Solar Eclipse

A solar eclipse is an astronomical event that occurs when the Moon passes between the Moon and the Sun, partially or completely blocking sunlight from reaching Earth. This event has been a subject of great interest throughout human history, both scientifically and culturally.

Types of Solar Eclipses

Solar eclipses are categorized into four types based on their observational appearance:

Total Solar Eclipse

This occurs when the Moon completely covers the Sun. During this time, the Moon’s shadow falls on Earth, and observers located within the shadow’s umbra (complete shadow) see the Sun entirely obscured.

• Solar eclipses occur only during the New Moon phase.
• The Moon’s diameter, as seen from Earth, is nearly equal to that of the Sun.
• If the Moon is at its closest position to Earth (perigee), it can fully cover the Sun.
• In such cases, the sky darkens briefly, stars may become visible, and the temperature can drop noticeably.

The maximum duration of a total eclipse can be up to 7 minutes and 31 seconds.

Annular Solar Eclipse

This occurs when the Moon passes directly in front of the Sun but does not completely cover it. During this eclipse, the center of the Sun is blocked by the Moon, while its edges remain visible, creating a visual effect known as the “ring of fire” or “light ring”.

The Moon’s orbit is elliptical, meaning its distance from Earth is not constant.

• When the Moon is farther from Earth (apogee), it appears smaller,
• and therefore cannot fully cover the Sun.

This results in an annular eclipse because the Moon’s apparent diameter is smaller than that of the Sun.

The maximum duration of an annular eclipse can be up to 12 minutes and 30 seconds.

Partial Solar Eclipse

A partial solar eclipse occurs when the Moon covers only a portion of the Sun. During this event, the Sun appears partially darkened; no part is completely blocked. Observers are located within the Moon’s penumbra (partial shadow) region.

• A total or annular eclipse does not occur when the Sun, Moon and Earth are not perfectly aligned.
• The Moon passes in front of the Sun but only obscures part of it.
• This phenomenon typically occurs because the Moon’s orbit is slightly inclined relative to Earth’s.

The total duration of a partial solar eclipse is the time from its first contact to its final contact.

• Total eclipse duration: Average of 2–3 hours
• Maximum obscuration time: Typically between 2 and 7 minutes

Hybrid (Mixed) Eclipse

A hybrid solar eclipse is when the same eclipse appears as a total solar eclipse in some regions and as an annular solar eclipse in others. This is a very rare celestial event (occurring approximately once every ten years) and is also known as an “annular-total eclipse” (technical).

• At the beginning of the eclipse, the Moon is too far from Earth to fully cover the Sun → an annular eclipse is observed.
• As the eclipse progresses, the relative distance between the Moon and Earth decreases → a total eclipse occurs.
• As the eclipse ends, it may revert to an annular phase.

Due to Earth’s spherical shape, parts of the shadow may fall as total (umbra) while others fall as annular (antumbra).

The total duration of a hybrid solar eclipse (from start to finish): 2–3 hour, the total or annular phase: may last between 30 seconds and 5 minute (varies depending on observation).

Conditions for a Solar Eclipse

A solar eclipse can occur only during the New Moon phase. However, not every New Moon produces an eclipse because the Moon’s orbit is inclined by approximately 5 degree relative to Earth’s orbit. As a result, the Moon usually passes above or below the Sun. For an eclipse to occur, the Moon must be at one of its nodes, the points where its orbit crosses the plane of Earth’s orbit around the Sun.

How Frequently Do Solar Eclipses Occur?

Solar eclipses occur more frequently than commonly assumed, but they are not visible from every location on Earth.

How Many Occur Per Year?

• There are at least two and at most five solar eclipses each year.
• These eclipses may be total, partial, or annular.
• However, most of these eclipses are visible only from specific regions of Earth.

Scientific Significance

Solar eclipses are of great value to astronomers for studying the structure of the Sun. In particular, during total solar eclipses, the Sun’s corona can be clearly observed. Additionally, Einstein’s General Theory of Relativity was supported by observations made during the total solar eclipse of 1919.

Impact of Solar Eclipses on Humans

Historical and Cultural Impact

Throughout history, solar eclipses have been regarded in many cultures as sacred, frightening or prophetic events.

• Ancient Chinese, Mesopotamian, Maya and Indian civilizations interpreted eclipses as signs of divine anger or bad omens.
• For example, the solar eclipse of 585 BCE ended the war between Lydia and the Medes, as soldiers viewed it as a divine sign.
• In some cultures, rituals such as drumming and shouting were performed during eclipses to drive away evil spirits.

Psychological Effects

Solar eclipses, particularly due to the sudden darkness and changes in the sky, can induce confusion, fear or awe in some individuals.

• The temporary darkness experienced during observation can cause anxiety, stress or unease in some people.
• However, among individuals with scientific knowledge, curiosity, excitement and wonder are typically dominant emotions.
• Eclipses can trigger philosophical reflections such as “cosmic awareness” or the feeling of how small we are in the universe.

Physiological Effects

Observing a solar eclipse directly does not cause physical harm — if proper viewing equipment is used.

However:

• Looking directly at the Sun with the naked eye can cause serious and permanent damage to the retina. This condition is called “solar retinopathy”.
• The reduction in ambient light during an eclipse may cause brief disruptions in some people’s body rhythms (circadian clock).
• Some humans, like animals, may become temporarily inclined to enter a sleep or rest mode during the brief darkness.