Modern science lacks a unifying, interdisciplinary theory of life. In other words, current theories are unable to explain why life is the way it is and not any other way.

Dr. David Grinspoon writes about Charley Lineweaver’s review of “Scientists Debate Gaia,” a collection of essays gathered from an American Geophysical Union conference and by the published by MIT press. Charles H. Lineweaver is a Senior Fellow at Australia National University’s Planetary Science Institute.

He explained that James Lovelock (shown) proposed the Gaia hypothesis, in which Earth is an organism or system capable of self-regulation. He wondered: Can the existence of life be recognized from the chemical composition of a planet’s atmosphere? What would the Earth be like now, if life had never evolved on it? Would there be oxygen in the air? Would the surface temperature be hot like Venus or cold like Mars? In the mid-60’s, NASA consulted James Lovelock to assist in developing instruments for the Viking spacecraft to detect life on Mars.

He concluded that it wasn’t necessary to send a spacecraft to Mars. All you needed was to determine the composition of the Martian atmosphere –- if life was there, the atmosphere should be in chemical disequilibrium as it is on Earth. Recent observations, have detected methane on Mars indicating life.

Determining what life is and how to recognize it is the Holy Grail of astrobiology. To make progress, we need to explore the Martian subsurface and analyze the atmospheres of the nearest terrestrial planets. Lovelock’s Gaian chemical equilibrium test for the presence of life is fundamental to these efforts. Both NASA and ESA are putting their astrobiological money into interferometric infrared spectroscopy to look for the traces of chemical disequilibrium in planetary atmospheres as the primary biomarker.

Lovelock thought that terrestrial life didn’t just passively produce chemical disequilibrium. There seemed to be some element of control or regulation. In 1978, he published a book called “Gaia” that described how the entire biosphere behaves like a living creature suggesting our Earth is alive.

Gaian science and astrobiology have very similar programs. Astrobiologists look at the stars and ask “What has life done to the planets out there and how can we recognize it?” Gaian scientists have been looking at the Earth for decades asking “What has terrestrial life done to our planet and how can we recognize it?” Astrobiology and Gaian science often remain separate fields of inquiry. Astrobiology attracts mainly astronomers and biologists, while Gaian science attracts atmospheric chemists, geologists and concerned ecologists.

The thin Martian atmosphere is mainly composed of carbon dioxide. Planetary scientists have studied the atmosphere of Mars for any signs of gases such as methane that could be generated by life. In this collection, Gaian scientists believe that over the past four and a half billion years, the Sun’s luminosity has increased by about 30 percent, but the temperature of the Earth’s surface doesn’t seem to have followed in step. Lovelock hypothesized that the biosphere regulates the Earth’s surface temperature. There are two obvious ways to do this: Regulate the albedo (light reflected by the planet) and/or regulate the abundances of greenhouse gases in the atmosphere.

Lovelock invented the parable of Daisyworld to demonstrate that the biosphere could regulate the albedo. A nice Gaian extension of this idea is J. Scott Turner’s analysis of the thermo-regulation of termite colonies. So if a termite ecosystem can evolve to do it, why can’t a big one like the Earth? Thus, Gaia does what good scientific ideas are supposed to do. It extends and extrapolates a fundamental theory, from individuals to groups to ecosystems, up to the entire biosphere.

The central debate of this book is: How can Gaia (Earth) be selfish? How can it do anything “for” itself? Will it protect itself from human destruction of the environment by causing earthquakes, earth lights, an ice age, or a great flood?

Tyler Volk’s book “Gaia’s Body” “Gaia is Life in a Wasteworld of By-products.” He proposed that the atmosphere is one giant waste dump. Life produces wastes, and these wastes build up and affect the environment. They become intolerable for some forms of life, but then along come new forms of life who take advantage of these waste products. Volk’s point is that poop just happens. Thus the effects of the biosphere’s wastes are certainly “by” but not necessarily “for” the biosphere..

Volk suggests using cycling ratios to measure “by and for the biosphere” and to determine how beneficial for life something may be. A cycling ratio is the amount of an element cycling through the Earth and biosphere, divided by the amount that would be cycling through the Earth in the absence of life. Volk estimates the cycling ratio of carbon to be about 200 times more carbon flowing through the veins of Gaia than would be cycling through an Earth without life from plate tectonics and volcanism.

A collection of observations by the Earth Observing System flagship Terra were stitched together into a seamless true-color mosaic of every square kilometer (.386 square mile) of our planet.

Dorion Sagan and Jessica Hope Whiteside’s “Gradient Reduction Theory: Thermodynamics and the Purpose of Life” discussed the second law of thermodynamics as the purpose of life. Agnostics looking for purpose in their lives would do well to digest this chapter with Lovelock’s suggestion that agnostics worship Gaia to fill their religious vacuum. There is grandeur and universality in this thermodynamic view of life that can be applied to life anywhere in the universe.

I’d like to see Gaian scientists recognize that Gaia is part of a larger whole – that the Earth is not a closed system and that Gaia has a mother. We begin to wonder whether our Galaxy is a life form called Galactea.

“It is a must read for any life form that is even pretending to look for extraterrestrial life. /

– See more at: http://www.astrobio.net/ Note: It’s logical Mother Earth or Gaia feels totally threatened by environmental abuse from Earth’s humans and that those humans who are not loving to Mother Earth may be removed.

*Main image for this post courtesy of http://fourthdimension-celestialdreams.blogspot.ca