Science News 1999
Bomb-Sniffing Bugs
The U.S. military is studying wasps, to see if they can find bombs, land mines, and biological and chemical weapons.
Nonstinging, parasitic wasps have been used for years to help farmers fight crop-eating pests. When plants are attacked or damaged, they release certain chemicals. Parasitic wasps can sense tiny amounts of these chemicals. The wasps find the bugs and lay eggs on their bodies. When the eggs hatch, the larvae eat the bugs.
The wasps can be trained to follow other smells, like chocolate or explosives. The training is done by exposing wasps to a particular smell while giving them sugar water. Afterwards, they will search for that particular chemical in order to find more sugar water.
The idea of using animals to locate weapons is not new. Bees and cockroaches are also being tested. And of course, bomb-sniffing dogs are commonly used. (7/99)
Weather Forecast: Sunny With Severe Solar Storms
Even if the Y2K computer bug turns out to be harmless, there's another threat just around the corner. Early next year, giant solar storms may disrupt your favorite high-tech gadgets.
The sun is a huge, fiery ball of gas. Energy, produced deep inside by atomic fusion, works its way out to the surface. That surface is not smooth and uniform. Instead, it is very active and constantly changing. The surface of the sun is "bubbly," similar to the bubbles seen in boiling gravy. (This is called solar granulation.) The upper layer vibrates, moving in and out about once every five minutes. There are large, dark patches, called sunspots, which are cooler and less bright than the surrounding areas. And there are magnetic storms and huge explosions, called solar flares.
The number of sunspots and storms changes over time. It reaches a maximum about once every 11 years. The peak of this cycle is expected to occur in January through April, 2000. When the massive bursts of energy reach the Earth, they could cause major problems in everything from power to communications to navigation. There is some good news though. This peak is expected to be less severe than in previous cycles. And, for the first time, a government satellite will detect these energy bursts and give advance notice to power and communication systems operators. (6/99)
Firefighting With Diapers
You never know where you may find the idea for a new invention. Firefighter John Bartlett found inspiration from disposable diapers. While fighting trash fires, he noticed that diapers were one of the few things that did not burn.
Disposable diapers are so absorbent because they contain very long molecules called polymers. These giant polymers act like tiny sponges, soaking up many times their own weight of water. Mr. Bartlett's idea was to use these polymers to fight fires. With help from others, he developed "Barricade Fire-Blocking Gel". When sprayed onto homes and other buildings, the gel protects them from burning for up to 6 days. The gel is nontoxic and, unlike disposable diapers, it is biodegradable. Maybe this good idea will spread faster than a summer wildfire. (5/99)
Sunscreen for Plants
Plants need light. But surprisingly, they can get too much of a good thing. And at least one shade-loving plant makes its own sunscreen to protect against too much light.
Plants collect and store energy from sunlight using a process called photosynthesis. Photosynthesis is a complicated series of reactions. When plants get too much light, some of these reactions actually slow down. Then, unstable, high-energy molecules can build up and damage the leaves.
Scientists have shown that at least one shade-loving plant makes sunscreen to protect itself from too much light. The scientists exposed some leaves of these plants to high-intensity light. They found that other leaves, still in the shade, produced antioxidants. Antioxidants are chemicals which destroy the dangerous molecules and protect the leaves from damage. (This is similar to the way some antioxidant vitamins protect humans.) One part of the plant was able to send a warning, possibly using hydrogen peroxide as the messenger. This allowed the rest of the plant to protect itself from danger. (4/99)
Giant Prehistoric Crocodile
Deinosuchus lived in Texas and Montana about 70 million years ago. It had a skull six and a half feet long, and could easily snap up medium-sized dinosaurs for dinner. This prehistoric crocodile was almost 33 feet long and 11,000 pounds, more than 5 times bigger than the largest crocodiles of today. How did it get so big? Scientists believe that Deinosuchus lived for about 50 years, and continued to grow throughout its life. Other animals generally stop growing when they reach adulthood. (3/99)
Planet Pluto
Pluto is the ninth planet in our Solar System. Or is it?
