Cosmic Dust Doomed Dinosaurs?
The earliest fossil animal embryos, dating from the Precambrian era, were found by American, Taiwanese, and Chinese scientists in phosphate deposits in China's Guizhou province. Some of these remarkably preserved, 570-million-year-old fossils are no larger than a grain of sand and show detailed multiple-cell division. This discovery indicates that multicellular animal life evolved earlier than researchers had previously thought.
Simulating nuclear-weapon explosions requires the ability to calculate what happens to billions of data points in a fraction of a second. The Department of Energy (DOE) has contracted IBM Corporation to build a 10-trillion-operation-per-second computer system so that it can calculate the effects of weapons in our nation's stockpile without detonating real nuclear bombs.
This advanced supercomputer is slated for installation at the DOE's Lawrence Livermore National Laboratory in the year 2000. It will be the world's fastest computer, capable of 10 TeraOps (10 trillion operations per second). It would take a person with a handheld calculator 10 million years to do the same number of calculations that the 10-TeraOps computer will be able to do in one second. Even faster computers are on the way. The DOE plans to build a 30- and a 100-TeraOps computer system in the future.
Slimy Cave Critters
Researchers exploring a mile-deep area of a Mexican cavern called Cueva De Villa Luiz (Cave of the Lighted House), in the state of Tabasco, discovered strange viscous colonies of single-cell organisms hanging from the cave's limestone walls and ceiling. The unidentified bacteria were dubbed ?snot-tites? because they hang in slimy white masses resembling stalactites. These bizarre microorganisms?found nowhere else?get most of their energy by oxidizing sulfur from the noxious hydrogen-sulfide fumes in the cave. They excrete drops of acid as strong as battery acid.
Two new fossil animals with distinct imprints of feathers and many dinosaur features were found in China's Liaoning province. Dating back more than 120 million years, the feathered specimens add considerable weight to the theory that birds evolved directly from dinosaurs.
One of the new species, Protarchaeopteryx robusta, has symmetrical feathers similar to those of modern flightless birds, suggesting that it could not fly. The other new species, called Caudipteryx zoui, is covered with primitive feathers that also lacked the aerodynamic quality necessary for flight.
In addition, a 65- to 70-million-year-old bird fossil was discovered by a team of international scientists on the African island nation of Madagascar. The fossil, named Rahona ostromi, offers evidence of a close relationship between dinosaurs and birds. The creature had a two-foot wingspan and what seem to be well-developed feathers, indicating that it was a capable flyer. Unlike most birds, however, it also had a long bony tail, and a large, sickle-like killing claw at the end of a thick second toe on the hind foot. This unique toe-and-claw is identical to that of theropod dinosaurs called ?maniraptorans,? which many scientists believe gave rise to birds.
Meanwhile, skeptics of the theory that birds descended from dinosaurs cite studies of modern bird and reptile embryos that suggest that birds and dinosaurs took different evolutionary paths. They found that bird wings developed from ?fingers? corresponding to the digits of the human hand?the index, middle, and ring fingers?while reptile forelimbs have three digits corresponding to the human thumb, index, and middle fingers. Critics claim that these developmental differences cannot be reconciled.
Scientists have long thought that the effect of gravity between the galaxies would eventually slow the acceleration rate of the expanding universe that was created by the force of the Big Bang. This assumption is now being questioned. Astronomers studying supernovas (exploding stars) have discovered evidence that the universe may in fact be gaining momentum.
Although they cannot explain why galaxies seem to be moving away from each other at a faster rate, some astronomers theorize that a mysterious antigravity force in the cosmos may be causing the universe to gain speed.
Celestial ?Old Faithful?
NASA researchers observing a disk of matter surrounding a black hole in the constellation Aquilla have discovered that the disk periodically hurls jets of hot gas in opposite directions from the black hole at nearly the speed of light (650 million miles per hour). At half-hour intervals the black hole replenishes the disk by pulling fresh material from the surface of a nearby ?companion? star and then undergoing another disruption, behaving much like a heavenly version of Old Faithful geyser in Yellowstone Park. Each eruption is estimated to eject 100 trillion tons of matter, using an amount of energy equivalent to six trillion times the annual energy consumption of the entire United States.
A 113-million-year-old baby dinosaur fossil was found in the Pietraroia limestone formation in Italy's Benevento province with much of its soft tissue intact, including muscles, intestines, and liver. The extraordinary discovery of this prehistoric creature's fossilized organs is expected to provide scientists with important information about dinosaur anatomy.
