Bobbie Sellers wrote:
On 4/21/26 10:41, The Horny Goat wrote:
On Sat, 28 Mar 2026 02:00:16 -0000 (UTC), Lawrence D?Oliveiro
<ldo@nz.invalid> wrote:
If, back when our Solar System was young, there were other stars
around much closer than that -- perhaps born out of the same gas/dust
cloud; could their gravitation perturbations on the (at that time
shared) Oort Cloud have been the cause of the Late Heavy Bombardment?
So that eased off after the various littermate stars drifted apart.
It has been postulated that the planet Jupiter started that way long
before there was life on Earth.
˙˙˙˙Lately I have read headlines that assume that Sol had 6,000
equivalent stars
in a nursery across the Galaxy and from which it was ejected to move to the peripheral arm of the Galaxy.˙ But on Earth we had a terrific impact
before complex
life evolved that tore the Moon out of the crust of the Earth.˙ Life may have
already existed in the Universe even before the Earth was conglomerated.
I think this is certain to be the case.
˙˙˙˙We know that the early Sol system was heated by an isotope of
Aluminium
British spelling, I like it!
which could have only come from an exploding previous star.
That would be aluminum-26, which has a half life of about 700,000 years,
so cannot be primordial but is produced in supernovae.
The idea that Al-26 was necessary to heat objects in the early solar
system was apparently first deduced by Harold Urey, Asimov's bete-noir
at Columbia (Urey thought that Asimov was just biding time until he
could get into med school).
I was told long ago that the Al-26 evidence dated the first solid
objects in the solar system to about 25 million years after the
supernova. But now other isotopes, Iron-60 among them are used, and I
can't see if these confirm the earlier result.
The core of the
Earth could have come from one or more supernova. The Iron of the Core is
one of the reasons we have atmosphere and that live is not scoured from
the surface of the Earth by solar radiation.
The most astonishing thing I have learned about the deep earth in recent
years is that much of the lower mantle is transparent. Propagation of
energy by light is actually an important factor in it's thermal
structure. Never in a million years would I have guessed that.
William Hyde
˙˙˙˙bliss
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