The theory of Panspermia suggests that the Earth was seeded with basic life forms
which were extra-terrestrial and that evolution did not have its beginnings here
This theory offers a longer time frame for the most basic of life-forms, the archaea,
to have evolved. Although these microbes are primitive, their genes can synthesise
at least 2000 proteins and they also have an array of non-functional genes, suggesting
a long pre-history.
But the Panspermia Theory, constrained by the present theory for the formation of
the Solar system, assumes that life must have originated somewhere outside the Solar
My theory of Planetary Metamorphosis offers a location for the original beginnings
of life within the Solar system. I suggest that life may have formed on a ‘previous
planet’, billions of years ago. At the end of its life cycle, the previous planet
may have disintegrated and its fragments formed asteroids and comets which were then
propelled around the Solar System. Impacts of this debris with younger planets could
have facilitated the transfer of life-forms (such as methanogens, deep within rock).
Methanogens can live deep within the Earth crust and withstand temperatures as high
as 100 degree C. So it is feasible that they can survive within a huge asteroid as
it enters a planet’s atmosphere.
The only resources methanogens require for sustaining their life are hydrogen and
carbon dioxide gases. They use hydrogen to reduce carbon dioxide in their metabolic
processes and produce water vapour and methane as end-products. Both of these resources
can be found deep within the crustal rock of planets. The methane eventually breaks
down, by the action of ultra violet light, into carbon dioxide and more water vapour.
Methanogens on Gaseous Planets?
On planets like Neptune, Uranus, Saturn and Jupiter, hydrogen and carbon dioxide
is in abundance. Compounds required for protein synthesis also exist in the form
of ammonia. All these gaseous planets show the possible signature of methanogenic
life in that their atmospheres all have methane and water vapour in them. The blue-
green colour of Uranus is caused by a methane cloud made up of tiny crystals of
frozen methane (NASA- World Book at NASA). Methane forms 2% of its atmosphere. Here
the temperatures are around -215 degrees C but temperatures and pressures rise sharply,
the deeper the atmosphere is penetrated. So there will be a band where the atmospheric
conditions of temperature and pressure will provide the ideal conditions for methanogenic
According to ESA, Cassini-Huygens, there are three layers of cloud deck in Saturn’s
outer atmosphere. .The top visible cloud deck is made of ammonia clouds and this
extends down about 70 km and temperatures here are around -250 degrees C. The second
cloud deck is comprised of ammonium hydro-sulphide clouds at a temperature of around
-70 degrees C and these extend down to water clouds which start at 0 degree C and
I suggest that this water cloud layer could provide ideal conditions for methanogenic
life to exist.
Accumulation of Water
Methanogens may be singly responsible for the vast amount of water which is found
on Earth. If Earth was seeded with methanogens at least a billion years ago - when
it was the tiny core of a gaseous planet, quantities of water on Earth would have
increased exponentially alongside the exponential increase of the microbes, themselves.
Mars may not have been seeded with methanogens until perhaps only recently and this
would explain why there is no abundance of water on its surface. Plumes of methane,
however, have been discovered emanating from some areas of Mar’s surface and so there
is still the possibility that methanogens are present there too.