January 29, 2001
This image taken on Jan. 4 and 5, 2001, by the Ion and Neutral Camera (INCA) which is part of the Magnetospheric Imaging Instrument (MIMI) on NASA's Cassini spacecraft, makes the huge magnetosphere surrounding Jupiter visible in a way no instrument on any previous spacecraft has been able to do. The magnetosphere is a bubble of charged particles trapped within the magnetic environment of the planet.
For higher resolution image, click here.
In this picture, a magnetic field is sketched over the image to place the
energetic neutral atom emissions in perspective. This sketch extends in
the horizontal plane to a width 30 times the radius of Jupiter. Also shown
for scale and location are the disk of Jupiter (black circle) and the
approximate position (yellow circles) of the doughnut-shaped torus created
from material spewed out by volcanoes on Io, one of Jupiter's large moons.
Some of the fast-moving ions within the magnetosphere pick up electrons to
become neutral atoms, and once they become neutral, they can escape
Jupiter's magnetic field, flying out from the magnetosphere at speeds of
thousands of kilometers, or miles, per
second. Cassini's instrument for imaging the magnetosphere builds an image
from these atoms reaching the spacecraft, analagous to the way a normal
camera builds an image from photons.
Image Credit: NASA/JPL/ Johns Hopkins University Applied Physics
Additional information about Cassini-Huygens is online at http://saturn.jpl.nasa.gov.
Cassini is a cooperative project of NASA, the European Space Agency and
the Italian Space Agency. JPL manages the Cassini and Galileo missions for
NASA's Office of Space Science, Washington, D.C. JPL is a division of the
California Institute of Technology in Pasadena.