THE ACCRETION OF THE PLANETS
In the beginning, the Big Bang created the simplest of atomic nuclei,
Li but nothing much else. All the more massive nuclei were
created in the nuclear fires of stars.
Our planets are formed out of late materials = that have evolved through
the growth/explosions of large stars (throughout the history of the
Early Big Bang doesn’t create everything = only creates a few elements
Approximately 1 – 2 mil years after the Big Bang, large stars have formed
(some are Super nova) = once at Super Nova, they produce the rest of
From the dust of this nucleosynthetis, the elements of our Earth were formed and
from these our Earth and Sun and planets condensed.
The rest of chemistry produced when a star is at Super Nova, gets
Heavier elements get dispersed in and slowly get re-condensed into new
sets of stars
THE CONDENSATION OF THE SOLAR SYSTEM
About 5 × 10
years ago, when the universe was already, perhaps 8 × 10
old, at some gravitational centre, material from the clouds of dust and gas left
behind by supernoval explosions began to assemble the mass of our Solar
All elements known to exist in our Solar System, except for
Pm, pre-existed in the condensing cloud.
Promethium = exists in the Solar system, but NOT on Earth (exists
only in the Sun)
Can be created synthetically through nuclear reactors, but
doesn’t exist naturally on Earth.
Why no promethium on Earth?
The longest-lived isotope of promethium,
Pm has a half-life,
of only 30 years and so all of this element would
have been quickly lost to the cloud since no nucleosynthetic processes in