COSMIC ANCESTRY | Quick Guide | What'sNEW - Later - Earlier - Index | by Brig Klyce | All Rights Reserved | ||
What'sNEW Archives, March-April 2000
April 27: Most interstellar particles captured by Stardust are complex organic compounds, and not the expected minerals. This is the conclusion of the team from Max-Planck Institute, Garching, that manages the mass-spectrometer, CIDA, on NASA's Stardust spacecraft. "The first in-situ chemical analysis of interstellar dust particles produces a puzzling result: These cosmic particles consist mostly of 3-dimensionally cross-linked organic macro-molecules, so-called polymeric-heterocyclic-aromates. They rather resemble tar-like substances than minerals."
Cometary and Interstellar Dust Analyzer for comet Wild 2, by Jochen Kissel et al., doi:10.1029/2003JE002091, J. Geophys. Res., 30 Oct 2003. Tarlike Macro-Molecules Detected In Stardust, Max-Planck-Institut fur extraterrestrische Physik (+SpaceflightNow), 26 April 2000. Stardust Detects Organic Molecules, SpaceDaily, 27 April 2000. The Physical and Chemical Properties of Interstellar Dust and Dust in Comets: Possible Seeds for Life on Earth [CA reprint] by Franz R. Krueger and Jochen Kissel, May 2000. Analysis of Interstellar Dust is a related CA webpage. Can the Theory Be Tested? is a related CA webpage. Cross-Linked Hetero Aromatic Polymers in Interstellar Dust by N.C. Wickramasinghe, D.T. Wickramasinghe and F. Hoyle [CA preprint].
April 25: The 4th International Conference on Low-Cost Planetary Missions will be held at The Johns Hopkins University Applied Physics Laboratory, Laurel, Maryland, 2-5 May 2000. [Thanks Bruce Moomaw and Larry Klaes.]
April 21: Nanobacteria continue to surprise microbiologists. A team at the University of Queensland (UQ) in St. Lucia, Australia cultured specimens from several kilometers under the ocean floor, where temperatures of 170ºC and pressures of 2,000 atmospheres are reached. "It appears that the nanobes were not actively growing in the rock from which they were retrieved, but thrive when exposed to aerobic conditions." The organisms withstand "repeated exposure to vacuum, bombardment by the electron beam, and X-ray radiation—and continue to grow," said UQ team member Philippa Uwins. "They resemble actinomycetes and fungi except for their remarkably smaller size—namely, filaments of variable lengths with diameters of 20-128 nm." Many bacteriologists remain sceptical. April 14, 2000: The microbial biosphere as a "World Wide Web" — That's how Nobel laureate Joshua Lederberg sees it, "with DNA serving as the packets of data going every which way." The rate of evolution can be so rapid that, as he comments, "A year in the life of bacteria would easily match the span of mammalian evolution!" Lederberg is not considering closed bacterial systems, but his remark renews our puzzlement — if Darwinian evolution is capable of composing new genes for new functions, shouldn't it have done so in the closed-system bacterial experiments that have already run for ten years now? Lederberg goes on to mention, "Hundreds of segments of human DNA originated from historical encounters with retroviruses whose genetic information became integrated into our own genomes." This would exemplify the way life can evolve by acquiring new genetic programming in an open system. Joshua Lederberg, "The Microbial World Wide Web", p 291 v 288 Science, 14 April 2000 [link].In Real or Artificial Life... has more about the closed-system bacterial experiments, with updates. Viruses... is the related CA webpage. [Next-What'sNEW about HGT-Prev] 10 Mar 2021: local hub for HGT among bacteria, with updated links.
April 12: Conference Reports — Reports on NASA's First Astrobiology Conference at Ames Research Center, April 3-5, and the 31st Lunar and Planetary Science Conference in Houston, March 13-17, are available.
April 12: More on Contamination — Now that the return of soil samples from Mars has been delayed, there's more time to consider cross-contamination issues. We suspect that Mars-to-Earth transfer of material that could bring live germs has happened repeatedly and we do not want Mars exploration to be unnecessarily impeded. But it's good to listen to the conservatives. [Thanks, Barry DiGregorio.]
