The Longest Total Solar Eclipse in History and the Possibility of an Even Longer One
On April 8, 2024, a total solar eclipse will captivate parts of Mexico, the U.S., and Canada, while all of North America will witness at least a partial solar eclipse. The highlight of this celestial event will be the maximum length of totality, which refers to the duration when the sun’s face is entirely obscured by the moon. Clocking in at an impressive 4 minutes and 28 seconds, this period of complete darkness will occur near the village of Nazas in northwestern Mexico. While this may seem like an extraordinary occurrence, it pales in comparison to the longest total solar eclipse in history.
According to calculations from NASA, the longest totality ever recorded lasted a staggering 7 minutes and 28 seconds. This remarkable event took place on June 15, 743 B.C. in the Indian Ocean off the coast of Kenya and Somalia in Africa. However, there is a possibility for even longer periods of totality. Jean Meeus, an eclipse calculator, suggests that mathematically speaking, the longest totality possible on Earth is 7 minutes and 31 seconds. This extraordinary duration can be achieved within 5 degrees north of the equator in July when the sun is at aphelion, its farthest point from Earth. Additionally, for this phenomenon to occur, the observer must be positioned at the point of greatest eclipse, with the eclipse happening directly overhead around midday.
While there are no records of such a lengthy eclipse occurring in recent history, there is hope that we may inch closer to this limit in the future. Scientists have computed total solar eclipses far into the future, and one such event is predicted to take place on July 16, 2186. This eclipse will traverse the Atlantic Ocean off the coast of French Guiana and is expected to last an astonishing 7 minutes and 29 seconds. Dan McGlaun, an eclipse expert at Eclipse 2024, explains that during this particular eclipse, the moon’s shadow will occur above the center of the Earth. The moon will appear larger due to its proximity, while the sun will seem smaller as it will be relatively far away. These factors will converge to create an exceptionally long totality during the 2186 eclipse.
The 2186 eclipse shares common characteristics with other extremely long-duration eclipses. It will occur in July when the sun is farthest from Earth and near the equator. This event is part of Saros 139, a family of solar eclipses that has produced 71 occurrences between 1843 and 2601. Interestingly, another eclipse within this family is set to take place on April 8, 2024, as part of a series of progressing solar eclipses within the Saros 139 eclipse cycle. Michael Zeiler, an eclipse cartographer at GreatAmericanEclipse.com, describes the April 8 event as a prelude to the remarkable total solar eclipse of July 16, 2186. He notes that totality during the 2186 eclipse will last up to an astonishing 7 minutes and 29 seconds, which is very close to the theoretical limit of 7 and a half minutes.
While the longest eclipse in history occurred thousands of years ago and an even lengthier one won’t happen for over a century, there is a way to extend totality if you happen to have access to a supersonic jet. On June 30, 1973, seven scientists aboard the supersonic jet Concorde 001 flew at Mach 2 to prolong totality on the ground in Niger. They managed to extend the duration from 7 minutes and 4 seconds to an astounding 74 minutes. This total solar eclipse was part of Saros 136, which is also responsible for the following three total solar eclipses of extreme duration. The next occurrence is set for August 2, 2027, with a maximum totality of 6 minutes and 23 seconds near Luxor, Egypt. Subsequent eclipses will take place on August 12, 2045, off the coast of Florida and the Bahamas (maximum totality of 6 minutes and 6 seconds), and on August 24, 2063, in the North Pacific Ocean (maximum totality of 5 minutes and 49 seconds). The longest totality of the 21st century, lasting 6 minutes and 39 seconds, occurred on July 22, 2009, near Japan’s Ishinomura-Kitaio Island.
As we eagerly anticipate the upcoming total solar eclipse in April 2024, it is fascinating to explore the history and possibilities surrounding these celestial events. While the longest total solar eclipse in history remains a distant memory, the potential for an even lengthier one in the future sparks excitement and wonder. Whether you plan to witness these extraordinary phenomena firsthand or marvel at them