The Sun’s astrosphere is composed of several layers that include the heliosphere, heliosheath, heliopause and the termination shock. Heliosphere can be thought of as a bubble in space surrounding the sun. It shields and helps protect the earth from harmful intergalactic radiation. These radiations can destroy DNA and can make climate not suitable for existence. Without the heliosphere life on Earth would be impossible.

At the boundary of the heliosphere is the heliopause. This is supposed to be about 10 billion miles from the Sun. Its real distance though has not been exactly determined because it varies with the velocity of solar wind and the density of interstellar medium. The heliopause separates the solar system from other interstellar space. It is in this part of the Solar system that the charged particles from the Sun bump into the particles from other stars.

Inside the heliopause is the so-called termination shock. Due to the effect of particles from other stars, the solar wind in this region is slower than the speed of sound. The effect of these particles can cause some changes in the magnetic field, heating and compression. Finally, Heliosheath refers to the region between the heliopause and the termination shock.