Broadcast: November 18, 2003
This is Science in the News, from VOA Special English. I'm Bob Doughty.
And I'm Sarah Long. This week -- solar flares ... a new Table of the Elements, for astronomers ... and, later, social recognition among spiders and a possible new use for leeches.
On November fourth, the largest solar flare yet recorded shot from the sun. The National Oceanic and Atmospheric Administration, NOAA, has measured this kind of space "weather" since nineteen-seventy-six. NOAA says the flare produced a moderate solar radiation storm. This interfered with high frequency communications in the northern and southern parts of the world.
Solar flares are releases of energy that can block communications and affect the flow of electricity. They can expose airplanes to extra radiation. Crews on the International Space Station take shelter in areas most protected from the storm.
The sun has been in a period of high activity. Solar flares are common during such times. They can extend thousands of kilometers. They send powerful waves of radiation deep into space.
Solar flares are related to sunspots. These are areas that appear on the surface of the sun during times of high activity. Sunspots are cooler than surrounding areas.
Scientists say the presence of a group of sunspots for a long enough time changes magnetic fields above the surface of the sun. A solar flare starts when these magnetic fields change back. The effect is almost like that of a wound-up rubber band that returns to its normal form.
The magnetic change releases a burst of energy high above the sun. The burst is at five- to ten-million degrees.
The energy travels down to the surface. This causes an area to heat up and expand. Flare material shoots away from the sun. The speed can reach one-thousand-five-hundred kilometers a second. High-energy electrons, X-rays, radio and ultraviolet waves are expelled into space.
From Earth, the flare looks like a burst of flame from a fire. The energy speeds up tiny particles. These electrons become charged with unusually high amounts of energy. This can interfere with communications on Earth, one-hundred-fifty-million kilometers away.
Solar flares can also intensify the biggest light shows on Earth. The Aurora Borealis and the Aurora Australis take place above the poles. They can be seen at night mostly by people in the extreme north or south. But sometimes, during periods of high solar activity, they can be seen farther away.
Auroras happen when Earth’s magnetic field captures electrically charged particles from the sun. These particles are carried down toward the atmosphere and strike other particles, releasing light. The light is often green but can be any color.
Scientists and others who want to observe activity on the sun must have special equipment. People who look into the sun without this protection can permanently damage their eyes.
But the auroras are a way for people to see the powerful forces of the sun at work, as dancing lights in the night sky.
Anyone who studies chemistry knows about the Periodic Table of the Elements. This is a list that describes the qualities of the chemical elements on Earth. Now a planetary chemist has redesigned it to help scientists who study the creation of the sun and the planets.
Katharina Lodders is a professor at Washington University in Saint Louis, Missouri. She calls her work the Cosmochemical Periodic Table of the Elements in the Solar System.
An early version of the traditional Periodic Table of the Elements was published in eighteen-sixty-nine. A Russian chemist, Dmitri Mendeleev (DMEE-trih mehn-duh-LAY-uhf), developed it.
Professor Lodders collected information gathered by astronomers during the past forty years. Her list represents all the elements as they were about four-and-a-half thousand-million years ago. That is when astronomers believe the planets formed.
Her list gives estimates of the amounts of the elements relative to each other. It includes information about the temperature at which atoms combine and form solid substances. It uses colors to show the nature of the substances that form: metal, rock or sulfide.
Atomic numbers and atomic weights are not on this periodic table. Also missing are the temperatures at which elements melt or boil.
Most of the mass of our solar system is in the sun. So the sun tells us a lot about what the solar system is made of. In recent years, scientists again measured the amounts of oxygen and carbon in the sun. They found that the levels are lower than they thought they were.
Professor Lodders says this means there is less oxygen to form rock and ices. She says the discovery is important to understanding the chemistry of the larger planets, their moons and other icy objects, such as comets.
Professor Lodders says lists have been made before of the amounts of elements present in the solar system. But she says her new Cosmochemical Periodic Table represents the most recent findings.
Leeches are worms that eat the blood of animals and humans. For more than two-thousand years, doctors used leeches to remove blood from patients. They thought it was good for the health. Research in the middle eighteen-hundreds, however, showed no health gain.
Doctors once again use leeches, but this time to help save reconnected fingers, toes, lips and noses. Leeches also have been used to save tissue after breast cancer operations.
Doctors say the value of leeches is in the brown fluid from their mouths. The leeches leave their saliva around the bite wound in the skin. The saliva contains blood thinners to keep blood flowing smoothly. It also contains chemicals that prevent a person from feeling pain.
Now doctors in Germany have tested leeches to stop pain in the knee. Doctors at the University of Duisburg-Essen did the study. The Annals of Internal Medicine published the findings
The study involved fifty-one people with pain from osteoarthritis of the knee. Doctors gave almost half the patients a single treatment with four to six leeches for about one hour. The other patients received a medicine to put on their knee for twenty-eight days to ease the pain. The doctors reported that the people treated with leaches had better movement and less pain.
But the researchers say the treatment does carry the risk of infection. So they hope their work will help lead to a new kind of pain killer for arthritis that does the good of leeches, but without the bites.
A study has demonstrated the lasting influence of experiences early in life, at least in a kind of spider.
Eileen Hebets [HEH-bits] of Cornell University in Ithaca, New York, did the study. She says the findings show that social experience influences choice in mates. She says the study also shows that creatures without backbones, invertebrates, have social recognition.
The Proceedings of the National Academy of Sciences reported her findings. The National Institutes of Health provided money for the study.
The researcher studied wolf spiders because males have different appearances. Some have hair on their front legs. Or their markings might be of different colors. Other kinds of male spiders usually look alike.
The study involved female wolf spiders not yet old enough to mate. Eileen Hebets put them in containers with adult males of different looks. Later, once the females became adults, the highest rate of mating was with males that looked similar to those they had seen before. The females were more likely to attack other males that attempted to mate with them.
Mizz Hebets had painted the legs of the males either black or brown. The longer a female had been left with males painted one of the colors, the more likely she was to eat a male painted with the other. The researcher says the study also demonstrates how females can influence the passing and development of genetic qualities.
SCIENCE IN THE NEWS was written by Mario Ritter, George Grow and Nancy Steinbach. Our producer was Cynthia Kirk. This is Bob Doughty.
And this is Sarah Long. Join us again next week for more news about science, in Special English, on the Voice of America.