Scientists from NASA believe that the New Horizons spacecraft can see the "hydrogen wall" at the border of the system.
The "wall" in question is at the outer edge of our star system - where the solar wind bubble ends, and the mass of interstellar matter is too small to break through, so it gathers around and presses on it. Powerful emissions of matter and energy from the Sun are scattered over huge distances from the star, much further than Pluto's orbit. At some point, they dry up, and with them their ability to repel dust particles and other matter. A visible border is formed. On one side of it are the last remnants of the solar wind. On the other, there are clusters of interstellar matter, including hydrogen.
NASA is confident that the New Horizons probe, which crossed Pluto's orbit in 2015, will be able to see this border. The researchers wrote about this in a report published on August 7 in the journal Geophysical Research Letters. They argue that the probe will see excess ultraviolet light: according to scientists, this is the radiation that will come from the wall of galactic hydrogen. This signal was registered by two Voyagers back in 1992.
However, the researchers noted that the signal does not mean that New Horizons viewed the hydrogen wall or that it was seen by Voyagers. In fact, all three probes could detect ultraviolet radiation from some other source located much further in the galaxy.
However, Alice, the instrument on board New Horizons responsible for this detection, is more sensitive than any other Voyager on board. The researchers also noted that Alice will continue to operate for another 15 to 20 years. New Horizons will continue to scan space for ultraviolet light twice a year and send data back to Earth.
"If at some point the ultraviolet radiation disappears, then New Horizons has left a wall in the rearview mirror," the researchers explain. "But if the radiation does not disappear, therefore, its source is much farther - somewhere in distant space."
Vladimir Guillen
