Actor Leonard Nimoy passed away today aged 83. So to remember his famous role as science-officer Spock on board of the USS Enterprise I will share some space-geology-related posts:
In August 1881 the short-lived popular “Science” magazine published an article with a letter exchange by two amateur geologists – British Charles R. Darwin and the German Otto Hahn- discussing the possibility of extraterrestrial life. Just some years earlier Darwin had published a book “On Origin of Species”
proposing that complex life forms descended slowly over time from
simple ones, however as earth seemed to be too young (based on the erroneous calculations of a certain physicist known today as Lord Kelvin)
to explain the observed modern complexity, the origin of microorganisms
in space (which existence would predate the formation of earth) could
solve this apparent contradiction.
Life from outer space was not a new idea. Already in 1865 the German physician Hermann Eberhard Richter argued that life was an intrinsic property of the cosmos, transported in space on smaller rocky fragments, dormant microorganism could act like seed, evolving in short time into complex organisms after the host-rock impacted on a suitable planet.
Otto Hahn (1828-1904) was a
former lawyer turned to amateur naturalist and geologist, with a special
interest in the origin of life. Hahn was known by the scientific
community due his research on Eozoön or Eozoon (the
“dawn animal”) – an enigmatic Archaean fossil described in 1864 from
Canadian limestone-formations – believed to be some sort of gigantic
microorganism it predated all other known fossil organisms. However it
seemed strange that already the oldest life form would be a highly
evolved animal and Hahn himself doubted at first that it was even a fossil. In
1880, after carful investigation of some collected rock samples, Hahn
changed his mind and reclassified Eozoön as an ancient algae, renaming the fossil Eophyllum (“dawn plant”).
Fig.1.
Eozoon specimen, the regular lamination were interpretated as chambers
of a shelled organism or growth lines, image from DAWSON (1888): The Chain of Life in Geological Time. However in 1894 similar rocks were found in
material erupted by Mount Vesuvius, proving that this texture formed by
inorganic processes due the alteration of limestone by heat from
underground magma.
After this achievement, Hahn suddenly
started to find fossils of primitive organisms in all sorts of rocks,
not only in sedimentary rocks, but also ancient, partially melted,
metamorphic rocks and even igneous rocks like granite or basalt, completely crystallized from the molten magma. He published his observations in a 1879 book entitled “Die Urzelle”
– the primordial cell - arguing that in fact all observable rocks were
of some sort of sedimentary origin, composed by the shells of these tiny
primordial, yet unidentified, microorganisms – and send one copy also
to Charles Darwin, inviting him to promote this revolutionary discovery.
Hahn soon added even some extraterrestrial
material to his collection of microorganism-derived rocks. Not
surprisingly, also in samples of meteorites he discovered his primordial
cells, also what seemed to be sponges and even corals. He published his
discovery in the 1880 book “Die Meteorite (Chondrite) und ihre Organismen”
(The chondrite meteorites and their organisms), also one of the first
books including images of sections of extraterrestrial rocks. Hahn
argued that the studied meteorites were remains of a cosmic cloud of
gas, vapor and dust from which our solar system formed. In this
semi-liquid environment life formed, evolving at least to the stadium of
invertebrates. After the formation of the planets, agglomerated chunks
of matter transported these primitive organism onto earth, where they continued to evolve until the appearance of man.
Fig.2.
Frontispiece of Hahn’s “Die Meteorite (Chondrite) und ihre Organismen”
showing a supposed plant- or sponge-like fossil in a meteorite, today
reinterpretated as shattered mineral grain (Chondrule).
Also this book was send to Darwin, who –
as was his cautious manner – politely thanked for the gift, replying that the
proposed scientific hypothesis was sure worth of further investigation (but nothing more):
“If you succeed in convincing
several judges as trustworthy as Professor Quenstedt*, you will
certainly have made one of the most remarkable discoveries ever
recorded.” *[Friedrich August Quenstedt (1809-1889), famous German professor of mineralogy and geology]
However Hahn in a private letter to a friend claimed “Darwin pronounced: it is one of the most important elucidations ever made.”
Strangely also in the Science article of 1881 other very Darwin-unlike
behavior appears. Supposedly Darwin, observing under the microscope the
rock fragments, jumped from his seat exclaiming ”Almighty God! What a wonderful discovery! Wonderful!” and stating that indeed “life [came] down!” from space.
There survives no hard evidence that Hahn did visit Darwin at Down House
in Kent to show him his samples, but it also can’t be completely ruled
out. Maybe Hahn, before travelling to Canada for his research on
Archaean fossils, did also visit England. His idea of all rocks derived
from microorganisms, as strange as it may sounds today, was taken
serious at the time, at least by some naturalists. However Darwin had studied volcanoes and their igneous products,
so there is no doubt he did not share this part of Hahn’s visions. Also
it seems improbable that Darwin believed it necessary to relocate the
origin of life in outer space.
Darwin never addressed in public the
mystery of mysteries that is the origin of life. His theory of natural
selection deals with the diversification of already reproducing life
forms and was never intended (as creationists claim) to explain
the origin of life. In private letters he proposed a chemical evolution in a primordial soup, but he also acknowledged that his contemporary
science was yet not able to test this hypothesis.
As for the supposed to young age of
earth and to evolved terrestrial life forms, already Darwin published
various rebuttals to Lord Kelvin’s claims in later editions of his “Origin of Species”. There was – so he argued – plenty of time for terrestrial life to evolve, even without extraterrestrial intervention.
Bibliography:
PERETO, J.; BADA, J., & LAZCANO, A. (2009): Charles Darwin and the Origin of Life. Origins of Life and Evolution of Biospheres, 39 (5), 395-406
BRASIER, M. (2009): Darwin’s Lost World – The hidden history of animal life.Oxford University Press: 304
WYHE, van J. (2010): ‘Almighty God! What a wonderful discovery!’: Did Charles Darwin really believe life came from space? Endeavour, 34(3): 95-103