If you think chaos is
complicated in the case of simple objects (such as our inability to
predict the longterm velocities and positions of planets owing to
their nonlinear interactions with the sun and other planets) it's
far worse for
systems with essentially an infinite number of degrees of freedom
such as fluids or plasmas under the stress of nonlinear forces.
Then the word turbulence is fully justified.
Turbulence can be
studied on Earth easily by mapping such things as the density or
velocity of fluids in a tank. In space, however, where we expect
turbulence to occur in such settings as solar wind, interstellar
space, and the accretion disks around black holes, it's not so easy
to measure fluids in time and space. Now, a suite of four
plasma-watching satellites, referred to as Cluster, has provided the
first definitive study of turbulence in space.
The fluid in
question is the wind of particles streaming toward the Earth from
the sun, while the location in question is the region
just upstream of Earth's bow shock, the place where the solar wind
gets disturbed and passes by the Earth's magnetosphere (see figure
at Physics News Graphics). The waves in the
shock-upstream plasma, pushed around by complex magnetic fields, are
observed to behave a lot like fluid turbulence on Earth.
One of the
Cluster researchers, Yasuhito Narita (firstname.lastname@example.org) of the
Institute of Geophysics and Extraterrestrial Physics in
Braunschweig, Germany, says that the data is primarily in accord
with the leading theory of fluid turbulence, the so called
Narita et al., Physical Review Letters, 10
Contact Yasuhito Narita
Institute of Geophysics and Extraterrestrial Physics