June 15, 2011. With the current spectacular “winter” weather, there’s every chance that we’ll be treated to a spectacular viewing of a “red moon” tonight (just after 8.20), better known as a total lunar eclipse.
A total lunar eclipse occurs when the moon moves into the earth’s shadow, preventing the sun’s rays from striking the moon.
You won’t need any special equipment to witness this marvel of the natural world, or universe, the red moon can be appreciated by the naked eye. If you have a telescope, all the better.
According to the National Geographic website this lunar event will be the longest and deepest total lunar eclipse in more than a decade.
“The path that the moon is taking through Earth’s shadow is almost directly through (the shadow’s) centre, making for the longest possible path and so the longest duration,” said Ben Burress, staff astronomer at the Chabot Space & Science Centre in Oakland, California.
“The last eclipse that was as long as this one was in 2000, while the next won’t be until 2018, so this makes it a somewhat rare event.”
Why does the moon appear red, you might ask?
The website earthsky.org explains further: “The reason (that the moon will appear red) stems from the very air we breathe. If the Earth had no air, then Earth’s shadow on the moon during a lunar eclipse would appear black. The presence of Earth’s air means that, during a lunar eclipse, sunlight can filter through Earth’s atmosphere on to the shadow on the moon. This filtered sunlight makes the moon appear red during a total eclipse.
“But red isn’t the only colour of a totally eclipsed moon. An eclipsed moon can appear brown, red, orange or yellow. The colour depends on the presence of dust and clouds in Earth’s atmosphere. If there has been a major volcanic eruption, for example, the shadow on the moon will appear dark throughout an eclipse. In December 1992, not long after the eruption of Mount Pinatubo in the Philippines, there was so much dust in Earth’s atmosphere that the totally eclipsed moon could barely be seen.”