I read your cditorial on Mars, "The Dead Planet", with great
interest and enthusiasm: but one renarh in it is a prejudgment
against whey semeine a perplexing and controversial scientific question,
the independent evolution of any form oi life beyond the earth.

The Mariner photographs are vevty exciting but co far they
have solidified previous expectations. They have not intro-
duced new elemorts into the discussion that were not taken
account of in previous deliberations.

The main point to strees is that we still do not know
the abundance ard distribution of water cn Mars. However
much there is, almest all of it must be frozen, and this
makes it very difficult to decid? bauiween a vanishing layer
of hoerfrost at the poles and a thick plaaetary crust of
permafrost under a sumbaked surface. in either case, we have
the likelihocd cf scattered oases with Jocal conditions far
more congenisl to life than the average for the planet.
After all, too obtuse a view of the earth would have us all
submerged in a thousand fathone of salt water. Already, the
most exciting aspect of the Mariner pictures is indeed the
great variety of surface detail that they do show, including
beight patches oa some craters suggesting frost.

There are many cther questions that need far deeper study
before any swo20'ng souclusions are justified. While I doubt
that Mars has ever nad eynensive cceans, it is too early to
assert this as settled fast. How:ver, move Likely almost
all of its water has been frozen for most of its histovy.

The swing of general opinion abcut Mars has undcubtedly
been over-colored by lurid fantasies of canal-building
humanoids which have played no part in serious scientific
analysis. Now that these have been happily relegated to

solar systen can focus on rigorous £:ctual questions which
continue to have the deepest scient cic and philosophical

interest. Paramount emong these is whether life in any form
has evolved independently of the terrestrial system and man.

Letter to The Editor, New York Times

July 30, 1965 Joshua Lederberg