If you have a yen to avenge the destruction of the dinosaurs by smashing apart a comet with your bare ( spacesuited ) hand , it might be easier than you intend . An analysis of 67P / Churyumov - Gerasimenko suggests it is held together by forces a million clip weaker than styrofoam . The work could forge how we undertake frozen threats to our planet .
Dr Nicholas Attreeof Aix - Marseille Université , France , and scientists from 27 other institutions hit the books twenty overhanging cliffs seen by the Rosetta space vehicle as it circled 67P. know the comet ’s soberness , they were able to calculate the minimumtensile strengths(resistance to lengthwise tension ) required to keep these cliffs founder . The gravity is so feeble , just one ten - thousandth of Earth ’s , the ice and rock does n’t necessitate to be bound tightly at all . military unit of around 0.3 Pascals would be sufficient .
If that was all we sleep with , it would n’t enjoin us much . The calculated values are minimums , and the soldering could be much mellow . However , in a paper to be published inAstronomy and Astrophysics(preprint onArXiv.org ) , Attree and co - authors notice many overhang have gnaw material at their base , indicating cloth frequently come down off . Unless the fallen Methedrine once had radically different shapes to what persist , or was broken off by some more powerful disruptive force , it can be assumed the tensile strength of most , if not all of the comet ’s surface is not far from the calculated lower limit .
The cogitation also encounter 67P is quite homogeneous , at least on this cadence . Neither of the two outstanding lobes that form its odd human body has importantly larger overhangs than the other , as would be expect if they were made of different stuff . likewise , there is no trend for the overhangs to get large or smaller towards the full point where the lobes join .
“ low-pitched material strengths are supportive of cometary formation as a primaeval rubble pile or by collisional atomisation of a small ( tens of km ) body , ” the authors observe in their discipline . The rubble pile surmisal , where comets spring from small bite of rock candy and ice gently poke at into each other , has vie with manakin where they are formed by higher amphetamine impacts , creating more upstanding objects .
When ( not if ) the Earth is again threatened by a comet , we might push by a tightly bound object , but would need a different feeler to a broadly bound rubble galvanic pile . Having only examined one comet in this much detail , we ca n’t be sure that all such objects make in the same way of life . It ’s potential there are more powerfully bound “ dirty snowball ” whiz around the Solar System , and asteroid are a unlike affair totally . On a sample of one , it ’s clock time to start planning .
