Chapter 5
Organics on the Rocks: A Cosmic Origin
for the Seeds of Life
Cesare Cecchi-Pestellini
Abstract Interstellar gas phase chemistry is effective in producing a range of simple molecules, including many organic molecules. Such a chemical complexity can
be achieved through the processing of mixed ices on the surfaces of dust grains.
These complex organics are of great interest to astrobiology, but are simpler than the
molecules involved in biological processes. When ice-coated dust grains aggregate
together in protoplanetary discs, and eventually in planetesimals, a large volume
fraction remains unoccupied. The products of ice processing are retained within
these cavities and subjected the repeated processing and additions of metals from the
underlying grains. The nature of the chemistry in these cavities is in principle similar
to the famous Miller-Urey experiment in which a variety of amino acids was formed.
Perhaps clusters of dust grains could be the mechanism of forming and transporting
essential molecules to planet Earth.
5.1 Dust Thou Art
Few years ago in 2016, Kepler satellite observations evidenced unusual fluctuations in
the light from a star named KIC 8462852. This otherwise normal F-type star is slightly
larger and hotter than the Sun, and is located about 1480 light years from Earth, in
the constellation Cygnus. The odd behaviour of KIC 8462852, more popularly called
Tabby’s Star for its discoverer Tabetha Boyajian [1], whose flux dims by a tremendous amount without any regularly repeating signals, brought some researchers to
speculate about the existence of alien megastructures. Such a device, named a Dyson
sphere after the physicist Freeman Dyson who first explored this idea as a thought
experiment in 1960, would be a highly advanced piece of technology able to intercept
the power of the star, and divert it back to a planet. In an article published in the journal
Science [2], Dyson conjectured the existence of stellar power collection systems, with
sizes comparable to planetary orbits, that advanced civilizations in our galaxy could
C. Cecchi-Pestellini (B)
INAF - Osservatorio Astronomico di Palermo, Sicily, Italy
e-mail: cesare.cecchipestellini@inaf.it
© The Author(s), under exclusive license to Springer Nature Switzerland AG 2021
S. Montebugnoli and A. Melis (eds.), The Search for ExtraTerrestrial Intelligence,
Springer Proceedings in Physics 260, https://doi.org/10.1007/978-3-030-63806-1_5
27
Organics on the Rocks: A Cosmic Origin
for the Seeds of Life
Cesare Cecchi-Pestellini
Abstract Interstellar gas phase chemistry is effective in producing a range of simple molecules, including many organic molecules. Such a chemical complexity can
be achieved through the processing of mixed ices on the surfaces of dust grains.
These complex organics are of great interest to astrobiology, but are simpler than the
molecules involved in biological processes. When ice-coated dust grains aggregate
together in protoplanetary discs, and eventually in planetesimals, a large volume
fraction remains unoccupied. The products of ice processing are retained within
these cavities and subjected the repeated processing and additions of metals from the
underlying grains. The nature of the chemistry in these cavities is in principle similar
to the famous Miller-Urey experiment in which a variety of amino acids was formed.
Perhaps clusters of dust grains could be the mechanism of forming and transporting
essential molecules to planet Earth.
5.1 Dust Thou Art
Few years ago in 2016, Kepler satellite observations evidenced unusual fluctuations in
the light from a star named KIC 8462852. This otherwise normal F-type star is slightly
larger and hotter than the Sun, and is located about 1480 light years from Earth, in
the constellation Cygnus. The odd behaviour of KIC 8462852, more popularly called
Tabby’s Star for its discoverer Tabetha Boyajian [1], whose flux dims by a tremendous amount without any regularly repeating signals, brought some researchers to
speculate about the existence of alien megastructures. Such a device, named a Dyson
sphere after the physicist Freeman Dyson who first explored this idea as a thought
experiment in 1960, would be a highly advanced piece of technology able to intercept
the power of the star, and divert it back to a planet. In an article published in the journal
Science [2], Dyson conjectured the existence of stellar power collection systems, with
sizes comparable to planetary orbits, that advanced civilizations in our galaxy could
C. Cecchi-Pestellini (B)
INAF - Osservatorio Astronomico di Palermo, Sicily, Italy
e-mail: cesare.cecchipestellini@inaf.it
© The Author(s), under exclusive license to Springer Nature Switzerland AG 2021
S. Montebugnoli and A. Melis (eds.), The Search for ExtraTerrestrial Intelligence,
Springer Proceedings in Physics 260, https://doi.org/10.1007/978-3-030-63806-1_5
27