The persistence of life on Earth
Questions on habitability of the rocky planets
Hypothesis: An object with twice the
mass of Mars collided with a planet in Earths orbit 4.5 billion years ago.
The core of the proto-earth stayed intact, the core of the lesser planet
was assimilated but the rocky mantle and the atmospheres of both planets
would have been completely destroyed . Part of this mantle material was
blown into space and formed the moon. Most volatiles condensed on earth.
This cataclysmic event is relevant
to explaining the origin of earth's present kinetics. It explains the dynamics
of the planet; the 24 hour day, the continuing volcanism , plate tectonics
and most important, the recycling of carbon every two hundred million years.
It is this carbon cycle that has maintained the green house gases as well
as supplying the main nutrient for life.
Radioactive decay, gravitational contraction,
phase shifts and other impact events are also major sources of internal
See Scientific American July 1994 "The
Scientific Legacy of Apollo" by G.
The evidence so far seems to agree with the hypothesis that
given a suitable environments, we can expect life to exist on many planets
in our galaxy. The Drake Equation popularized by Carl Saigon is that intelligent
life such as ours occurs regularly on a small percentage of planets that
produce life. This however does not convey the uniqueness of self conscious
intelligent life! Nature is more likely to produce the sea horse or the
platypus duck than anything like the human brain. All of these structures
are unique or exceedingly rare. Normal life in the universe consists mostly
of sausage shaped organisms metabolizing simple molecules or photons.
Intelligent Life in the Galaxy
Humans are very strange creatures, there is nothing in
nature that came before with abilities anything like hominids. Whereas
other organisms use variations on physical themes such as swimming or more
efficient digestion, Humans have been successful by thinking. This is a
strange and unique ability. Yet it seems to be just a chance outcome. A
creature similar to modern chimps had the need to carry stuff and throw
rocks. These abilities are all that is needed to explain human anatomy.
Intelligence followed much later. Try running a computer simulation that
ends in intelligent life as we know it!
Let us never forget that most (80%) of life on this planet
is bacteria. Statistically the strangest part of all is that life in any
form has persisted for over 3.5 billion years on this planet Earth without
a cataclysmic event making the planet inhospitable for all life. Or even
more likely, an environmental change that destroyed all complex life forms.
For life to exist liquid water is required over this entire period.
Life is common and cheap and we will find many planets
just like Mars, where life existed at one period in time, but not for most,
or even a significant fraction of these planets histories.
Do We Come From?
Question: Considering the findings
from Martian Meteorite ALH84001. The fact that meteorites tend to fall
down to Earth from Mars and not the other way round. And that the relics
found are at least as old if not older than any Earth originating relics,
and that any life that may have formed on early earth would have been destroyed
by the Moon creating event. Then has the possibility that life on Earth
may be derivative from Mars been explored?
Subject: Re: webmail Date: Wed,
4 Sep 1996 13:42:08 EDT From: email@example.com (Scientific Experts) Organization:
Scientific American, New York, NY To: uupsi3!vyne.com!charlote (Charlotte)
Reply to: RE>webmail Dear Reader,
Thank you for submitting your question
to Scientific American.
We may be able to run an answer on our web site in the near future.
The possibility that life arose
on Mars and then traveled to the Earth has been discussed by several scientists,
of the co-authors of the paper describing the possible signs of fossil
life in the Martian meteorite).
Most responsible institutions keep
backups of their data off site in a physically different location. This
insures against calamities such as fire. We now have the technology to
do the same for all Earth life. The minimum requirements are:
1 The location is not on Earth.
(The two most cataclysmic events that are statistically plausible, object
impact and nuclear Armageddon would be insured against by this action)
2 The location has to be self sustaining.
This means the supplies of energy and materials would have to be local.
The economic reality of the situation would be dictated by the local environment.
Materials from earth could be stockpiled over time.
3 A representative sampling of
Earth's genetic heritage could be economically stored as embryos, spores
4 A colony of humans should be
self sustainable. But because of the gene bank the numbers need not be
great. The Moon may be the most practical place to start, but Mars may
be the best long term solution.
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