The nine-inch dinosaur specimen was named Scipionyx and belongs to the group called theropods, which includes Tyrannosaurus rex and velociraptors. Although the unique fossil was discovered by an amateur paleontologist a decade ago, it was not recognized as dinosaur remains until recently. It is the first dinosaur fossil ever found in Italy.
Earth Drags Space and Time
Einstein's theory of relativity predicts that large rotating objects should drag space and time around themselves as they turn. The first direct evidence of this phenomena was announced in March 1998 by an international team of NASA and other scientists, who discovered that Earth does indeed drag time and space around itself as it rotates. The researchers detected this effect, called ?frame-dragging,? by precisely measuring shifts in the orbits of two Earth-orbiting satellites (LAGEOS I and II). The team found that the plane of the orbits of the two satellites shifted about six feet (two meters) per year in the direction of Earth's rotation.
Frame-dragging is not unlike the effect of a bowling ball spinning in molasses. As the ball spins, it pulls the molasses around itself. Anything stuck in the molasses will also move around the ball. Similarly, as Earth rotates, it pulls nearby space and time around itself. This pull shifts the orbits of satellites near Earth.
NASA astronomers have discovered evidence of a solar system like our own forming around a youthful star known as HR 4796, some 220 light-years from Earth in the constellation Centaurus. (A light-year is about 5.88 trillion miles.) An infrared image taken by NASA shows a swirling disc of dust around the star. In the middle of the disc is an empty region that may have been swept clean when its dusty material was pulled into newly formed planetary bodies. Scientists think that this may be what our solar system looked like at the end of its main planetary formation phase.
The diameter of the planetary-forming disc orbiting the star is about 200 astronomical units (A.U.). The diameter of the cleared inner region is about 100 A.U., slightly larger than our own solar system. The hole in the doughnut-shaped disc is typical of what would be left by a moving celestial body, offering indirect evidence that a planet has been formed.
The discovery was made on March 16, 1998, from the new giant 10-meter (33-foot) Keck II telescope atop Mauna Kea, Hawaii, and confirmed by astronomers at Chile's Cerro Tololo Observatory.
Galactic Water Cloud
In April 1998 a team of U.S. astronomers reported finding a massive concentration of water vapor within the Orion molecular cloud, a giant interstellar gas cloud located near the Orion nebula. This gas cloud, which is a trillion miles across, generates enough water molecules in a single day to fill the Earth's oceans 60 times over.
Researchers believe the cloud provides an important clue to the origin of water in the solar system. Eventually, the water vapor in the cloud will freeze, turning into small ice particles. Similar ice particles are thought to have been present within the gas cloud from which our solar system formed.
The measurements were made by the Infrared Space Observatory (ISO) satellite, launched in November 1995 by the European Space agency and with the participation of NASA.
A Saharan Stonehenge
Scientists have confirmed that an assembly of huge stone slabs in Egypt's Sahara Desert is the oldest known astronomical alignment of megaliths in the world. Known as Nabta, the site is 6,500 to 6,000 years old, predating Stonehenge and similar prehistoric sites by about 1,000 years.
The site consists of a 12-foot-in-diameter stone circle, a series of flat, tomblike stone structures, and five lines of standing and toppled megaliths. Some of the slabs are nine feet high. Two sets of slabs are aligned in a north-south direction, while another pair provides a line of sight toward the summer-solstice horizon. An east-west alignment of megaliths is present, as are geometrical lines involving about a dozen additional stone monuments, the significance of which is not understood.
Dolly's Bonnie Baby
Dolly, the first mammal successfully cloned from an adult cell, gave birth to a healthy female lamb named Bonnie on April 14, 1998, at Roslin Institute in Edinburgh. The birth of Dolly's lamb confirmed the ability of clones to produce healthy offspring naturally. Dolly was mated with David, a 4-year-old Welsh Mountain ram.
Neanderthals Had Gift for Gab
Duke University scientists studying hypoglossal canal size in fossil skulls of Neanderthals and other ancestral humans have found evidence that some of these ancient species were probably capable of human speech as long as 400,000 years ago.
The hypoglossal canal is a bony channel that transmits messages from the cranial nerves that control voluntary movements of the tongue muscles. The canal is nearly twice as large in modern humans than in apes and chimpanzees who are incapable of speech. The hypoglossal canal size of Neanderthal and archaic Homo sapiens is similar to those of modern humans. Assuming that the size of the hypoglossal canal and its nerves indicate of the tongue's motor-control and vocal capabilities, it can be inferred that these species could coordinate their tongues to form humanlike speech.
