Solar flares are massive explosions in the
Sun’s atmosphere. A single “monster” solar
flare could cause up to $2 trillion worth of
damage on Earth, including the loss of satel-
lites and electricity grids. It also poses poten-
tial dangers to human life and health.
However, a new technique published
inNature Physics(tinyurl.com/oykoy8b)
will allow changes in the Sun’s magnetic
fields, which drive the initiation of solar
flares, to be monitored up to ten times faster
than previous methods, allowing for greater
advanced warning of potentially devastating
space storms.
The research team members, who span
universities in Europe, the Asia-Pacific and
the USA, harnessed data from both
NASA’s premier space-based telescope, the
Solar Dynamics Observatory, and theROSA (Rapid Oscillations in the Solar
Atmosphere) multi-camera system at the
National Solar Observatory in New
Mexico.
“Our new techniques demonstrate a
novel way of probing the Sun’s outermost
magnetic fields, providing scientists world-
wide with a new approach to examine, and
ultimately understand, the precursors
responsible for destructive space weather,”
said Dr David Jess of Queen’s University
Belfast.
Prof Damian Christian of California
State University added that understanding
the behaviour of our Sun’s magnetic fields
provides us with crucial information
surrounding the immense energy it
possesses.
The new technique will help facilitatefuture research, including the continual
measurement of magnetic fields in the outer
regions of the Sun’s atmosphere, which is
one of the key goals of the new $300 million
Daniel K. Inouye Solar Telescope. This will
be the largest solar telescope in the world
when construction is finished in 2019 on
the Pacific island of Maui.Every square inch of Saturn’s small moon Enceladus overlies a potentially
habitable ocean. Observations of Enceladus’ slight wobble as it orbits
Saturn can only be explained if the outer crust floats freely from the
inner core, according to scientists studying images taken by NASA’s
Cassini spacecraft. This means there is a globe-spanning ocean beneath
Enceladus’ icy surface.
Enceladus has been a prime location for studying the potential for life
in the solar system since 2006, when Cassini found a fine spray of water
vapour, icy particles and simple organic molecules erupting from
fractures near Enceladus’ south pole.
Measurements of the saltiness of geyser particles in 2009 proved
that they must emanate from a liquid reservoir, and a 2014 analysis of
Enceladus’ gravitational pull on the Cassini spacecraft demonstrated that
the liquid reservoir is at least a regional sea underlying the entire south
pole region.
The new results, derived using an independent line of evidence based
on Cassini’s images, prove that the regional sea is a widening of a global
ocean.
“The global nature of the ocean likely tells us that it has been there
for a long time, and is being maintained by robust global effects,” said
Matthew Tiscareno, a Cassini participating scientist at the SETI Institute.
Enceladus has a tiny wobble as it orbits Saturn. The icy moon is not
perfectly spherical, and because it goes slightly faster and slower during
different parts of its orbit, Saturn pulls and pushes the small moon back
and forth as it rotates.Tiscareno developed a series of dynamic models of this wobble, and
another group then tested each model against hundreds of Cassini
images of Enceladus’ surface at different times and from different
angles.
“If the surface and core were rigidly connected, the core would
provide so much dead weight that the wobble would be far smaller than
we observe it to be,” said Tiscareno. “This proves that there must be a
global layer of liquid separating the surface from the core,” he said.
The geysers deliver samples from this ocean to the surface regularly,
which makes Enceladus a prime candidate in the search for life beyond
Earth. Enceladus joins only Jupiter’s moon Europa in having an
extraterrestrial ocean that is known to communicate with its surface.JAN/FEB 2016|| 45David Reneke is an astronomy lecturer and teacher, a feature writer for major Australian newspapers and magazines, and a science correspondent for ABC and commercial radio.
Subscribe to David’s free Astro-Space newsletter at http://www.davidreneke.com
OUT OF THIS WORLD David Reneke
Saturn’s Moon Enceladus
Hosts a Global OceanA Milestone in Predicting Solar Flares
Illustration of the interior of Saturn’s moon Enceladus, showing a
global liquid water ocean between its rocky core and icy crust.
Credit: NASA/JPL-CaltechHuge solar flares could easily cause
trillions of dollars worth of damage to
Earth’s power and communications
systems. Credit: Gizmodo UK