How do we study the stars? - Yuan-Sen Ting

Kako preučujemo zvezde? Yuan-Sen Ting

Translator: Nika Kotnik Reviewer: Klavdija Cernilogar

The city sky is, frankly, rather boring.

Mestno nebo je pravzaprav precej dolgočasno.

If you look up at the patches of murk between buildings,

Če pogledate v temo med stavbami,

you might be able to pick out The Big Dipper,

boste morda lahko prepoznali Velikega medveda

or perhaps, Orion's Belt.

ali morda Orionov pas.

But hold on.

A počakajte.

Look at that murky patch again and hold our your thumb.

Poglejte ta mračni predel še enkrat in iztegnite palec.

How many stars do you think are behind it?

Koliko zvezd mislite, da je za njim?

Ten, twenty? Guess again.

Deset, dvajset? Pomislite še enkrat.

If you looked at that thumbnail-sized patch of sky

Če pogledate na ta del neba v velikosti nohta na palcu

with the Hubble Space Telescope,

s Hubblovim teleskopom,

instead of points of light, you'd see smudges.

bi namesto svetlobnih pik videli zmazke.

These aren't stars.

To niso zvezde.

They're galaxies, just like our Milky Way.

So galaksije, tako kot naša Mlečna cesta.

Cities of billions of stars,

Mesta z milijardami zvezd

and more than 1,000 of them are hidden behind your thumb.

in več kot tisoč se jih skriva pod vašim palcem.

The universe is bigger than you can see from the city,

Vesolje je večje, kot lahko vidite iz mesta,

and even bigger than the starry sky you can see from the countryside.

in celo večje od zvezdnega neba, ki ga lahko vidite na podeželju.

This is the universe as astrophysicists see it,

To je vesolje, kot ga vidijo astrofiziki,

with more stars than all the grains of sand on Earth.

z več zvezdami, kot je zrn peska na Zemlji.

By staring up at the stars at night,

S tem ko ponoči strmimo v zvezde,

you've taken part in the oldest science in human history.

smo del najstarejše znanosti v človeški zgodovini.

The study of the heavens is older than

Študija neba je starejša kot

navigation, agriculture, perhaps even language itself.

navigacija, kmetijstvo in morda celo jezik.

Yet unlike other sciences, astronomy is purely observational.

A za razliko od drugih znanosti astronomija temelji izključno na opazovanju.

We cannot control the parameters of our experiments from lab benches.

Ne moremo nadzorovati parametrov naših eksperimentov iz laboratorija.

Our best technology can send man to the moon,

Naša najboljša tehnologija lahko človeka pošlje na Luno

and probes to the edge of the solar system.

in se dotakne robov našega sončnega sistema.

But these distances are vanishingly small

A te razdalje so neznansko majhne,

compared to the yawning gulfs between stars.

ko jih primerjamo z zevajočimi prepadi med zvezdami.

So how can we know so much about other galaxies,

Kako lahko torej toliko vemo o drugih galaksijah,

what they're made of, how many there are, or that they're even there at all?

iz česa so sestavljene, koliko jih je in ali so sploh tam?

Well, we can start with the first thing we see when we look up at night: the stars.

No, lahko začnemo s prvo stvarjo, ki jo lahko vidimo ponoči: z zvezdami.

What we are trying to learn is their properties.

Poskušamo preučiti njihove lastnosti.

What are they made of? How hot are they? How massive? How old?

Iz česa so narejene? Kako vroče so? Koliko tehtajo? Koliko so stare?

How far are they from Earth?

Kako daleč so od Zemlje?

And believe it or not,

In verjemite ali ne,

we can learn all of these things simply from the light shining in the sky.

vse te stvari lahko izvemo iz luči, ki sveti na nebu.

We can decipher one kind of stellar message by turning starlight into rainbows.

Eno vrsto zvezdnega sporočila razberemo tako, da njeno svetlobo spremenimo v mavrico.

When you look at a rainbow on Earth,

Ko mavrico pogledate na Zemlji,

you're really looking at light from our Sun

v resnici gledate svetlobo Sonca,

being scattered through water droplets in the atmosphere

razpršeno skozi vodne kapljice v atmosferi

into all the different wavelengths that make it up.

v vse različne valovne dolžine, ki jo sestavljajo.

