Questions such as "are we alone?" and "what does the future hold for life on Earth?" have been pondered for millennia. But only in recent decades have advances in science and technology allowed us to confront the universe with some hope of answers. This explains the emergence of scientific journals devoted to life in the solar system and beyond. One of the first is Astrobiology , a US-based journal launched in 2001.
Astrobiology is a broad field. It encompasses the origin and evolution of life on Earth; the range of habitats that carbon-liquid-water life occupies here, and that life on any basis might occupy elsewhere; the identification and exploration of possible habitats beyond the Earth; and ways of detecting extraterrestrial life, in whatever form it occurs. The extraterrestrial domain is not confined to the solar system, but extends as far as technical limitations allow. At present this restricts us mainly to our cosmic backyard - the local region of our galaxy - except insofar as the search for extraterrestrial intelligence takes us well beyond this domain.
"Astrobiology" is a term that has been popularised by Nasa, an agency that has done much to advance the subject. This has had the positive effect of rendering obsolete several competing terms, such as "bioastronomy" (the name of Commission 51 of the International Astronomical Union) and "exobiology" (still preserved in the European Exo/Astrobiology Network Association). "Bioastronomy" is the youngest term, dating from 1982, "exobiology" dates from 1960, and "astrobiology", for all its recent ascendancy, is the oldest term, from 1941. But "astrobiology" still does not reflect the true breadth of the subject. To many astronomers, it seems to exclude the burgeoning science of extrasolar planets. This is probably why too small a proportion of papers in Astrobiology stray beyond the solar system. It is a long scientific journey from the existence of pre-biotic molecules on Earth to the possibility of an aquatic biosphere on Europa, to searching for "exo-Earths" and for life on them, perhaps even technologically intelligent life. But that is the true scope of astrobiology. There is more work to be done to impress on the exoplanetary scientific community that astrobiology journals are for them too, as alternative places of publication to the astrophysical journals.
Turning to the journal itself, the membership of the editorial board of Astrobiology more or less reflects the relative degrees of research activity in the US, Europe and elsewhere and, at about 80, is impressively long (although how much each board member is called on to do is another matter). As with the articles, experts on exoplanetary systems are underrepresented among the board.
Each issue varies in length between about 100 pages and 250 pages. There is an unusually wide range of categories of contributions, mainly comprising: research papers (sometimes as collections around one topic); rapid communications (less than 3,000 words); occasional subject reviews and mini-reviews; book reviews; hypothesis papers (to encourage discussion and hypothesis testing) and education papers (of interest to scientists involved in education and outreach, and also to those offering training in astrobiological research). In some issues of the journal, most of the space is devoted to papers/abstracts from meetings. All this makes for a lively range of offerings on a host of fascinating topics.
The layout is spacious. Research papers tend to be the lengthiest offerings, and can be as long as 30 printed pages. Consequently, in some issues, there are only two or three papers. However, this generosity provides authors with plenty of opportunity to be expansive although, one hopes, without being long-winded. Text, diagrams, illustrations and tables are clear, as is the organisation into sections and subsections.
Sub-subsections are not always so clearly delineated, and the lack of numbering does not help.
The generous space allocated to some illustrations has sometimes resulted in the unfortunate consequence of the text reference coming one or more pages before the illustration itself. The references are given in the text by author and year (far better than by number) and the references list includes article titles - a welcome feature, as is the page range given for an article rather than just the starting page. The copy-editing is up to the high standard expected of quality journals.
The associated website, www.astrobio.net, is excellent, full of news and hot topics, and it also has an archive. The publishers are at www.liebertpub.com where calls for papers and other information on astrobiology may be found.
Overall, Astrobiology is a welcome addition to the range of scientific journals, in an area that is growing fast and will surely be of prime importance in this century, as our instruments and understanding improve, moving us towards what, I believe, will be the discovery within the next few decades of life elsewhere. At the very least, on this timescale I believe we will discover potential habitats beyond the solar system, just as we have Mars and Europa as firm candidates within it.
Barrie W. Jones is professor of astronomy, Open University.
Editor - Sherry L. Cady
Publisher - Mary Ann Liebert, Six times a year
Price - Institutions $423.00, individuals $143.00
ISSN - 1531 1074