CORNELL UNIVERSITY
Center for Radophysics and Space Researcy
ex

SPACE SCIENCES BUILDING

Ithaca, New York 14853

Telephone (607) 256-4971 Liboratory for Planezasy Sroiiss
February 27, 1976

Dr. Joshua Lederberg

Department of Genetics

Stanford University School of Medicine
Stanford, California 94305

Dear Josh:

Thanks for your recent note. Yes, I think I remember
reasonably clearly how we met. I had moved to Madison, Wisconsin
because I couldn't bear Williams Bay, Wisconsin, the site of
Yerkes Observatory, which was where graduate students in astronony
at Chicago were supposed to do their classes and research. At
Madison I knew some people in the biology department because I
had been earlier a student of H. J. Muller; in addition, Lynn was
a graduate student there in cytology. Through one of those routes
I met Jim Crow, and it is through him that we met. I can remember
giving a colloquium on the origin of life or perhaps the surface
of Mars at Jim's behest in the biology department (I don't think
it was in the genetics department) at a time before you and I met.
I am sure of the timing because I had been told thet you were
ferocious and ate graduate students for breakfast; and I was ap-
prehensive that I would be eaten publicly in the question period
after the talk. But you were out of town, I think, and did not
attend. At any rate, our first meeting was arranged by Jim, and
as I recall, it was in the afternoon and you and Esther came over
for a talk. You were anxious to learn about planetary atmospheres
and surfaces and questions of planetary cosmogony. TI remember you
mentioned the analogy between an interstellar dust zrain and a
bacterium and that you described the contents of your paper with
Dean Cowie, which had not yet been published in Science. I think
that dates our meeting in 1958 -- perhaps spring, but I may be:
mistaken. Among other recollections of that period: I lent you a
mumber of references including my copy of the second edition of
Gerard Kuiper's Atmospheres of the Earth and Planets, the cover of
which was coming off. You returned it with a repaized cover which
I thought was extremely considerate. I remember being impressed
that you had been calculating Hohmann transfer trajectories for
interplanetary flight. We went so far as to write up the draft of
a proposal on possible alternative genetic systems, alternative tc
the nucleic acids on other planets. It was never submitted and
probably wisely so. I think it was then and probabiv still is
premature. But I wish I could find it in my files. I would love

 
try
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to re-read it. Also, you took me by to talk with Verner Suomi, and
I ean renenber discussing with him possible instrumentation for
automatec lunar landings. Neither Verne nor I were involved with
spacecraft missions at that time; however, right now we find our-
selves co-investigators on the imaging experiment of Mariner
Jupiter/Saturn. My chief recollection of ovr conversations was the
delight I took in then, what an effective learning experience they
were for me, and how well we communicated: there were many times
when we were able to say only a few words for the full idea to be
communicated. In thinking back on those days, I feel that if not
for the encouragement by H. J. Muller and yourself, I might not have |
had the covrage to seriously pursue what later has come to be called
exobiology.

With all good wishes,

Cordially,
Carl Sagan
cS/cesk