Chapter 17
Life in the Universe
Chemists have been inspired by Nature for hundreds of years,
not only trying to understand the chemistry that occurs in living
systems, but also trying to extend Nature based on the learned
facts.
— Kirsten Zeitler
Summary From an estimate of the number of planets in our galaxy that orbit
in the habitable zone of their star and that have the right range of size to hold
a light atmosphere, astrobiologists expect there to be millions of examples of life
throughout the galaxy. Whether these life forms have evolved to the point of being
able to destroy all life on their planet is a more difficult calculation. In this chapter,
we explore the requirements for life and the conditions needed for life’s initiation
and progression.
17.1 Minimum Requirements for Life
Life can develop where there was no life before. We have at least one example on
the Earth. Clearly, (1) the materials, (2) the energy flow, and (3) the environmental
conditions must be just right.
(1) Certain materials are necessary: Those that combine in a number of ways to
allow for complexity in the system, and that are capable of transformations both
into and out of higher energy states in the given environment.
(2) There must be a source of relatively high energy states that can do work, and a
sink to deposit energy, such as in the form of heat.
(3) The environment must allow the materials of life to be accessible and capable
of intimate mixing.
© Springer Nature Switzerland AG 2020
W. C. Parke, Biophysics, https://doi.org/10.1007/978-3-030-44146-3_17
613
Life in the Universe
Chemists have been inspired by Nature for hundreds of years,
not only trying to understand the chemistry that occurs in living
systems, but also trying to extend Nature based on the learned
facts.
— Kirsten Zeitler
Summary From an estimate of the number of planets in our galaxy that orbit
in the habitable zone of their star and that have the right range of size to hold
a light atmosphere, astrobiologists expect there to be millions of examples of life
throughout the galaxy. Whether these life forms have evolved to the point of being
able to destroy all life on their planet is a more difficult calculation. In this chapter,
we explore the requirements for life and the conditions needed for life’s initiation
and progression.
17.1 Minimum Requirements for Life
Life can develop where there was no life before. We have at least one example on
the Earth. Clearly, (1) the materials, (2) the energy flow, and (3) the environmental
conditions must be just right.
(1) Certain materials are necessary: Those that combine in a number of ways to
allow for complexity in the system, and that are capable of transformations both
into and out of higher energy states in the given environment.
(2) There must be a source of relatively high energy states that can do work, and a
sink to deposit energy, such as in the form of heat.
(3) The environment must allow the materials of life to be accessible and capable
of intimate mixing.
© Springer Nature Switzerland AG 2020
W. C. Parke, Biophysics, https://doi.org/10.1007/978-3-030-44146-3_17
613