For the past 20 years, Pluto has actually been closer to the Sun than Neptune has. Pluto's orbit is much more elliptical (or elongated) than the almost circular orbits of the other planets. Because of this, it crossed Neptune's path in 1979. Pluto reached its perihelion (or closest approach to the Sun) in 1989 at a distance of 4.4 billion km (2.7 billion miles.) Neptune's average distance from the Sun is about 4.5 billion km (2.8 billion miles.) On February 11, 1999, Pluto passes back across Neptune's orbit. It is heading outward towards aphelion (its farthest point), a distance of 7.4 billion km (4.6 billion miles) away from the sun. It will be 220 years before Pluto and Neptune cross paths again.
Pluto's orbit is not the only thing unusual about this planet. Pluto is the smallest planet, about 2300 km (1400 miles) in diameter. This is about half the size of Mercury, and smaller than seven moons. Scientists think Pluto has a rocky core surrounded by a thick layer of frozen water and methane. This is very different than the composition of the other outer planets, the gas giants. It is similar to that of many small, frozen objects found outside of Neptune's orbit.
These differences led to rumors that Pluto was about to be demoted. There were suggestions by the International Astronomical Union (IAU) that Pluto would become Minor Planet Number 10,000, or maybe Trans-Neptunium Object Number 1. But it turned out that Pluto has a fan club. There were so many complaints that the idea was dropped. The IAU says that there were never plans to take away Pluto's status as a planet. They were just considering adding to another list, too. (2/99)
Elementary
Russian scientists have reported making a new element in the laboratory - atomic number 114. The last new element, atomic number 112, was found in 1996. (An element's atomic number tells how many protons are in its nucleus.)
Only about 90 different elements occur naturally. The others have been made in laboratories. Many of these heavy man-made elements last only fractions of a second. Then they decay (break down) into lighter atoms. But atomic number 114 is different. It lasted 30 seconds before it decayed. This is 100,000 times longer than atomic number 112. Scientists had predicted that heavy, longer-lived atoms like this would be found.
It took 40 days to produce a single atom of number 114. It was made by bombarding plutonium (atomic number 94) with atoms of calcium (number 20.) Scientists detected the atom of number 114 when it decayed into lighter atoms. Other scientists around the world will now try to repeat the experiment. (2/99)
Once in a Blue Moon - Twice
Once in a blue moon - it's an expression used for something that rarely happens. A blue moon is also the second full moon in a calendar month. This year will have a blue moon. Twice. First in January, and then again in March.
Just how often is "once in a blue moon"? There are about 29 1/2 days between full moons. An average calender month is about 30 1/2 days long. If there is a full moon at the very beginning of a month, it is possible to have a second full moon at the end of that month. On average, once in a blue moon is about every 2 1/2 years. But sometimes there are two blue moons in a single year. When this happens, about 4 times each century, the first blue moon is always in January. The second is usually in March, but may be in April or May. The next year with two blue moons will be 2018.
The phrase "blue moon" has an interesting history and several different meanings. It was used as long ago as the year 1528 to mean that something was impossible or absurd. Later, it was used to describe something that never or rarely happened. Using the phrase "once in a blue moon" to mean the second full moon in a month started much more recently. It has been traced back to a 1943 almanac. But it was not commonly used until it appeared as a question in the game "Trivial Pursuit" in 1986.
Of course, the moon sometimes really does appear blue in color. For example, in 1883, the explosion of the volcano Krakatoa put so much dust into the atmosphere that sunsets appeared green and the moon appeared blue around the world for almost two years. (1/99)
Feeling the Heat
1998 was the hottest year on Earth since 1860, and maybe the warmest in the last 1000 years. According to the World Meteorological Organization (WMO) the global surface temperature was 0.58°C above the average set for 1961-1990. And a separate study by NASA scientists agrees that 1998 was well above the previous temperature record. El Nino, the warm current in the Pacific Ocean, may have contributed to the year's record temperatures. With El Nino now gone, some scientists think that 1999 may cool off slightly from last year's high, but will not return to the 1961-1990 average.
The Earth's surface temperature has increased by almost 0.7°C since the beginning of this century. The 10 warmest years since the mid-1800's, when people began keeping records, have all occurred since 1983. Seven of those 10 occurred since 1990.
Most scientists now believe that human activity is at least partly responsible for the rise in temperature. Burning oil and coal releases gases like carbon dioxide (CO2.) These "greenhouse gasses" trap heat in the atmosphere, which increases the Earth's surface temperature. (1/99)
