Life and Death of a Star
Each of us, in the immortal words of the American poet Walt Whitman, “…are the journeywork of the stars, no less than the leaves of grass.” As Carl Sagan would put it later in the twentieth century – “Our lives, our past and our future are tied to the sun, the moon and the stars… We humans have seen the atoms which constitute all of nature and the forces that sculpted this work… and we, who embody the local eyes and ears and thoughts and feelings of the cosmos, have begun to wonder about our origins… star stuff contemplating the stars, organized collections of ten billion billion billion atoms, contemplating the evolution of nature, tracing that long path by which it arrived at consciousness here on the planet earth… Our loyalties are to the species and to the planet. Our obligation to survive and flourish is owed not just to ourselves but also to that cosmos ancient and vast from which we spring.”
If we could watch the night sky over a period of millions of years, we would witness the stars undergo an astonishing sequence of transformations. Thanks to a new generation of telescopes we can follow the unfolding life story of a star from the moment of its first gestation as a prostellar object forming in a majestic cosmic nebula, through to the moment of birth.
Astronomers have developed the telescopic equivalent of ultrasound, a camera sensitive to infrared light which monitors prenatal suns incubating inside clouds of hydrogen gas and the first fleeting moments of a newborn protostar as it announces its arrival on the cosmic scene with a copious flux of ultraviolet energy.
The science of our epoch has allowed us to follow the life after death of a star and follow its reincarnation from the moment of its tumultuous death to the formation of new generations of stars, and at least in our nook of the galaxy, the formation of planets, life and sentience.