616
17 Life in the Universe
17.2 Life Elsewhere
Astrobiologists study the conditions on other heavenly bodies and space to see if life
has or can form there. There are several objectives. One is to learn, by comparison,
more about how life formed on Earth. A second is to see if there are any other
ways to evolve life. A third is to prepare for the discovery of other intelligent life.
NASA’s Kepler project has found hundreds of extrasolar nearby planets, many that
would support life. The SETI project (Search for Extraterrestrial Intelligence) looks
for signals from other beings, at frequencies cleverly selected and bearing a ‘hello’
artfully coded, perhaps with a preface of enticing math identities. Likely originating
hundreds or thousands of light-years away, we could not, as individuals, respond
to any signal sent by such intelligent beings. But we might learn something from a
long message in a radio wave directed toward us.
If we humans apply our intelligence and reasoning, our drive to explore and
expand will inevitably lead us to form colonies on bodies in our solar system and
those in extrasolar systems. With relativistic spaceships, individuals will be able to
travel, in their own lifetime, to locations where other intelligent life may have been
detected, although centuries or millennia may pass before Earthlings will hear of
the progress of such explorations.
17.3 Self-stabilizing Life Systems
In the evolution of the Earth, there was a time, over three billion years ago, when
the atmosphere contained little oxygen. Molecular life forms had developed near hot
vents on the ocean floor, metabolizing sulfur, and taking advantage of the plentiful
organic molecules and chemical gradients. Encapsulated organisms, the archaea and
bacteria, evolved. Viral particles soon followed. After the Earth cooled to have a
surface temperature below about 70 ◦ C (higher temperatures prohibit photosynthetic
processes) 2.3 billion years ago, cyanobacteria came about, utilizing the energy of
sunlight, together with water and dissolved carbon dioxide, to produce carbohydrates and other organic material needed for the structure, growth, reproduction,
and the activity in life. Fungi evolved with a symbiotic relationship with bacteria.
As the basic photosynthetic process is 6 CO 2 + 6 H 2 O → (C 6 H 12 O 6 ) + 6O 2 , excess
oxygen was released by the plants while carbon dioxide was captured.
Life systems, being mutagenic, respond across generations to changes in the
environment, provided that the time for environmental changes causing a measurable effect on survivability is longer than the time needed to improve life in the
new environment. This time needed for improvement can be linked to the time
required for genetic changes, to the production of memory (records) containing
survival strategies passed across generations, or to intelligent redesigns for life
systems capable of making purposeful self-correcting changes.
17 Life in the Universe
17.2 Life Elsewhere
Astrobiologists study the conditions on other heavenly bodies and space to see if life
has or can form there. There are several objectives. One is to learn, by comparison,
more about how life formed on Earth. A second is to see if there are any other
ways to evolve life. A third is to prepare for the discovery of other intelligent life.
NASA’s Kepler project has found hundreds of extrasolar nearby planets, many that
would support life. The SETI project (Search for Extraterrestrial Intelligence) looks
for signals from other beings, at frequencies cleverly selected and bearing a ‘hello’
artfully coded, perhaps with a preface of enticing math identities. Likely originating
hundreds or thousands of light-years away, we could not, as individuals, respond
to any signal sent by such intelligent beings. But we might learn something from a
long message in a radio wave directed toward us.
If we humans apply our intelligence and reasoning, our drive to explore and
expand will inevitably lead us to form colonies on bodies in our solar system and
those in extrasolar systems. With relativistic spaceships, individuals will be able to
travel, in their own lifetime, to locations where other intelligent life may have been
detected, although centuries or millennia may pass before Earthlings will hear of
the progress of such explorations.
17.3 Self-stabilizing Life Systems
In the evolution of the Earth, there was a time, over three billion years ago, when
the atmosphere contained little oxygen. Molecular life forms had developed near hot
vents on the ocean floor, metabolizing sulfur, and taking advantage of the plentiful
organic molecules and chemical gradients. Encapsulated organisms, the archaea and
bacteria, evolved. Viral particles soon followed. After the Earth cooled to have a
surface temperature below about 70 ◦ C (higher temperatures prohibit photosynthetic
processes) 2.3 billion years ago, cyanobacteria came about, utilizing the energy of
sunlight, together with water and dissolved carbon dioxide, to produce carbohydrates and other organic material needed for the structure, growth, reproduction,
and the activity in life. Fungi evolved with a symbiotic relationship with bacteria.
As the basic photosynthetic process is 6 CO 2 + 6 H 2 O → (C 6 H 12 O 6 ) + 6O 2 , excess
oxygen was released by the plants while carbon dioxide was captured.
Life systems, being mutagenic, respond across generations to changes in the
environment, provided that the time for environmental changes causing a measurable effect on survivability is longer than the time needed to improve life in the
new environment. This time needed for improvement can be linked to the time
required for genetic changes, to the production of memory (records) containing
survival strategies passed across generations, or to intelligent redesigns for life
systems capable of making purposeful self-correcting changes.