Everybody knows about the imaginary line on the Earth's surface that lies equidistant from the North Pole and the South Pole, but what else do you know about it? Here are some lesser-known facts - not to mention a few myths - about the equator.
Centre of the Earth
The equator is just under 25,000 miles long. Because the Earth bulges at the centre the equator is the longest of our planet's five main circles of latitude, each one based on the relationship between the Earth's axis of rotation and the Earth's orbit around the sun.
Astrologers have also identified an imaginary circle in the heavens, obtained when the Earth's equator is projected into the night sky. This is known as the celestial equator.
By definition the latitude of the Earth’s equator is 0 degrees, while the Tropic of Cancer and the Tropic of Capricorn each lie at 23.5 degrees latitude.
Night, Day and Seasons
The equator itself crosses the land or territorial waters of 14 countries. If you live on the equator you will experience the quickest rates of sunrise and sunset in the world, taking a matter of minutes.
These places also have a constant twelve hours of day and night throughout the year, while north or south of the equator day length increasingly varies with the seasons.
In its seasonal movement through the sky, the Sun itself passes directly over the equator only twice each year, on the March and September equinoxes.
It is mistakenly believed that the weather on the equator stays the same. While tropical areas along the equator can experience wet and dry seasons, other regions may well be wet for much of the year.
While temperatures at the equator are very high, there is one single point on the equator where you’ll find snow. The highest point on the equator is 4,690m, on the south slopes of Volcán Cayambe in Ecuador so in theory you could go skiing on the equator.
In what might seem to be a contradictory pair of facts, the parts of the Earth that lie on the equator mark both the area with the world's greatest concentration of natural biodiversity and also human poverty.
It is also the case that almost half the world's rainforests are concentrated on the equator in just three countries; Brazil, Congo and Indonesia.
It has been said that water spirals down plug holes in different directions depending on which hemisphere you are in. This is a myth, based on the effects of Coriolis, which refers to when the rotating earth causes the winds to deflect to the right in the northern hemisphere and the left south of the equator. The effect Coriolis has on water going down sinks is minimal. The truth is that water tends to flow down the plug-hole in the direction it is introduced into a sink!
A common belief is that that the moon always appears to flip upside down once you cross the equator. While this is not exactly a myth, it is not generally the case.
If you want to see the moon turn upside down, you just have to watch long enough during a day, and you will generally see an exact upside down for a short while. Simply put, the moon can appear to flip upside down, but not very often and certainly not only at the equator.
Crossing the Line
There exists a seafaring tradition that all sailors who cross the equator during a sea voyage must join rituals initiating them into what is known as "The Solemn Mysteries of the Ancient Order of the Deep".
Those who have never "crossed the line" are referred to as "pollywogs" and are required to undertake various initiation rituals performed by those members of the crew who have made the journey before in order to pay respect to King Neptune of the Deep. Upon completion of the initiation ceremony, the “pollywogs” are then known as "trusty Shellbacks".