e20200160-12
Interdisciplinary study of the synthesis of the origin of the chemical elements...
Figure 11:
Initial average temperatures in the interplanetary
medium as a function of solar distance (not to scale). Only
substances that are solid at high temperatures can form rocky
planets, like Venus and Earth, while the “ices” concentrated in
cooler regions such as Jupiter’s orbit and beyond. Note these
temperatures are
not
the planets’ ones, which are determined
by the energy balance between solar energy, inner energy and
what is radiated back to space.
rectly as a condensation of the nebula, and not by the
aggregation of planetesimals. Regardless of this, a proto-
jupiter functioned as a center that attracted and spread
a large number of planetesimals. In fact, it is believed
that he was the “culprit” forspreading a good part of the
“ice” planetesimals towards the inner planets, where they
melted/evaporated.
However, the
water
content of these planetesimals
could condense and formed Earth’s oceans, which other-
wisewould be a much drier planet. The protojupiter was
also responsible for the scattering of small ice planetesi-
mals up to distances of perhaps
∼
100 000 AU, where
we they can still be found.
These bodies are still in very distant orbits, but from
time to time disturbances from neighboring stars “push”
some into the interior Solar System, and they can be
observed from Earth as comets. Near the “protojupiter”,
planetesimals reached enormous speeds, and so their col-
lisions were very violent,preventing them from forming a
protoplanet. This is the origin of the asteroid belt that is
located between Mars and Jupiter, in other words, aster-
oids are
not
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