5 P. Luigi Luisi, “Chemical Aspects of Synthetic Biology,” Chemistry and Biodiversity 4 (2007): 603.
6 For a detailed, accessible discussion of minimal cell definitions and the rich history of the concept, see Regis, What Is Life? My colleagues Jack Szostak and George Church are working on different approaches, but they encompass the conceptual framework of the synthesis. J. Szostak, D. Bartel, and P. Luigi Luisi, “Synthesizing Life,” Nature, January 18, 2001; and A. Forster and G. Church, “Towards Synthesis of a Minimal Cell,” 1.
7 There is some tantalizing evidence that cosmic and planetary environments might influence the choice of symmetry of some biomolecules; see D. Glavin and J. Dworkin, “Enrichment of the Amino Acid L-isovaline by Aqueous Alteration on CI and CM Meteorite Parent Bodies,” Proceedings of the National Academy of Science USA 106 (2009): 5487.
8 A mirror system might allow molecular biology experiments that suffer from less contamination and are easier to perform to high fidelity. If minimal cells can be maintained, their accelerated evolution might teach us the basics of designing a minimal genome, akin to what Jack Szostak refers to as a “protocells arms race.” J. Szostak, “Learning About the Origin of Life from Efforts to Design an Artificial Cell,” Konrad Bloch Lecture, Harvard University, November 23, 2010. Such a genome might be central to the transition from prebiotic chemistry to biochemistry.
9 Examples of this approach that are relevant to origins of life research are the pioneering work of the A. Eschenmoser Group, for example, A. Eschenmoser, “Searching for Nucleic Acid Alternatives,” in Chemical Synthetic Biology, ed. P. L. Luisi and C. Chiarabelli, (Hoboken, NJ: John Wiley, 2011), 12. Breakthrough work on nucleotides synthesis in prebiotically plausible planetary conditions was done by the J. Sutherland Group. M. Powner, B. Gerland, and J. Sutherland, “Synthesis of Activated Pyrimidine Ribonucleotides in Prebiotically Plausible Conditions,” Nature, May 14, 2009.
10 Generation II life is different from Generation I evolving (via cultural evolution) to a postbiological state, as discussed by Steven Dick, “Cultural Evolution, the Postbiological Universe, and SETI,” International Journal of Astrobiology 2 (2003): 65, and references; or the “closer to us humans who transcend biology” of Ray Kurzweil or the Homo evolutis of Juan Enriquez.
11 The story follows the research done after the discovery of well preserved mummies in burials dating 3,000–4,000 years ago in the Tarim basin, around several ancient cities that later became an essential part of the Silk Road, as described in J. Mallory and V. Mair, The Tarim Mummies (London: Thames & Hudson, 2000).
12 Sven Hedin, Der Wanderde See, 2nd ed. (Leipzig: Brockhaus, 1941).
13 J. Mallory and V. Mair, The Tarim Mummies.
INDEX
Absorption lines, spectrum
Amino acid
Ammonia
Arrhenius, Svante
Artificial cells
Astronomical unit
Atmosphere (planetary)
Bakos, Gaspar
Basalt
Beaulieu, J.-P.
Biochemistry
Bonds,
chemical
weak
Borucki, William
Brown dwarf
Brown, Tim
Brownlee, Donald
Butler, Paul
Camera
Carbonate-silicate cycle
See also CO2 cycle
Carbon dioxide
Cells
Charbonneau, David
Chemical landscape
Church, George
Civilizations
Columbus, Christopher
Convection
Cook, James
Copernican revolution
Core-mantle boundary
D” layer
Core (planetary)
CoRoT mission
CoRoT-7
Cosmic microwave background (CMB)
Crust (planetary)
Darwin, Charles
Darwin project (ESA)
Davies, Paul
Deep biosphere
Deinococcus radiodurans
Dick, Steven
Differentiation (planetary)
Disk (proto-planetary)
DNA
Doppler effect
Doppler shift, See Method, Doppler shift
Doppler wobble, See Method, Doppler shift
Earthquakes
Eclipse (planets)
Eclipse (stars)
Einstein, Albert
Electromagnetic waves
Electrons
Elements, chemical
origin
Enriquez, Juan
Enzymes
Eratosthenes
Evolution,
Darwinian
of the atmosphere
stellar
theory of
Extremophiles
False positives
Fermi, Enrico
Fermi paradox
51 Peg
Force(s)
electromagnetic
gravitational
Frail, Dale
Gassendi, Pierre
Generation I and II life
Genetic molecules
Geochemical cycle
Geological timescale
GJ1214
Gibson, D.G.
