Our own solar system and other planetary systems are composed of organic dust created in the outflows in dying stars. Here, we examine an unlikely source of carbonaceous material in interstellar space, the harsh environment of Wolf-Rayet (WR) stars. We have used spectroscopic data from the Short Wavelength Spectrometer on the Infrared Space Observatory to examine infrared emission and absorption features in the 6 to 9 μm spectral region of hot massive WC-type WR stars. We conclude that these features are due to amorphous carbon dust in their circumstellar environment.

The Moon forms one end-member in the planetary mass series Earth-Venus-Mars-Mercury-Asteroids-Moon (Weissman 1999). Having a detailed understanding of the nature and evolution of the two end-members of this series, rather than of just the Earth, has increased the value of other data and inferences by orders of magnitude. As a consequence of obtaining an understanding of the evolution of a second planet, we now can look at other terrestrial planets with far greater insight than ever would have been possible otherwise (Fig. 1).

Martian Meteorite ALH84001 contains four unusual features which have been interpreted as possible signatures of relic biogenic activity. After six years of intense study by the world's scientific community, the current status of the biogenic hypothesis is reviewed and shown to still be valid. Furthermore additional features have been observed in two younger Martian meteorites. The strongest argument for possible evidence of biogenic activity within the ALH84001 meteorite is the presence of truncated hexa-octahedral magnetite crystals which are only known on Earth to be the products of biology.

The main goals of the French Mars exploration program are the development of a netlander for geophysical studies. This project is conducted in the framework of a consortium of European partners (Finland, Germany and Belgium), and an orbiter vehicle of the future Mars sample return mission (MSR) is being developed in cooperation with NASA. Also, we discuss the preparatory program for volatile and rare gas analysis, sample pollution, site selection and Astrobiology.

There are currently five space missions en route to or planned for comet encounters. It is important for the success of each mission that its target be characterized as fully as possible prior to the encounter. This progress report analyses initial photometric results for 11 comet nuclei for the Stardust, Rosetta, Deep Impact, CONTOUR, Deep Space 1, and the proposed Comet Nucleus Sample Return missions from a database of comet CCD images. Our 17-year database contains more than 20,500 images of ∼160 comets taken during > 1,500 observing hours (Pittichová & Meech 2000). We are undertaking a program to observe these 11 comets over a wide range of heliocentric distances to obtain information about their behavior and composition that will be particularly useful to the space missions.

The recent discoveries of small bodies in the outer solar system in the vicinity of the Kuiper belt are revolutionizing solar system formation concepts by providing critical dynamical and compositional clues to its earliest epochs. However, the rapidly accelerating discovery rate means that follow-up observations for orbit determination cannot keep up. We report here on an innovative test program to assess the potential of a small (2-m class) educational outreach telescope to engage in an efficient recovery program. Recovery observations have been obtained over the course of 22 nights using the University of Hawaii 2.2m telescope during 9 observing runs. We targeted over 200 objects and have achieved a 75% success rate. We obtained time resolved resolved light curve photometry on 2000 OK67, and the partial light curve suggests a period T > 12 hr.

Haberle et al. (1996) and Joshi, Haberle & Reynolds (1997) demonstrated that for a planet receiving Earth-level insolation, a 100 mb pure CO2 atmosphere would carry enough heat flux to the dark side of a synchronously rotating planet (SRP) to prevent the atmosphere freezing out there. For a 1,500 mb pure CO2 atmosphere and 0.8 Earth insolation, liquid water could survive over much of the planet. Such high partial pressures of CO2 may seem like special pleading, but in fact, they are not essential for habitable conditions. The effective grey optical depth of the present terrestrial atmosphere (with just 350 ppm CO2, and H2O as the principal greenhouse gas) is approximately 0.9, as against 1.0 for a 1,000 mb pure CO2 atmosphere, so the latter serves merely as a useful approximation (for a truly Earth-type atmosphere, temperatures would be a few degrees lower over the lit hemisphere). Heath et al. (1999) concluded that even forest-habitable conditions, suitable for Earth-like trees (Heath 1996) were not to be ruled out on the basis of present knowledge. Recent work by Joshi (2004) has modelled the range of climatic options for certain land-sea distributions, and these leave the door open for further investigations of combinations of geography and insolation compatible with forest-habitability.

