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Dust gathered by spacecraft found to come from outside solar system

Aug. 18, 2014
Courtesy of the University 
of Leicester, U.K.
and World Science staff

Dust grains brought to Earth by NASA’s Star­dust space­craft probably orig­i­nat­ed in the in­ter­stel­lar dust stream, which comes from out­side the so­lar sys­tem, re­search­ers have con­clud­ed.

With the help of am­a­teur par­ti­ci­pants, sci­en­tists said they iden­ti­fied sev­en dust par­t­i­cles and residues, more than a thou­sand times smaller than a grain of sand, whose char­ac­ter­is­tics are con­sist­ent with in­ter­stel­lar dust. Un­der­stand­ing what the grains are made of may shed light on the so­lar sys­tem’s forma­t­ion, since this sort of ma­te­ri­al is be­lieved to be what gen­er­ates new stars and plan­e­tary sys­tems.

The stu­dy, led by An­drew West­phal at Uni­vers­ity of Cal­i­for­nia, Berke­ley, is pub­lished in the jour­nal Sci­ence. The Star­dust space­craft used gi­ant tiles made out of aer­o­gel and alu­mi­num foil to col­lect the dust sam­ples. Aer­o­gel is an ex­tremely light­weight syn­thet­ic ma­te­ri­al, some­times de­scribed as “solid smoke.”

“We know from as­tro­nom­i­cal ob­serva­t­ions that there is a stream of par­t­i­cles that reaches our So­lar Sys­tem from in­ter­stel­lar space,” the vast ar­eas be­tween stars, Bridg­es said. “Our re­sults show us what this star­dust—from which our So­lar Sys­tem formed—ac­tually is.

“Some of these grains formed in suns pre­dat­ing ours, so we are look­ing be­yond our own So­lar Sys­tem when we study them,” he added. “We have al­so learnt a lot about how to col­lect and an­a­lyze these ti­ny grains, which are less than one mil­lionth of a me­ter in size, which will be im­por­tant in fu­ture mis­sions.”

The find­ings are based on an anal­y­sis of specks col­lected by NASA’s Star­dust mis­sion launched in 1999 to col­lect dust sam­ples from the com­et Wild 2 and re­turn them to Earth for stu­dy. Star­dust also col­lected dust com­ing from the di­rec­tion of the con­stella­t­ion Oph­iu­chus, or the Ser­pent Bear­er.

All anal­y­sis was non-destructive of the par­t­i­cles, but sub­se­quent tests will ul­ti­mately have to de­stroy some of the par­t­i­cles to con­firm their or­i­gin con­clu­sive­ly, West­phal said. “We have lim­it­ed the anal­y­ses on pur­pose,” he added. “These par­t­i­cles are so pre­cious. We have to think very care­fully about what we do with each par­t­i­cle.”


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Dust grains brought to Earth by NASA’s Stardust spacecraft probably originated in the interstellar dust stream, which comes from outside the solar system, researchers have concluded. With the help of amateur participants, scientists said they identified seven dust particles and residues, more than a thousand times smaller than a grain of sand, whose characteristics are consistent with interstellar dust. Understanding what the grains are made of may shed light on the solar system’s formation, since this sort of material is believed to be what generates new stars and planetary systems. The study, led by Andrew Westphal at University of California, Berkeley, is published in the journal Science. The Stardust spacecraft used giant tiles made out of aerogel and aluminum foil to collect the dust samples. Aerogel is an extremely lightweight synthetic material, sometimes described as “solid smoke.” “We know from astronomical observations that there is a stream of particles that reaches our Solar System from interstellar space,” the vast areas between stars, Bridges said. “Our results show us what this stardust—from which our Solar System formed—actually is. “Some of these grains formed in suns predating ours, so we are looking beyond our own Solar System when we study them,” he added. “We have also learnt a lot about how to collect and analyze these tiny grains, which are less than one millionth of a meter in size, which will be important in future missions.” The findings are based on an analysis of specks collected by NASA’s Stardust mission launched in 1999 to collect dust samples from the comet Wild 2 and return them to Earth for study. Stardust collected dust coming from the direction of the constellation Ophiuchus, the Serpent Bearer. All analysis was non-destructive of the particles, but subsequent tests will ultimately have to destroy some of the particles to confirm their origin conclusively, Westphal said. “We have limited the analyses on purpose,” he added. “These particles are so precious. We have to think very carefully about what we do with each particle.”