Astronomy played supporting roles in the ill-fated ship's maiden voyage and in the blockbuster movie that followed.

To the best of my knowledge, there was no staff astronomer aboard the RMS Titanic when it set out from Southampton, England, in 1912 on its first and only voyage. If there had been, I wonder if the course of its tragic history would have been any different?

I can only imagine the beauty of the night sky on April 14th as the ship steamed westward toward New York. The seas were dead calm and the sky alive with stars that night. As passenger Lawrence Beesley would later recount in The Loss of the SS Titanic, "The night was one of the most beautiful I have ever seen: the sky without a single cloud to mar the perfect brilliance of the stars..."

Notably, there was no Moon in the sky that night. The absence of its light, together with the calm sea, apparently made it impossible for the ship's lookouts to spot the approaching white hulk of an iceberg before Titanic sideswiped it at 11:40 p.m. Within three hours, the battered ship had cleaved in two and sunk, claiming the lives of some 1,500 passengers and crew.

We will never know the source of that particular berg, but in the spring of 1912 mariners were aware that a great many of them had worked their way into the North Atlantic's shipping lanes. In trying to reconstruct the accident's sequence of events, some experts later argued that a hot arctic summer in 1911, followed by an especially mild winter, had triggered higher rates of glacial creep and the calving of icebergs where they meet the sea in Greenland.

Another astronomical wrinkle is explored by Donald Olson and Russell Doescher of Texas State University, together with S&T senior contributing editor Roger Sinnott, in the magazine's April issue. They followed an astronomical lead first tossed out in 1995 by oceanographer Fergus Wood.

As Wood envisioned it, the iceberg formed a few months earlier on the west coast of Greenland, in or near Diskø Bay, due to extremely high tides. Those super-swells resulted from a rare convergence of astronomical factors: within a single 27-hour span on January 4th, Earth came its nearest to the Sun, the Moon was its nearest Earth, and the Moon was full.

But it's unlikely that the iceberg could have crossed more than 1,600 nautical miles (3,000 km) of ocean to the impact point in just three months. Olson, Doescher, and Sinnott solve that timetable by postulating that the iceberg had formed earlier and become grounded along the coast of Labrador or Newfoundland, only to be freed by the extreme (perigean) tides of early January. It's well worth reading their entire article, "Did the Moon Sink the Titanic?"

There's more!

When director James Cameron set out to capture the ship's voyage and dramatic sinking in his 1997 blockbuster film Titanic, he put a premium on getting all the details exactly right. So it came as a complete surprise to astronomer Neil deGrasse Tyson that Cameron botched the scenes showing the night sky.

The movie shows its heroine, Rose (played by Kate Winslet), staring up at the sky as she floats on wood scraps after the ship's sinking. "There is only one sky she should have been looking at," Tyson snorts, "and it was the wrong sky!" Worse, he adds, the left half was a mirror reflection of the right half.

After seeing this astro-gaffe, Tyson (who's director of the Hayden Planetarium in New York City) wrote a letter to Cameron, politely pointing out the error. Cameron never responded. Undeterred, Tyson raised the issued again when the two met at a NASA gathering five years later — and a third time over dinner in 2005. As Tyson tells it, Cameron finally retorted, "Well, last time I checked, Titanic has grossed $1.3 billion worldwide. Imagine how much more it would have grossed, had I gotten the sky correct."

Yet just two months after getting his planisphere handed to him on a platter, Tyson got a call from the post-production team working on a special 10th-anniversary "director's cut" of the movie. Cameron wanted to fix the stars after all! So Tyson cranked out a plot of the sky as it would have appeared that night, using Starry Night software. Then, he adds, "I reached deep into my amateur astronomer roots" to adjust the scene as it truly would have appeared.

"I was a chihuahua nipping at his ankles for 10 years," Tyson tells me, but that persistence paid off. When the 3-D version of Titanic made its debut this week, viewers could see that Cameron had changed virtually nothing of the original — except the sky full of stars over Rose's head.