Here's why:
* Extremely low density: The space between the Earth and the Sun is incredibly sparse, with far fewer particles than even the best vacuums we can create on Earth. There are a few atoms per cubic centimeter on average.
* Solar wind: The Sun constantly emits a stream of charged particles called the solar wind. This wind does contribute to the very low density of particles in interplanetary space.
* Dust and debris: There are also tiny particles of dust and debris from comets, asteroids, and other celestial objects. These particles are very thinly dispersed.
* Cosmic rays: High-energy particles from deep space also travel through interplanetary space.
So, while not a perfect vacuum, the space between the Earth and the Sun is incredibly close to it. It's essentially a vast expanse with very little matter present.
