voyager finds a Kelvin wall

[beej]

the universe is fascinating

https://www.iflscience.com/nasas-voyager-spacecraft-found-a-30000-50000-kelvin-wall-at-the-edge-of-our-solar-system-79454

On August 25, 2012, Voyager 1 became the first spacecraft to go beyond the heliosphere and cross the heliopause, followed by Voyager 2 in 2018. Prior to the Voyager spacecraft crossing the heliopause, scientists didn't really know where the boundary would be, but the fact that the probes hit it at different distances helped support a few predictions about it.

"Scientists expected that the edge of the heliosphere, called the heliopause, can move as the Sun's activity changes, sort of like a lung expanding and contracting with breath," a NASA statement explains. "This was consistent with the fact that the two probes encountered the heliopause at different distances from the Sun."

While not a hard edge, or a "wall" as it has sometimes been called, here both spacecraft measured temperatures of 30,000-50,000 kelvin (54,000-90,000 degrees Fahrenheit), which is why it is sometimes also referred to as a "wall of fire".  The craft survived the wall as, though the particles they measured were extremely energetic, the chances of collision in this particle-sparse region of space are so low that not enough heat could be transferred to the duo.

I had never heard of this before. It's fascinating that everything that comes into the solar system has to pass through a wall of 50-90,000 deg Fahrenheit temperature wall.