A peek inside Jupiter
Galileo probe yields some secrets
May 22, 1996
Web posted at: 1 a.m. EDT
WASHINGTON (CNN) -- Data from the probe dropped into Jupiter's atmosphere by the spacecraft Galileo reveal surprising information about the planet's weather and evolution, NASA scientists said Tuesday. But the wealth of new information solved few of the planet's mysteries, and, in fact, gave rise to some new ones.
For an hour as it fell last December, the probe monitored Jupiter's winds, composition, water content, temperature and pressure, radiation and lightning.
Scenes through the eyes of the probe
(731K QuickTime movie)
Scientists say they have found out more about how Jupiter first formed and how it has evolved over the last 4.5 billion years. They said they were surprised by some of the information fed back about the planet:
- There is only one cloud layer, not multiple cloud layers. The cloud is made up of ammonium.
- The composition of the atmosphere has been affected by the impact of many asteroids and meteors. Scientists think the Earth's makeup in its early history was also greatly affected by such bombardments.
- The winds of Jupiter extend deep into the atmosphere -- from the planet's cloud-tops to 10,000 miles (16,000 kilometers) below its gassy, roiling surface. They blow at around 400 miles an hour, twice as fast as a tornado.
"The fact that the winds go all the way down means that it's the heat from the interior of Jupiter that's driving the wind," said Richard Young, a NASA scientist based at Ames Research Center in Mountain View, California.
The prevailing winds are so regular they may be responsible for the colored bands clearly visible through Earth-based telescopes, he said.
Roughly analogous to the jet stream, the major weather-maker on Earth, the winds of Jupiter are straighter, with fewer latitudinal dips and wiggles, creating weather patterns that last for centuries, Young said.
Why so little water?
One puzzle is why there is so little water on Jupiter. Probe data showed miniscule amounts, about a 10th of what was expected. If Jupiter formed the same way Earth and the other planets did, from a primitive blob of gas and dust, there should be more.
One theory holds that Jupiter formed around a dense, rocky core about 10 times the size of Earth, leaving water locked in the planet's heart. Doubters wonder why water stayed behind while gases moved out to the atmosphere.
The Galileo probe's data confirmed what many scientists have long believed: Jupiter would not be hospitable to Earth-type life forms. "We didn't see anything that would indicate that there was any kind of biology going on Jupiter," Young said.
What's next for Galileo
As the Galileo orbiter circles Jupiter for the next two years, one focus will be on Europa, a Jovian moon about the size of Earth's moon.
Europa is covered with a thick ice crust, but some scientists believe there may be liquid water beneath the ice. And where there is liquid water, there might be life.
Reuters contributed to this report.
- Galileo provides surprises about Jupiter - January 23, 1996
- Galileo probe of Jupiter reveals surprising data - January 22, 1996
- Galileo finally comes through for NASA - December 8, 1995
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