PERTH, Australia -- "The most difficult search in human history": that's the way Australia's prime minister described the hunt for Malaysia Airlines Flight 370 Thursday.
There were no signs in the southern Indian ocean of the Boeing 777 -- another day of agony for families waiting for answers.
"Paul meant the world to me," said Danica Weeks, whose husband Paul was one of the 239 people on board the flight. "Paul was my world. My world is now ended."
Danica first learned that the plane was missing when she was contacted by a journalist.
"I dropped the phone and I just dropped the phone, screaming," she said. "I ran out -- instantly I thought the plane's crashed, as anyone would, logically. And I just ran out to the backyard, and I remember just screaming, screaming uncontrollably."
Paul had left his wife and their two sons, Jack and Lincoln, in Australia to start a new job as a mechanical engineer in Mongolia.
"We were going to grow old and live down the road from my boys, whether they liked it or not, so we could be around the grandkids," Danica said.
Asked what she is telling her sons, Danica tearfully replied, "Jack is too young -- he's 11 months, so he doesn't understand."
"But Lincoln understands, and I've explained that Dad's gone," she said. "And we go out every night, and we look at the stars, and we pick out the brightest star, and, you know, he says, 'Good night, Daddy.'"
Like other family members, Danica is angry that she was notified the plane had been lost via text message.
She said she isn't able to think about the possibility that the plane will never be found.
"I have nothing, you know, I have nothing now, and I want to find out the truth," she said. "This is my next step. I want to find out the truth, and I will fight, because if Paul was in my shoes, he would be fighting to find out what happened to me."
Finding the truth about what happened on board Flight 370 is the aim of the search in Australia, as well as a criminal investigation in Malaysia. But the men leading both of those operations now admit we may never know what caused the tragedy.