Guru Magazine - - CONTENTS -

What is the best ad­vice for stay­ing alive when a flam­ing ball of in­ter­stel­lar de­bris plum­mets into the Earth? We’re go­ing to have to be­lieve in a di­vine author and pray, pray, and pray some more. Never fear though! Becky Martin has an as­ter­oid im­pact sur­vival guide.

NASA chief Charles Bolden re­cently gave some ad­vice of what to do if there was an im­pend­ing as­ter­oid col­li­sion. His guid­ance was sim­ple: we should “pray”. Now there’s a cheer­ful thought. But just how likely is this dooms­day sce­nario and what – apart from pray­ing – can we do to sur­vive?

It’s a lot­tery and there’s a good chance we’ll lose

Our planet is be­ing con­tin­u­ally pelted by so­lar sys­tem de­bris. Yet we are rarely aware of this daily galac­tic pummelling: most ob­jects fiz­zle away high in the at­mos­phere where they are too dis­tant for their shock waves to reach us. (The ex­cep­tions are the ‘fall­ing stars’ that we wish upon – though th­ese aren’t ac­tu­ally stars but fiery lumps of space rock or me­tal that va­por­ise as they plum­met through our at­mos­phere.) Some­times, how­ever, pro­jec­tiles can sur­vive their jour­ney through our at­mos­phere and reach the ground – at which point they are termed ‘me­te­orites’. It is es­ti­mated that over 500 me­te­orites reach the sur­face of the Earth in this way ev­ery year. In the world of in­ter­stel­lar pro­jec­tiles, it’s sur­vival of the fittest, as only the strong­est iron rocks reach the Earth in one piece. So, when have as­teroids re­ally made an im­pact here on Earth? Well, how about the Tun­guska

event of 1908? Tun­guska was an ‘air­burst’ event, dur­ing which the as­ter­oid or comet dis­in­te­grated in the lower at­mos­phere. Al­though there was no col­li­sion, it cre­ated a shock­wave that was suf­fi­cient to fell trees across an area of 1000 km2 (250,000 acres) and the blast yield has been es­ti­mated at 10-20 mega­tons – 1,000 times more pow­er­ful than the nu­clear bomb used over Na­gasaki in the Sec­ond World War. But we should per­haps be more con­cerned about a re­cur­rence of what­ever caused the 180 me­tre wide Chicx­u­lub crater over 65 mil­lion

years ago, which co­in­cided with the start of the Cre­ta­ceous-Palaeo­gene ex­tinc­tion event. The Chicx­u­lub me­te­orite dis­rupted the global ecosys­tem and wiped out half the species on Earth, in­clud­ing the di­nosaurs (al­though thank­fully it ul­ti­mately re­sulted in our dom­i­nance in the food chain). Un­like the rep­tiles, we have large brains and a space pro­gramme and there­fore re­ally shouldn’t suc­cumb to the same fate. (Well, that’s what we’re hop­ing.) So are we likely to ex­pe­ri­ence an apoc­a­lyp­tic im­pact in the near fu­ture? The NASA nearEarth Ob­ject mon­i­tor­ing pro­gramme has iden­ti­fied 1,408 near-Earth Ob­jects that rep­re­sent po­ten­tial haz­ards thanks to their size and tra­jec­tory. The Torino scale is used to rate the im­pact haz­ard as­so­ci­ated with as­teroids: a neg­li­gi­bly small chance of col­li­sion is rated 0, while a cer­tain im­pact and im­pend­ing global disas­ter is given a 10. To give you some per­spec­tive, the most danger­ous as­ter­oid is the fear­somely-named VK184, which is com­ing close to us some­time be­tween 2048 and 2057. It has a gar­gan­tuan Torino rat­ing of 1. The Apophis and AG5 as­teroids have also whipped up con­cern in the me­dia, al­though there is cur­rently lit­tle sci­en­tific ev­i­dence to back up scare­mon­ger­ing (but a lack of sci­en­tific ev­i­dence hasn’t stopped im­pacts in the past!) So, while the odds of an apoc­a­lyp­tic as­ter­oid strike caus­ing mas­sive ca­su­al­ties and de­struc­tion of our ex­is­tence are cur­rently in­finites­i­mally small, the po­ten­tial con­se­quences of such an event would be enor­mous. So let’s get pre­pared for catas­tro­phe, just in case…

How to: sur­vive an as­ter­oid im­pact

The sci­en­tific com­mu­nity has de­vel­oped some in­ter­est­ing tools to in­ves­ti­gate what would hap­pen if an as­ter­oid strike ac­tu­ally hap­pened. Top sci­en­tists have also come up with some rather un­con­ven­tional strate­gies to mit­i­gate for disas­ter. Im­pe­rial Col­lege and Pur­due Univer­sity work with a sim­u­la­tion called the Earth Im­pact Ef­fects Pro­gramme to as­sess the risk of a ‘mod­er­ate’ as­ter­oid im­pact. It of­fers po­ten­tially hours of fun. You can se­lect a pro­jec­tile, its fi­nal des­ti­na­tion, its speed, and the an­gle of im­pact, and the web­site will tell you if you will sur­vive, or if you will be squashed by de­bris, killed by an earth­quake, or burned alive. Cur­rent sci­en­tific strate­gies listed by NASA to evade the im­pend­ing doom of an as­ter­oid col­lid­ing with Earth in­clude de­flect­ing the as­ter­oid us­ing slow-push-pull ‘grav­ity trac­tors’, ki­netic im­pact, nu­clear bom­bard­ment and other ex­plo­sives, as shown in the side box . But what would be the con­se­quences of a colos­sal and un-de­flectable as­ter­oid hit­ting the Earth? The strength of the ini­tial im­pact would dev­as­tate the sur­round­ing en­vi­ron­ment and un­con­trol­lable wild­fires would rapidly spread. The im­me­di­ate event would be fol­lowed by an ‘im­pact win­ter’, as enor­mous clouds of ash and dust en­ter the at­mos­phere, block­ing out the sun. This loss of sun­light would kill pho­to­syn­thetic plants and al­gae that hadn’t al­ready been oblit­er­ated by fire or ex­treme cold. Es­sen­tially, any an­i­mal larger than an al­li­ga­tor would prob­a­bly starve. The Com­mit­tee to Re­view Near-Earth Ob­ject Sur­veys and Haz­ard Mit­i­ga­tion strate­gies rec­om­mend a civil de­fence plan for prepa­ra­tion and re­cov­ery that is based upon the stan­dard ‘all-haz­ards’ pro­to­cols for evac­u­a­tion, shel­ter, re­sponse and re­cov­ery for as­ter­oid im­pact sur­vival. They also con­sider the im­pli­ca­tions of pos­si­ble as­ter­oid events, as shown in the next sec­tion. Even if an as­ter­oid is too large to be de­stroyed or de­flected there should still be time to pre­pare for the im­pact. Op­tions for the in­di­vid­ual sur­vival­ist in­clude de­vel­op­ing one’s mil­i­tary knowl­edge and hoard­ing food within an old nu­clear bunker be­fore the im­pact. Fol­low­ing the im­pact, one should re­main within the bunker for six months, be wary of ban­dits upon emerg­ing, and en­sure a use­ful sup­ply of guns and am­mu­ni­tion for hunt­ing and bar­ter­ing within a post-apoc­a­lyp­tic world. So, given all this, per­haps the most use­ful sur­vival strat­egy might be to set­tle in for a night in front of Mad Max to pick up tips...?


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