What a week it has been for comet - lovers . First came the news that the European Space Agency ’s Solar Orbiter hadsailed serendipitouslythrough the tail of condemn Comet ATLAS , then Modern analysis suggested that the first interstellar comet , Comet 2I / Borisov , will in all likelihood make it out of the solar systemrelatively whole . Turning this duo into a terzetto is the uncovering of the longest cometary tail yet measured .
At least 7.5 time as long as the distance between the Earth and the Sun ( over a billion kilometers , or 621 million Roman mile ) , Comet 153P / Ikeya - Zhang ’s ion tail is nearly double the length of the previous track record - holder , Comet Hyakutake . In ordering to make this immense discovery , however , researchers had to revisit datum from nearly 20 eld ago .
When NASA’sCassini spacecraftwas traveling between the orbits of Jupiter and Saturn back in 2002 , it detected an increase number of proton . This event has go unexplained for all these age , but a squad of UK and US researchers now believe that these proton in fact came from the ionize rear end of Comet 153P / Ikeya - Zhang .
Interactions between the Sun and an orbiting comet can cause it to shedtwo types of tail . Perhaps the more intimate one is the dust tail , acquire as the solar radiation melts the comet ’s core , retch out a lead of dust and gas that had been trapped in the so - called “ marked-up snowball . ” The other is the ion tail end , formed when inert gas in the comet ’s core becomes ionized by the radiation . In Comet 153P / Ikeya - Zhang ’s type , proton strip from hydrogen gas during this ionization could be transmit by the solar wind in the counseling of the space vehicle .
Therefore , as the team concluded in their paper , available on the pre - print serverarXiv , the comet ’s location coupled with the proton numbers registered by Cassini comprehensively suggests that the spacecraft did in fact pilot through Comet 153P / Ikeya - Zhang ’s ion buns . A closer tone at the observe proton told the investigator that they had travel a distance of 6.5 astronomical units ( the length between the Earth and the Sun ) from the comet comatoseness , which , when the comet ’s orbital change during the measurements is accounted for , implies a minimal tail duration of more than 1 billion kilometer .
As probes have only crossed comet ’s tails a handful of times , the possibleness of this phonograph recording being broken again is highly likely , investigator toldNew Scientist . stargazer will be greatly foresee the results from the Solar Orbiter ’s fundamental interaction with Comet ATLAS .
[ H / T : NewScientist ]
