In the sky

J. RAMANAN

Stars are born when the swirling dust in the intergalactic voids are condensed by the gravitational force. These dust particles also form planets.

The basic difference between a star and a planet is the size. If any condensing dust sphere aspires to become a star it should really be very big in radius.

Take for example, the sun. The radius of the sun is 700,000 km. In front of the sun. In comparison the Earth is a mere dot - 6,378 kms in radius. Even the radius of Jupiter is only 71,398 km.

The gravitational pressure makes all particles fall towards the centre of the condensing sphere. There is also an internal pressure building up to resist the gravity. If the radius of the sphere is more, the particles which are falling towards the centre has to travel a long distance to reach the centre and faces more resistance from the internal pressure.

At some distance inside, the pressure crosses the through hold limit and starts off the nuclear fusion reaction and marks the birth of the star.

Whereas, for a smaller sphere like earth, the radius is too small for this internal pressure to build up to start the nuclear reaction. So, after all the earth can never aspire to become a star by any natural means.

Send this article to Friends by E-Mail

Section  : Features
Previous : Holiday in India Quiz - Answers
Next     : Young World Quiz (June 16, 2001)