The obscuring of one celestial body by another, causing a temporary dimming of light.An eclipse is an astronomical event that occurs when one celestial body moves into the shadow of another, temporarily blocking its light. The most familiar types are solar eclipses, where the Moon passes between the Sun and Earth, and lunar eclipses, where Earth passes between the Sun and the Moon, casting a shadow on the Moon. Eclipses have been observed and recorded for millennia and have played a significant role in the history of astronomy.
Eclipses have been recorded since ancient times, with Babylonian and Chinese astronomers predicting them as early as the 2nd millennium BCE. The Greek philosopher Thales is said to have predicted a solar eclipse in 585 BCE. The modern understanding of eclipses was solidified by Kepler's laws of planetary motion in the 17th century.
A solar eclipse happens when the Moon's shadow falls on Earth's surface. The Moon's shadow has two parts: the umbra, where the Sun is completely blocked, and the penumbra, where only part of the Sun is obscured. A total solar eclipse occurs only within the narrow path of the umbra, while a partial eclipse is seen from the penumbra. A lunar eclipse occurs when the Moon passes through Earth's shadow, which can also be total or partial. The geometry of the orbits means that eclipses do not happen every month because the Moon's orbit is tilted relative to Earth's orbit around the Sun.
Eclipses have been used to test general relativity, as during the 1919 solar eclipse that confirmed the bending of starlight by the Sun's gravity. They also provide opportunities to study the Sun's corona and the Moon's surface composition.
A total solar eclipse is the only time when the Sun's corona is visible to the naked eye from Earth, and the path of totality is typically only about 100 miles wide.






