20 Questions About Solar and Lunar Eclipses: True or False?

False. Between two and five solar eclipses occur every year. The last time five solar eclipses occurred in the same year was in 1935; the next time will be in 2206.

False. Up to five lunar eclipses can occur in one year if penumbral eclipses are included. In 1879, for example, there were five: four penumbral eclipses and one partial eclipse. The next one will be the partial lunar eclipse on August 27–28, 2026.

True. There can be five solar eclipses and two lunar eclipses, as in 1935, or four solar eclipses and three lunar eclipses, as in 1917.

False. The annular phase can last up to about 12 minutes and 29 seconds. During the annular solar eclipse on January 15, 2010, for example, the maximum phase lasted 11 minutes and 8 seconds over the Indian Ocean near the Maldives.

True. The theoretical maximum duration of totality is about 7 minutes and 32 seconds. The total solar eclipse on July 16, 2186, will come very close to this limit: totality will last about 7 minutes and 29 seconds.

True. A solar eclipse occurs when the Moon passes between Earth and the Sun and completely or partially covers the solar disk. This alignment is possible only at New Moon. On August 12, 2026, the New Moon will produce a total solar eclipse visible from Spain and other regions.

True. This is rare, but possible if one eclipse occurs at the beginning of the month and another at the end. For example, solar eclipses occurred on July 1 and 31, 2000, and on March 1 and 30, 1150.

False. The path of totality is much narrower: its maximum possible width is about 270 km. The Moon’s penumbra, from which a partial eclipse is visible, can cover a region several thousand kilometers wide.

False. Mars has two moons, Phobos and Deimos, but both are too small to completely cover the solar disk. When they pass in front of the Sun, they produce transits or partial eclipses, not total solar eclipses like those visible from Earth.

False. The Moon is moving away from Earth at a rate of about 3.8 centimeters per year. In approximately 600 million years, it will appear too small to completely cover the Sun, and total solar eclipses will no longer occur.

False. The speed of the Moon’s shadow changes along the eclipse path. A speed of 1,800 km/h is approximately one of its lowest values; near the beginning and end of the path, the shadow can move at several thousand kilometers per hour.

True. On June 30, 1973, seven scientists aboard the supersonic Concorde 001 followed the Moon’s shadow over Africa at nearly Mach 2. This allowed them to remain in totality for 74 minutes. From a fixed point on Earth’s surface, the totality of that eclipse lasted no more than 7 minutes and 4 seconds.

True. When we observe a lunar eclipse from Earth, our planet is positioned between the Sun and the Moon. For an observer on the lunar surface, Earth would cover the Sun, producing a solar eclipse.

True, although the story has not been fully confirmed. According to Herodotus, Thales of Miletus predicted that an eclipse would occur during the year of the war between the Medes and the Lydians. This account is generally associated with the total solar eclipse on May 28, 585 BCE.

True, with some qualifications. During the total solar eclipse on May 29, 1919, astronomers observed that the Sun’s gravity deflected starlight approximately as Albert Einstein had predicted. The results provided some of the first observational evidence for general relativity, which was later confirmed by much more precise measurements.

False. British astronomer Nevil Maskelyne filmed a total solar eclipse in North Carolina on May 28, 1900. Considered the oldest known film of a solar eclipse, the footage is more than 125 years old and has been digitally restored by the British Film Institute.

False. Total solar eclipses can occur in the polar regions. The total eclipse on March 20, 2015, reached the North Pole, while the eclipse on December 4, 2021, was visible from Antarctica and the South Pole.

True. Some species react to the sudden darkness as though night has fallen. Certain birds have been observed returning to their roosts, insects changing their behavior, and some spiders taking down their webs and rebuilding them after the eclipse. However, not all animals react in the same way.

True. When solar radiation suddenly decreases, the temperature can fall by several degrees during totality. Under certain conditions, the drop can approach or even exceed 10°C, although it depends on the climate, time, and observing location.

True. Normally, the brightness of the solar disk makes the faint corona impossible to see. During totality, when the Moon completely covers the Sun, the corona appears around the dark disk. It can be viewed without eye protection only during the total phase; before and after totality, eclipse glasses or suitable solar filters must be used.