The baseline time span for this database is (publication years)
1997-2007 from the sixth bimonthly update (an 11-year period). The
resulting database contained 989 (10 years) and 338 (2 years) papers; 2,510
authors; 49 nations; 138 journals; and 747 institutions.
Interviews, first-person essays, and profiles about
people in a wide variety of fields which pertain to
this special topic of Astrochemistry.
OVERVIEW
Astrobiology is the discipline that explores all aspects of the origin of
life in the universe. One of the biggest challenges in astrobiology is the
giant step from no life to some life. At the base of that towering cliff
stand the astrochemists, who are charged with explaining the formation of
organic molecules in interstellar space and the means by which those
molecules can be delivered to planetary surfaces without being destroyed.
This month, Special Topics launches into space to check out progress in
astrochemistry over the past decade and over the past two years. The key
papers in this field involve a sequence of smaller steps. Fundamental data
on the origin and abundance of the chemical elements lie at the base,
followed by understanding formation mechanisms for hydrocarbon molecules in
space. Molecules form in cold dense interstellar clouds, and the
observation and identification of interstellar molecules continues apace.
But an interstellar cloud cannot produce life as we know it, so the
molecules have to be packaged and sent elsewhere.
The first stage of assembly is to condense the organics onto interstellar
dust grains or to freeze them in interstellar ices. Either way, the next
step is bulking up the dust into asteroids and meteorites, and accreting
the ices into comets. Dust formation takes place in the envelopes of
low-mass stars. In the final stages of star formation the gaseous and solid
phases of the interstellar molecules lie in a disc from which small bodies
and planets form.
The final stage of delivery is for the small bodies to bombard the planets.
Life on Earth may have arisen after a cataclysmic event 3.9 billion years
ago when asteroids and comets pounded the inner solar system. The craters
on the Moon and elsewhere are the testimony to this assault.
Evidence of this scenario is sought in meteorites, the oldest solid objects
you can hold in your hand. When asteroids hit Mars they expelled stones
into planetary orbit, and some of these have landed on Earth, famously
Martina meteorite ALH84001, which appears to have fossil bacterial
structures. The development of instrumentation to detect biomarkers on Mars
is a priority.
Methodology: To construct this database, papers were
extracted based on topic-supplied keywords for Astrochemistry. The keywords
used were as follows:
(astrobio* OR astrochem*)
The baseline time span for this database is (publication years)
1997-2007 from the sixth bimonthly update (an 11-year period). The
resulting database contained 989 (10 years) and 338 (2 years) papers; 2,510
authors; 49 nations; 138 journals; and 747 institutions.
Rankings: Once the database was in place, it was used to
generate the lists of top 20 papers (two- and ten-year periods), authors,
journals, institutions, and nations, covering a time span of 1997-2007
(sixth bimonthly, an 11-year period).
The top 20 papers are ranked according to total cites. Rankings for author,
journal, institution, and country are listed in three ways: according to
total cites, total papers, and total cites/paper. The paper thresholds and
corresponding percentages used to determine scientist, institution,
country, and journal rankings according to total cites/paper, and total
papers respectively are as follows: