Note4Students
From UPSC perspective, the following things are important :
Prelims level: Physical Geography (Annular Solar Eclipse)
Why in the News?
An annular solar eclipse will be visible in parts of South America on October 2, 2023. It, however, will not be visible from India.
What is a Solar Eclipse?
- A solar eclipse occurs when the Moon moves between the Earth and the Sun, blocking the Sun’s light either fully or partially, casting a shadow on certain parts of the Earth.
- There are four types of solar eclipses:
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- Total Solar Eclipse: When the Moon completely blocks the Sun, turning the sky dark. People in the path of a total solar eclipse can witness the Sun’s corona (its outer atmosphere), which is normally hidden by the bright sunlight.
- Annular Solar Eclipse: Occurs when the Moon is at or near its farthest point from Earth. The Moon does not fully cover the Sun, leaving a visible ring of fire around the Moon. This is what people in parts of South America will witness on October 2, 2023.
- Partial Solar Eclipse: Happens when the Moon blocks only a part of the Sun, giving it a crescent shape. During both partial and annular eclipses, areas outside the Moon’s umbra (the darkest part of its shadow) experience a partial eclipse. It is the most common type of solar eclipse.
- Hybrid Solar Eclipse: The rarest type, where the eclipse shifts between total and annular as the Moon’s shadow moves across the Earth. Some places see a total solar eclipse, while others see an annular one.
Frequency of Solar Eclipses
- A solar eclipse can only occur during the new moon, when the Moon and Sun are aligned on the same side of the Earth.
- A new moon happens approximately every 29.5 days because that is the time it takes for the Moon to orbit the Earth.
- However, solar eclipses don’t happen every month. They occur two to five times annually, but not every new moon results in an eclipse.
- Why don’t they occur every month:
- The Moon’s orbit around the Earth is tilted by about 5 degrees compared to the Earth’s orbit around the Sun.
- This means the Moon’s shadow usually misses the Earth.
- A solar eclipse only occur when the Moon crosses specific points in its orbit, called nodes, where the Moon’s orbit intersects the plane of Earth’s orbit around the Sun.
- When a new moon occurs at one of these nodes, a solar eclipse is possible.
PYQ:[2019] On 21st June, the Sun (a) does not set below the horizon at the Arctic Circle (b) does not set below the horizon at Antarctic Circle (c) shines vertically overhead at noon on the Equator (d) shines vertically overhead at the Tropic of Capricorn |
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