Page 151 - Innovator's Science-8

become noticeable only after long intervals. Today, astronomers rely on the
sidereal year to keep track of the Earth's position in its orbit around the Sun.

For thousands of years, people – especially in India – have observed the sky
carefully and developed their own calendars. Earth revolves around the
Sun, and without the help of modern tools, their keen observations

revealed repeating patterns in nature. From these patterns, they learned
that a year lasts about 365 days, which helped them make calendars. For
example, they observed that the Sun's position at sunrise shifts slightly

from true East through the year. In summer, it rises a bit north of East, and in
winter, a bit south of East. These farthest points happen during the
solstices, around June 21 and December 21 each year.

When the Sun appears to move northward – from December to June – it is
called Uttarayan ; its southward journey, from June to December, is known
as Dakshinayan . This yearly cycle corresponds closely with the pattern of
changing seasons.

Sun rises exactly in the Path of Sun one In the past, the equinoxes and solstices were also tracked by
East and sets exactly in June solstice
the west on equinoxes identifying the stars that rose at sunset. Ancient Indian texts
Path of Sun like the Surya Siddhanta noted that the pattern of stars,
on December
solstice
Capricorn (called Makar in India), would be in the background
of the Sun around the winter solstice during those ancient
times.

Over time, various calendars developed in India to meet

Uttarayan from December to June different regional and cultural needs. A number of these
calendars are used in different parts of India to track time and

celebrating festivals.

LUNI-SOLAR CALENDARS

There is a special type of calendar called a luni-solar calendar that mainly
uses the Moon's phases to count days and months but also adjusts to stay in
sync with the seasons. Since 12 lunar months add up to about 354 days, this

is nearly 11 days shorter than a solar year. Over 2 to 3 years, this difference
adds up to almost a whole month. To fix this, an extra month (called Adhika
Maasa, or intercalary month), is added every few years in these calendars.
This keeps the lunar months and the solar year aligned. These luni-solar
calendars mix both solar and lunar calendar ideas and are used in many

parts of India.
In many Indian luni-solar calendars, the months have names like Chaitra,

Vaisakha, Jyeshtha, Ashadha, Shravana, Bhadrapada, Ashwin, Kartika,

151
Science-8