Scientists say water volcanoes may exist on Ganymede

By Hemesh Patel
Daily Bruin Staff

On Earth, new land is formed by volcanoes spewing deadly molten
lava onto the surface, but in other areas of the solar system, this
lava is made of liquid water ““ warm enough for humans to
touch.

Scientists at UCLA and NASA suspect that such volcanoes were
partly responsible for creating the land surface of Ganymede,
Jupiter’s largest moon.

Jeff Moore, a planetary geologist for NASA, Paul Schenk of the
Lunar and Planetary Institute in Houston, Texas, and David Gwynn, a
second-year graduate student in geography at UCLA authored the
report, which is published in this month’s issue of
Nature.

Gwynn could not be reached for comment because he is on a leave
of absence.

Scientists suspect that volcanoes erupted on the icy moon, which
has a temperature below 200 degrees Fahrenheit.

“In Ganymede’s case, lava does erupt, but it is
water,” Moore said.

Compared to liquid magma on Earth, which can reach temperatures
above 1,200 degrees Fahrenheit, the water lava in Ganymede would
have been just above freezing.

Using recent photographs taken by the Galileo satellite and
previous snapshots from the late ’70s taken by the Voyager
satellite, the group hypothesized that liquid water was present on
the surface as early as 1 billion years ago.

The photographs were put together to produce three-dimensional
topographic images of the moon’s surface.

Researchers noted in the report that two distinct types of land
surface exist on the moon ““ one type is bright and flat and
the other is dark and rugged.

According to the report, one stretch of flat terrain was found
to extend about 900 kilometers ““ about the distance from St.
Louis to New Orleans.

The findings proposed that volcanic activity on the icy moon may
have produced the bright and flat terrain.

Moore compared the two land types to fresh and dirty snow.

The dark terrain is older, allowing more dirt to settle into it,
whereas the bright terrain is younger and may have been formed by
water lava, which is cleaner, he said.

This idea is one of two major theories explaining the land types
on the moon.

“It is not clear whether this is caused by volcanoes or by
tectonic motion,” said Margaret Kivelson, UCLA professor of
space physics.

She said the competing theory suggests that the ice broke apart
by earthquake-like motions, allowing something to push up, creating
a flat surface.

That “something” may be water, according to
Kivelson’s research which indicates that something is flowing
underneath the surface of this moon.

“It is not clear whether or not it is water or ice,
because ice is able to drift,” she said.

Krishnan Khurana, a research geophysicist who works with
Kivelson, said strong evidence points toward a salty ocean beneath
the icy layer of Ganymede’s surface.

The understanding of Ganymede and other planets in the solar
system is becoming more and more clear each day.

“In the late ’70s, people used to think the bright
areas on the moon were 3 1/2 billion years old, but now we think
they are as young as 1 billion years old,” Moore said.

This amount of time makes up the last quarter of the solar
system’s history.

Even though there seems to be a source of heat, keeping the ice
molten, scientists say they do not have enough information to
speculate whether or not there are signs of life on Jupiter’s
largest moon.

“Liquid water is the building block of life,”
Khurana said. “But life would also require many other
chemicals.”