WHEN THE SUN GOES DARK

What is eclipse?
It is an astronomical event that occurs when an astronomical object (Earth) is temporarily obscured by another body (Moon).

SOLAR ECLIPSE:
(Note: Whatever written in Italics is absolute high yield points for any competitive exam.)

Solar eclipse always occur on New Moon day.

Why Solar eclipse doesn't occur every New Moon day?
Because Moon's orbital plane makes 5° angle with Earth's orbital plane and hence minimising chances of alignment of node of Earth's and Moon's orbit simultaneously.

Types of Solar Eclipse:
 

1.Partial solar eclipse:
*Most common type
*Visible in region under umbral and penumbral shadow during TSE & ASE.

2.Annular Solar eclipse(ASE):
*Also called as Ring eclipse.

*Possible when magnitude is less than 1. 

(Magnitude is the ratio of angular size of Moon to  that of Sun from Earth.)

*Usually occurs when Moon is at apogee of it's orbit.
*Visible in region under Reverse umbral shadow.

This image will also clear your basic concepts of shadow.

3.Total Solar eclipse (TSE):
*Possible when magnitude is greater than 1 .
*Visible  in region under Umbral shadow.
*Due to craters and valleys on Moon 'Bailey beads' then 'Diamond ring' can be seen in TSE.

4.Hybrid Solar eclipse:
*Most rare type
*Possible when magnitude is exactly 1.
*TSE will be visible in region under Umbral shadow while ASE in the region under Reverse umbral shadow.

Why Solar eclipse is Important?

✨On 28th July 1851, 1st photograph of solar corona was taken by Julius Borkowski.
✨To study Sun's Chromosphere and Corona.

✨On 18th August 1868, Pierre Janssen discovered 'He' gas spectral lines in Sun's atmosphere at Guntur, AP, India.  
✨On 22nd January 1898, near Ultra violet spectral lines was discovered in Sun's Chromosphere at Ratnagiri, Maharashtra, India
✨In 1908, George Hale discovered the presence sunspot with magnetic properties in Sun's photosphere.
✨On 29th May 1919, Einstein's General theory of Relativity was proved by Arthur Edington.
 
*Solar eclipse is possible when New moon day occurs 18.75 days before/after the alignment of  nodes i.e. within duration of 37.5 days known as 'eclipse season'.

This image also explains why solar eclipse 2 weeks before/after is always associated with Lunar eclipse.

*2 eclipse season makes one eclipse yr of 346.6 days.

*Minimum 2 and maximum 5 solar eclipses can occur in a yr.

However maximum 7(5+2) eclipses can occur in a yr.

*Maximum possible duration of Totality is 7 min 31 seconds and is directly proportional to Magnitude.

*Eclipses repeat after duration of 18 yrs 11 days and 8 hours called as Saros Cycle because of same relative position of Earth, Moon and Sun.

Are such wonderful phenomenon of TSE and ASE occur with other planet also?
No, it is possible only with Earth because Sun is not only 400 times larger than Moon but also 400 times farther than Moon which makes their angular size equals to that of Moon from Earth.

Recent News:
Annular Solar eclipse on 21st June 2020.
Annularity will be visible from states like Rajasthan, Haryana, Uttarakhand and UP of India from nearly 10 O'clock.

For simplicity of topic we will discuss Lunar eclipse in the next post.  
To visit the post: Click here.

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