At Brains: A dialogue on Philosophy of Mind and Related Matters Richard Brown asks the question:
What is striking (to me) about these stories, besides the overal ‘cool factor’ of space stuff, is that these scientists clearly do not think that life is multiply realized. They are looking for planets of about this size (Earth) with water and land masses (Jupitar is ruled out, Mars is in) and they seem to implicitly assume that life on other planets (if we find it at all) will be simple stuff like bacteria. Does this represent a serious flaw in their strategy? I don’t think so. We don’t really have any reason, except our imagination and intuitions, to expect life elsewhere in the universe to be other than carbon-based and water dependent. This makes me wonder why philosophers have such strong intuitions about multiple realizability… [Richard Brown at Brains]
Well…science is nothing if not pragmatic. Millions of years of evolution have equipped us with pattern determination capabilities with biases. Thousands of years of science have augmented these capacities with even more selective sensitivity (or focus - this is not a pejorative remark). Meanwhile, multiple realizability is a concept that has emerged from a history of attempts to devise context-independent logics. These two histories are divergent. Pragmatically, scientists would be crazy to look for things about which they have no intuitions - this is expensive science after all. Any demonstration that the formal representation of a living process had (logically) “near” neighbours is hardly likely to impress someone who has to do the hard work of looking for actual realisations.
No-one (to my knowledge) has ever made sense of the concept, “nearby”, in possible-world semantics. However, fitness landscapes are another matter. On a fitness landscape the concept of “nearby” actually means something. Things can be nearby but unreachable. Perhaps we should distinguish strong from nuanced intuitions about multiple realisability (MR). That way we can support MR but take our cues about reachable space from emprical research. Most philosophical debates about multiple realisability pay no attention to the constraints involved in the material genesis of systems so it’s hardly likely that they will converge with contextually embedded scientific research programmes (where the context includes the methodologies, technologies, pedagogies and institutions as well as the object of the science).
I would hate anybody to have missed this. The BBC and Astrobiology have reported on the discovery of a 1.5x earth radius extrasolar planet with an average temperature of between 0 and 40 degrees centigrade. The discovery was originally reported in an ESO (European Southern Observatory) press release. The results are published in a Letter to the Editor of Astronomy and Astrophysics1 that can be downloaded here.
“We have estimated that the mean temperature of this super-Earth lies between 0 and 40 degrees Celsius, and water would thus be liquid,” explains Stéphane Udry, from the Geneva Observatory (Switzerland) and lead-author of the paper reporting the result. “Moreover, its radius should be only 1.5 times the Earth’s radius, and models predict that the planet should be either rocky - like our Earth - or fully covered with oceans,” he adds.
“Liquid water is critical to life as we know it,” avows Xavier Delfosse, a member of the team from Grenoble University (France). “Because of its temperature and relative proximity, this planet will most probably be a very important target of the future space missions dedicated to the search for extra-terrestrial life. On the treasure map of the Universe, one would be tempted to mark this planet with an X.“[ESO Outreach]
In 2005 a Neptune sized planet (17 times earth mass) was discovered orbiting Gliese 581. The results were published in a Letter to the Editor of Astronomy and Astrophysics (which can be downloaded here)2. [Via ESO Outreach]
In 2003 the same team had discovered a Jupiter sized planet around the same star. [via ESA]
[via The BBC and Astrobiology]
[UPDATE: Space.com reported this yesterday and does a great job of capturing the impact of the discovery]
- 1. Udry, S., Bonfils, X., Delfosse, X., Forveille, T., Mayor, M., Perrier, C., Bouchy, F., Lovis, C., Pepe, F., Queloz, D., Bertaux, J.-L. (2007) “The HARPS search for southern extra-solar planets: XI. An habitable super-Earth in a 3-planet system”, Astronomy and Astrophysics. [Online] Internet: http://obswww.unige.ch/~udry/udry_preprint.pdf (Accessed 25 April 2007)
- 2. Bonfils, X., Forveille, T., Delfosse, X., Udry, S., Mayor, M., Perrier, C., Bouchy, F., Pepe, F., Queloz, D., Bertaux, J.-L. (2005) “The HARPS search for southern extra-solar planets: VI. A Neptune-mass planet around the nearby M dwarf Gl 581″, Astronomy and Astrophysics 443, L15–L18, DOI: 10.1051/0004-6361:200500193
Galaxy Abell 2667. NASA, ESA, and J. -P. Kneib (Laboratorie d’Astrophysique de Marseille)
A Macrch 2007 press release from the HubbleSite details new Hubble observations, made by an international team of astronomers led by Luca Cortese of Cardiff University, United Kingdom:
While looking at galaxy cluster Abell 2667, astronomers found an odd- looking spiral galaxy (shown in the upper left hand corner of the image) that plows through the cluster after being accelerated to at least 3.5 million km/h by the enormous combined gravity of the cluster’s dark matter, hot gas and hundreds of galaxies. As it speeds through, it rams into the hot gas that permeates the cluster. Its gas and stars are pulled away by the gravitational tidal forces exerted by the cluster, just as the forces exerted by our moon and sun pull the Earth’s oceans..[HubbleSite]
[From HubbleSite]
The adaptive optics of the Keck Telescope in Hawaii can produce some stunning image enhancements. In 2004 teams from Berkeley/SSI and Wisconsin used the adaptive optics system to make dramatic new discoveries about the rings and atmosphere of Uranus. The Keck Observatory houses the world’s largest optical and infrared telescopes. The Keck I telescope went online in May 1993; Keck II started observing in October 1996. The Keck observatory has never really received the attention that hubbble gained for itself, despite its spectacular successes. (More ….)
Space Daily have reported on plans by the Chinese National Development and Reform Commission to build the World’s largest radio telescope, a 500 meter aperture spherical telescope (FAST). The telescope’s ‘observation capacity will be 10 times over that of the world’s current biggest steerable radio telescope, with a 100-meter aperture’. The plans involve the cooperation of the NDRC, the Chinese Academy of Sciences (CAS), and the National Astronomical Observatory.
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