April 9, 2000: A DNA virus... could have been the ancestor of the eukaryotic replication system. This profound conclusion comes from molecular biologist Luis P. Villarreal in a 30-page review article published as Chapter 15 in a new medical book, Origin and Evolution of Viruses. Early in the article Villarreal states unequivocally, "In bacteria and their DNA viruses, the major process of genetic adaptation and evolution involves the horizontal transfer of genetic elements... [by] either... virus infection or... various parasitic genetic elements that use a virus-like replication/mobilization process" (emphasis added). Also, sequences show that the DNA polymerase gene in T4 (a virus that infects bacteria) is related to DNA polymerase genes in eukaryotes and their viruses. Ultimately, concerning eukaryotes, he asks, "Could virus-mediated large-scale gene transmission allow the evolution of complex characteristics not attainable by point changes?" Cosmic Ancestry also makes this suggestion. In our experience, the most straightforward interpretation of data pertaining to evolution often comes from the medical field. April 6: Astrobiology Conference — Flying over drying Mono Lake, the varied reds of Bryce Canyon, and the deep relief of the Lake Powell terrain, I can easily imagine that this is Mars. Detailed images of the red planet were everywhere at the Astrobiology Conference. One of the aims of the meeting was to contribute to the establishment of astrobiology as a legitimate discipline, and there it succeeded. Life may exist on other planets, and Earth science is relevant on Mars, Europa and elsewhere. Science can begin to suggest where life-as-we-know-it is possible in other solar systems, and even other galaxies. But of course the conference cannot be easily encapsulated. Selected points of interest to us were —
April 3: The First Astrobiology Conference at NASA's Ames Research Center began with "standing rooom only" in the lecture hall. The theme of the morning session was water, and opening speaker Phillip Ball concludes that it is necessary for life. Richard Greenberg explained that the ice on Europa must be thin, and Robert Pappalardo said it's more lilkely thick — both expect to find life there. Then Jody Deming told how diatoms thrive in brine pores in sea ice at minus 15 degrees centigrade. Paul Hoffman was especially entertaining and edifying on the new "snowball earth" theory — runaway freezing followed by very fast thawing at least twice just before the Cambrian explosion. Not counting the introductory ones, there were fifteen science lectures. Finally came the poster session with posters arranged into 31 categories. Among the ones near mine were those of Robert Folk (nannobacteria — as he spells it) and Everett Gibson et al. (Mars geology). There are no posters or scheduled talks on computer models that even claim to mimic macroevolutionary progress, but simple panspermia is well represented. The conference runs until Wednesday evening, 5 April.
April 1: NASA's Astrobiology Science Conference, 3-5 April. More than 300 posters and 49 oral presentations are scheduled at NASA's Ames Research Center, Mountain View, California. I will present one of the posters. March 29: Shallow craters called "Carolina Bays" cover the coastal plain of the southeastern United States. The craters are elliptical, with their long axes nearly parallel. They range from 200 feet to 7 miles in longest diameter. They were most likely created by fragments of a comet that slowed and disintegrated after striking the atmosphere from the northwest. At ground level the bays resemble ordinary fields, marshes, or ponds. Many have been drained and cultivated. But seen from above they still are quite noticeable. The number of them is estimated from 500,000 to 2,500,000. Their age is recent — probably less that 15,000 years. An intriguing finding is that sediments from some of them contain bacterial species different from any known on Earth. ...None of the clones exhibited an exact match to any of the 16S rDNA sequences deposited in numerous databases. "This suggests that most of the bacteria in Rainbow Bay are novel species," said Lawrence Shimkets, a University of Georgia biologist, in 1997.
"Previously Unknown Bacteria Discovered By University Of Georgia Researchers In Features Called Carolina Bays," University of Georgia Press Release, 9 April 1997.
March 28: NASA's report on the recent Mars mission failures is out. The Polar Lander probably crashed because it received a premature signal to shut off its descent engine. Shutoff was supposed to be prompted when the lander's legs flexed as it touched down; but the shutoff could have been prompted prematurely if the legs bounced when the parachute opened. The problem was not detected before launch, because the parachute-deployment and touchdown sequences were tested only separately. If there's life on Mars, do we investigate, or stay clear?
March 23: Extraterrestrial gases trapped in molecular cages are found around the world in a sediment layer that marks the extinction event 65-million years ago, and in the Murchison and Allende carbonaceous meteorites. Among the gases are isotopes of helium that cannot be earthly. The cages made of carbon molecules are nicknamed "buckyballs," short for Buckminster Fullerine, after the inventor of geodesic domes. [Thanks, Randy Bowen.]
March 22: Life on Europa gets a favorable assessment from University of Arizona astronomer Richard Greenberg. He will present the case at the First Annual Astrobiology Conference, April 3-5, at NASA's Ames Research Center, California.
