This is SCIENCE IN THE NEWS in VOA Special
English. I'm Steve Ember.
I'm Shirley Griffith. This week, we will
tell about evidence that something big struck the planet Jupiter. We will also tell about a long ignored organ
in the body. And we will tell how
scientists are using lobsters to help protect the sea environment.
Space discoveries are usually made by scientists whose
job is to study astronomy. After all,
they observe the skies with huge ground-based and costly space telescopes. But last month, a computer programmer from Australia
made an exciting discovery of an unusual event in Earth's solar system.
Wesley found an unusual dark marking in Jupiter's atmosphere using his amateur telescope. Operators of the Hubble Space Telescope said
the dark spot is about two times the length of the United States. Scientists believe it is evidence that a
large object struck Jupiter, cutting a hole in the atmosphere of the huge,
Wesley saw the spot near Jupiter's extreme south on July nineteenth. At first, he thought it was the shadow of one
of Jupiter's four big moons. He captured
images of the spot and studied a picture that he had taken earlier of the same
area on Jupiter.
Mister Wesley was sure he had found something new, he quickly contacted professional
astronomers about his find. Leigh
Fletcher and Glenn Orton were among the first people he told of the discovery. They work for the American space agency's Jet
Propulsion Laboratory in California.
The Americans had planned to use the Infrared Telescope
Facility on top of Hawaii's Mauna Kea volcano the following night. When they used the telescope to create images
of the planet, they found an area that appeared dark in light the human eye
could see. But using infrared light, the
spot appeared bright. That is because
the force of the object hitting Jupiter pushed very reflective particles high
into the planet's atmosphere.
may never know exactly what struck Jupiter. The incident probably took place within a day or two of Mister Wesley's
observation. But scientists think it was
either a comet or rock from space.
Reports of solar system objects
striking each other are extremely rare. But
astronomers have seen a similar collision. It took place exactly fifteen years ago. Comet Shoemaker-Levy Nine broke up and struck
that event, astronomers were able to observe the icy comet long before it
struck the solar system's biggest planet. But the object that struck Jupiter in July is estimated to have been
much smaller and harder to see than comet Shoemaker-Levy. Astronomers say it was probably less than one
kilometer in size -- too small to see from Earth.
most recent collision with Jupiter brought attention to how the huge planet's
gravity affects our solar system. Some
scientists have called Jupiter the protector of the inner planets -- and our
own Earth -- from objects from the outer solar system. But others note that Jupiter's powerful
gravitational field can just as easily send an object into Earth's path as push
it deeper into space.
Marchis is an astronomer with the University of California at Berkeley. He says the surprise collision clearly
justifies the need for programs that search the skies for small space objects
that could threaten earth.
The spleen was once known in western literature as an
organ that caused a person to be sleepless and sad. For example, in his poem "Spleen," the
nineteenth century French writer Charles Baudelaire describes a cheerless world
where nothing is beautiful.
For years, the duties of the
spleen were generally not considered very important. In fact, a person whose spleen has been
damaged can survive without it. People
who suffer severe physical injuries can burst their spleen and have it removed
The human spleen is an organ about the
size of a closed hand. It is above the
stomach, under the ribs on a person's left side. The spleen is part of the body's lymphatic
system. This system fights infection and
helps keep the body's fluids in balance.
recent report shows that the small organ has a much more important job in the
body's defense system than once believed. Researchers at Massachusetts General Hospital and Harvard Medical School
wrote the report. It shows that the
spleen stores huge numbers of white blood cells called monocytes.
Masses of these monocytes leave the spleen in the event
of an injury like a heart attack, wound, or infection. They gather in the damaged tissue and help it
Nahrendorf helped to write the report in Science magazine. He describes the monocytes in terms of
military language. He says they are like
a standing army that you only deploy in times of crisis.
have long known that bone marrow produces and contains monocytes. But the writers of the report knew that the
number of monocytes in the blood stream was too low to explain the millions of
them present after an injury to the heart. They discovered that the additional monocytes were coming from the
researchers used mice to carry out an experiment. They studied what areas of the spleen store
the monocytes. And they gave the mice
heart attacks to study the deployment of monocytes from the spleen.
information about the spleen brings new meaning to a report published in
nineteen seventy-seven. At that time,
researchers studied more than seven hundred American soldiers who had had their
spleens removed because of battle injuries. They also studied a similar sized group of soldiers who had suffered
injuries but kept their spleens. The
soldiers without spleens were two times as likely to die of heart disease as
the soldiers who still had their spleens.
is a form of large, brown seaweed. It
grows in watery forests in a number of areas.
Kelp forests provide a protected home and food for many
kinds of sea life. Scientists once
thought that these forests existed only in moderate and cold climates. Two years ago, however, they were also found
in warm ocean waters near Ecuador.
kelp forests is usually a welcome discovery. Some economies depend on fishing for lobsters, rockfish or other
creatures that need the forests. People
harvest kelp to get alginic acid. The
substance is used in toothpaste and medicine for stomach problems. And people active in water-sports like to
dive and row boats in kelp forests.
However, a small, colorful creature
called the long-spined sea urchin is destroying kelp in some areas. The urchin is shaped like a ball. It also has sharp, finger-like spines.
example, urchins are ruining coral reefs in waters near Australia. Scientists at the University of Tasmania say
the urchins are wrecking areas in which many fish and shellfish grow. The scientists say abalone and lobsters are
among the urchins' victims.
the lobsters are fighting back. The scientists
say seven hundred fifty large rock lobsters were released a year ago in waters
near Tasmania's northeast coast. University of Tasmania scientist Scott Ling says there is evidence that
they have been eating the sea urchins.
lobsters are being placed in waters that scientists consider at high risk in
Tasmania's southeast. Mister Ling says
the hope is that they will prevent further development of sea urchins.
The lobsters are identified with markers and colored
dye so fishermen will not catch them. And the fishermen are said to be cooperating.
The American state of California is another area where
long-spined sea urchins have been destroying kelp forests. Southern California has lost ninety percent
of its watery forests since the nineteen sixties. The state has employed divers to remove
urchins along its southern coast. They
are being moved to a new home about one and one half kilometers away. The job is not easy. Currents are strong and the creatures
sometimes cut the skin of the divers.
the diving team has been doing its work two times a week. On one recent day, one thousand five hundred
sea urchins got a new home in deeper water. And many kelp forests now have a more secure future.
This SCIENCE IN THE NEWS was written by Dana Demange,
Mario Ritter and Jerilyn Watson. Our
producer was Brianna Blake. I'm Shirley
And I'm Steve Ember. Listen again next week for more news about
science in Special English on the Voice of America.