Lawyers for Gary McKinnon, who claims to have hacked into more than 73,000 U.S. computer systems, including those operated by the military services and NASA, started their argument today against his extradition to the United States to stand trial. The 44-year-old hacker allegedly started breaking into U.S. computer systems from his London residence "in 1999, looking for evidence of extraterrestrial beings and technology, which he believed the U.S. government was hiding," according to an article posted by ComputerWeekly.com. U.S. lawyers argue McKinnon caused more than $900,000 in damage hacking into U.S. government systems. McKinnon, who hacked under the name Solo, argued that the United States tried to coerce him into waiving his rights for an extradition hearing. The five judges hearing the arguments will take up to two weeks to issue their ruling.