SCIENCE OBSERVER
In the News
This roundup of notable recent items about scientific research,
culled from news reports, was compiled from Science in the
News Daily and Science in the News Weekly, free
electronic newsletters produced by Sigma Xi. Online:
sitn.sigmaxi.org and www.americanscientist.org/sitnweekly
The Solar System Loses One of Its Planets
The International Astronomical Union stripped Pluto of its status as
a planet, reclassifying it as a "dwarf planet" under
historic new guidelines. The newly adopted scheme also includes a
third category of objects, "small solar system bodies"
such as asteroids and comets. The decision was reached after days of
debate among 2,500 astronomers at the union's general
assembly—a debate that is not yet over. The list of
astronomers in disagreement with the assembly's decision includes
Alan Stern of the Southwest Research Institute, who calls the
decision "sloppy science," and Harvard professor Owen
Gingerich, chair of the definition committee, who implied that the
decision was hijacked in a "revolt" by one subgroup.
http://www.washingtonpost.com/wp-dyn/content/article/2006/08/24/AR2006082400109.html
Gene May Explain Boost in Brain Power
Researchers have found a clue as to why human mental
capacities are so much greater than those of chimpanzees. A gene
that has undergone significant change in the human line since the
two species split some 5 million years ago may partly account for
the accelerated evolution of our brains. Although the investigators
do not know exactly what the RNA product of this gene does, they
believe it is active at a key time and place in embryonic
development when the brain is growing at its fastest pace.
Pollard, K. S. et al. An RNA gene expressed during cortical
development evolved rapidly in humans. Nature
443:167–172 (September 14)
Ozone Hole May Soon Shrink in Size
David Hofman and Susan Solomon, two scientists who had helped alert
the world to the existence of a menacing hole in the stratospheric
ozone layer above Antarctica, recently reported that this worrisome
feature of the atmosphere appears to have stopped widening. After
the hole was discovered in 1986, international agreements were
reached to end the use of ozone-depleting chemicals
(chlorofluorocarbons, or CFCs), and these measures may allow the
hole to "heal" completely sometime over the next century.
http://news.bbc.co.uk/2/hi/science/nature/5276994.stm
Dark Matter Really Does Exist
After studying data from a long-ago collision of two giant clusters
of galaxies, some astronomers claim that they have found proof that
subatomic dark matter actually does exist and plays a central role
in creating and defining gravity throughout the universe. For
decades, scientists have theorized that much of the universe is made
up of nearly undetectable dark matter and dark energy. Others prefer
alternative interpretations. This latest finding will no doubt
influence an active debate among physicists and cosmologists.
Clowe, D. et al. A direct empirical proof of the
existence of dark matter. The Astrophysical Journal
648:L109–L113 (September 10)
Not a Newfound Human Species
A new study casts serious doubt on the proposal that the ancient
bones of a diminutive hominid found two years ago on the Indonesian
island of Flores represent those of an entirely new species of
ancestral human. Scientists from Indonesia, Australia and the United
States conducted a comprehensive analysis based on their own
firsthand examination of the available bones, which include a single
mostly complete skull. The evidence, they report, suggests that the
enigmatic skull belonged to a pygmy human who suffered from a
developmental abnormality.
Jacob, T. et al. Pygmoid Australomelanesian Homo
sapiens skeletal remains from Liang Bua, Flores: Population
affinities and pathological abnormalities. Proceedings of
the National Academy of Sciences of the U.S.A.
103:13421–13426 (September 5)
Many Dinosaurs Yet to Be Discovered
Two-thirds of the world's fossil dinosaurs may still await
discovery, according to a new statistical analysis. Paleontologists
had identified 285 dinosaur genera between the early 1800s and 1990,
but that number has since jumped to 527, an increase of 85 percent.
This observation implies that the current fossil boom will likely
continue, particularly as new lands are explored. The authors of the
new study estimate the total number of "recoverable"
genera at 1,844. They predict that 400 new varieties will be
discovered in the next 30 years as paleontologists explore
fossiliferous beds of appropriate age in China, Argentina and
elsewhere in the world. The pace of new dinosaur discoveries should
level off finally sometime in the 22nd century.
Wang, S. C., and P. Dodson. Estimating the diversity of
dinosaurs. Proceedings of the National Academy of Sciences of
the U.S.A. 103:13601–13605 (September 12)
First Tree Genome Sequenced
An international team of researchers has sequenced a tree genome.
The four-year effort was the first of its kind. The black
cottonwood, a variety of poplar, was chosen because it has
relatively little DNA. It is hoped that sequencing trees can help
the forestry industry to improve its products, including alternative
fuels such as bioethanol. It may also be possible to engineer trees
that can capture greater-than-normal amounts of carbon dioxide from
the atmosphere.
Tuskan, G. A. et al. The genome of black
cottonwood, Populus trichocarpa(Torr. & Gray).
Science 313:1596–1604 (September 15)