The Solar System is truly vast from our perspective, and yet has a boundary. You may wonder where exactly is the boundary of the Solar System. The answer may lie in a gigantic bubble blown by the Sun, known as the heliosphere.

The Sun emits a constant stream of charged particles called the solar wind. The solar wind blows against the interstellar medium (mostly neutral gases and dusts) along its path and clears out a bubble-like region surrounding the Sun and the Solar System, and is called the heliosphere. The solar wind flows unimpeded through the Solar System far beyond even the region of Pluto until its motion slows abruptly by the outside pressure of the interstellar medium in "termination shock". The solar wind continues to slow as it passes through the "heliosheath". Going further, the solar wind arrives at the edge of the heliosphere, or "heliopause", and is halted by the pressure from interstellar gas. Beyond the heliopause is interstellar space. This bubble blown by the Sun acts as a shield against some harmful cosmic radiation, protecting the lives on Earth!

It is perhaps difficult to imagine how the heliosphere is formed, but with some daily necessities you may simulate it yourself at home. Please stay tuned!

Image credit: NASA/IBEX/Adler Planetarium