NASA‘s New Horizons spacecraft has helped scientist study a mysterious phenomenon at the bound of the Solar System , where particles from the Sun and interstellar blank space interact .
This region , about 100 times further from the Sun than Earth , is where uncharged hydrogen atoms from interstellar space meet charged speck from our Sun . The latter gallop out from our Sun in a bubble called theheliosphere .
At the point where the two interact , eff as the heliopause , it ’s thought there is a work up - up of hydrogen from interstellar space . This create a sorting of “ wall ” , which disperse incoming ultraviolet visible radiation .
About30 years agoNASA ’s Voyager 1 and 2 spacecraft first detected this bulwark , and now New Horizons has constitute new evidence for it . A newspaper describing its findings will be put out inGeophysical Research Letters .
“ We ’re meet the doorstep between being in the solar neighbourhood and being in the beetleweed , ” Dr Leslie Young from the Southwest Research Institute in Colorado , one of the cobalt - author on the newspaper , toldScience News .
New Horizons made the detection using its Alice UV spectrometer , drive measure from 2007 to 2017 . It witness an ultraviolet glow bed as a Lyman - alpha line of descent , which is made when solar particles hit hydrogen atom .
We see this ultraviolet glow all over the Solar System . But at the heliopause , there looks like an extra source make by the wall of hydrogen , creating a larger gleam . Beyond the paries there ’s more ultraviolet light compared to in front of it , propose it ’s being dot by the wall .
" This distant source could be the signature of a bulwark of atomic number 1 , form near where the interstellar flatus encounters the solar wind , " the research worker wrote in their paper .
The theory is not definitive yet . It ’s possible that another source of ultraviolet light in our coltsfoot could be cause this background signal gleam . To retrieve out for sure , New Horizons will continue looking for the rampart about twice a class .
At some point , New Horizons will cross the wall , if it exists , so the amount of ultraviolet light it detects will decrease . That would provide some additional grounds that the paries is really there .
Voyager 1 and 2 are both past the wall now , so they ’re unable to make any further detections . But New Horizons is only 42 times further from the Sun than Earth , a length it has taken about 12 years to achieve , and is currently on its way to explore a new target calledUltima Thulehaving flown past Pluto in 2015 .
If our estimates are correct , then by the time the missionary post ends in about 10 to 15 years , it should hopefully have just about made it to the wall . At that point , we might really know for sure if it ’s there or not .
