the amount of hours that Ms. Abramovic will spend in a completely empty gallery space. Unlike “The Artist is Present”, there is no chair in the space, it’s a totally black space. No plan is her plan… nothingness. “The idea is that the public is my material, and I am theirs”. If you happen to visit London this summer and are curious, check out “512 Hours” which is at the Serpentine Gallery through August 25th.