At https://dailygalaxy.com/2025/11/nasa-voyager-finds-blazing-wall-of-fire/ … NASAs Voyager 1 and 2 are still beaming back information. They are somewhere within, or without. the boundary of our solar system. In fact, they are in the heliopause – beyond the heliosphere. This is where interstellar space begins. They have now reached a seering world that reaches temperatures of thousands of degrees kelvin. It was dubbed a wall of fire – but it is a magnetic boundary where solar influences are repelled by the interstellar medium. The temperature is estimated to be between 30 and 50 thousand kelvin. A trifle hot. In spite of that, the region is sparse, yet the spaceships keep sending back information. They have recorded the kinetic energy of the charged particles moving at immense speed in what is now empty space.
The Sun sends out a constant flow of charged particles itself. This is what is known as the solar wind. Ultimately, at the edge of the solar system, it is impeded by the interstellar medium. The solar wind is rebounded and a great bubble has formed around the solar system. As it travels through space this forms a sort of bow shock – and is therefore elongated in shape as it is moving, like a boat through water The bubble is the heliosphere and the two Voyager spacecraft have passed through that barrier. They are now in the heliopause – where pressure between the solar wind and cosmic rays form a sort of balance, or trough. The Voyages, spaced years apart, passed through the heliosphere at different times – at different distances from the Sun. Scientists now know that the heliosphere expands and shrinks depending on how much solar activity there is. At the moment we can imagine that activity is high. In a couple of years it will die back down until the next solar cycle ramps up. Basically, the boundary of the heliosphere is not fixed. It breathes in, and out. This rhythm of inflation and contraction is one of the most fascinating discoveries of the Voyager programme.
The heliosphere is a bigger version of the magnetosphere that surrounds the Earth. That is also a bubble and protects the Earth from too much radiation via the solar wind particles. Some of that radiation gets through, especially during powerful CME events. Life is therefore adapted to a certain amount of radiation. The same is true of the heliosphere. Cosmic rays from elsewhere in the universe seep through – and on occasion a powerful blast will pierce the heliosphere and the solar system will be awash with cosmic rays. Until the heliosphere reasserts itself. One can imagine even bigger versions of the magnetosphere and heliosphere out there in deep space. They could even be of galactic size – protecting galaxies, yet prone to the same occasional breach. That is awesome.
At https://phys.org/news/2025-10-solar-gamma-rays-mystery-sun.html … new research suggests high energy gamma rays might offer a key to unlock the mystery surrounding the Sun’s magnetic fields. Are they the result of the Sun’s magnetic field interacting with cosmic rays from interstellar space?