BBC Focus - 03.2020

Q&A

SACHINSHAW,VIAEMAIL

ISTHERE ANYWHERETHAT’S

COMPLETELY BACTERIA-FREE?

Bacteriahavecolonisedtheplanetmorethoroughlythan

anyotherclassoforganism.Theylive11kmdeepinthe

PacificOcean,andataltitudesof40km,nearthetopofthe

stratosphere.Therearebacteriathatliveinsolidrock,

metabolisingradioactivewaste,andevensomethatsurvive

inboilingwater.TheincrediblydryAtacamaDesertinChile

wasoncethoughttobelifeless,butin 2006 scientistsfound

bacteriatherethattakeadvantageoftheminuteamounts

ofmoistureabsorbedfromtheairbysaltyrocks.Inour

ownenvironment,wecanreducethenumberof

bacteriabutnoteliminatethementirely.One

specieshasevenevolvedtosurvivethe

rigoroussterilisationprocessusedinNASA

cleanrooms.Infact,probablytheonly

placeonEarththatwecanbe

confidentwillalwaysbeentirely

bacteria-freeis thelava

craterofanactively

erupting volcano. LV

QUESTION OF THE MONTH

EMAIL YOUR QUESTIONSTO [email protected] TWEET US@SCIENCEFOCUSQA

WINNER

Sachinwinsa pairofOutlierGold

earphones,worth£94.99.These

stylishearphoneshave 14 hoursof

playtimepercharge,or 39 hours

whencoupledwiththechargecase.

TheyarecompatiblewithAppleSiri

andGoogleAssistant,boastSuper

X-Fiaudio,andareevensweatproof

too.uk.creative.com

Planescanandhaveflownintospaceforover 50 years– thoughnotthekindyou
seeattheairport.That’sbecauseconventionalplanesneedairforbothpropulsion
andlift,andspaceis essentiallya vacuum.
ThefirstplanetoreachspacewastheX-15,designedinthemid-1950sfortheUS
NationalAdvisoryCommitteeforAeronautics(NACA),forerunnerofNASA.It made
itsfirstflightinJune1959,usingthin,stubbywingsforgeneratingliftandstability
whiletravellingatoverfivetimesthespeedofsound,plusa revolutionaryformof
rocketmotorwhosepoweroutputcouldbevariedlikea conventionalaircraft
engine.In1963,anX-15usinga propellantofoxygenandethylalcoholreachedan
altitudeofover100km,widelyrecognisedasthealtitudeatwhichspacebegins.
ThelessonslearnedwerefedintotheSpaceShuttleprogramme and today’s
commercial spaceplane ventures like Virgin Galactic.RM

JASONWEBB,TENNESSEE

WHY DOES SMELL AFFECT TASTE?

Strictlyspeaking,tasteonlyoccursinthemouth,and

referstooneofthefivebasicsensationsdetectedby

thetastebuds– sweet,salty,sour,bitterandsavoury

or‘umami’.Yournose,however,detectsaroma,which

canidentifya muchwiderrangeofthousandsof

volatilecompounds.Thesumofthesetwosensations

is whatweperceiveasflavour, andsobothplayan

important role in our overall experience of food.LV

DENNISROBERTSON,SHEFFIELD

WHY CAN’T WE FLY PLANES INTO SPACE?

TheX-15was

thefirstplaneto

reach space