Fifty years ago , a ball of fire streaked across the sky of Victoria , Australia , scattered into three fragments , and clangour - shore , spray fragments over 13 straight kilometers ( 5 square miles ) . Now , scientists have let out stardust trapped inside the meteorite , time - stamping the interstellar grains to 5 - 7 billion geezerhood ago .
" This is one of the most exciting study I ’ve worked on,“saidlead author Philipp Heck , a curator at theField Museumand an associate prof at the University of Chicago . " These are the oldest solid material ever determine , and they tell us about how stars form in our galaxy . "
Compared to a superstar , our lives are little – particle of gumption in the cosmic timeframe of millions to billions of years . When adept die , their particle be adrift out into space to finally shape Modern stars , satellite , moon , and meteorites . The stardust , called presolar grains - minerals , are only found in about 5 percent of meteorite on Earth , each speck get along in at a mighty 1/100th the size of it of a stop on this page .
Pieces of theMurchison meteorite , as it is call , were send off to museums all over the world , with the Field Museum receiving the heavy chunk . To isolate the presolar grain – so named for originate before our star – bits of the meteorite were crushed into powder and separated , giving the final product a “ rotten peanut butter ” look . The textile was then dissolved with acid until only the interstellar grain were left for the team to analyze .
To maturate the presolar grains , the squad used exposure age data since dating of interstellar dust directly is not possible . " We count the atoms produced in the cereal that form by interaction with cosmic - rays , " Heck told IFLscience . " In particular we counted corpuscle of atomic number 2 and neon that formed by these interactions . We retrieve we know how many are produced per unit of time and thus can calculate an years by just calculate how many atoms of each species are present . I compare this with assign out a bucket in a rainstorm . assume the rain is constant , the amount of water that hoard in the bucket tells you how long it was exposed . "
Most of the grain were between 4.6 to 4.9 billion years old , but some were even older . This makes the interstellar grains even older than the planet they crash - landed on – Earth at 4.5 billion years sure-enough . The resultant role are published in the journalPNAS .
" We also found that there are many more vernal grains than expected , " said Heck . " We assign this to a infant boom in whizz geological formation that acquire stars 7 billion year ago which started to puff up out dust 4.9 billion years ago , ' only ' 300 million class before the beginning of the solar organization . This is how we think the “ young ” grain formed . "
The quad cloth is evidence bring to a long - standing debate on whether star formation is constant , created at a unbendable rate , or if it ebbs and flows over time . The grain from the Murchison meteorite suffer the hypothesis that the nascence of stars can chance in episodic bursts .
" But thanks to these grains , we now have direct grounds for a period of enhanced principal formation in our coltsfoot 7 billion long time ago with samples from meteorite . This is one of the key finding of our study , " said Heck . The grains also stick together in clustering , " like granola , " in a mental process " no one thought was possible at that scale . "
" I was surprised to witness that the grains travelled through interstellar blank as large cluster ( prominent than 200 micrometer ) , probably have together by some organic guck , analog to but obviously smaller than granola clusters held together by sugar !
" It ’s so exciting to appear at the history of our galaxy , " added Heck . " Stardust is the sure-enough material to reach Earth , and from it , we can learn about our parent stars , the stemma of the carbon in our bodies , the source of the atomic number 8 we take a breather . With stardust , we can trace that stuff back to the meter before the Sun . "
