Why in the news?
A rare Total Solar Eclipse will be visible across North America on April 8.
What are Eclipses?
- Eclipses are astronomical events that occur when the sun, moon, and Earth align in specific ways.
- There are two primary types of eclipses: solar and lunar.
- A solar eclipse happens when the moon comes between the sun and Earth during a new moon, blocking out the sun’s light.
- Conversely, a lunar eclipse occurs when the Earth is positioned between the sun and the moon during a full moon, casting a shadow on the moon.
What is a Total Solar Eclipse?
- During a total solar eclipse, the moon passes between the sun and Earth, entirely covering the face of the sun along a small path of our planet’s surface.
- This is called the “path of totality.”
- The daytime sky turns dark, similar to dusk or dawn, and nocturnal animals have been known to wake up, confused into believing night has arrived.
Stages of a Total Solar Eclipse
A total solar eclipse unfolds in several distinct stages.
- It starts with a partial eclipse phase as the moon begins to pass between Earth and the sun, partially blocking it and leaving the sun looking like it has a crescent shape.
- In the subsequent Baily’s Beads phase, points of light from the sun shine around the moon’s edges because of the irregular lunar topography, producing small beads of light.
- In the diamond ring phase, a single bright spot appears along the lunar edge even as the sun’s atmosphere leaves a ring of light around the moon. This phenomenon precedes totality.
- After totality, the other phases repeat as the moon keeps moving along its path until the eclipse ends.
Other types of solar eclipses:
- Partial Solar Eclipse
- This happens when the sun, moon and Earth are not exactly lined up.
- The sun appears to have a dark shadow on only a small part of its surface.
- Annular Solar Eclipse
- An annular eclipse happens when the moon is farthest from Earth. Because the moon is farther away from Earth, it seems smaller. It does not block the entire view of the sun. The moon in front of the sun looks like a dark disk on top of a larger sun-coloured disk. This creates what looks like a ring around the moon.
- During a solar eclipse, the moon casts two shadows on Earth. The first shadow is called the Umbra. This shadow gets smaller as it reaches Earth. It is the dark centre of the moon’s shadow.
- The second shadow is called the Penumbra. The penumbra gets larger as it reaches Earth. People standing in the penumbra will see a partial eclipse. People standing in the umbra will see a total eclipse.
Why don’t solar eclipses happen at every New Moon?
- The reason is that the Moon’s orbit tilts 5° to Earth’s orbit around the Sun.
- Astronomers call the two intersections of these paths nodes.
- Eclipses only occur when the Sun lies at one node and the Moon is at its New (for solar eclipses) or Full (for lunar eclipses) phase.
- During most (lunar) months, the Sun lies either above or below one of the nodes, and no eclipse happens.
PYQ:2013: Consider the following phenomena 1. Size of the sun at dusk 2. Colure of the sun at dawn 3. Moon being visible at dawn 4. Twinkle of stars in the sky 5. Polestar being visible in the sky Which of the above are optical illusions? (a) 1, 2 and 3 (b) 3, 4 and 5 (c) 1, 2 and 4 (d) 2, 3 and 5
Practice MCQ:Which of the following statements best characterizes a Total Solar Eclipse? (a) A total solar eclipse occurs when the Moon partially blocks the Sun, leaving a visible ring of sunlight around the Moon’s silhouette. (b) During a total solar eclipse, the Moon completely covers the Sun, casting a shadow on a narrow path on the Earth’s surface called the umbra. (c) Total solar eclipses occur more frequently than partial solar eclipses due to the precise alignment of the Sun, Earth, and Moon. (d) Total solar eclipses can only be observed from specific locations on Earth, making them rare and highly sought-after astronomical events. |
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