By SETH BORENSTEIN
AP Science Writer
WASHINGTON - After an entire century that included two high-profile government investigations and countless books and movies, we're still debating what really caused the Titanic to hit an iceberg and sink on that crystal-clear chilly night.
Maybe there's more to blame than human folly and hubris. Maybe we can fault freak atmospheric conditions that caused a mirage or an even rarer astronomical event that sent icebergs into shipping lanes. Those are two of the newer theories being proposed by a Titanic author and a team of astronomers.
But the effort to find natural causes that could have contributed to the sinking may also be a quest for an excuse - anything to avoid gazing critically into a mirror, say disaster experts and Titanic historians.
New theories and research are important "but at its most basic what happened is they failed to heed warnings and they hit the iceberg because they were going too fast," said James Delgado, director of maritime heritage at the National Oceanic and Atmospheric Administration.
With this week's 100th anniversary of Titanic's sinking, the interest in all things Titanic is steaming faster than the doomed cruise ship on its maiden voyage.
One of the novel new theories says Titanic could have been the victim of a mirage that is similar to what people see in the desert. It's the brainchild of Tim Maltin, a historian who has written three books about Titanic. The latest, an e-book titled "A Very Deceiving Night" emphasizes how the atmosphere may have tricked the Titanic crew on a cloudless night.
"This was not avoidable human error," Maltin said in a telephone interview from London. "It's just about air density difference."
It was a beautiful clear night and for a couple of days, there had been something strange going on in the air over the North Atlantic, reported by all sorts of ships, including the crew on Titanic, Maltin said.
The unusually cold sea air caused light to bend abnormally downward, Maltin said. The Titanic's first officer, William McMaster Murdoch, saw what he described as a "haze on the horizon, and that iceberg came right out of the haze," Maltin said, quoting from the surviving second officer's testimony.
Other ships, including those rescuing survivors, reported similar strange visuals and had trouble navigating around the icebergs, he said.
British meteorologists later monitored the site for those freaky thermal inversions and said 60 percent of the time they checked, the inversions were present, Maltin said.
The same inversions could have made the Titanic's rescue rockets appear lower in the sky, giving a rescue ship the impression that the Titanic was smaller and farther away, Maltin said.
Physicists Donald Olson and Russell Doescher at Texas State University have another theory in Sky &Telescope magazine that fits nicely with Maltin's. Olson - who often comes up with astronomical quirks linked to historical events - said that a few months earlier, the moon, sun and Earth lined up in a way that added extra pull on Earth's tides. The Earth was closer to the moon than it had been in 1,400 years.
They based their work on historical and astronomical records and research in 1978 by a federal expert in tides.
The unusual tides caused glaciers to calve icebergs off Greenland. Those southbound icebergs got stuck near Labrador and Newfoundland but then slowly moved south again, floating into the shipping currents just in time to greet the Titanic, the astronomers theorized. Maltin said the icebergs also added a snaking river of super-cold water that magnified the mirage effect.
Tides and mirages may have happened, but blaming them for Titanic's sinking "misses the boat," said Lee Clarke, a Rutgers University disaster expert and author of the book "Worst Cases."
"The basic facts of Titanic are not in dispute: The boat was going too fast in dangerous waters," Clarke said. If Titanic had stopped for the night because of ice like the British steamship Californian did, "tides and mirages wouldn't have mattered."
On April 14, the day it hit the iceberg, the Titanic received seven heavy ice warnings, including one from the Californian less than an hour before the fateful collision. The message said: "We are stopped and surrounded by ice." Titanic sent back a message that said "Shut up. We are busy."
Clarke said people keep looking for additional causes "because if it's nature or God, then we're off the hook, morally and practically."
Yale disaster expert Charles Perrow said he found the mirage theory plausible, especially because cold air played visual tricks that were a factor in a 1979 airplane crash in Antarctica that was originally blamed on pilot error.
Steven Biel, who wrote "Down with the Old Canoe: A Cultural History of the Titanic Disaster," said he understands the search for other reasons.
"There's something appealing about retrospectively gaining control over an event that's centrally about uncertainty and contingency and lack of control," he said.
Seth Borenstein be followed at http://twitter.com/borenbears