‘Light from JADES-GS-z14-0 travelled 14 billion years to us — it mirrors how special our lives are’ - Times of India (2024)

'; var randomNumber = Math.random(); var isIndia = (window.geoinfo && window.geoinfo.CountryCode === 'IN') && (window.location.href.indexOf('outsideindia') === -1 ); //console.log(isIndia && randomNumber < 0.9 ); if(isIndia){ // code for showing ctn ad $('#fluid-container').remove(); return; } $('.top2brdiv').remove(); $('#fluid-container').append(adContainer); })() Can you tell us about your recent discovery of two ancient galaxies?

■ This is part of the JWST Advanced Deep Extragalactic Survey (JADES). Last year, when we got our first JADES data, ultra-deep images of hundreds of thousands of galaxies, I wrote a paper which, from the images alone, identified galaxies that emerged in the first 600 million years after the Big Bang. Last winter, we got observations confirming these distances — two of the objects I’d written about were the farthest or from the earliest times humans have ever seen. One galaxy is from 290 million years after the Big Bang and another, 310 million years. So, we’re seeing some of the first galaxies created — this is very profound.

These are remarkably bright — what are the implications of what you write of as ‘a shining cosmic dawn’?

■ As the paper by S. Carniani et al, where I’m the second author, describes, there are two galaxies — one is more in line with the type of brightness expected. However, the farthest one, termed JADES-GS-z14-0, is very bright, four to five times brighter than the other. To be that bright, you need a lot of stars or a good deal of star formation. The fact that this red galaxy is so bright — at only 290 million years after the Big Bang — stresses our models for how quickly we think galaxies could form stars.

Also, this is 1,700 light years across — that’s significantly larger than other galaxies which are usually 200 light years across. We could explain its brightness by surmising that perhaps, the galaxy is experiencing a crazy burst of stars being born and we’re seeing it at the peak of that. There could be other explanations, like when stars are formed in the early universe, the gas clouds that make them are different to the ones which form stars later. This is a real puzzle though as we weren’t expecting to see something so bright at this distance.

CLOUDY SKY: JWST’s ‘Horsehead Nebula’ has hydrogen, methane and ice clouds (Image: Nasa, ESA, CSA, K Misselt, A Abergel)

Could oxygen and hydrogen be present in these galaxies?

■ Jakob Helton, a graduate student I work with in the University of Arizona, saw this galaxy was very bright at longer wavelengths than can be seen with the NIRCam instrument we were using. When we looked at it with MIRI, another instrument, we saw it was even brighter — this shows there is potentially the existence of light that is a glowing ionised hydrogen or even oxygen gas. We need to continue observations but this would have larger implications — oxygen is created inside stars. Those stars then end in supernova explosions. As this galaxy emerged just 290 million years after the Big Bang, that requires very early supernovas. Generally, it’s thought that as we go back in time, we see less of the heavier elements like oxygen. The fact that there is potentially oxygen here is very exciting.
Finding this emphasises how astronomy means reaching into time. We expect the universe to become more simplistic going backwards — but here, the potential presence of oxygen is like finding a smartphone in ancient Rome.

Is there a possibility of life here?

■ We probably can’t find that. Developing life on Earth needed four billion years — this galaxy is just 290 million years old after the start of things. The basic building blocks were beginning while life is so fragile, it needs a long time to grow.

How many stars does this contain?

■ When we modelled JADES-GS-z14-0, we found it’s got 500 million stars in it. This is more than the other galaxy which has only 100 million stars. So, this one has four to five times the num ber of stars’ worth of stuff in it. We’ll need longer wavelength observations to nail this down though.

You’re the first person to see these galaxies — how did that moment feel?

■ I’ve actually found all three of the current distance record-holders as I discovered GS-z13-0 some years ago. But JADES-GS-z14-0 was special — when I found it, I was quite suspicious because it had all the hallmarks of trying to trick us. I was sceptical until we finally confirmed its properties. When you discover these things, it’s just one tiny smudge among thousands — but the confirmation of its distance was a very important moment. That showed how this smudge in fact represents light that travelled for 14 billion years to us — and I was the first person on Earth to see it. Our team was the first group of people to grapple with what that meant. Being part of such a collective of scientists, who put years into this, is a huge privilege. The distance record will be broken by another scientist eventually but it feels good to be part of an assemblage which has pushed human understanding forward by looking a tiny bit into the past.

SPIRALLING IN SPACE: Captured by Webb and Hubble, galaxy NGC 1566 spirals
Humans can’t organise life on Earth too well — why is studying space important?

■ We humans tend to think we come into existence when we are born. We imagine we possess our cells and atoms — but we are just borrowing these, from the food we eat, the air we breathe. These atoms are ours for the tiniest moment. If we trace the energy that goes into our thinking, our heart beating, our blood pumping, you’ll see this has always existed.

Eventually, the atoms in your fingertips and brain, the carbon in your body, go into the centre of stars. Astronomy is very humbling — it teaches us that we are the product of so many things happening in the universe. Looking back at these galaxies helps us learn how the universe began to put life together, starting with the earliest stars, with complex materials which formed other stars and eventually — in one galaxy, around one planet — we formed. All these things had to happen and go right for us to be here — this teaches us life is incredibly precious. We humans don’t treasure life in the way we should or see it as this magnificent product of 14 billion years of things happening. We tend to look at trees, plants and other animals and think, ‘We can do what we want with them because we’re better than them’ — but they are just different expressions of the same idea in the universe, which is putting all life together, atom by atom.

STARSTRUCK...

● Humans have always been fascinated by the stellar world. Hypatia of the 4th century AD was an astronomer of Alexandria, Egypt, where she made plane astrolabes which could calculate dates and times based on the positions of stars and planets. Although Hypatia could imagine the heavens on a plane surface, petty jealousies caused her to be a martyr to a mob

● Galileo was an Italian astronomer of the 16th century — he used telescopes to observe the Milky Way, Jupiter’s satellites, Saturn’s rings and sunspots. An advocate of heliocentrism – the breakthrough idea that Earth revolved around the sun, not the other way around — Galileo was punished with house imprisonment. However, it is not possible to arrest an astronomer’s mind and he then wrote about the geometry of motion

● Sawai Jai Singh of 18th century India, maharaja of Amber, was a proficient astronomer. He built astronomical complexes with building-sized instruments like equinoctial dials to calculate eclipses and the locations of stars. He built Jaipur, the famed ‘pink city’, but his scientific buildings are testament to his far-seeing mind

Research: Encyclopaedia Britannica, CNN, The London Review of Books, The Guardian, Smithsonian Magazine