Studying the Raw Material of the Sun
This September 8, NASA is set to bring back a tiny sampling of the raw material of the Sun, a sample weighing no more than a few grains of salt.
Image right: Practice recovery of sample return capsule. + Click for full image. Image credit: NASA/JPL.
The solar particles are sealed inside the Genesis
sample return capsule, a disk about the size of a
truck tire, that will drift toward Earth's surface
beneath a parachute.
In labs specially designed to measure small
numbers of atoms, scientists will begin years of
close examination of the particles in search of
new information about how the Sun and its
family of planets came into being.
The sample is composed of the invisible ions
(atoms stripped of many of their electrons) that
flow off the Sun -- making up what's called the
"solar wind." The solar wind streams
constantly throughout our solar system. Like
water flowing around a stone in a river, the
solar wind moves along the outside of the
magnetic fields of Earth and other planets.
Sometimes, we can see an effect produced by
the solar wind in the form of aurora near the
Earth's poles. The glowing curtains of light are
the colorful result of these particles spiraling
into Earth's atmosphere along the magnetic
field lines that dip inward at the poles.
Scientists have long wanted to capture a sample
of particles straight from the Sun. While the
Sun is mostly made up of hydrogen and helium,
there are small amounts of all other elements as
well. The exact composition of the Sun is yet to
be determined, as is an understanding of how
that chemical makeup resulted in the diverse
collection of planets and other bodies in the
For the Genesis scientists, it is crucial that the
particles be pure and unaltered from any
interaction with Earth's magnetic field. To
obtain this pristine sample, a spacecraft had to
be sent deep into space, far beyond the
extensive magnetic environment of Earth.
NASA's Genesis, a robotic spacecraft, was
launched in August 2001 from Cape Canaveral,
Florida. It traveled to an area in space between
Earth and the Sun where the gravity of the two
bodies is balanced. There, it collected solar
wind particles for more than two years from an
area in space far from the interfering effects of
The particles were embedded in specially
designed and manufactured, high-purity wafers
of sapphire, silicon, diamond and other
materials. Now this pure sample of solar
particles is being brought to Earth.
+ For more information see the Frequently Asked Questions page
NASA's Jet Propulsion Laboratory