Stephen Hawking said there is only one way for humanity to survive another millennium.
"We must continue to go into space for the future of humanity," Hawking said. "I don't think we will survive another 1,000 years without escaping beyond our fragile planet."
The famed physicist spoke via hologram – created using two cameras in his office – before sold-out audiences Saturday and Sunday at the Sydney Opera House, reported the Australian Broadcasting Company.
John Webb, who helped organize the lecture and oversees the Big Questions Institute at the University of New South Wales, said governments tend to overlook long-term solutions to important topics because they cost too much and offer little immediate return.
He said Hawking fears that humanity will ultimately be undone by its innate aggression – which has possibly outlived its usefulness.
"That may have been useful at some point in the early history of humanity, enabling us to find food and get a partner and things like that, but he thinks that aggression that remains with us today is now the thing that could well end up destroying us,” Webb said. "I think he's put a time on it to make us realize we've got to take better control of what we're doing."
The 73-year-old Hawking, who suffers from a motor neuron disease, encouraged his audience to appreciate the wonder of the universe and to make sense of what they see.
"Be curious, and however difficult life may seem, there is always something you can do and succeed at,” he said.
Hawking took questions from the audience – and he used a lighthearted one about the recent departure of Zayn Malik from the pop group One Direction to make a larger point about theoretical physics.
"My advice to any heartbroken young girl is to pay attention to the study of theoretical physics because, one day, there may well be proof of multiple universes,” Hawking said.
"It would not be beyond the realms of possibility that somewhere outside of our own universe lies another, different universe and, in that universe, Zayn is still in One Direction," he added.