Presentation on theme: "Astrobiology in the Context of a Research University Dimitar D. Sasselov Center for Planetary Astrophysics & Department of Astronomy Harvard University."— Presentation transcript:
Astrobiology in the Context of a Research University Dimitar D. Sasselov Center for Planetary Astrophysics & Department of Astronomy Harvard University
One of Humankind’s Biggest Questions: What is the path from Stars to Life ? One of the last remaining unresolved questions It has become tractable by modern science Major emerging discipline - one could lead !
The “Essence” of Life Resolving the “Chicken-&-Egg” problem of nucleic acids vs. proteins - too much complexity ? Solution: RNA-catalyzed RNA replication !
The “Essence” of Life Find how Darwinian behavior can emerge from chemistry Develop synthetic self-replicating molecules Membranes & vesicles - cell division before cells ! RNA (red) adsorbed into clay, inside a vesicle (green) - Szostak lab (2004).
The Ultimate Leap: Chemistry to Life Prebiotic chemistry: find a plausible route to “self-replicators”; Prebiotic chemistry: on mineral surfaces, inside atmospheric particles, and ice-eutectic reactions; Prebiotic chemistry: on the young Earth, other planets and in space ?
Co-evolution of Planets and Life Life as a planetary phenomenon: constraining the chemical pathways that led to life. Unearthing the evidence - how did it all begun on Earth ? The next big question - was Mars alive ? A fossil cyanobacterium in circa 1.5 Gyr old sedimentary rocks - (A. Knoll).
The Universe is the “stage”… Planets - cradles for life in a hostile Universe Search & exploration: by end of decade - know planets like Earth Formation & stability of planetary systems Artist concept of a hot Jupiter
The Planetary Perspective The initial condition: chemical makeup & isotopes; Precise timeline of early events. A pre-solar SiC grain from the Murchison meteorite. 2 microns
The Planetary Perspective Precise timeline of early events. Jacobsen (2003)
Planets Orbiting Other Stars Number of planets discovered around stars like our Sun: 154 planets 14 multiple planet systems
Mass-Radius diagram: Konacki, Torres, Sasselov, Jha (2005) All known transiting extra-solar planets
HD b: a Hot Jupiter
The Next Step: Find Planets like Earth Lynnette Cook
KEPLER: Search for Earth Twins GOAL: discover ~12 Earths in habitable zones; also - thousands of giant planets like Jupiter. NASA Mission - launch in 2007 Transit Search: ~100,000 stars Can detect planets like our Earth
Why in a University ? A major emerging discipline. Education: a bridge b/n life & physical sciences –Undergraduate: e.g. Harvard Melton/Gross committee –Graduate: specialized courses; workshops –Public outreach: immense potential (lecture series, etc)
Special thanks to team members: S. Jacobsen, J. Szostak, A. Knoll, S. Martin, M. Shair
The Other Known Transiting Extrasolar Planet HD b: Dimming of light due to transit, observed with HST. Brown, Charbonneau, Gilliland, Noyes, Burrows (2001) Tells us DIRECTLY: Planet radius, INDIRECTLY: Planet density Planet composition
Model: Seager & Sasselov 2000 Detection: Charbonneau et al 2002
NASA’s Terrestrial Planet Finder Find and characterize Earth-like planets Reduce the glare of the parent star by one million to one billion Launch date 2015 Observe stars within 50 light years Alcatel Space Industries