Ever since Stargate, a favorite
theme of science fiction is "the portal"--an extraordinary opening in
space or time that connects travelers to distant realms. A good portal is a stable (won’t collapse
unexpectedly) shortcut, a guide, a door into the unknown. If only they actually
existed....
Well according to a NASA-funded
researcher at the University of Iowa, they sort of do exist. While he calls them x points, others choose a more descriptive name.
"It's called a flux transfer
event or 'FTE,'" says space physicist David Sibeck of the Goddard Space
Flight Center. "Ten years ago I was pretty sure they didn't exist, but now
the evidence is incontrovertible."
Indeed, today Sibeck is telling an
international assembly of space physicists at the 2008 Plasma Workshop in
Huntsville, Alabama, that FTEs are not just common, but possibly twice as
common as anyone had ever imagined.
Researchers have long known that
the Earth and sun must be connected. Earth's magnetosphere (the magnetic bubble
that surrounds our planet) is filled with particles from the sun that arrive
via the solar wind and penetrate the planet's magnetic defenses. They enter by
following magnetic field lines that can be traced from terra firma all the way
back to the sun's atmosphere.
"We used to think the
connection was permanent and that solar wind could trickle into the near-Earth
environment anytime the wind was active," says Sibeck. "We were
wrong. The connections are not steady at all. They are often brief, bursty and
very dynamic."
Several speakers at the Workshop
have outlined how FTEs form: On the dayside of Earth (the side closest to the
sun), Earth's magnetic field presses against the sun's magnetic field.
Approximately every eight minutes, the two fields briefly merge or
"reconnect," forming a portal through which particles can flow. The
portal takes the form of a magnetic cylinder about as wide as Earth. The
European Space Agency's fleet of four Cluster spacecraft and NASA's five THEMIS
probes have flown through and surrounded these cylinders, measuring their
dimensions and sensing the particles that shoot through. "They're real,"
says Sibeck.
Now that Cluster and THEMIS have
directly sampled FTEs, theorists can use those
measurements to simulate FTEs in their computers and predict how they might behave. Space physicist Jimmy Raeder of the University of New Hampshire presented one such simulation at the Workshop. He told his colleagues that the cylindrical portals tend to form above Earth's equator and then roll over Earth's winter pole. In December, FTEs roll over the north pole; in July they roll over the south pole.
measurements to simulate FTEs in their computers and predict how they might behave. Space physicist Jimmy Raeder of the University of New Hampshire presented one such simulation at the Workshop. He told his colleagues that the cylindrical portals tend to form above Earth's equator and then roll over Earth's winter pole. In December, FTEs roll over the north pole; in July they roll over the south pole.
Sibeck believes this is happening
twice as often as previously thought. "I think there are two varieties of
FTEs: active and passive." Active FTEs are magnetic cylinders that allow
particles to flow through rather easily; they are important conduits of energy
for Earth's magnetosphere. Passive FTEs are magnetic cylinders that offer more
resistance; their internal structure does not admit such an easy flow of
particles and fields. (For experts: Active FTEs form at equatorial latitudes
when the IMF tips south; passive FTEs form at higher latitudes when the IMF
tips north.) Sibeck has calculated the properties of passive FTEs and he is
encouraging his colleagues to hunt for signs of them in data from THEMIS and
Cluster. "Passive FTEs may not be very important, but until we know more
about them we can't be sure."
Observations by NASA's THEMIS spacecraft and Europe's Cluster probes suggest that these magnetic portals open and close dozens of times each day. They're typically located a few tens of thousands of kilometers from Earth where the geomagnetic field meets the onrushing solar wind. Most portals are small and short-lived; others are yawning, vast, and sustained. Tons of energetic particles can flow through the openings, heating Earth's upper atmosphere, sparking geomagnetic storms, and igniting bright polar auroras.
NASA is planning a mission called "MMS," short for Magnetospheric Multiscale Mission, due to launch in 2014, to study the phenomenon. Bristling with energetic particle detectors and magnetic sensors, the four spacecraft of MMS will spread out in Earth's magnetosphere and surround the portals to observe how they work.
NASA is planning a mission called "MMS," short for Magnetospheric Multiscale Mission, due to launch in 2014, to study the phenomenon. Bristling with energetic particle detectors and magnetic sensors, the four spacecraft of MMS will spread out in Earth's magnetosphere and surround the portals to observe how they work.
Just one problem: Finding them.
Magnetic portals are invisible, unstable, and elusive. They open and close
without warning "and there are no signposts to guide us in," notes
Scudder.
"In the late 1990s, NASA's
Polar spacecraft spent years in Earth's magnetosphere," explains Scudder,
"and it encountered many X-points during its mission."
Data
from NASA's Polar spacecraft, circa 1998, provided crucial clues to finding
magnetic X-points.
Image
Credit:
NASA
Because Polar carried sensors
similar to those of MMS, Scudder decided to see how an X-point looked to Polar.
"Using Polar data, we have found five simple combinations of magnetic
field and energetic particle measurements that tell us when we've come across
an X-point or an electron diffusion region. A single spacecraft, properly
instrumented, can make these measurements."
This means that single member of
the MMS constellation using the diagnostics can find a portal and alert other
members of the constellation. Mission planners long thought that MMS might have
to spend a year or so learning to find portals before it could study them.
Scudder's work short cuts the process, allowing MMS to get to work without
delay.
It's a shortcut worthy of the best
portals of fiction, only this time the portals are real. And with the new
"signposts" we know how to find them.
Meanwhile, high above your head, a new portal is opening, connecting your planet to the sun.
So “Once more unto the breach, dear friends, once more;”
Source(s):
So “Once more unto the breach, dear friends, once more;”
____________________________________________________________
About Rick Ricker
An IT professional with over 21 years experience in Information Security, wireless broadband, network and Infrastructure design, development, and support.
For more information, contact Rick at (800) 399-6085 x502
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