Cosmic 'enigma' yields its secrets
Quasars - once called the most enigmatic objects in the universe - have lost much of their mystery. A quasar (quasi stellar object) is a pint-size powerhouse that outshines a galaxy of a billion stars. Alan P. Lightman of the Harvard-Smithsonian Astrophysical Observatory notes that, were Boston a galaxy in terms of size and power output, a quasar would produce the power of the entire United States within the volume of a baseball.
How can anything so small be so powerful? Where does it fit in the cosmic scheme? Some experts had previously speculated that new kinds of physical laws were at work. Today, they need no such assumption.
Lightman told a recent American Physical Society session that quasars now have extended our knowledge of galaxies. He explained that, since the first quasar was discovered Aug. 5, 1962, ''evidence has accumulated to show a continuous range of energetic activity, starting with normal galaxies, going through active galaxies, and joining the less luminous quasars.''
Quasars may be powered by black holes. These are objects so compact that nothing escapes their powerful gravitational attraction.
Gas and dust falling into such an object release energy like falling water in a power station. If the gas has a magnetic field and the black hole rotates, this field can become tangled. This process extracts some of the black hole's rotational energy.
Lightman said the brightest quasars are now believed to use the ''water power'' effect. The less luminous quasars tap rotation.
Astronomers have also wondered whether quasars are distant or nearby. If they are close, their luminosity estimates would be so reduced they would no longer seem such prodigious powerhouses.
The so-called redshift sets the distance. The faster an object recedes, the redder its light appears. Also, in the expanding universe, the more distant an object is, the faster it recedes. Thus the reddening of its light indicates both speed and distance.
Quasar redshifts suggest vast cosmic distances. But doubters argue they are nearby objects whose light is reddened by processes other than recession. This dissent is fading. For example, Bruce Margon of the University of Washington and Ronald A. Downes and Hyron Spinrad of the University of California have found the first quasar clearly associated with a distant rich cluster of galaxies. Their report in Nature calls this ''further support for the argument for a cosmological interpretation of QSO [quasar] redshifts.''
Thus the quasars have yielded basic secrets. Lightman noted that ''our understanding of these distant objects will always be built upon a pyramid of uncertain inferences. . . .'' Yet, as cosmologist Michael Rowan-Robinson of Queen Mary College, London, observed last November in New Scientist, ''Today the drama remains but much of the mystery has been resolved.'' Is your nose a compass?
Magnetic material has been found in creatures as diverse as bacteria and birds. It often seems related to navigational ability. Recently three British scientists have found magnetic bone - bone containing ferric iron deposits - in the human sinus.
This begs the question - do we navigate by our noses?
Reporting their findings in Nature, R. Robin Baker, John H. Kennaugh, and Janice G. Mather of the University of Manchester warn against jumping to this conclusion. Baker has led several experiments with students in which he claimed to show an innate ability to navigate using Earth's magnetic field. But, as he and his colleagues now point out, these results are scientifically controversial.
The scientists suggest at least three ''tentative'' hypotheses for the presence of the magnetic material. This might be a storage site for excess bodily iron from which iron is withdrawn when needed. Alternatively, the iron-bearing material may somehow be involved with growth and repair of bones. And, finally, this may indeed be a magnetic ''compass.''
If the latter hypothesis were proved correct, it would give new meaning to the aphorism ''follow your nose.'' How the lizard gets away
Lizards often escape predators by leaving their disposable tails in the predator's jaws. It appears that the tails themselves, acting as autonomous entities, can aid their owners' escape.
In some lizard species, tails can act on their own, thrashing about vigorously in the predator's mouth. Not only does a highly active tail attract the predator to this disposal part of the lizard's body, it also makes it harder for the predator to subdue the tail and swallow it. This gives the lizard more time to get away.
Benjamin E. Dial of Texas A & M University and Lloyd C. Fitzpatrick of North Texas State University, who describe this discovery in Science, say the thrashing is only one example of muscle contraction in autonomous body parts of vertebrate or invertebrate animals. They expect that research in other animals may show a common physiological basis for this useful ability. 'Hungry' galaxy
Astronomers have suspected that some galaxies grow by swallowing their neighbors. Donald Schneider and James Gunn, using the 5-meter Hale Observatory telescope, have found a massive galaxy they suggest may have gobbled up nine of its fellows.
This is one of a class of supergiant elliptical galaxies, many of which have several concentrations of stars within them. It is as though they had several galactic nuclei. They often lie at the center of a dense galaxy cluster. Thus they are suspected of swallowing other galaxies that wandered too close and were captured.
The galaxy in question - known as v2w 311 or Abell 407 - lies at the center of a sparse cluster of galaxies. Reporting it in the Astrophysical Journal, Schneider and Gunn interpret their data as indicating that the outer parts stripped off the nine swallowed galaxies now form a large halo around the supergalaxy.
The two astronomers say they expect the nine nuclei will merge into one in about 2 billion years. They also note that ''it is difficult to understand how such an object can exist.'' The galaxy cluster in which it lies is so sparsely populated it is hard to envision how it managed to engulf nine victims.
Here is a new puzzle for astronomers, one that Gunn and Schneider say they ''are fortunate to observe.''