Question – 72
Why shouldn’t Amavasya occur on Trayodasi?
Amavasya is a segment in the lunar orbit when the moon comes in between the sun and the earth. The lunar orbit is divided into 30 parts (360 degrees) with each part known as a Tithi. Halfway through it, that is, at the 15th tithi, Paurnamī occurs (covering 180 degrees). In the next 15th tithi, Amavasya occurs (Another 180 degrees). Each tithi is given a Sanskrit name, based on the number of tithi-s. But one should know that the Sanskrit names used for the numbers are NOT adopted for the tithi.
For example, Ekam for number 1 is Pratipat or Prathama when it represents the 1st tithi.
Similarly, Dve is for 2, which is Dwitiya for the second tithi.
Treeni for 3, is Tritiya for the third tithi.
Now for double digit numbers,
Dasha is for 10, but it is Dashamī for the 10th tithi.
Ekadasha for 11, but it is Ekadashī for the 11th tithi.
Dwadasha for 12, while it is Dwadashī for the 12th tithi.
Trayodasha for 13, but it is Trayodashī for the 13th tithi.
In the Mahabharata, Vyasa states, “trayodaśīm Amāvāsyāṃ” which he had never heard of (MB: 6.3.28).
So, he refers to the 13th tithi of the moon’s phase and not the 13th day.
A day is different from tithi.
The day is dina or divasa or saura, measured by the movement of the sun whereas as a tithi is the phase of the moon, measured by the distance travelled by the moon, away from the sun.
A day has more or less the same duration because it is dependent on the motion of the earth which is perceived by the time between one sun rise to the next sun rise.
But tithi may take different lengths of time within a lunar month depending on the perigee and apogee of the lunar orbit. Because of this three tithi-s can occur in two days (called Tri-dina spruk) or two tithi-s may measure less such that one of them would end well within two consecutive sun rises (Kshaya tithi).
Now we will see how a tithi is measured.
A tithi has12-degree length. This is calculated by the distance between the sun and the moon. For example, the first tithi, Prathama starts at the point the moon leaves the edge of the sun as seen from the earth. The moon may not be exactly crossing the sun and may be higher or lower than the location of the sun as seen from the earth. We consider what is called the longitude of the sun. The moment the moon leaves that longitude, the first tithi, known as Shukla (waxing) Prathama starts. Even as the moon is moving ahead, the sun will also be moving in the same direction. The gap between the moon and the sun, when it completes 12 degrees, the first tithi is over and the second tithi, namely Dwitiya starts. Like this, the moon crosses 14 tithi-s to enter Paurnamī (Full Moon Day) which is the 15th tithi.
Counted from Paurṇamī, the 15th part occurs on the No-moon day (Amavasya) between 168 and 180 degrees. At times Amavasya had started before 168 degrees but ended up between 168 and 180 degrees (from 14th to 15th phase), but it can never start in the 13th phase, i.e., Trayodaśī (between 144 and 156 degrees). If Amavasya had started on Trayodaśī, it clearly implies that something went wrong with the moon and that its orbit had changed.
This is a terrific Ganesh moment, for, such a pre-occurrence of Amavasya before 156 degrees can never happen in Nature.
Vyasa did not spoon-feed us will all the details. He wanted us to think and explore. That is why he seemed to have inserted the Ganesha part to send a message to all the future readers of the Mahabharata to strain their grey cells to pick out the extraordinary events that happened in the months prior to the war.Click here for the next question