Jupiter Findings
Lowly 2000
the U.S. space agency's Galileo probe suggest that the planet's bulk
composition has not changed since it formed several billion years ago,
scientists said on Monday.
Scientists analysing data from the Galileo probe revised some of the
initial findings they had announced in January, one month after the probe
made a suicidal plunge into Jupiter's hostile atmosphere.
The scientists, who presented the updated findings at a conference in
Houston, also estimated that winds on Jupiter can rage at more than 400
miles (640 km) per hour, higher than their earlier estimates of up to 330
miles (530 km) an hour.
The scientists said they now believe that the ratio of helium to
hydrogen by mass in Jupiter's atmosphere is about 24 percent, similar to
that of the sun. In January, they had estimated the ratio for Jupiter, the
solar system's largest planet, at about 14 percent.
The new ratio between helium and hydrogen, elements that make up 99
percent of Jupiter's atmosphere, suggests Jupiter's bulk composition has
not changed since the planet formed several billion years ago, National
Aeronautics and Space Administration (NASA) scientists said.
``This then confirms that Jupiter is much hotter in its interior than
its neighbour Saturn, the next largest planet in the solar system,''
Galileo probe project scientist Richard Young said. ``It also may force
scientists to revise their projections for the size of the rocky core
believed to exist deep in the centre of Jupiter.''
Jupiter, a giant gas planet, has no surface like Earth's.
The scientists said that several heavy elements including carbon,
nitrogen and sulphur are more abundant on Jupiter than in the sun.
``This implies that the influx of meteorites and other small bodies
into Jupiter over the aeons since its formation has played an important
role in how Jupiter has evolved,'' said Young, a scientist at NASA's Ames
Research Centre near San Francisco.
However, minimal organic compounds were detected suggesting the
chances of finding biological activity on Jupiter similar to that found on
Earth are extremely remote, the scientists said.
Further analysis of probe data has confirmed the preliminary report
that the Jovian atmosphere appears to be relatively dry, they said.
Previous studies had predicted a water abundance for the planet of
twice the solar level, based on the sun's oxygen content. But actual probe
measurements suggest Jupiter's atmosphere contains less water than the
sun.
Galileo, launched from the space shuttle Atlantis in 1989, took six
years to travel to Jupiter. The spacecraft released a probe which entered
Jupiter's atmosphere last December, sending back 57 minutes of data before
disintegrating.
The spacecraft itself is set to continue orbiting Jupiter for the next
two years, sending back more information.
The project has cost about $1.35 billion.
23:31 03-18-96