Student Article
Does Our Solar System Have a Protective Wall?
Heliopause (noun): The boundary where the solar wind meets the wind from other stars.
Solar wind (noun): A stream of particles from the Sun.
Cosmic rays (noun): Energetic particles from space.
Did you know our Solar System has a special boundary that protects us?
Meet the edge: the heliopause
Our Solar System has a special boundary called the heliopause. This is where the solar wind from the Sun meets the wind from other stars. The solar wind is made of tiny particles like protons and electrons. The heliopause is like a bubble that surrounds our Solar System.
How far out is it?
The border is very far from the Sun, about 120 times farther than Earth is. In the other direction, it goes out even farther — at least 350 times the Earth-Sun distance.
Space force field: why it matters
This bubble protects us from harmful cosmic rays that come from space. Cosmic rays are very energetic particles that can be dangerous. The heliopause helps keep most of them away from Earth.
Hot but harmless
NASA's Voyager 1 and Voyager 2 spacecraft have traveled far enough to cross the heliopause. They found that the temperature just outside the heliopause is very high, but the particles are spread out, so it's not like a real wall.
© Dr. Alastair Gunn / Our Media
Heliopause (noun): The boundary where the solar wind meets the wind from other stars.
Solar wind (noun): A stream of particles from the Sun.
Cosmic rays (noun): Energetic particles from space.