When Japan ’s Hayabusa spacecraft photographed the asteroid Itokawa in 2005 , scientists were puzzled by what they saw : The total volume of boulder strewn about its surface were great than the volume of the craters they were supposed to have come from . Now physicist have an answer … by analyze the movement of nuts .
It ’s holler the “ Brazil testicle effect , ” constitute after the anecdotical observation that whenever you vertically shake a jounce full of nuts , the largest ones always terminate up on top . Esther Inglis - Arkell has previouslywritten about this complex phenomenon , but the abridged rendering is that when there are only a few large particles — and all are of adequate density — shaking create spaces beneath the large particles that small ace can descend into . This has the effect of pretend the big particle rise .
The Brazil Nut Effect : Why the biggest nutty emanation to the top
As the Physics arXiv Blogreports , a newstudypublished by a enquiry squad led by Soko Matsumura at the University of Dundee speculates that collisions between asteroids create vibrations that cause great bowlder to arise to the surface , like Brazil nuts .
But can that same dynamic occur under downcast - gravitational force conditions . To find out , the scientists carry simulation by fulfil a contained with 1,800 lowly particle , plus one heavy one , three - clip bigger , at the bottom :
They feign the soberness of Earth , the Moon and several asteroid including Eros and Itokawa . And they show that if they reduce the military strength of the vibrations to agree the level of gravity , then the Brazil nut outcome occurs in all cases , provided that the oscillation fastness are above some decisive doorway that turn the chondritic material from solid - ilk to fluid - like .
The key question , of course , is whether the oscillation in these experiment are similar in strength and frequency to those that occur when rock candy collide with asteroids , such as Eros and Itokawa . Matsumura and co. say that the simulations show this is exactly the fount . “ In both cases , we anticipate that the critical Brazil nut gist oscillation speeds are comparable to the seismic speeds that can create volcanic crater , ” they say .
And they calculate that large boulders should rise to the surface of Itokawa or Eros in a few 60 minutes or about a twenty-four hour period . “ This implies that unless the seismal shaking lasts for more than a couple of hours , one impact might not be enough for a large block to uprise to the surface , and that multiple wallop would be necessary to convert the surface significantly , ” they add .
It ’s an peculiarly appropriate solution to the mystery , since the Itokawa asteroid itself behave an uncanny resemblance to a giant peanut .
asteroidsPhysicsSpace
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