Blast into 2025: Conquer the Astronomy Challenge – Your Cosmic Adventure Awaits!

The solar wind is primarily composed of a stream of charged particles, predominantly protons, which are the nuclei of hydrogen atoms. These particles are ejected from the Sun's outer layers due to the extremely high temperatures and the dynamic nature of solar activity. As the Sun continually expels this material, it creates a flow of particles, including protons and electrons, that moves radially outward through the solar system.

This continual outflow can influence planetary atmospheres and create phenomena such as auroras when these particles interact with Earth's magnetic field. While the solar wind does contain electrons, the key component of the solar wind is indeed the protons, which constitutes the majority of the particle mass. Thus, the correct understanding centers around the idea that the solar wind is fundamentally a stream of protons moving away from the Sun, which directly aligns with the characteristics of this solar phenomenon.