Life

lifeOrigin of Life

 

Astrobiology Research Program


Astrobiology may be defined as "the origin, evolution, distribution, and future of life in the universe." Astrobiology is an exciting, and fertile area of multi-disciplinary Origins research because it is being driven by 4 recent scientific revolutions.

 

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Exoplanets imaged directly around the star HR8799 using the Hale telescope.

(i) The discovery of over 1000 extrasolar planets around other stars.   The largest population appears to be the SuperEarths, which range from one to ten Earth masses and are unknown in our own solar system.   At this writing, about a dozen of these systems are suspected to involve orbits in the "habitable zones" - close enough that the radiation of host stars is sufficient to keep such SuperEarth planets warm enough to have liquid water on their surfaces.    These are candidates for  life-sustaining worlds.

 

 

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Thermophiles ('heat-loving' organisms) produce bright colors in Grand Prismatic Spring, Yellowstone National Park.

(ii) The discovery of extremophile micro-organisms on Earth that live in conditions of extreme temperatures, acidity, salinity, etc., which broadens considerably the range of habitats where we might hope to find life on other planets in our solar system and other planetary systems.


(iii) The rapid advances in genome sequencing that enable comparative analysis of large numbers of organisms at the whole genome level, thereby enabling the study of evolutionary relationships on the earliest branches of the tree of life.


(iv) The enormous efforts being made by NASA and ESA (and more recently, the CSA) to send probes to look for water, biomolecules, and life on Mars and Titan, and possibly the ice-covered, oceanic moon of Jupiter - Europa.


Our research programs are designed to attack key aspects of these four areas. On the astronomical and astrophysical side of this question, the search for extrasolar planets has opened up new and unexpected aspects of planetary systems. Jovian mass planets orbit very close to their central stars, some at distances interior to the orbit of Mercury in our Solar System. This has generated one of the most-active and most-exciting research efforts in modern astronomy. If such massive planets can be found so close to their central stars, then where are the terrestrial type of planets like the Earth and Mars? Will these exosolar systems robustly show the existence of terrestrial planets, or will these turn out to be rare?

At the same time, the disks of gas out of which stars and their planetary systems form are now observed routinely around young stars of solar type mass. Recently, such disks have even been observed around very low mass (brown dwarf) stars that are only a few percent of the mass of our Sun, as well as around very massive stars. Understanding how planetary systems form and how terrestrial planets might appear in them are among the most-important aspects of modern astronomy. Indeed, the Long Range Plan (LRP) for Astronomy and Astrophysics in Canada (chaired by Pudritz) ranked the study of planetary formation as one of the nations top goals in astronomy. The ALMA (Atacama Large Millimeter Array) telescope being constructed in Chile, in which Canada plays a very significant role, as well as the Thirty Metre Telescope, which commenced construction in 2014 in which Canada hopes to have a 20% share, are, respectively, the highest priority major facility and highest priority construction in Canada's LRP2000 and 2010.   Both projects have, as key elements of their scientific plans, the study of protostellar disks and planetary formation. The search for life in these systems is just a step away.

On the biological side, the discovery of extremophiles - microorganisms living in extreme conditions on the Earth - has provided tremendous momentum to the search for life. Given the existence of living things in hydrothermal vents, Arctic seas, permafrost and ice, as well as deep subsurface (1-5 km) regions of the Earth, there is now every scientific reason to think that life may be found in places such as Mars and Europa. The enormous effort invested in Martian exploration has now made it clear that abundant water in the forms of seas and lakes existed on Mars and, therefore, the permafrost layers there might be an abode for current life. At the same time, life that is found under the polar ice on the Earth makes it plausible that microorganisms could be found in the ice-covered ocean of Europa.

Finally, biologists now have the direct tool to understand perhaps the very origins of life, itself, through the use of gene sequencing - which has powered the genomics revolution. The astonishing rate at which gene sequences from a wide variety of organisms are being determined makes it possible to develop increasingly accurate models for the tree of life and thereby derive insights into the characteristics of the earliest life forms that developed on the Earth. This together with the amino acids that are most common in the proteins of these earliest organisms provide insight into the nature of the prebiotic soup out of which the earliest organisms developed. The presence of key organic molecules such as amino acids and membrane-forming amphiphiles in meteorites such as the famous Murchison's meteorite make it increasingly likely that the building blocks of life were formed by the organic chemistry that occurs in interstellar, star-forming clouds and protostellar disks.

 

Overview of OI Research Program in Astrobiology

Our long-range goal for the astrobiology research program is to chart the formation of life - from the formation of planetary systems and creation of biomolecules and habitable conditions - to the characteristics of the first organisms that appeared on Earth and possibly other planets. Our research team has the broad range of interests necessary to achieve these goals, including observational, experimental, theoretical, and computational experts, who provide a complementary set of state-of-the-art laboratories and equipment.

We highlight, in point form, our proposed research programs (documented below) in 3 basic and related directions:

(1) Conditions for Life
The nature and formation of planetary systems; the timing and origin of habitable conditions (water, biomolecules, energy sources) on planets and moons; the origin of water, organic molecules, and amino acids that characterize pre-biotic conditions. People: David Deamer (U.C. Santa Cruz, biochemist, formation of early membranes and RNA), J. Di Francesco (observations of interstellar biomolecules), R. Jayawardhana (observational search for planets), R. Pudritz (disk theory, planet formation theory and simulations, astrochemistry), J. Wadsley (planetesimal interactions, 3D protoplanetary simulations).

(2) Origin of Life
Prebiotic conditions; complexity and autocatalytic sets; habitats and energetics of early life; nature of the first cells. People: P. Higgs (bioinformatics, phylogenetics), Maikel Rheinstadter (experimental biophysics studies of membrane structure and macromolecule formation), C. McKay (NASA Ames; search for life on Mars), G. Slater (geochemistry, biomolecules in subsurface environments), and Ying-Fu Li (biochemist, RNA world).

(3) Extremophiles
Nature of terrestrial microbial life in extreme conditions; Mars analogue studies; microbial life in Arctic and Antarctic conditions. People: R. Gupta (biochemistry, RNA and protein genes), C. McKay (NASA Ames; Arctic and Antarctic microbial life), L. Rothschild (NASA Ames, extremophiles), J. Stone (extreme-tolerant organisms), W. Vincent (polar microbial ecosystems; team-leader of ArcticNet), L. Whyte (chair Astrobiology Working Group, Mars-analogue studies).

Click on the above links for additional information.

Additional information about our Astrobiology Research Program are accessible here.