Let there be gamma rays
It was one of the first coughing turnovers of the cosmochemistry engine.
The NASA Swift satellite has detected the oldest known star detonation in the universe… 13 billion years old. The previous record was only about 200 million years younger, but at such an early epoch of our universe – which is itself only 13.7 billion years old – 200 million years becomes a significant amount of time. The gamma ray burst heralding this ancient star’s end occurred about 700 million years after the universe instantiated, which is just about as old as a star can be.
According to a very bad article about this discovery on CNN.com, this new oldest gamma burst erupted from a star of about 30 to 100 solar masses…. meaning it probably used to be a supergiant or hypergiant star. The CNN.com piece is a bad article because it says:
“Telescopes around the world swiveled to focus on the explosion, soon picking up infrared radiation, which travels more slowly than gamma rays. Berger waited for the visible light which he expected to come next.“
I can’t believe this made it past the science editor. Oh, that’s right… there probably isn’t one. In brief, all electromagnetic radiation (which includes light) always travels at the local velocity of light at all times and everywhere. What that article tried to say was that the first bright flash that happens during a massive supernova is brightest in the gamma ray region of the electromagnetic spectrum. The gamma blast reaches a catastrophic peak of searing intensity, then proceeds to cool through the gamma and X-ray bands, then passes through a temperature range where visible light shines, then finally dims to emit infrared light for a long, long time.
Anyway, back to the oldest gamma burst. At such an early stage of the universe’s evolution, that star would have been made almost entirely of virginal hydrogen and helium, and essentially nothing else. The first stars had no stars to preceed them, and so incorporated no fusion ash of heavier elements such as carbon, oxygen, nitrogen and iron. Only after several generations of primal supergiants congealed, burned out, and detonated would the interstellar medium begin to accumulate enough heavy atoms to form particles of ice and rock.
Fortunately for planets and life, there were probably many super- and hypersuns around back then to get the job started. Such massive stars only live for a few million years – mere moments, cosmologically – then explode, forming a black hole and spewing metals into the surrounding void-ocean of primordial hydrogen, from which stars emerge and into which dead stars deposit their cooling remains. After only a few hundred million years of this, galaxies probably started to accumulate enough metals to make icy, rocky worlds… the first planets ever to exist. Ours is not one of those planets… Earth came along about 8.4 billion years later. Those first, most-primal planets are probably now long dead, circling star corpses or drifting through empty space….
… or ARE they?