“The Answer to the Great Question… Of Life, the Universe and Everything… Is… Forty-two,’ said Deep Thought, with infinite majesty and calm.”
That quote from Douglas Adams’ “The Hitchhiker’s Guide to the Galaxy” has pacified the inquisitive for a long time, even though it’s fiction. However, scientists kept looking and this week announced they had found the source of all life in the universe. Is it 42? A number close to 42? Something from another book? Will it change everything?
“The initial–final mass relation (IFMR) links the birth mass of a star to the mass of the compact remnant left at its death.”
OK, the conclusions by Paola Marigo, an astronomer at the University of Padua in Italy, and his team of authors of a new study published in the journal Nature Astronomy, won’t take seven and a half million years to explain like Deep Thought’s answer in the book. On the other hand, they may require the connection of some pretty remote dots – namely, one from the birth of a star and the other from its death. As recounted in the study’s press release, the team started with the idea that all life needs carbon, so following carbon back to its source is the same as following life on the same path. Every carbon atom in the universe came from stars that successfully fused three helium nuclei. Those atoms were then dispersed throughout the universe – a scattering of the seeds of life. What kind of star has this capability? Find that and you find the source of life.
“From the analysis of the observed Keck spectra, it was possible to measure the masses of the white dwarfs. Using the theory of stellar evolution, we were able to trace back to the progenitor stars and derive their masses at birth.”
The “Keck spectra” refers to the W. M. Keck Observatory in Hawaii used by the astronomers. The two generally held hypotheses were that carbon either came from low-mass stars that became white dwarfs at the end of their lives, or those that became massive supernovas. While expecting the “initial-final mass relation” between a star’s mass at birth and at death to be constant, the team was shocked to find that white dwarfs were much larger at the end. That gave them the answer.
“Now we know that the carbon came from stars with a birth mass of not less than roughly 1.5 solar masses.”
Computer models showed that stars at least 1.5 times the mass of our own Sun had cores which grew slow enough to achieve massive proportions before dying in a transformation into a white dwarf, exploding their carbon into space. That stellar death becomes a birth of life … eventually.
“These findings place stringent constraints on how and when carbon, the element essential to life on Earth, was produced by the stars of our galaxy, eventually ending up trapped in the raw material from which the Sun and its planetary system were formed 4.6 billion years ago.”
Which explanation makes more sense – that one or “42”? Would it help if it was said with infinity majesty and calm?