James Cameron's Titanic, coming soon, as they say, to a cinema near you, is billed as an epic, action-packed romance. Destiny, we are told, has brought together two young souls, "daring them to nurture a passion that would change their lives forever; nothing is going to come between them - not even something as unimaginable as the sinking of Titanic".
The unimaginable happened, however, early on April 15th, 1912, when the great ship struck an iceberg and sank with the loss of 1,500 lives.
The icebergs of the northern hemisphere come mainly from the glaciers of Greenland. As new snow accumulates on the icecap, the ice underneath is forced to slide down the valleys, edging its way seawards in a great slow-moving river.
Ultimately part of the glacier overhanging the sea breaks off and floats away as a large independent chunk of ice; we say an iceberg has been "calved".
In the early months of the year, bergs freshly calved from these northern glaciers are held up by the pack ice which surrounds and anchors them, but with the coming of spring the ice begins to move. Since seven-eighths of an iceberg is under water, its movement is influenced more by ocean currents than by wind.
The majority of Greenland icebergs, therefore, are carried south by the Labrador current to pass by the east coasts of Labrador and Newfoundland.
It was a perfect night, that night in April 1912. Weather charts show a small anti-cyclone centred just south-east of Newfoundland, resulting in a dead calm in the zone of the collision. Some say that this lack of wind was an important factor in the tragedy, since even a slight breeze might have caused small waves at the base of the iceberg, making it more visible.
In the event, the first warning of disaster was the sighting of a "slight haze" directly ahead of the ship; a not-uncommon occurrence when a large bank of ice reduces the temperature of the air in contact with it sufficiently for condensation to produce a thin veil of mist or apparent haze.
The high death toll was in no small measure due to the very low temperature of the water in the Labrador current, a chilling 2 C. Indeed, if the ship had been a mere 150 miles to the south of its final position, it would have been in the Gulf Stream, and a sea temperature of 14 C would have allowed those thrown into the water a much greater chance of survival.
But then perhaps the Titanic would not have struck an iceberg.