Ten newly found moons of Jupiter include
a 'wrong-way driver'
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[July 18, 2018]
By Will Dunham
WASHINGTON (Reuters) - Astronomers on
Tuesday announced the discovery of 10 more moons of Jupiter, bringing to
79 the number known to be circling the giant gas planet, including one
"wrong-way driver" that appears destined to crash into other moons
sharing its orbital highway.
All the newly identified moons are relatively small. While Jupiter, the
fifth planet from the Sun, has large moons such as Ganymede - the
biggest in the solar system with a diameter of 3,273 miles (5,268 km) -
the new ones range in size from about six-tenths of a mile (1 km) to 2.5
miles (4 km). That is tiny compared to Jupiter's diameter of 88,846
miles (142,984 km).
A research team led by astronomer Scott Sheppard of the Carnegie
Institution for Science in Washington has identified 12 small Jovian
moons, including the 10 described on Tuesday. Sheppard said these moons
were probably objects that formed near Jupiter during the early days of
the solar system and were "captured" by the planet's strong
"Jupiter is like a big vacuum cleaner because it's so massive," Sheppard
said. "These objects started orbiting Jupiter, instead of falling into
it. So we think they're intermediate between rocky asteroids and icy
comets. So they're probably half ice and half rock."
The most interesting of the new moons is Valetudo (pronounced
val-eh-TOO-doh), named after the ancient Roman god Jupiter's
great-granddaughter, the goddess of health and hygiene. Valetudo orbits
Jupiter in the same direction that the planet spins, but a bunch of
other small moons share the same orbital path while traveling in the
[to top of second column]
NASA's Juno spacecraft captures Jupiter's southern hemisphere, as
the spacecraft performed its 13th close flyby of Jupiter on May 23,
2018. Picture taken May 23, 2018. NASA/JPL-Caltech/SwRI/MSSS/Kevin
M. Gill/Handout via REUTERS
"Valetudo's going down the highway the wrong way, so it's very
likely it will collide with these other objects. It probably has
collided with them over time," Sheppard said.
Jupiter's 79 known moons are the most of any planet in the solar
system, followed by the 62 identified around the giant ringed gas
planet Saturn. Sheppard said Jupiter and Saturn may actually have a
similar number of moons, with some of Saturn's smaller ones not yet
A moon is defined as any object, regardless of size, that orbits a
planet, not the Sun. Only the two innermost planets in the solar
system, Mercury and Venus, have none. Of Jupiter's 79 moons, 26
remain unnamed, including nine of the 10 new ones.
(Reporting by Will Dunham; Editing by Bernadette Baum)
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