We have developed a new numerical technique for simulating dusty-gas flows. Our code incorporates gas hydrodynamics, self-gravity and dust drag to follow the dynamical evolution of a dusty-gas medium. We have incorporated several descriptions for the drag between gas and dust phases and can model flows with submillimetre, centimetre and metre size “dust”. We present calculations run on the APAC1 supercomputer following the evolution of the dust distribution in the pre-solar nebula.

The race to build a quantum computer has led to a radical re-evaluation of the concept of information. In this paper I conjecture that life, defined as an information processing and replicating system, may be exploiting the considerable efficiency advantages offered by quantum computation, and that quantum information processing may dramatically shorten the odds for life originating from a random chemical soup. The plausibility of this conjecture rests, however, on life somehow circumventing the decoherence effects of the environment. I offer some speculations on ways in which this might happen.

Long before the idea of spontaneous generation was incorporated by JeanBaptiste de Lamarck into evolutionary biology to explain the first emergence of life, the possibility that other planets were inhabited had been discussed, sometimes in considerable detail, by scientists and philosophers alike (Lazcano 2001). More often than not, these were speculations that rested on the idea of a uniform universe but with little or no empirical basis. Today our approaches to the issue of life in the Universe have changed dramatically; neither the formation of planets nor the origin of life are seen as the result of inscrutable random events, but rather as natural outcomes of evolutionary events. The interconnection between these two processes is evident: understanding the formation of planets has major implications for our understanding of the early terrestrial environment, and therefore for the origin of living systems.

Terrestrial evolution encompasses many levels, from proteins to societies. Potentially any level can be encompassed by a multidimensional “habitation box”, of which only a minute fraction is occupied. on the basis of evidence from evolutionary convergence it is argued that life elsewhere will not only be similarly constrained, but also strangely similar.

It is sometimes asserted that the rapidity of biogenesis on Earth suggests that life is common in the Universe. We critically examine the assumptions inherent in this argument. Using a lottery model for biogenesis in the Universe, we convert the observational constraints on the rapidity of biogenesis on Earth into constraints on the probability of biogenesis on other terrestrial planets. For example, if terrestrial biogenesis took less than 200 Myr (and we assume that it could have taken 1 billion years) then we find the probability of biogenesis on terrestrial planets older than ∼ 1 Gyr, is > 36% at the 95% confidence level. However, there are assumptions and selection effects that complicate this result: although we correct the analysis for the fact that biogenesis is a prerequisite for our existence, our result depends on the plausible assumption that rapid biogenesis is not such a prerequisite.

We present a summary of ground-based work being done to gain an understanding of primitive comet, Centaur and Kuiper belt object compositions. We are seeing a diversity of compositions in outer solar system small bodies with respect to the presence of water and organics which may reflect both primordial differences and evolutionary processes.

From observations of fragmentation events, clues to a gravitational aggregates structure of some comets nuclei are given. From in-situ and remote light scattering observations, a very high porosity is estimated for dust in comae. These results suggest a possible survival of cometary organics during atmospheric entry at the epoch of intense bombardment. In the coming years, new missions to comets and laboratory measurements on the ISS, will be used to assess such a scenario.

Interplanetary dust particles (IDPs), ∼ 10μm particles from comets and asteroids, have been collected by NASA from the Earth's stratosphere. We compared carbon X-ray Absorption Near-Edge Structure (XANES) and Fourier Transform Infra-Red (FTIR) spectra of anhydrous and hydrated interplanetary dust particles and found that anhydrous and hydrated IDPs have similar types and abundances of organic carbon. This is different from results on meteorites, which show that hydrated carbonaceous meteorites contain abundant organic matter, while anhydrous carbonaceous meteorites contain less carbon mostly in elemental form. But all anhydrous carbonaceous meteorites are depleted in moderately volatile and volatile elements in a pattern that suggested they experienced temperatures in excess of 1200°C, a temperature sufficient to destroy any organic matter they originally contained, while many anhydrous IDPs show no evidence of severe heating. These IDP results indicate that the bulk of the pre-biotic organic matter in extraterrestrial materials formed before aqueous processing, possibly by irradiation of C-bearing ices or by a Fisher-Tropsch type process operating in the gas phase of the nebula or in the interstellar medium.

