Re: The Great Oliver Richman Magnetic Field Detection Test - was Gravity is not a force which acts on objects at a distance.

I wonder if Ollie felt this baby...

A Giant Breach in Earth's Magnetic Field
12.16.2008


Dec. 16, 2008: NASA's five THEMIS spacecraft have discovered a breach
in Earth's magnetic field ten times larger than anything previously
thought to exist. Solar wind can flow in through the opening to "load
up" the magnetosphere for powerful geomagnetic storms. But the breach
itself is not the biggest surprise. Researchers are even more amazed
at the strange and unexpected way it forms, overturning long-held
ideas of space physics.

"At first I didn't believe it," says THEMIS project scientist David
Sibeck of the Goddard Space Flight Center. "This finding fundamentally
alters our understanding of the solar wind-magnetosphere interaction."

The magnetosphere is a bubble of magnetism that surrounds Earth and
protects us from solar wind. Exploring the bubble is a key goal of the
THEMIS mission, launched in February 2007. The big discovery came on
June 3, 2007, when the five probes serendipitously flew through the
breach just as it was opening. Onboard sensors recorded a torrent of
solar wind particles streaming into the magnetosphere, signaling an
event of unexpected size and importance.

Right: One of the THEMIS probes exploring the space around Earth, an
artist's concept. [more]

"The opening was huge?four times wider than Earth itself," says Wenhui
Li, a space physicist at the University of New Hampshire who has been
analyzing the data. Li's colleague Jimmy Raeder, also of New
Hampshire, says "1027 particles per second were flowing into the
magnetosphere?that's a 1 followed by 27 zeros. This kind of influx is
an order of magnitude greater than what we thought was possible."

The event began with little warning when a gentle gust of solar wind
delivered a bundle of magnetic fields from the Sun to Earth. Like an
octopus wrapping its tentacles around a big clam, solar magnetic
fields draped themselves around the magnetosphere and cracked it open.
The cracking was accomplished by means of a process called "magnetic
reconnection." High above Earth's poles, solar and terrestrial
magnetic fields linked up (reconnected) to form conduits for solar
wind. Conduits over the Arctic and Antarctic quickly expanded; within
minutes they overlapped over Earth's equator to create the biggest
magnetic breach ever recorded by Earth-orbiting spacecraft.

Above: A computer model of solar wind flowing around Earth's magnetic
field on June 3, 2007. Background colors represent solar wind density;
red is high density, blue is low. Solid black lines trace the outer
boundaries of Earth's magnetic field. Note the layer of relatively
dense material beneath the tips of the white arrows; that is solar
wind entering Earth's magnetic field through the breach. Credit: Jimmy
Raeder/UNH. [larger image]

The size of the breach took researchers by surprise. "We've seen
things like this before," says Raeder, "but never on such a large
scale. The entire day-side of the magnetosphere was open to the solar
wind."

The circumstances were even more surprising. Space physicists have
long believed that holes in Earth's magnetosphere open only in
response to solar magnetic fields that point south. The great breach
of June 2007, however, opened in response to a solar magnetic field
that pointed north.

"To the lay person, this may sound like a quibble, but to a space
physicist, it is almost seismic," says Sibeck. "When I tell my
colleagues, most react with skepticism, as if I'm trying to convince
them that the sun rises in the west."


Sign up for EXPRESS SCIENCE NEWS delivery
Here is why they can't believe their ears: The solar wind presses
against Earth's magnetosphere almost directly above the equator where
our planet's magnetic field points north. Suppose a bundle of solar
magnetism comes along, and it points north, too. The two fields should
reinforce one another, strengthening Earth's magnetic defenses and
slamming the door shut on the solar wind. In the language of space
physics, a north-pointing solar magnetic field is called a "northern
IMF" and it is synonymous with shields up!

"So, you can imagine our surprise when a northern IMF came along and
shields went down instead," says Sibeck. "This completely overturns
our understanding of things."

Northern IMF events don't actually trigger geomagnetic storms, notes
Raeder, but they do set the stage for storms by loading the
magnetosphere with plasma. A loaded magnetosphere is primed for
auroras, power outages, and other disturbances that can result when,
say, a CME (coronal mass ejection) hits.

The years ahead could be especially lively. Raeder explains: "We're
entering Solar Cycle 24. For reasons not fully understood, CMEs in
even-numbered solar cycles (like 24) tend to hit Earth with a leading
edge that is magnetized north. Such a CME should open a breach and
load the magnetosphere with plasma just before the storm gets
underway. It's the perfect sequence for a really big event."

Sibeck agrees. "This could result in stronger geomagnetic storms than
we have seen in many years."

A video version of this story may be found here. For more information
about the THEMIS mission, visit http://nasa.gov/themis

SEND THIS STORY TO A FRIEND

Author: Dr. Tony Phillips | Credit: Science@NASA
.

Relevant Pages

  • Re: Holes in Earchs magnetic cloak let the sun in
    ... two large holes that are letting in disruptive solar winds, ... Scientists at the American Geophysical Union meeting in San Francisco ... the storms were entering the Earth's magnetosphere. ... magnetic field was aligned opposite to that of the Earth's. ...
    (soc.retirement)
  • Re: gps after nagnetic field loss?
    ... GPS satellites are at 4 earth radii. ... The magnetosphere of Earth is a region in space whose shape is primarily ... solar wind plasma and the interplanetary magnetic field. ... Without the magnetic field, this alpha radiation would ...
    (sci.geo.satellite-nav)
  • A Giant Breach in Earths Magnetic Field
    ... A Giant Breach in Earth's Magnetic Field ... Earth's magnetic field ten times larger than anything previously ... Solar wind can flow in through the opening to "load up" the ... magnetosphere for powerful geomagnetic storms. ...
    (sci.space.news)
  • Re: Mushield box
    ... >> made mushield box would be preferable. ... > to blank most of the ambient magnetic field. ... A magnetic shield for weak fields is ... they go beyond the magnetosphere which extends tens of ...
    (sci.physics)
  • Cluster opens a new window on magnetic reconnection in the near-Earth space (Forwarded)
    ... Cluster opens a new window on 'magnetic reconnection' in the near-Earth ... the Earth's magnetic field. ... The Earth's magnetic field creates a buffer zone, the magnetosphere, ...
    (sci.astro)
Loading