What causes a solar eclipse?

A solar eclipse occurs when the Moon passes directly between the Earth and the Sun, blocking all or part of the Sun’s light from reaching the Earth. This alignment causes the Moon to cast a shadow on the Earth’s surface, leading to the temporary darkening of the Sun as seen from certain locations. For a solar eclipse to happen, three key conditions must be met. First, it must be a new moon phase, when the Moon is positioned between the Earth and the Sun. Second, the Moon’s orbit must intersect the plane of the Earth’s orbit around the Sun (called the ecliptic) at the right time—this is because the Moon’s orbit is tilted about 5 degrees relative to Earth’s orbit, so perfect alignment doesn’t occur every month. Third, the observer must be located within the Moon’s shadow on Earth, which can be the darker central shadow called the umbra (leading to a total eclipse) or the lighter outer shadow called the penumbra (leading to a partial eclipse). In summary, a solar eclipse is caused by the Moon blocking the Sun’s light due to a precise alignment of the Sun, Moon, and Earth during a new moon, combined with the observer’s location falling within the Moon’s shadow. This alignment is relatively rare and brief, making solar eclipses fascinating and special astronomical events.