Blockbuster Big Bang
In May 1998 astronomers announced that they had measured the most violent explosion ever found in the cosmos?a stupendous gamma-ray burst that released a hundred times more energy than they had theorized previously, making it the most powerful explosion since the Big Bang. The unprecedented gamma-ray burst, designated GRB 971214, was observed by researchers using satellites from NASA's Compton Gamma Ray Observatory (which measured brightness) and the Italian/Dutch BeppoSax (which pinpointed location). Although the burst was discovered in mid-December 1997, its distance from Earth had just been calculated.
The burst originated in a faint galaxy about 12 billion light-years from Earth. Although the explosion lasted a mere 50 seconds, the energy released was almost equal to the amount of energy radiated by our entire galaxy over a couple of centuries. The cosmic fireball released several hundred times more energy than an exploding star or supernova, and its flash was as bright as the entire universe.
Gamma-ray bursts are mysterious flashes of high-energy radiation that appear from random directions in space and typically last a few seconds. First detected by U.S. Air Force Vela satellites in the 1960s, their origin remains unknown.
Mammals and Dinosaurs Coexisted
Overwhelming evidence from the largest evolutionary study of gene sequences ever performed suggests that the major group of mammals and birds emerged well before the mass extinction of the dinosaurs 65 million years ago.
According to the research done by a scientific team at Penn State, mammals were definitely living on Earth during the Cretaceous period, from 70 million to 100 million years ago. Scientists don't know what these mammals looked like or if they were very abundant, but the genes of their descendants seem to confirm their existence.
The research team sifted through many thousands of vertebrate gene sequences from hundreds of species to find those that develop mutations at a constant rate over time. They then used these sequences to trace the history of each species back to its time of origin. For many species, research yielded origin dates similar to those based on fossil dating; for others, however, genetic clues pointed to a much earlier time.
The study suggests that the evolution of mammals occurred gradually, as a result of the isolation of breeding groups when the continents broke apart, rather than suddenly, by the rapid filling of ecological niches left vacant when the dinosaurs became extinct.
Down Memory's Divided Lane
Psychologists studying patients with brain damage have concluded that the left side of the brain is used for language tasks and the right side for spatial and pictorial information. Scientists who make images of the brain at work, however, have concluded that the left side is used for memorization and the right side for retrieval.
A new study by researchers at Washington University School of Medicine at St. Louis found that when a person is told to remember a word, a region on the left side of the brain is activated. When a person is told to remember an image, a region on the right side is activated. Both regions are activated when a person is asked to recall an image they can name.
First Extrasolar World Image
In 1998 astronomers using the Hubble Space Telescope took the first direct photograph of what may be a planet outside our solar system. Previous extrasolar planets have been discovered only by indirect means such as gravitational wobbles in their parent stars. The young planet, called TMR 1C, is located within a star-forming region in the constellation Taurus. It appears to lie at the end of a 130-billion-mile-long filament structure, suggesting that it had been flung from the vicinity of a newly forming pair of binary stars.
At a distance of 450 1ight-years, the same distance as the newly formed stars, this possible planet would be 10,000 times less luminous than the sun. It is estimated that if the planet is a few hundred thousand years old, the same age as the newly formed star system that may have ejected it, then it is two to three times the mass of Jupiter, the largest planet in our solar system.
Cosmic Dust Doomed Dinosaurs?
A controversial study by researchers at the University of Florida and Carnegie Institution theorizes that space dust in Earth's atmosphere and changes in the planet's orbit may have started the gradual extinction of dinosaurs and other life thousands of years before a massive asteroid collision dealt the final blow.
Currently, Earth is accumulating about 30,000 metric tons of cosmic dust from interplanetary space each year. The scientists found that most of this dust comes from just three families of asteroids (Eos, Themis, and Koronis) in the solar system's asteroid belt. As Earth orbits the sun, it passes through this cloud of dust particles, capturing some of the dust in its atmosphere. The study showed that the amount of dust captured depends on the shape (ellipticity) and tilt (inclination) of Earth's orbit. These vary periodically due to the gravitational pull of other planets. The dust buildup rises and falls in about 100,000 periods that correspond to ice-age cycles.
Space dust could remain at high levels in the atmosphere for periods of thousands of years, and any associated cooling would also persist for this length of time. If the amount of dust in Earth's atmosphere altered the climate, the change would cause gradual extinction.
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