A highly anticipated recent NASA press conference which promised to "discuss an astrobiology finding that will impact the search for evidence of extraterrestrial life" fell rather flat when it was revealed that what they were talking about was arsenic, not ETs. But scientists are excited because the discovery of bacteria that can thrive on arsenic–an element that is toxic to most humans and animals–means that our ideas of what it takes for life to develop on a planet need to be expanded. The bacteria was found in Mono Lake in California. CNN quotes researcher Ariel Anbar as saying, "Life as we know it requires particular chemical elements and excludes others, but are those the only options?read more