The first total lunar eclipse in almost three years should be turning the moon pink, coppery or even a blood red this morning. But this phenomenon can only be witnessed in North and western South America and northern Europe, weather permitting.
Coinciding eerily with the northern hemisphere’s mid-winter solstice, the eclipse is happening because the sun, the earth and its satellite are directly aligned, and the moon swings into the cone of shadow cast by its mother planet.
The moon does not become invisible, though, as there is still residual light that is deflected towards it by our atmosphere.
Most of this refracted light is in the red part of the spectrum and as a result the moon, seen from earth, turns a reddish, coppery or orange hue, sometimes even brownish.
“Western Europe will see the beginning stages of the eclipse before moonset, while western Asia will get the later stages after moonrise,” said Nasa’s veteran eclipse expert Fred Espenak.
The eclipse lasts three–and–a–half hours, from 6.33 a.m. to 10.01 a.m. GMT, although the stage of total eclipse – when the moon heads into the “umbra” cast by the earth – lasts from 7.41 a.m. to 8.53 a.m. GMT.
Two factors affect an eclipse’s colour and brightness, said the US astronomy magazine Sky & Telescope.
“The first is simply how deeply the moon goes into the umbra. The centre of the umbra is much darker than its edges,” it says.
“The other factor is the state of earth’s atmosphere along the sunrise-sunset line. If the air is very clear, the eclipse is bright. But if a major volcanic eruption has polluted the stratosphere with thin haze, the eclipse will be dark red, ashen gray, or blood-black.”
Lunar eclipses have long been associated with superstitions and signs of ill omen, especially in battle.
The defeat of the Persian king Darius III by Alexander the Great in the Battle of Gaugamela in 331 BC was foretold by soothsayers when the moon turned blood-red a few days earlier. And an eclipse is credited with saving the life of Christopher Columbus and his crew when they were stranded without supplies on the coast of Jamaica.
According to legend, Columbus, looking at an astronomical almanac compiled by a German mathematician, realised that a total eclipse of the moon would occur on February 29, 1504.
He called the native leaders and warned them if they did not help, he would make the moon disappear the following night. The warning, of course, came true, prompting the terrified people to beg Columbus to restore the moon – which he did, in return for as much food as his men needed.