As the Voyager space probes continue their journey out of the solar system, they approach a region called the Local Interstellar Cloud, more commonly known as “local fluff.”
The 30 light year-wide cloud consists of helium and hydrogen atoms. Scientists believe the fluff is located within a large gaseous region created by supernova explosions, which occurred about 10 million years ago.
As Merav Opher and colleagues described in the December 24 issue of Nature, the local fluff is able to survive due to its stronger than expected magnetization. The magnetic field present within the cloud compliments its lack of exceedingly high temperatures, therefore providing the necessary pressure to counter the crushing force of the supernova’s remains, and avoid obliteration.
The local fluff is positioned at the edge of the solar system, and is held in place by the sun’s magnetic field, which, in combination with the solar wind, creates a protective bubble around the solar system called the heliosphere. The heliosphere serves as the solar system’s armour against interstellar clouds like the local fluff, as well as cosmic rays.
The pressure the local fluff exerts is not only capable of resisting destruction by the supernova exhaust, but it also exerts pressure and condenses the heliosphere itself. Although the solar wind — a stream of charged particles ejected from the sun — helps expand the magnetic bubble, the discovery of the local fluff’s magnetization signifies that other local interstellar clouds may also possess this characteristic, which could result in further compression of the heliosphere.
While it would take hundreds of thousands of years for our solar system to switch to a new local interstellar cloud, if we were to entertain the idea and hypothesize the events, further compression of the heliosphere could allow cosmic rays to enter within the solar system, changing terrestrial climate, while also reducing the distance between Earth and interstellar space.
Although the presence of the local interstellar cloud is a relatively recent discovery, next week we will analyze a star that has been studied for many years, and like our Sun, is also present within the local fluff. Until then, splendid space expeditions await.
