Recently, NASA’s New Horizons spacecraft spotted a glow, which scientists believe could be the “hydrogen wall” existing at the edge of our solar system. The aforementioned “hydrogen wall” is the exterior barrier of the solar system: the location in between where the sun’s solar winds end, and a cloud of interstellar matter too fine to be able to proceed through the solar wind—a bubble of charged particles created by the Sun—builds up.
On August 7, NASA researchers published a paper explaining New Horizons’ observation of excess ultraviolet light; this light could be produced by a wall of cosmic hydrogen. Additionally, researchers stated that New Horizons will scan for ultraviolet light twice a year from now on to determine if it has passed the wall, signaling an exit from our solar system. On the other hand, if the light does not fade, it could mean that the boundary is farther out in space.
Unfortunately, this light is not a definite sign of the “hydrogen wall” as it could be originating from a different source in the galaxy. However, the two Voyager spacecrafts spotted a similar ultraviolet signal in 1992, and the instruments on board New Horizons are more precise and sensitive than those on the Voyagers.
Do you think we have reached the end of our solar system?