How Does Life Begin and Develop?
Objective
1
Sources of 0rganics on Earth
Objective
2
Origin of Life's Cellular Components
Objective
4
Genomic Clues to Evolution
Objective
5
Linking Planetary and Biological Evolution
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: Does Life Exist Elsewhere in the Universe?
Natural
Migration of Life
Objective 10: Understand the natural processes by which life can migrate from one world to another.
The observational data that demonstrates the availability of organic molecules and water throughout the cosmos raises the possibility that living systems can exist beyond Earth. Other data allow us to argue that life could be transported between planetary bodies and could, possibly, become established on another world. Current models indicate that there are natural means to propel organisms into interplanetary space. For example, meteorites that originated on Mars have been found on Earth; these samples verify that such an exchange of planetary material has occurred. In addition, experimental evidence from the orbiting Long Duration Exposure Facility and from at least one Surveyor lunar lander indicates that some common terrestrial microorganisms can survive in excess of five years. Finding life in extreme environments on Earth suggests that life might survive in liquid water niches on other planetary surfaces, and that certain life forms may be common throughout our Solar System. For several reasons pertinent to astrobiology, we must determine if life from one world can establish an evolutionary trajectory on another.
Implementation
Near- to mid-term:
- Establish models to determine
probabilities for life's transport to, and survival on another planet.
- Search for evidence of an
external origin for terrestrial life, or of exchanges between the biosphere
of Earth and of that Mars or other planets. Search for this evidence
in meteorites, in geologic samples and in the biochemistry of life.
- Sample and analyze cometary material to search for evidence of extraterrestrial life or its precursors. Examine meteor storms, comet coronae and tails, and cometary debris collected by orbiting satellites.
Future extensions:
- The potential seeding of Earth
life on other planetary surfaces, both intentionally and unintentionally,
is possible.
- Understand the interplanetary transportation and survivability of organisms and use this information as a basis for quarantine of samples returned to Earth