A new study suggests that the Sun may have had a close encounter with another wizard , explain the strange orbit of objects in the outer Solar System .
" When we think of our Solar System , we commonly assume that it ends at the outermost known satellite , Neptune . However , several thousand celestial bodies are hump to move beyond the orbit of Neptune , “ Susanne Pfalzner , astrophysicist at Forschungszentrum Jülich , explained in astatement . " It is even suspected that there are tens of 1000 of aim with a diameter of more than 100 klick [ 62 miles ] . Surprisingly , many of these so - called trans - Neptunian object move on eccentric orbits that are inclined relative to the common orbital airplane of the planets in the Solar System . “
It is a bit of a mystery why these target are incline the agency they are . The strange orbits of some of these Trans Neptunian Objects ( TNOs ) has led some squad to advise they are being shepherd by an elusiveninth planet , that our agreement of gravity is incorrect atlow speedup , or that the larger planets in our Solar System shepherded them into these orbits as they migrated through the other Solar System . But the new team believes they have an explanation for these unusual orbits : a asterisk passing by our own Sun several billion years ago in our history .
The team ran 3,000 simulations of scenario where stars of various masses passed by our own at different distances . Though we have only discovered an judge 1 - 10 percent of TNOs , making further observance and cogitation of their orbits necessary for a full account , the team found that a close flyby of a slightly small mavin than our own could produce a Solar System that calculate unusually similar to how it looks today .
" The best match for today ’s outer Solar System that we find with our feigning is a ace that was slightly light than our Sun – about 0.8 solar masses , “ Amith Govind , co - source on the paper , explained . " This star flew past our sunlight at a distance of around 16.5 billion kilometres [ 10.3 billion miles ] . That ’s about 110 sentence the distance between the Earth and the Sun , a slight less than four times the length of the outermost major planet Neptune . “
The simulation produced a number of TNOs in retrograde orbits . At first , this worried Pfalzner , as it suggested that the computer simulation may not have produced a Solar System that look like our own .
" Only later did I get word that a few retrograde TNOs have indeed been discovered recently , ” Pfalzner toldSky & Telescope .
Close clash are more mutual in the very early solar day of star shaping , when stars are still part of their " nativity clump " , sometime in the first 10 million age .
" Even in humble - density clusters , ∼1 % of solar - type lead experience such an meeting , " the squad wrote in their discipline . " couch this number in perspective , in the first 10 Myr of their life , at least 140 million solar - type stars in the Milky Way ( possibly ten times more ) have feel an meeting similar to the Sun ’s . "
later on penny-pinching showdown are potential , however , and the team estimates that there is a 20 - 30 percent probability that the Sun had such an encounter in the 4.5 billion years since the Solar System ’s establishment .
One problem is that there ’s a good probability Neptune ’s orbit would have been affected by such a close meeting , though the squad find that in a quarter of scenarios the ice heavyweight could have been " shield " from the effects of the other wiz by fundamentally fly behind it .
It is an interesting idea , and hopefully one that can be try further . When theVera C. Rubin Observatorybegins work in 2025 it will bring home the bacon more information on TNOs as it discovers them , allowing the squad to test their hypothesis further .
The study is published inNature Astronomy .
