STARS, GALAXIES AND

CONSTELLATIONS

PRESENTATION 1: BY SIDDHI SHAH

WHAT ARE STARS?

A star is a luminous sphere of plasma held together by its own gravity.It is composed of hydrogen and helium.

HOW ARE THEY FORMED?

The formation of a star begins with Gravitational Instability within a molecular cloud, caused by Regions Of Higher Density. Once a region reaches a sufficient density of matter, it begins to collapse under its own gravitational force. As the cloud collapses, dense Dust And Gas form “Globules". As a globule collapses and the density increases, the gravitational energy converts into heat and the temperature rises. When the cloud has approximately reached the stable condition, a Protostar forms at the core. With the time, this star also gains its shape and size

CONSTELLATIONS

A Constellation is a specific area of the Celestial Sphere.There are 88 officially recognized constellations, covering the entire sky.

Ursa Major or Great BearUrsa Minor or Little BearOrion or HunterScorpius, Leo and Sagittarius.,

URSA MAJOR OR GREAT BEAR

URSA MINOR OR

LITTLE BEAR

SCORPIUS AND HUNTER

ORION

AND

LEO

GALAXIESA galaxy is a gravitationally bound system of stars, stellar remnants, interstellar gas and dust, and dark matter.Approximately 170 billion (1.7 × 1011) galaxies exist in the observable universe.

NGC 4414, a typical spiral galaxy in the constellation Coma Baronies

The Sombrero galaxy (M104), a bright nearby spiral galaxy.

NGC 1427A, an example of an irregular galaxy, 52 million light-years away

Thank You.Siddhi Shah (Designing)

Sayammi Doshi(Information)Mansi (Information)