What is the Heliosphere?
The heliosphere is a large bubble in space created by the solar wind from the Sun. At the fringes of the heliosphere, the solar wind collides with gases from the interstellar medium and stops being the dominant space weather. The heliosphere is huge — its closest boundary is about 100 AU (astronomical units, or Earth-Sun distances) away, while its farthest boundary its 200-300 AU distant. The heliosphere is shaped elliptically, like the tail of a comet, because of the Sun’s fast motion through the interstellar medium as it orbits the galactic center. As stated, the cause of the heliosphere is the solar wind. The solar wind is a continuous stream of charged particles, mostly free electrons and protons, which flow from the Sun at a velocity of 400 to 700 km/s (about 1,000,000 mph). This works out to 6.7 billion tons per hour, or a mass equal to the Earth every 150 million years. While this sounds like a lot, it is actually very diffuse due to the vastness of space. Besides the solar win