The unique rarefied flow and flash heating in meteors creates physical conditions that can change exogenous organic matter into unique prebiotic molecules. with the exception of rare giant comet impacts, most infalling matter at the time of the origin of life was deposited in the atmosphere during the meteor phase. Much new data has been obtained from observations in the Leonid Multi-Instrument Aircraft Campaign; a series of NASA and USAF sponsored Astrobiology missions that explored the 1998–2002 Leonid meteor storms. Here, we provide an overview of some of this recent insight, which provides a framework in which the prebiotic chemistry can be studied.

Sixty five million years ago a huge asteroid collided with the Earth and ended the long reign of the dinosaurs. In the aftermath of this catastrophic event, the mammals arose and eventually mankind came to dominate the surface of the planet. The Earth, however, has not been free from severe impacts since the time of the dinosaur killer. We examine the likely frequency of major impact events over the past 65 million years, the evidence for these impacts and the predicted consequences of various types of impacts. It is evident that the mammals had to survive frequent severe disruptions to the global climate, and it is likely that over the past 5 million years hominids were faced with several catastrophic global events. Smaller but strategically located impact events could bring down our civilisation if they occurred today. Mankind has recently developed the expertise to predict and mitigate future impacts, but political and financial support are lacking.

Migration processes of comets and asteroids from the outer regions of the solar system, including the Edgeworth–Kuiper belt, are regarded as important mechanisms for the formation and evolution of the inner planets. These minor bodies may be responsible for the delivery of volatile matter to the inner planets and thus be responsible for the origin of life. We estimate that the cumulative mass of icy comets impacting on the Earth during the formation of the giant planets is similar to the mass of water in the Earth oceans, and that Mars acquired more water per unit planet mass than Earth. We find that these cometary objects mostly evolved from typical near-Earth orbits and Encke-type orbits with aphelia located inside the orbit of Jupiter, and played a greater role than those with Jupiter-crossing orbits. The relative importance of comets and chondrites in the delivery of volatiles is constrained by the observed fractionation patterns of atmospheric noble gas abundance.

Impact craters are prominent landforms on all objects with a solid surface in the solar system. The formation of an impact structure is a high-energy, high-temperature transient event which introduces large amounts of energy into a limited area. This energy can, in part, be expanded on the creation and activation of a hydrothermal system within and even outside of the crater. Depending on the crater size and geology of the target region, this hydrothermal system may persist for extended periods of time. Such impact-induced hydrothermal systems could well have provided conditions supportive of the development of life on the early Earth and it is not unreasonable to assume that similar conditions could have led to life-favoring circumstances on other planets and satellites.

We discuss how the spectral mismatch between solar radiation at the Earth's surface and the two absorption maxima (440 and 680 nm) of the dominant chlorophyll pigments can be explained as an evolutionary accident of the marine habitat in which photosynthesis evolved on Earth. The geometric rigidity and great stability of chlorophyll make it a likely “universal pigment” given this, together with the spectral absorption properties of water, the evolution of photosynthesis on Earth-like planets (ELPs) orbiting in the habitable zones of A, F and G stars should be relatively straightforward. However for ELPs orbiting cool K and M stars, the effects of variable UV emission from the ELP at earlier epochs and the high absorption of red light by water could lead to a “feast and famine” existence for photosynthetic organisms in the ELP ocean. Pull exploitation of the cool star radiation when UV activity has declined may lead to an evolution of the photosynthetic machinery from the terrestrial two photon to a three photon system.