Total solar eclipse on April 8: Frequently asked questions

While earth rotates eastward on its axis, the moon orbits in the same direction but at a slower pace. During a solar eclipse, the moon's eastward motion becomes apparent as it traverses across the sun from west to east. (Photo: Joseph Corl via Unsplash)

Eclipses captivate our curiosity and imagination. The celestial event often sparks numerous questions. Let's delve into some of the most frequently asked questions to shed light on the mysteries surrounding solar eclipses.

How long does a total solar eclipse last?

Total solar eclipses vary in duration. They can span from a brief 10 seconds to an awe-inspiring 7.5 minutes. Remarkably, the longest recorded total solar eclipse in history is projected to take place on July 16, 2186, lasting an impressive 7 minutes and 29 seconds. Conversely, the shortest total solar eclipse occurred on February 3, 919 CE, lasting a mere 9 seconds.

Why don’t eclipses occur every new moon?

Despite the regularity of new moons, eclipses do not happen every time. The moon’s orbit, slightly tilted with respect to the sun-earth line, dictates eclipse occurrence. Sometimes, the moon’s shadow is too high or too low above earth, preventing an eclipse.

How do modern-day scientists predict eclipses?

Predicting eclipses requires understanding the intricate motions of earth, the moon, and the sun. Astronomers employ Newton's laws and complex equations, inputting current positions and speeds of these celestial bodies into computers to calculate eclipse occurrences accurately. Forecasts are incredibly precise, accurate to less than a minute over centuries.

What is the Saros Series and Cycle and how does it predict solar eclipses?

Eclipses occur in patterns known as Saros Series and Cycle. A Saros Series spans 223 lunar months and predicts eclipses with remarkable accuracy. Every 18 years, 11 days, and 8 hours, the sun, earth, and moon return to similar relative positions, initiating a new cycle. Eclipses belonging to the same Saros Cycle share similarities, occurring approximately 11 days later in the year than the last one and featuring comparable paths across earth's surface.

Why do eclipse tracks move eastward even though earth rotates from west to east?

While earth rotates eastward on its axis, the moon orbits in the same direction but at a slower pace. During a solar eclipse, the moon's eastward motion becomes apparent as it traverses across the sun from west to east, dragging its shadow along an eastward trajectory across earth’s surface.

How many types of solar eclipses are there, and how often do they occur?

Eclipses follow a predictable cycle known as the Saros cycle, lasting 6,585 days.

Solar eclipses occur when the moon passes between the earth and the sun, casting a shadow on our planet. There are three main types of solar eclipses: total, partial, and annular.

Total solar eclipses are the most striking, completely obscuring the sun and plunging the area into darkness during totality. This rare phenomenon unveils the sun's corona, offering a captivating sight for observers within the path of totality.

Partial solar eclipses occur when the moon covers only a portion of the sun, leaving a crescent-shaped sliver of sunlight visible from earth. While not as dramatic as total eclipses, partial eclipses still provide a fascinating glimpse into celestial mechanics and are visible to a wider audience.

Annular solar eclipses take place when the moon appears smaller than the sun, leaving a ring of sunlight visible around its edges. This creates a "ring of fire" effect, with the sun's bright disk surrounded by a glowing halo of light.

Although solar eclipses are more common than perceived, they rarely occur in the same location. Typically, there are approximately two total solar eclipses on earth every three years, but their shadow is only about fifty miles wide. On average, a specific location on earth will witness two total solar eclipses every four hundred years.

Eclipses follow a predictable cycle known as the Saros cycle, lasting 6,585 days. The saros cycle is named after the Greek word for repetition. Every 18 years, 11 days, and 8 hours, a similar eclipse path emerges as the sun, earth, and moon align. During this period, there are typically anywhere between four and seven eclipses. This cycle allows scientists and researchers to anticipate future eclipses, allowing them to study them. For instance, the path of the 2023 annular eclipse will repeat on October 25, 2041 over China and Japan.