The Suns Heliosphere and Heliopause
Explanation:
Where does the Sun's influence end? Nobody is sure.
Out past the orbits of
Neptune and
Pluto
extends a region named the
heliosphere where the
Sun's magnetic field and particles from the
Solar Wind continue to dominate.
The surface where the
Solar Wind drops below
sound speed is called the
termination shock and is depicted as the inner oval in the
above computer-generated illustration.
It is thought that this surface occurs as close as 75-90
AU -- so close that a
Pioneer of
Voyager spacecraft may
soon glide though it as they exit the
Solar System at about 3 AU/year.
The actual contact sheet between the Sun's
ions and the Galaxy's ions is called the
heliopause and is thought to occur at about 110 AU.
It is depicted above as the middle surface.
The Sun's
heliopause moves through the
local interstellar medium
much as a boat moves on water, pushing a
bow shock out in front,
thought to occur near 230 AU.
Authors & editors:
Robert Nemiroff
(MTU) &
Jerry Bonnell
(USRA)
NASA Web Site Statements, Warnings,
and Disclaimers
NASA Official: Jay Norris.
Specific
rights apply.
A service of:
LHEA at
NASA /
GSFC
& Michigan Tech. U.
