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.

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 that 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.

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.”