As the Moon orb the Earth , the Earth revolve the Sun , and the Sun orbits the center of the Milky Way , oscillate up and down proportional to the galactic plane as it does so .

A new subject field has suggest that this motion of our star through the coltsfoot potentially require us through regions of space that could affect our planet ’s climate . According to the cogitation , the Solar System may have passed through an interstellar cloud so dense that it may have interfered with the flow rate of the solar wind , potentially cooling the planets .

The Solar System is protect , to some extent , from the interstellar medium ( ISM ) by ourheliosphere .

" The Sun sends out a constant flow of charge subatomic particle call the solar wind , which ultimately travels past all the planets to some three time the space to Pluto before being hinder by the interstellar medium,“NASA explains . " This forms a elephantine bubble around the Sun and its planet , get it on as the heliosphere . "

The Solar System is currently in a 1,000 - light - year - all-embracing " Local house of cards " , or " local interstellar swarm " ( LIC ) . This " house of cards " is a plenty less dense than distinctive interstellar distance , with 0.001 atom per cubic centimeter compared to the typical0.1 atoms per cubic centimeter . The Solar System will result this thin region of space in the next few thousand class and lead once more into the interstellar medium .

Looking at the Solar System ’s path , and mapping the Local Ribbon of Cold Clouds , the squad obtain we have likely traveled through denser regions in the past .

" In the ISM that the Sun has traversed for the last duet of million years , there are cold-blooded , compact clouds that could have drastically affected the heliosphere , " the squad explain in their newspaper . " We search a scenario whereby the Solar System went through a cold gun cloud a few million year ago . "

Though research on the outcome of traversing such realm has been sparse than molecule in the local house of cards , the team believes it could have contract our heliosphere , which in turning had an force on our mood . Our heliosphere is protective , and as it contract some of the material in these denser area could reach Earth .

" big amounts of neutral hydrogen as a result of an brush with cold clouds with density above 1,000   cm−3will alter the chemistry of Earth ’s atmosphere , " the squad write . " Very few works have investigated the climatical effects of such encounters quantitatively in the context of encounters with dense giant molecular clouds . Some argue that such high densities would deplete the ozone in the mid - ambiance ( 50–100   km [ 31–62 miles ] ) and finally chill the Earth . "

The squad say that geological grounds of increased amounts of60Fe ( iron 60 ) and244Pu ( plutonium 244 ) isotopes find in frosting pith , the ocean , Antarctic blow , and sample distribution of the Moon , could be evidence of these particles make Earth as we traversed the Local Lynx of Cold Cloud 2   million years ago .

These isotope are spat out by supernovas and neutron genius merger , which then become trapped by interstellar rubble . These isotopes in the geological record have antecedently been explained as being broadcast here by a close supernova , but the current squad believes they could be explain better by particles trapped in the swarm , as a close - by supernova would collapse the heliosphere to distance of 1 AU ( the length between the Earth and the Sun ) , while a further afield supernova would not fix enough60Fe on Earth .

“ This newspaper is the first to quantitatively show there was an brush between the Sun and something outside of the solar system that would have affected Earth ’s climate , ” space physicist at Boston University , Merav Opher , suppose in astatement , later adding , " but as soon as the Earth was away from the cold swarm , the heliosphere steep all the planets , including Earth . "

The muscle contraction of the heliosphere could have lasted from hundreds of years to a million yr , according to the team , and it is likely we will encounter another such heliosphere - contract swarm within another million years or so .

While interesting , there is a lot more to find out .

" This piece of work should be revisited with modernistic atmospheric modelling , " the squad write . " It has been suggested that climate changes around this metre could have affect human evolution . The hypothesis is that the emergence of our speciesHomo sapienswas determine by the need to adapt to climate change . With the shrinkage of the heliosphere , the Earth was exhibit directly to the ISM . "

The composition is published inNature Astronomy .