Brain Booster for UPSC & State PCS Examination
Topic: Solar Eclipse
Why in News?
- On June 21, it was not just a summer solstice having the longest day of the year but also an annular solar eclipse witnessed in major parts of the world, including India.
Solar Eclipse Phenomena
- When Moon comes between the Sun and Earth, the shadow falls on the surface of the Earth. The Sun is entirely covered by the Moon for a brief period. Those places that are engulfed by the dark, dense umbral shadow of the Moon experience the total solar eclipse.
- A total solar eclipse occurs when the Moon passes directly between the Earth and the Sun, completely blocking the Sun's light. During an annular solar eclipse, the Moon does not completely cover the Sun as it passes, leaving a glowing ring of sunlight visible.
- An annular eclipse can only occur under specific conditions. The Moon must be in its first lunar phase, and it must also be further away from Earth on its elliptical orbit, appearing smaller in the sky than it usually would. Because the Moon appears smaller under these circumstances, it cannot fully block out the Sun, forming what's called a "ring of fire" or "ring of light."
- Partial solar eclipses happen when the Moon comes between the Sun and Earth, but the Moon only partially covers the Sun's disk.
Solar Eclipse 2020
- On June 21, the annular eclipse started for the people of Congo in Africa and progress through South Sudan, Ethiopia, Yemen, Oman, Saudi Arabia, the Indian Ocean and Pakistan, before entering India over Rajasthan. It then moved on to Tibet, China, Taiwan, before ending at the middle of the Pacific Ocean.
- In some places, the summer solstice happened on the same day as the annular solar eclipse, an event that won't happen again until June 21, 2039. ( During the solstice, the Earth’s axis – around which the planet spins, completing one turn each day – is tilted in a way that the North Pole is tipped towards the Sun and the South Pole is away from it.
About Heliophysics
- Heliophysics is the science of the Sun and the physical connections between the Sun and the solar system.
- Solar eclipses have provided natural laboratories for intriguing scientific discoveries.
- The sun may be the Earth's closest star, but this body's very brightness makes it a challenge to observe. The light from the solar body drowns out the fainter corona, the outer atmospheric layer of the star, a wispy region that becomes visible when the moon completely blocks the face of the sun during a total solar eclipse.
- Before scientists could send satellites to space to study the corona, which became possible during the space age, researchers used solar eclipses to probe how the corona varied over 11 year solar cycle
- Eclipses also provided insights into coronal mass ejections (CMEs), material from the Sun that is spewed into space via enormous explosions. If a CME collides with Earth, the event can harm power and communication systems, as well as astronauts in space. With the Sun blocked during an eclipse, these clouds of charged particles could be spotted.
- Solar prominences, the large accumulation of cooler gas held in place in the atmosphere by the Sun's magnetic field, were also first recorded during a solar eclipse.