Friday, January 2, 2015

Astronomy Special:Voyager I Detects Third Shock Wave

Voyager I,which was launched in 1977,has experienced its third shock wave in deep space.This wave is the longest in duration-it started in February 2014 and continues to this day.The spacecraft is still making significant discoveries more than thirty-seven years after its launch,calling home every day.The waves are created when the Sun emits a coronal mass ejection and a cloud of magnetic plasma from its surface,which results in a pressure wave that hits the interstellar plasma where Voyager I is,causing ionised gas to resonate or vibrate like a bell.
Voyager I executed flybys of Jupiter and Saturn before heading for interstellar space,finally leaving the solar system in August 2012,a study published in Science magazine reckons.It left the heliosphere,the region of the solar wind.Voyager chief scientist Ed Stone confirmed this in September 2013.It will fly past distant comets in 30,000 years and near another star in 40,000 years,traveling now at more than 38,000 miles an hour.
According to Leonard Burlaga of NASA's Goddard Spaceflight Center in Greenbelt,Maryland,this remarkable shock wave event raises questions that will stimulate new studies of the nature of shocks in the interstellar medium.Why has the third shock wave lasted so long?How fast is the wave moving?How broad a region does it cover?The first of Voyager I's shock waves was from October to November 2012;the second was from April to May 2013.
Voyager I's twin,Voyager II,was launched 16 days ahead of Voyager I on 20 August 1977;Voyager I followed on 5 September 1977.Each spacecraft weighs 722 kilograms.Voyager II will likely follow Voyager I out of the solar system in a few years-it had made a detour to fly by Uranus and Neptune,the only spacecraft ever to have visited these outer planets.

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