Gliese
Gliese
Gliese
Goldilocks hypothesis
Granite
Greenhouse gas
HAT (project)
HD
HD
HMS Challenger
HR8799
Habitable planets
Habitable potential
Habitable zone
Handedness
Hart, Michael
Homo sapiens
Home evolutis
Horowitz, Paul
Horrocks, Jeremiah
Howard, Andrew
Hoyle, Fred
Humboldt, Alexander von
Hydrogen
Hydrogen sulfide
Jha, Saurabh
Joyce, Gerald
Jupiter
hot
-like
super-
Initial conditions
Kaltenegger, Lisa
Kant-Laplace model
Kasting, James
Kepler, Johannes
Kepler’s laws of planetary motion
Kepler’s law of planetary volumes
Kepler mission (NASA)
Kepler-11
Knoll, Andrew
Konacki, Maciej
Kulkarni, Shri
Kurzweil, Ray
Latham, David
Life,
definition
Light
infrared
visible
UV
Lissauer, Jack
Mantle (planetary)
Marcy, Geoffrey
Mars
Martian meteorites
Mason, Charles and Dixon, Jeremiah (Mason-Dixon Line)
Mayor, Michel
Mercury
transit of
MEarth (project)
Meteorites
Methane
Method (for planet discovery)
astrometry
direct imaging
Doppler shift
gravitational lensing
timing
transit
wobble. See Method, astrometry, Doppler shift
Microbes
Minimal artificial cell
Mirror life
Miller, Stanley
Moravec, Hans
Mycoplasma mycoides JCVI-syn1.0
Neptune
hot
mini-
-like
Newton, Isaac
Nisenson, Peter
O’Connell, Richard
OGLE (team)
OGLE-TR-33
OGLE-TR-56
OGLE-2005-BLG-390Lb
Oganov, A.
Olivine
Ono, S.
Orbital eccentricity
Orbital inclination
Orbital period
Orbital speed
Origins of life
Paczynski, Bohdan
Panspermia
Papaliolios, Costas
Perovskite
Photometry
Photons
Planet-metallicity trend
Planets
Earth-like
carbon
dwarf
exo
extrasolar
gas giant
habitable
ocean
pulsar
rocky
terrestrial
transiting
with habitable potential
Plate tectonics
Polymers
Post-perovskite
Press, Bill
Proteins
PSR 1257+12
Queloz, Didier
RNA
Rivera, Eugenio
Rose, Gustav
Saturn
Scale
large-molecule
Schroedinger, Erwin
Seager, Sara
Selsis, Franck
Silica
Silicate
Silicon
Silicon carbide
SLiME
Spectrum
Spectroscopy
Spores
Sulfur dioxide
Sunspots
Super-Earths
definition
discovery
habitability
models (interior)
models (atmosphere)
transiting
Super-Mercury
Super-Moon
Super-Venus
Synthetic biology
Synthetic genomics
Szostak, Jack
Tectonic plates
Telescope
Timescale
Todorov, Tzvetan
Torres, Guillermo
Transit timing variations
Transit planet candidates
Tree of life
Uranus
Valencia, Diana
Venter, J. Craig
Venus
transit of
Vesicles
Ward, Peter
Water
ice
iceand
Watson, James and Crick, Francis
Whitney, Charles
Wickramasinghe, Chandra
Wobble, See Method, astrometry, Doppler shift
Wolszczan, Alex
a
Angular momentum is the product of mass, velocity, and size of a rotating body; left on its own, the body will conserve its angular momentum. If its size is shrinking, the body has to rotate faster to compensate for the decrease in size. The mass of gas and dust that surrounds a young star shrinks toward it while orbiting around it and attains a flat disk shape.
b
Here I use the word “mass.” The mass of an object measures the amount of stuff (atoms or matter) in that object. Mass and gravity are interrelated: the strength of the force of gravity depends on the mass—a more massive body exerts a stronger force (or pull). Colloquially, we often say weight or heavy, instead of mass or massive. This is imprecise and leads to confusing statements, so I’ll insist on saying mass and massive.
c
Walt Whitman’s poem “When I Heard the Learn’d Astronomer” has upset generations of scientists, as they will tell you that math does not keep them from looking up in awe at the stars.
d
Note the new term I have introduced: “scale.” In astrophysics this term means a characteristic range—of size, or of time, energy, and so on. For example, we speak of a galactic scale (sizes of 1020 to 1025 m) versus a quantum scale (sizes of 10—10 to 10—15 m); and we use shorthand notation—powers of ten—to write those very large (or very small) numbers.
e
The definition of system as a combination of related elements organized into a complex whole is what I use here to refer to life for a lack of a better word.
f
A network is a pattern of branching and interconnected lines, circuits, things, and so on; the pattern does not have to be ordered.
g
An isotope occurs when the atomic nucleus of the same element (same number of protons) has a different number of neutrons.
Copyright © 2012 by Dimitar Sasselov
Published by Basic Books,
A Member of the Perseus Books Group
All rights reserved. No part of this book may be reproduced in any manner whatsoever without written permission except in the case of brief quotations embodied in critical articles and reviews. For information, address Basic Books, 387 Park Avenue South, New York, NY 10016-8810.
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Illustrations by Sandra L. Cundiff and Michael Hardesty
Library of Congress Cataloging-in-Publication Data Sasselov, Dimitar D.
The life of super-Earths : how the hunt for alien worlds and artificial cells will revolutionize life on our planet / Dimitar Sasselov.
p. cm.
Includes bibliographical references and index.
eISBN : 978-0-465-02340-0
4. Life—Origin. 5. Life on other planets. I. Title.
QH326.S27 2012
576.8’39—dc23
2011036888
The Life of Super-Earths Page 16