And we study the light from other stars,

Ko preučujemo svetlobo drugih zvezd,

we can create rainbows on demand using not water droplets,

lahko po potrebi ustvarimo mavrice, in to ne z vodnimi kapljicami,

but other specific instruments that disperse light.

temveč z drugimi posebnimi instrumenti, ki razpršijo svetlobo.

When we look at the scattered light from our sun,

Ko pogledamo razpršeno svetlobo našega Sonca,

we see something strange: dark lines in our rainbow.

vidimo nekaj čudnega: temne črte v naši mavrici.

These lines are the characteristic fingerprints of atoms.

Te črte so značilni prstni odtisi atomov.

Each type of atom in the solar atmosphere soaks up light at specific wavelengths,

Vsaka vrsta atoma v Sončevi atmosferi vpija svetlobo pri različnih valovnih dolžinah

and the amount of absorption depends on how many of these atoms there are.

in količina absorbcije je odvisna od števila atomov.

So by observing how much light is missing at these characteristic wavelengths,

S tem, koliko svetlobe manjka na valovnih dolžinah,

we can tell not only what elements are in the Sun's atmosphere,

lahko povemo, kateri elementi so v Sončevi atmosferi

but even their concentrations.

kot tudi njihove koncentracije.

And the same idea can be applied to study other stars.

In enako idejo lahko uporabimo pri preučevanju drugih zvezd.

Make a spectral rainbow, see what's missing,

Naredimo spektralno mavrico, pogledamo kaj manjka

and figure out which elements are present.

in ugotovimo, kateri elementi so prisotni.

Bingo. Now you know what stars are made of.

Bingo. Sedaj veste, iz česa so narejene zvezde.

But we aren't restricted to just the wavelengths that our eyes perceive.

A nismo omejeni samo na valovne dolžine, ki jih zaznajo naše oči.

Consider radio waves.

Pomislite na radijske valove.

Yes, they can bring the Billboard Top 100 to your car,

Ja, lahko ponesejo Billboardovo lestvico Top 100 v vaš avto,

but they can also travel almost unimpeded through space.

a lahko tudi potujejo skoraj neomejeno skozi vesolje.

Because they've come so far,

Ker so prišli tako daleč,

radio waves can tell us the very early history of the universe,

nam lahko radijski valovi povedo zgodnjo zgodovino vesolja,

from just a few thousand years after The Big Bang.

od samo nekaj tisoč let po velikem poku.

We can also study the infrared light, emitted by colder objects,

Lahko preučujemo tudi infrardečo svetlobo, ki jo oddajajo hladnejši objekti,

like the gas and dust clouds in space,

kot na primer oblaki plina in prahu v vesolju,

and the ultraviolet light from the hot stars recently born from those clouds.

in ultravijolično svetlobo vročih zvezd, pravkar rojenih iz teh oblakov.

Studying different wavelengths not only gives us

Preučevanje različnih valovnih dolžin

a more complete picture of any single object

nam da bolj popolno sliko posameznega objekta

but also different views of the universe.

pa tudi drug pogled na vesolje.

For this reason, astrophysicists use several different kinds of telescopes

Zato astrofiziki uporabljajo več različnih vrst teleskopov,

covering the spectrum from the infrared to the ultraviolet to the X-ray,

ki pokrivajo spekter od infrardečih prek ultravijoličnih do x-žarkov,

from giant radio dishes to giant silver mirrors to space satellites,

od velikih radijskih krožnikov do velikih srebrnih ogledal in vesoljskih satelitov,

detecting light that would be otherwise blocked by the Earth's atmosphere.

ki zaznavajo svetlobo, ki bi jo drugače zaustavilo Zemljino ozračje.

Astrophysicists don't just see

Astrofiziki ne vidijo samo

the billions of stars among the billions of galaxies in the universe.

milijarde zvezd med milijardami galaksij v vesolju.

They hear, feel and sense them through many channels,

Slišijo, čutijo in zaznajo jih skozi mnoge kanale,

each revealing a different story.

od katerih vsak pripoveduje drugačno zgodbo.

But it all begins with light, the kind we can see and the kind we can't.

A vse se začne s svetlobo, s tisto, ki jo lahko vidimo, in tisto, ki je ne.

Want to know the secrets of the Universe?

Želite izvedeti skrivnosti vesolja?

Just follow the light.

Samo sledite svetlobi.