The Sun gives off more than just light. It also sends out fast bits of material called “charged
.”
Every second, more than 300,000
of this material flows out in all directions from the Sun. We call this outflow the
“
,”
even though it is very different from any wind on Earth. The solar wind impacts everything in the Solar System, including all of the
.
Earth’s magnetic field acts like a
that deflects the solar wind around our planet, and this helps to
life on our home world.
Observations of
(whose long tails extend away from the Sun) first led scientists to suspect that there was a continuous outward flow of stuff from the Sun.
In the early 1960s, a young scientist named Marcia (MAR-shah) Neugebauer (NOY-geh-baa-wur) first measured the solar wind near Venus using an
instrument that was carried on a NASA
called
Mariner 2. This was the first successful mission to another planet.
The solar wind “blows” a giant, bubble-like shape in space we call the
.
The first part of this word relates to the Sun god “Helios” from Greek
.
“Sphere” means an area of activity or interest, like the atmo
sphere or bio
sphere. So “heliosphere” means the area of outer space affected
by the Sun’s activity. The heliosphere extends outward from the Sun more than two times farther than the orbit of the dwarf planet
!
Scientists called
are still debating the shape of this “bubble” around our Solar System, and how it changes as the Sun’s activity changes.
While some NASA missions study the nature of the entire heliosphere, the NASA PUNCH mission studies only the solar wind of the
heliosphere between the Sun and Earth. The NASA Parker Solar Probe mission flies really close to the Sun, just “touching” the solar
,
which is the outer part of the Sun where the solar wind begins.
Only three human-made objects have travelled beyond our heliosphere. All three are NASA spacecraft called
Pioneer 10,
1 and
Voyager 2. They all launched in
.
Decades later they left the region of space influenced by the Sun, and now they travel through the vast space between the stars!