在火星可以大声(At Mars can be loud).docVIP

在火星可以大声(At Mars can be loud) 　　sund dies quil in the ld, thin air f ars researhers have deled a sund ave traveling thrugh the artian atsphere and reprt that it desn’t g far--even a lan er’s rar dies after a hundred eters r s the del presents an unusuall detailed piture f h sund travels in an alien atsphere and hints at hat it uld tae t uniate n the red planet 　　the shrie f a bab, an abulane’s siren, r a vilin snata are all essentiall the sae thing: aves f pressure traveling thrugh the air sund an als travel thrugh ater, r a slid lie the grund, but beause leules ust bup int eah ther t prpagate the pressure ave, the denser the ediu the better hfbeats r ftsteps travel farther thrugh the grund than thrugh the air, fr exaple, beause the leules in air have t travel further t bup int ne anther than thse in sil, thus lsing energ re quilthe artian atsphere is stl arbn dixide and nl 07% as dense as earth’s is, s sund shuld fade re quil but the details f h sund aves travel in the artian atsphere ere unlear and uld be iprtant t future ars issinsn, a puter del has given a leule-b-leule ap f h sund ves n ars graduate student aanda hanfrd and phsiist lle lng f pennslvania state universit in state llege presented the del last ee at a eeting f the austial siet f aeria eeting in prvidene, rhde island the del is unusual in its leular apprah; st austial dels f sund treat the ediu it travels thrugh as a ntinuus bl ith average prperties suh dels are fine fr dense atspheres lie earth’s, but treating the air lie a lse bunh f freeheeling leules is re realisti fr ars’ rarefied atsphere, sa the researhers 　　hanfrd and lng first set up a virtual bx filled ith abut 10 illin arbn dixide leules flating abut randl, at the sae densit as the artian atsphere a sund ave then appeared n ne side f the bx, and the del alulated its prgress arss t the ther side, puting nansend b nansend exatl h the arbn dixide leules buped and ved the results sh that a nise that uld travel several ileters n earth uld die a