Other wordly weather: a clue to life elsewhere
(Aug. 30, 2001)
Among the most exciting upcoming developments in astrobiology are spaceborne optical interferometers – arrays of telescopes working as one – that will be able to image the planets of other solar systems and analyze their spectra. Several such projects are in the works, including the pioneer Starlight mission (a.k.a. Space Technology 3 and the New Millennium Interferometer) and the much more ambitious Terrestrial Planet Finder and ESA's Darwin. Now comes news from a group at Princeton that the faint light from far-off planetary systems could be used, with the help of a piece of software, to tell about the distribution of land, water, and cloud-cover. Such information would be valuable in indicating which worlds are most promising in the further search for life (and also providing those in the SETI community with specific promising targets at which to point their detection gear).
Dust to dust: Thoughts on Fred Hoyle's passing
(Aug. 26, 2001)
Always a Hoyle admirer, I was sad to hear of his death last week (April 22). In a world of scientific orthodoxy, Fred Hoyle went out of his way to see the other side of the argument. For the last quarter century he has been the most vociferous proponent of the panspermia hypothesis, insisting that not only complex molecules can form between the stars but so too can life itself. Well, most of us haven't quite caught up to him on the latter part of that thesis but Hoyle has certainly been vindicated in his belief – stated several years before the first organics were found in interstellar clouds – that there are amino acids, sugars, etc, in the voids between suns. And, of course, NASA is now getting ready to look for primitive cellular material in space. So, who knows?
But Fred Hoyle's fame does rest entirely or even mainly on his panspermia notions. Without question he was one of the most distinguished astrophysicists of his generation, providing vital clues to several puzzles in nucleosynthesis and stellar evolution. He will also be remembered for his long (and not-quite-lost-yet) battle against the Big Bang theory – ironically, a term he coined. And lastly, and most fondly, he will be remembered for his science fiction, including A for Andromeda and, best of all, The Black Cloud. For an obituary by his colleague Chandra Wickramasinghe, go here.
New Kuiper Belt object bigger than Ceres
(Aug. 24, 2001)
It seems that the Kuiper Belt – the band of ice-rock bodies that extends beyond the orbit of Pluto (and to which Pluto probably once belonged) – is to going to have some interesting surprises for us. The newly-discovered KB object, temporarily designated 2001 KX76, has been confirmed as exceeding in size the previously largest-known asteroid, Ceres. This makes it the biggest known object in the solar system after the Sun and nine planets. For more, go here.
More conventional exoplanets starting to appear
(Aug. 16, 2001)
It's pleasing to note that one of the predictions I make in my new book Life Everywhere is already starting to come true-namely, the first "normal" extrasolar planets are beginning to be discovered. Because of the search methods conventionally used in planet-hunting, it's the super-big, super-close-in worlds that tend to be picked up first. To date, our list of exoplanets is dominated by "hot Jupiters" and "eccentric Jupiters". But now it seems, as the planet searches become more sensitive (and long-running), the first signs of normally-placed gas giants are starting to appear. That most successful of planet-hunting teams, Geoff Marcy and Debra Fischer at the University of California, Berkeley, and Paul Butler at the Carnegie Institution, Washington, have announced evidence of another planet in the 47 Ursae Majoris system, already to known to harbor a super-Jupiter in a circular orbit at a distance of about 2 AU. Now the team say they have detected wobbles caused by a world with about three-quarters the mass of Jupiter in a near-circular orbit further out. As Fischer remarks: "With 47 Ursae Majoris, it's heartwarming to find a planetary system that finally reminds us of our solar system." Almost certainly, it will the first of many.
Following its successful launch, NASA's Genesis spacecraft is heading toward the first Lagrangian point in Earth's orbit from the vicinity of which it will conduct its mission-to collect samples of the solar wind and interplanetary dust using high-purity wafers set in wing-like arrays. Three years from now, the samples that it's gathered – 10 to 20 micrograms of pristine interplanetary dust – will be recovered in a return capsule over the Utah desert. As its name implies, Genesis will help shed light on the makeup of the cloud from which the solar system formed. But will it also help us understand more clearly the origin of life? One of the hottest issues in astrobiology today concerns the relative importance of indigenous (home-grown) vs. exogenous (incoming) matter in the steps leading to the first organisms on a world. Few astrobiologists would yet be prepared to suggest that life, or even protolife, might originate in space and then seed new-formed planets. But that is precisely what a Polish research team is claiming. The group at Jagiellonian University believe they have created a biogenic molecule simply by exposing space dust to high-energy radiation. As in the case of another recent claim – of alien bacteria from the upper atmosphere – the astrobiological community will need a great deal of convincing. But these are certainly interesting times.
Other Earths – the odds just shortened
(Aug. 11, 2001)
Earthlike planets may be common even in binary star systems according to a new theoretical study by Stephen Kortenkamp at the University of Maryland and his colleagues. The work, published in the August 10 issue of Science, suggests that, in some cases, the presence of another large object besides the main star – either a companion star or a gas giant – could actually encourage the growth of small worlds. In the past, astronomers suspected that while terrestrial planets might be able to form in widely-separated binary systems they may not be able to build up in systems where the separation was only 10-100 times the Earth-Sun distance. According to the new computer model, says Kortenkamp, "you could have terrestrial planets forming when the stars are closer together than traditionally thought."
Regular visitors to this site will have noticed a hiatus in my normally regular coverage of astrobiological news. In fact, I've just returned home to Minnesota after a month-long trip to England and Scotland, drinking warm beer, walking the fells (now accessible again after the foot-and-mouth outbreak), and catching up with family and friends. My reading on the journey consisted of one of Ben Bova's excellent hard SF novels – Venus (available from all good airport bookstores!) His speculations about possible Venusian lifeforms helped while away the hours on the plane and the stop-overs at Keflavik – highly recommended.
Space bugs claim met with skepticism
(Aug. 5, 2001)
The most recent claim by Chandra Wickramasinghe and his colleagues at Cardiff University, Wales, that they have recovered alien microbes from high in the Earth's atmosphere has been given a cool response by other astrobiologists. Wickramasinghe told a conference that a balloon flight at an altitude of 41 kilometers had recovered clumps of microbes that most probably had their origin in outer space. He and Fred Hoyle have long advocated the view that life can develop in interstellar space and be delivered to planets by passing comets. But this remains an unorthodox hypothesis and most scientists will tend to suspect that the newly-found organisms have been lofted from the Earth's surface unless more detailed tests at the genetic level suggest otherwise.
The official NASA verdict on the Viking biology experiments is that they drew a blank in the search for Martian life. But a quarter of a century after the twin probes reached the surface of the Red Planet, some in the scientific community are starting to question that verdict.
