Roadmap Banner Introduction Principles Home Objectives Goals


How Does Life Begin and Develop?

Objective 1
Sources of 0rganics on Earth

Objective 2
Origin of Life's Cellular Components

Objective 3
Models for Life

Objective 4
Genomic Clues to Evolution

Objective 5
Linking Planetary and Biological Evolution

Objective 6
Microbial Ecology

Does Life Exist Elsewhere in the Universe?

Objective 7
The Extremes of Life

Objective 8
Past and Present Life on Mars

Objective 9
Life's Precursors and Habitats in the Outer Solar System

Objective 10
Natural Migration of Life

Objective 11
Origin of Habitable Planets

Objective 12
Effects of Climate and Geology on Habitability

Objective 13
Extrasolar Biomarkers

What is Life's Future on Earth and Beyond?

Objective 14
Ecosystem Response to Rapid Environmental Change

Objective 15
Earth's Future Habitability

Objective 16
Bringing Life with Us beyond Earth

Objective 17
Planetary Protection


Question: How Does Life Begin and Develop?
Sources of Organics on Earth

Objective 1: Determine whether the atmosphere of the early Earth, hydrothermal systems or exogenous matter were significant sources of organic matter.


Determining the primary sources and nature of organic matter from which living systems emerged on the prebiotic Earth is still a controversial endeavor. The key proposed sources include synthesis in the atmosphere of the early Earth; synthesis in warm hydrothermal systems or in geothermal subsurface environments; delivery to the early Earth by comets, meteorites and microscopic, interplanetary dust particles; or some combination of these possibilities. Each hypothesis leads to different predictions about the composition and availability of organic starting material and the nature of the earliest pre-metabolic processes leading to the origin of life. We must, therefore, determine the relative contributions of each of these sources of organic material to life's origins on the primitive Earth, and define and characterize those mechanisms that allowed adequate concentrations of these chemicals for the necessary interactions and reactions to occur.


Near to mid-term:

  • Using space missions and infrared telescopes, explore how organics, initially synthesized in the interstellar dust cloud from which the Solar System was formed, are chemically altered before they are delivered to earth. This research will help to determine the chemical structure and composition of exogenous organic compounds and the extent to which they contributed to the inventory of prebiotic organics on earth. This task will benefit from missions to analyze organic material in both interplanetary dust particles as well as meteor showers. In addition, ground, air (SOFIA) and space-based (SIRTF) observatories will provide key data.

  • Conduct realistic laboratory simulations of chemical reactions under the conditions existing on planetary bodies, on the surface of the primitive earth and in hydrothermal vents. Investigate the potential of the synthesized compounds to contribute to the formation of biological structures.

  • Perform computer modeling of prebiotic chemical synthesis in different environments taking into account appropriate external constraints, such as energetics, temperature, pressure, and surface catalysis potential.

  • Examine the geological record for evidence of environmental conditions on the early earth. Examine ancient rock formations for the signature of early life in the form of microfossils, isotope ratios and mineral assemblages, and obtain evidence for the redox state of the earth mantle near the time of the origin of life. A reducing mantle was essential to maintain a reducing atmosphere on the prebiotic earth.

  • Study natural environments (e.g., hydrothermal vents) as models for primordial chemistry.

Future extensions:

  • Perform space missions to characterize more precisely quantities and compositions of exogenous and sub-surface organic material.

  • Construct integrated models of the chemistry on the prebiotic earth that include contributions from different sources of organic matter and environmental constraints.

  • Perform planetary subsurface missions to obtain virgin endogenous material.

  • Perform planetary missions to understand possibilities for prebiotic evolution.

Questions? Comments?

Responsible NASA Official:
Mary Voytek

Last Updated: October 27, 2014