Saturday, May 13, 2006

How Super Earths form, searching for life in Jovian satellites and science fiction’s treatment of astrobiology

Welcome! “Alien Life” tracks the latest discoveries and thoughts in the various elements of the famous Drake Equation. Today’s news:
g Stars - A new explanation for forming super-Earths suggests that they are more likely to be found orbiting red dwarf stars — the most abundant type of star - than gas giant planets like Jupiter and Saturn. The theory, by Alan Boss of the Carnegie Institution's Department of Terrestrial Magnetism, describes a mechanism whereby UV radiation from a nearby massive star strips off a planet's gaseous envelope, exposing a super-Earth. See
g Abodes - One of the primary goals of astrobiology is to determine how common habitable planets are. Most astrobiologists expect that habitable planets would likely be terrestrial planets—small, rocky planets like Earth, Mars, or Venus—rather than gas giants such as Jupiter. Now scientist Charley Lineweaver and student Daniel Grether, both of the University of New South Wales in Australia, have estimated the number of terrestrial planets in our Milky Way galaxy: Up to 30 billion. See
g Life - Mars and the ice-covered satellites of Jupiter are currently the most favorable sites for the search of extraterrestrial life. The motivation for the search for life in the Solar System is the evidence of liquid water in the early history of Mars and, at present, in the interior of at least two of the galilean satellites (Callisto and Europa). Hydrothermal vents on the Earth's sea floor have been found to sustain life forms that can live without direct solar energy. Similar possible geologic activity on Europa, caused by tidal heating and decay of radioactive elements, makes this Jovian moon the best target for identifying a separate evolutionary line. This search addresses the main problem remaining in astrobiology, namely, the distribution of life in the universe. We explore ideas related to Europa's likely degree of evolution, and discuss a possible experimental test. The total lack of understanding of the distribution of extraterrestrial life is particularly troublesome. Nevertheless, technical ability to search for extraterrestrial intelligence, by means of radioastronomy, has led to remarkable technological advances. In spite of this success, the theoretical bases for the distribution of life in the universe are still missing. The search for life in the Jovian satellites can provide a first step towards the still missing theoretical insight. See
g Intelligence - A forensic anthropologist at Middle Tennessee State University is one of a select number of scientists to participate in the examination of a skeleton that could force historians to rewrite the story of the entire North American continent. See
g Message - A lot of science fiction doesn’t offer a particularly accurate description of SETI. Here’s one piece that does: Carl Sagan’s “Contact,” published by Simon & Schuster in 1985. In this story, the discovery of radio signals from extraterrestrial intelligence leads humanity to re-evaluate its self-image. The heroine is loosely based on Jill Tarter, the scientist who leads one of the major scientific searches for signals today.
g Cosmicus - The idea of tourism in space is the central story line in a number of well-known and not-so-well-known science fiction stories. It also plays a significant part in a number of other stories, and gets some sort of mention in even more. See
g Learning - How are key concepts of astrobiology treated in science fiction? See Note: This article is from 2001 and intended to be used as part of a classroom lesson.
g Imagining - Like first contact stories? Then be sure to read Isaac Asimov’s short story "Nothing for Nothing," published in the Feb. 1979 issue of IASFM.
g Aftermath - Would dutiful American citizens trust the government to handle first contact with extraterrestrials and rush to get information to the public? See Note: This article is from 1999.