Expert: Jayendra Upadhye - 6/2/2005

Question
What is supernova?Is it possible earth will face the same phenomenom as the other planets which will explode in the future?

Answer
Hi Jack,
(opps! that sort of sounded lik a "highjack" but let it go at that..)
Firstly planets never go supernova!
It is stars with mass greater than few solar masses, that become supernovas at the end of their red giant phase, at the end of their lives.
Such a star being masive, needs to burn fuel at a greater rate in order to maintain its size against the terrific crushing "weight" of its overlying atmosphere.
Over time it consumes all of its hydrogen which it "burnt" and converted into helium. When this stage is reached, the inner core contracts, and "helium burning" phase starts.
At this stage so much heat is liberated, that the outer layers of the star are pushed out and it becomes a red giant star.
Thus successively helium, carbon, oxygen sulphur etc are synthesized until the star needs to manufacture iron to help sustain the enrgy it needs to remain stable.
Iron cannot be synthesized by any stellar core, so energy production stops. Within seconds the core implodes into a neutron star (much much harder than diamond). The outer layers slowly come crashing down.
These layers crash on the extremely compact and hard neutron star surface and rebound outwards.
This rebounding "shock wave" of matter punches thru (sometimes about just) the infalling matter and it is this stage that we call a supernova!
The beginning is a giveaway tell tale flash of hard x rays from the core, and a neutrino burst.
Then in a day or two, the shock wave bursts out of the overlying infalling debri and there is a flash that equals all the output of the whole galaxy in radiance!
Most of the trans iron elements are synthesized in this turmoil.
unstable radioactive elements are also generated and depending on their half lives, begin decaying almost the moment they are created.
As the expanding cloud of gas and dust cools, oxygen combines in a huge conflagration with whatever it can burn, yielding water and sio2 (sand), and other salts are similarly created.
THE SUPERNOVAS are the reason why we exist.
The carbon, sulphur, iron and salt in our body is not from our sun but from the supernova that seeded it's creation!
Jayen