Vernal Equinox

Please read some astronomy explained in simple words.

On 20th March, the day time 
and night time are equal

VERNAL  EQUINOX

 20th March. Astronomically this day  is known as " Vernal Equinox  "

Which means equal day and night.( equi +nox = equal + night )

The sun crosses the  celestial equator and 

 Moves  in the celestial sphere from South to North.

From the next day ,  for the people of northern hemisphere ( India), 

Day time will be increasing and night time will be decreasing.

For the people of southern hemisphere ( Australia)

Night time will  be  increasing  and day time will be  decreasing.

On 22st September, the Sun will move from northern hemisphere to southern .

It is called Autumnal equinox. On  that day also, the Day and night will  be equal.

From  the next day,  

The day time will be gradually increasing  and  the night time will be decreasing for them.

On Vernal equinox and Autumn equinox , the day and night will be almost the same.

The longest day will be on June Solstice, which on 21 June  2013.

The longest night will be on  December Solstice, which on 21st December 2013. 

Year 2013 has some peculiar aspects.

In the month of March, there are 5 Fridays, 5 Saturdays, 5 Sundays.

Apart from this, ,  there are 5 eclipses in this year.

2 solar ( sun ) and 3 lunar (moon) eclipses.

April 25th Lunar

May 10th Solar

May 25th Lunar

Oct  18th Lunar

Nov  3rd  Solar

( in 2011, 4 solar and 2 lunar = 6

  in 2012 , 2 solar and 2 lunar = 4 

  in 2013 , 2 solar and 3 lunar = 5 

  in 2014 , 2 solar and 2 lunar = 4 

  in 2015,  2 solar and 2 lunar = 4 )

What is an eclipse ?

If the  the moon  hides  the Sun , it is solar.

If the shadow of the earth falls on the moon , it is lunar.

What is the maximum number of eclipses in a year ? 

7 eclipses.

4 solar and 3 lunar = 7

5 solar and 2 lunar = 7

Which years do the  7 eclipses ocurred ?

.......

.......

1935 ( 5 solar and 2 lunar = 7 )

1982 ( 4 solar and 3 lunar = 7 )

When  do  the next 7 eclipses in a  year  will occur ?

2038 ( 4 solar and 3 lunar = 7  ) 

What is the minimum number of eclipse in a year ?

2 eclipses , all solar. 

Can there be a year without eclipses ?

No, there cannot be a year without  eclipses.

On what days do  the eclipses occur ?

Always Solar eclipse will occur on  a New Moon day.

Always Lunar eclipse will occur  on a Full Moon day.

What is Saros cycle ?

According to this, an eclipse will be repeated on the same day 

After 6585.3213 days or  roughly 18 years 11 days. 

The wonder is, this fact was found out by ancient Babylonian astronomers 

Several  centuries before Christ.

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To know more, please go to my blog.  click 

http://titbitsfromvincent.blogspot.com/2011/06/in-this-year-2011-there-are-six.html