We all might be aware of the cover provided by the earth’s magnetic field which protects us from many cosmic rays and also acts as a cover from the solar wind which is very ironic. We also may be aware of the beautiful phenomenon caused by this effect called Aurora Borealis. In this article we discuss about the magnetic wrap created by a mentor on solar system-The Sun, and also some of the discoveries relating to it.
The magnetic bubble created due to the sun’s activity where the children of sun orbit it peacefully is termed as Heliosphere. Studies were made on this sphere and its boundaries over the last decade. It is found that the boundary is not smooth and it seems that they shrink and stretch over the years. IBEX (Interstellar Boundary Explorer) is a small explorer microsatellite and a technology demonstration mission of NASA. It aims to study the interstellar boundary which is the region between our solar system and interstellar space.
Before we get into the discovery made, we could discuss about the solar cycles which lasts roughly 11 years as the sun swings from seasons of high to low activity. It is mainly because the sun flips its North and South magnetic poles in a cycle where in 11 years a shift will occur which causes the expel of higher active solar wind and the heliosphere expands like a balloon. It helps us to discover the boundary where these solar wind particles meet with the interstellar winds.
The solar wind as soon as leaving the sun’s atmosphere rushes out in all directions with tremendous velocity and hits the interstellar medium. Along the way, the solar wind picks up ionized atoms of interstellar gases they have wriggled into the heliosphere. Solar wind particle rove around for another six months and some collide with interstellar gases and become energetic neutral atoms (ENA) and some of them travel back to the earth and thus make it to IBEX’s range. Since the particles are neutral, they follow a straight direction. IBEX uses a process pretty similar to sonar. It notes their direction and energy. It only detects one ENA every second and maps the interstellar boundary.
Now, for the first time we have an entire solar cycle data from IBEX. The results show the shifting outer heliosphere in great detail. Starting in 2014, there was a huge and prolonged increase in solar wind pressure, which is around 50% harder than the previous years. They travel outward for a year and hit the edge of the heliosphere. After roving there for another year some become ENA (Energetic Neutral Atoms) and some travelled back to the earth. Between 2017 and 2019 a few of returning ENAs reached IBEX. The map resulted have two important regions nose and tails. From the studies, scientists have found that the nose and tails were not symmetrical as ENAs from the 2014 event have returned from the nose but not from the tails yet which indicated the tails are farther away from the sun. This paints us a picture of heliosphere more like a comet rather than a bubble moving through the space. The picture similar to a comet with the sun close to the front and the tail farther behind.
This founding could also explain another feature known as IBEX ribbon. Which we could discuss in another article.
References: NASA
Have a look at the First Interstellar Parallax Experiment By New Horizons
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