the.com/heliosphere
the sun's personal force field, blowing solar wind until it loses the argument with interstellar space.
means a vast bubble of charged particles and magnetic field blown outward by the sun, marking where solar influence gives way to the rest of the galaxy.
from coined mid-20th century from helios (sun) and sphere, once astronomers realized the solar wind does not just fizzle out but carves a bubble through the interstellar medium.
voyager 1crossed its edge in 2012, still transmitting
shapemore windsock than perfect sphere, astronomers now think
boundary namecalled the heliopause, the actual edge
sizestretches roughly 100 times earth-sun distance