Lit­tle green men un­likely to phone home

The Weekend Australian - Review - - Books -

The good news is that 80 light years away from Earth and count­ing, the fee­ble re­mains of what was once a tele­vi­sion sig­nal mark the fron­tier of hu­man­ity’s great scream into the cos­mos. The bad news is that it may well be footage of Hitler open­ing the 1936 Olympics. But who is there to see it any­way?

Jim Al-Khalili, an Iraqi-born British the­o­ret­i­cal physi­cist and broad­caster, has gath­ered a use­ful cross-sec­tion of the bright­est minds in space sci­ence to an­swer this ques­tion. Aliens does a very good job of it. Al-Khalili’s book goes far be­yond the what and the where and the when of ex­trater­res­trial-hunt­ing to the big­gest co­nun­drum of all: why bother?

Let’s start with the sci­ence. In 1900 the Prix Pierre Guz­man held out 100,000 francs to the first per­son to make con­tact with life on an­other planet. Mars didn’t count be­cause it was con­sid­ered too easy. At least they had clar­ity then, even if it was the clar­ity of ig­no­rance.

Today we have no idea what to ex­pect. Or rather, we have so many ideas that we hardly know what to do with them.

Half a cen­tury ago Frank Drake, an Amer­i­can as­tronomer, de­vised an equa­tion for work­ing out how many other ra­dio-com­mu­ni­cat­ing civil­i­sa­tions might be dot­ted across the Milky Way. It says a good deal about how far we have come since then that the plau­si­ble an­swers range from 0.000000000091 to 160 mil­lion. Aliens does not duck this un­cer­tainty. “There are no alien civil­i­sa­tions,” writes Matthew Cobb, a zo­ol­o­gist from the Univer­sity of Manch­ester. Take the odds of life emerg­ing out of noth­ing, he says, mul­ti­ply them by the odds of it find­ing a way to make enough en­ergy to grow big­ger than a sin­gle cell, then mul­ti­ply that by the odds of it be­com­ing in some way con­scious of it­self, and then once again by the odds of it in­vent­ing TV, and you have an ex­tremely small num­ber that may as well be zero.

At the other end of the spec­trum stands Nick Lane, the evo­lu­tion­ary British bio­chemist who made his name with his book The Vi­tal Ques­tion, ar­gu­ing that wher­ever there is rock, wa­ter and car­bon diox­ide — i.e., ba­si­cally ev­ery­where — you have a good shot at life. Some­where in the mid­dle is Sara Sea­ger, a USCana­dian Mas­sachusetts In­sti­tute of Tech­nol­ogy as­tro­physi­cist, who has cus­tomised the Drake equa­tion to show that if we are very, very lucky our space tele­scopes might just de­tect a sin­gle alien life form from the im­print of its chem­istry on the light from a dis­tant star.

Or per­haps it will be a ro­bot. Martin Rees, the As­tronomer Royal, notes that the win­dow be­tween a so­ci­ety de­vel­op­ing space­wor­thy tech­nol­ogy and that same so­ci­ety blow­ing it­self to both­er­a­tion is prob­a­bly so brief that the first alien in­tel­li­gence we meet is likely to be ar­ti­fi­cial. Or in­com­pre­hen­si­ble.

“Even if in­tel­li­gence were wide­spread in the cos­mos,” Rees re­marks in an es­say that would be down­right bleak if any­body else had writ­ten it, “we may only ever recog­nise a small and atyp­i­cal frac­tion of it. Some ‘brains’ may pack­age re­al­ity in a fashion that we can’t con­ceive. Oth­ers could be living con­tem­pla­tive en­er­gy­con­serv­ing lives, do­ing noth­ing to re­veal their pres­ence.”

If you lower your stan­dards and drop the re­quire­ment for ex­trater­res­trial life to be bright enough to op­er­ate a toaster, the prospects im­prove. Mars re­mains the best bet. Its child­hood was re­mark­ably sim­i­lar to Earth’s un­til piti­less winds from the sun stripped away the red planet’s at­mos­phere. The tem­per­a­tures may fall as low as mi­nus 153C and the ground may be cease­lessly bat­tered by mu­ta­genic cos­mic rays, but it is plau­si­ble that sin­gle-celled or­gan­isms may have sur­vived some­where be­neath the crust on a diet of stones.

Ence­ladus, a satel­lite of Saturn, and Europa, one of Jupiter’s moons, look as though they har­bour promis­ingly warm oceans be­neath their frozen ex­te­ri­ors. The true wild­card, though, is Ti­tan. This grim par­ody of Earth, an­other moon of Saturn, is the only other place in the so­lar sys­tem where we have seen sta­ble liq­uid at the sur­face. Sadly that liq­uid is a reser­voir of methane cold enough to make ba­nanas as frag­ile as porce­lain. Still, life could be brood­ing in its depths at the sort of fu­ne­real pace nor­mally as­so­ci­ated with Dos­to­evsky nov­els.

This book is al­ways lu­cid and some­times un­ex­pect­edly beau­ti­ful. If it con­tra­dicts it­self, it

Newspapers in English

Newspapers from Australia

© PressReader. All rights reserved.