The Economist - USA (2020-02-01)

70 Science & technology The EconomistFebruary 1st 2020

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yborgs,part-mechanicalhuman

beingssuchastheCybermenin

“DoctorWho”,area long-established

featureofsciencefiction.Buttheword

itselfisshortfor“cyberneticorganism”,a

definitionnotself-evidentlylimitedto

themechanisationofhumans.Extendit

topart-mechanicalanimalsandcyborgs

alreadyexist.Theyhavebeencreatedin

theformofinsectsthathavehadchips

implantedinthemtobringthemunder

thewhimofhumancontrollers,whoare

thusabletodirectthewaysthattheir

chargeseitherscuttleorfly.

Thisweekseestheideaextendedstill

further.NicoleXuandJohnDabiri,a pair

ofresearchersatStanfordUniversity,in

California,haveannouncedinScience

Advancesthecreationofthefirstcyborg

jellyfish.Thatmightsounda joke.Butit

opensthepossibilityofusingjellyfishas

cheappropulsionsystemsforunderwa-

terprobes.

DrXuandDrDabiripicked,asthe

chassisfortheircyborg,a common

speciescalledAureliaaurita(pictured).

Likeallothermembersofthephylum

Cnidaria,Aurelialacksa brain.Itsbody

beingradiallysymmetrical,itsnervous

systemistoo.Inparticular,theopening

andclosingofitsbell,whichpropelsit

throughthewater,canbetriggeredby

anyoneofeightneuralpacemakers

distributedaroundthebell’speriphery.

AfteranextensivestudyofAurelia’s

electrophysiology,DrXuandDrDabiri

wereabletodesignanartificialpacemak-

erthathijackedthismechanism.It hasa

lithiumpolymerbatteryanda small

processorchiptocontrolthepatternof

theelectriccurrentgenerated.Thewhole

thingweighsabouttengrams—atenthof

theweightofanadultAurelia.

Usingtheirartificialpacemaker,Dr

XuandDrDabiriwereabletoturbo-

chargea jellyfish’sprogressthroughthe

water.Theycouldspeedit uptoalmost

threetimesitsnormalvelocityand,

surprisingly,thisrequiredonlytwiceas

muchenergyasnormalmovement.

High-speedjellyfishareunlikely,of

themselves,tobemuchuse.Butif a more

sophisticatedprosthesiscansteerthe

animalaswellascontrollingitsspeed,

thenthetechnologyofcyborgCnidaria

willbeinbusiness.Researcherselse-

wherearetryingtodevelopswimming

robotsforoceanexploration.Prototypes

ofthese,however,requirebetween 10

and1,000timesasmuchenergyasthe

devicedevelopedbyDrXuandDrDabiri

becausea robot’sbatterymustprovide

propulsivepoweraswellasrunningthe

controlsystem.A cyborggetsitsenergy

forpropulsionbyfeeding.

A steerablecyborgjellyfish,fitted

withinstrumentsaswellasa control

pack,wouldthereforebea boonfor

marinescientists.Jellyfishgoevery-

where.Picktherightspeciesandyou

coulddivetothedeepestpartsofthe

ocean.Then,oncethecyborg’smission

wasaccomplished,it couldbesteered

backtothesurfaceanditsinstruments—

andthedatatheycontain—recovered.

CyborgCnidaria

Marinescience

Halfmachine,halfjellyfish.Thelatestthinginoceanexploration

Doctor Who’s next opponent?

leaks would have released, between them,

142,000 tonnes of methane. This made the

Turkmenistani leak far bigger than the

97,000 tonnes of methane discharged over

four months by a notorious blowout at a

natural-gas storage facility in Aliso Can-

yon, California, in 2015, which is reckoned

to have been the worst natural-gas leak yet

recorded in America.

There have been other big leaks, too.

Last year a group of researchers led by Ilse

Aben of the Netherlands Institute for Space

Research studied tropomi images of a

blowout at a natural-gas well in Belmont

county, Ohio. This began on February 15th

2018 and took three weeks to control. In a

paper published in the Proceedings of the

National Academy of Sciencesin December

2019, Dr Aben and her colleagues calculated

from the images that the blowout was re-

sponsible for the equivalent of a quarter of

the annual oil and gas industry’s methane

emissions in the entire state of Ohio.

Methane can be detected spectroscopi-

cally. Like other gases, it absorbs light at

characteristic frequencies. With a spec-

trometer mounted on a satellite it is possi-

ble to analyse light reflected from Earth for

signs of the gas. As with the satellites that

carry them, spectrometers come in many

shapes and sizes. tropomican also detect

the spectral signs of other polluting gases,

such as nitrogen dioxide, sulphur dioxide

and carbon monoxide. It rides in a large

bird, the Copernicus Sentinel-5P satellite,

launched in October 2017, and in all weigh-

ing 980kg. The detector has an extensive

view, looking at a strip of Earth 2,600km

wide with a resolution that means a single

pixel in the image represents an area 7km

by 3.5km.

Observing things more closely is the

speciality of Claire. This 15kg “nanosat”,

about the size of a microwave oven, was

launched in June 2016 to measure carbon

dioxide and methane emissions. With a

field of view 12km wide and a resolution

better than 50 metres by 50 metres, Claire

can spot leaks from individual industrial

plants. ghgsat aims to launch two more

methane-hunting nanosats later this year.

Claire surveys industrial facilities on

behalf of firms that want to monitor their

emissions. ghgSat’s chief executive, Ste-

phane Germain, says employing satellites

to do this is more reliable than using terres-

trial methods. In November he plans to roll

out a new service. This will provide a digital

image of Earth which users will be able to

zoom in on to explore continually updated

patterns and hotspots of methane emis-

sions. The map will have an average resolu-

tion of 2km by 2km and be free to use—al-

though if companies want to look at things

more closely they will need to pay.

Other methane-hunting satellites are

coming. These include one due for launch

in 2022 by Methanesat, an affiliate of the

Environmental Defence Fund, an Ameri-

can non-profit organisation. The 350kg sat-

ellite will cost $88m to build and put into

orbit. It will scan an area of land 200km

wide with a resolution of 1km by 1km. Ac-

cording to Methanesat, it will be the most

sensitive to emission levels yet, being able

to detect methane concentrations as low as

two parts-per-billion. Data collected by the

satellite will be publicly available.

Having a number of complementary

eyes-in-the sky will be an important way to

help reduce methane emissions. Although

Donald Trump has proposed rolling back

Obama-era requirements for oil and gas

companies to detect and fix methane leaks,

the gas has commercial value so it does not

make business sense to waste it. On top of

that, for firms seeking to burnish their

green credentials, plugging leaks is one of

the most effective things they can do to

help combat climate change. 7