March 19: The Mars sample return mission is postponed. No samples will be returned before 2010. More generally, "The search for life on the Red Planet will have to slow down until people on Earth have worked out how to land on Mars without crashing," said Dr. Carl Pilcher, head of NASA's planetary exploration program, at the annual Lunar and Planetary Science Conference in Houston, Texas, March 13-17. After two recent failed Mars missions, we agree that the slowdown is warranted. We welcome, by the way, Pilcher's characterization of the Mars program as a search for life — that seems new. [Thanks, Barry DiGregorio.]
March 18: DNA can be installed into plant cells ten times more easily in space than on Earth. This indication comes from soybean experiments conducted by John Glenn in 1998. The analysis was published by the American Chemical Society in January, 2000. A team led by Purdue University agronomist Richard Vierling plans more experiments with soybeans on the next space shuttle, scheduled for launch April 13.
March 18: "A striking increase in the cratering rate over the last 400 million years" is indicated by research on tiny glass beads gathered with regolith from the moon by Apollo 14 astronauts. The research team from the University of California, Berkeley, even comments that the increase coincides roughly with the Cambrian explosion. This suggestion has been controversial. [Thanks, Kevin Keogh.]
March 18: Organics on Mars may have left traces overlooked by the Viking landers. A team at the University of Florida says that metastable intermediate salts should remain after the oxidation of organics. Future missions could look for these salts in situ. Viking's failure to detect organics on Mars, in 1976 - 1977, caused NASA to announce that there was no evidence for life on Mars. If these salts are found, NASA will have reason to reconsider. [Thanks, Barry DiGregorio.]
March 9: The microfossils in Tatahouine are biological. This is the conclusion of a multi-disciplinary team from France that examined fragments of the Tatahouine meteorite and the soil where it fell, in 1931. Carefully grown cultures produced forms resembling those also found in ALH 84001, the famous meteorite from Mars. Many critics have said that microfossils smaller than about 200 nanometers in diameter are too small to be biological. This research demonstrates that the smaller forms are "at least remains of bacteria." The work follows up a preliminary report by members of the same team, in 1998. [Thanks, Larry Klaes.] Evidence that nanobacteria are biological also comes from a pair of biochemists from Finland who found that they "can be cultured with a doubling time of about 3 days." They suggest that cells "may fragment into numerous tiny units that can later be reassembled... to produce a fully competent replicant form." This evidence was presented at a conference in Denver, 20-22 July 1999. And a team of Russian bacteriologists proposes that "formation of nanocells is a common response of bacteria to stress." Furthermore, nanocells that had formed under microwave stress "grew, formed a cell envelope, and reversed to initial shapes and sizes." These findings were presented at a conference in San Diego, 20-22 July 1998.
March 8: A carbonaceous asteroid was observed passing Earth. "1998 KY26" was slightly more than twice as distant as the moon when it was studied, 2-8 June 1998. It is roughly 30 meters in diameter (smaller than some of the telescopes aimed at it!), and rotating once every 10.7 minutes (a surprisingly rapid spin). "Part of a recently recognized, potentially abundant subpopulation of small near-Earth asteroids..., it is more accessible to a spacecraft rendezvous than any of the other ~25,000 known asteroids with secure orbits." Of further interest to us, its optical and radar properties indicate that its composition is similar to carbonaceous chondrites. "They contain complex organic compounds as well as 10-20% water. Some carbonaceous chondrites contain amino acids and nucleic acids." [Thanks, Andrew Yee and CC-NET.]
March 3: An essay opposing panspermia, "Plausibility, Significance and the Panspermia Epidemic," by Jon Richfield is reproduced on a new "Replies" page. The ensuing correspondence is also there.
March 2: NASA may crash Galileo to avoid contaminating Europa. NASA believes that the Galileo spacecraft that has been in space for 11 years may still contain viable germs. NASA also believes there may be life in the ocean under Europa's icy surface. Both possibilities are real enough that NASA will take action to assure that Galileo avoids Europa.
March 2: Stanislav Zhmur says that the fossils in Murchison are not earthly contaminants. In English, he writes, "Now referring to contamination. I'll give only the facts, which minimize this problem referring to the remnants of microorganisms that have been examined. This refers to all carbonaceous meteorites, Murchison included.
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COSMIC ANCESTRY | Quick Guide | What'sNEW - Later - Earlier - Index | by Brig Klyce | All Rights Reserved |