How It Works - UK (2020-05)

http://www.howitworksdaily.com How It Works 087

Has a huge

meteorite

ever been

recorded

hitting the

Earth?

LianaChalupka

Itdependswhatyoumeanby

‘hittingtheEarth’,becausemost

spacerocksenteringtheEarth’s

atmospherebreakupintosmall

fragments,orvaporisecompletely,

beforetheyreachtheground.The

biggestimpactthatwasliterally

recorded,innumerousv ideos,

happenedin 2013 overChelyabinsk

inRussia.Beforeit brokeupthat

objectwasaround12,000tonnes–

hugebyanystandards– butthe

largestsur v iv ingfragmentisa mere

654 kilograms.Thatpalesin

comparisontothe60-tonneHoba

meteoriteinNamibia– butthatfell

toEartharound80,000yearsago,

longbeforerecordedhistory.AM

Why can’t anything get colder

than absolute zero (-273.15°C)?

Julia West

n Ata microscopiclevel,temperatureisa measureoftheaverageenerg yof

atomsandmolecules.Atabsolutezerotheyareallinthe‘groundstate’– the

lowestpossibleenerg ythatquantumphysicsallowsthemtoreach.AM ©

Getty

Want

answers?

Sendyourquestions

to...

HowItWorks

magazine

@HowItWorksmag

howitworks@

futurenet.com

What is a CCD

and why is it so

important?

Gwen Morgan

n A charge-coupled dev ice (CCD) is an image

sensor similar to a digital camera’s CMOS

sensor, but is much better at imaging ver y

faint objects. This makes CCDs ideal for

astronomical applications. AM

© NASA

Vapour trail from the

massive space rock that

crashed to Earth near

Chelyabinsk in 2013

© Getty