THREAT FROM M OUTER SPACE E

Over 26 un­de­tected as­ter­oids roids en­tered Earth's at­mos­phere here be­tween 2000 and 2013

Down to Earth - - CONTENTS - SOMA BASU

THE CHANCES OF a “city-killing” as­ter­oid strik­ing Earth are much higher than sci­en­tists pre­vi­ously thought. A re­cent re­port has found that more than 26 as­ter­oids reached Earth’s at­mos­phere be­tween 2000 and 2013—a num­ber much higher than es­ti­mated. The find­ings re­leased by the Nu­clear Test Ban Treaty Or­ga­ni­za­tion on April 24, 2014 sug­gest that some of the as­ter­oid ex­plo­sions were more in­tense than the nu­clear ex­plo­sion that wiped out Hiroshima in 1945.

The re­port says that while most of these as­ter­oids ex­ploded too high in the at­mos­phere to cause se­ri­ous dam­age, the one that fell in Chelyabinsk, Rus­sia, in Fe­bru­ary last year dam­aged hun­dreds of build­ings and in­jured more than 1,600 people. The re­port points out that none of the 26 as­ter­oid im­pacts was de­tected in ad­vance, sug­gest­ing the need for a bet­ter mech­a­nism to warn of as­ter­oids ap­proach­ing Earth.

The ur­gency to de­velop such a mech­a­nism is grow­ing by the day. “Since we don’t know where or when the next ma­jor im­pact will oc­cur, and be­cause none of these 26 as­ter­oid ex­plo­sions was de­tected in ad­vance, it means the only thing pre­vent­ing a catas­tro­phe from a ‘city-killer’ as­ter­oid is blind luck, ”says Ed Lu, ceo and co-founder of the B612 Foun­da­tion, a pri­vate body ded­i­cated to pro­tect Earth from as­ter­oids.

The B612 Foun­da­tion has part­nered

" Since we don't know where or when the next as­ter­oid im­pact will oc­cur, the only thing pre­vent­ing a catas­tro­phe is blind luck" Ð Ed Lu, CEO of B612 Foun­da­tion

with Ball Aero­space, an Amer­i­can space­craft man­u­fac­turer, to build the Sen­tinel In­frared Space Te­le­scope Mis­sion. The Sen­tinel Mis­sion will place a te­le­scope in an ob­long Venus-like tra­jec­tory to or­bit Earth.

An as­ter­oid ap­proach­ing the at­mos­phere can be de­flected by ei­ther chang­ing its course by an im­pact on its sur­face by a space­craft, or by trans­port­ing the as­ter­oid to an or­bit around Earth us­ing an air­craft.The as­ter­oid can also be hit with a nu­clear bomb, but such an ex­plo­sion is banned un­der the UN peace treaty.

“You can­not de­flect an as­ter­oid you don’t even know is headed to Earth,” says B612 co-founder and chair emer­i­tus Rusty Sch­we­ickart, who flew on the Apollo 9 mis­sion in 1969. The goal of the B612 mis­sion is to lo­cate as­ter­oids be­fore they come near Earth so that sci­en­tists have enough time to pre­pare a de­flec­tion mis­sion.The project is ex­pected to be launched in 2017.

Be­sides the pri­vate ini­tia­tive, sev­eral gov­ern­men­tal agencies are also look­ing for op­tions to iden­tify as­ter­oids and de­flect them. In Oc­to­ber 2013, the UN passed a res­o­lu­tion call­ing for the es­tab­lish­ment of an In­ter­na­tional As­ter­oid Warn­ing Group that would mon­i­tor po­ten­tially de­struc­tive ex­trater­res­trial ob­jects. The de­ci­sion was taken af­ter the As­so­ci­a­tion of Space Ex­plor­ers pub­lished a re­port stat­ing the need for in­ter­na­tional co­op­er­a­tion on the is­sue.

nasa, on its part, has an­nounced an As­ter­oid Grand Chal­lenge in which it has in­vited govern­ment agencies and sci­en­tists to lo­cate as­ter­oids so that they can be an­a­lysed for the threat they pose to the planet. nasa is also plan­ning to launch the As­ter­oid Re­di­rect Mis­sion that will use ro­bots to cap­ture and re­di­rect po­ten­tially haz­ardous as­ter­oids to a sta­ble or­bit around the moon.

The Or­gan­i­sa­tion for Eco­nomic Co­op­er­a­tion and De­vel­op­ment (oecd) is also plan­ning to set up a fo­rum and find tech­nolo­gies that may be used to de­tect as­ter­oids in a bet­ter way. In­dia is a mem­ber of the oecd.

Even the Euro­pean Union is run­ning a project to brace against as­ter­oid collisions. The mis­sion is called neoshield (Near Earth Ob­ject shield) and it part­ners with var­i­ous Euro­pean uni­ver­si­ties and re­search cen­tres.

As­ter­oids, big and small, will con­tinue to move to­wards Earth and Lu be­lieves that un­less the de­tec­tion mech­a­nism is strength­ened, one will even­tu­ally hit us.

Chunk of the as­ter­oid that

ex­ploded over Rus­sia on Fe­bru­ary 15, 2013. The ex­plo­sion had in­jured over 1,600 people

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