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Like I said, astronomers are pretty sure that population III stars exist, but we haven’t directly seen them. Now, though, we’ve got the best candidate yet for a galaxy full of them.

There are a few ways in which pop III stars are different from modern ones, but the biggest one is that they contain no elements heavier than helium. They’re also expected to be bigger and hotter than other stars, and to form in relatively small clusters, rather than enormous galaxies like the Milky Way. Most of them would have formed and exploded between about 100 million and 400 million years after the big bang – which would make them so distant that they’re almost impossible for us to see.

That’s why the latest candidate for a galaxy full of them, called LAP1-B, was such a surprise. It is at a distance that means we see it as it was about 800 million years after the big bang, which is remarkably late for pop III stars to have formed. But it seems to check all the boxes for a galaxy containing these primordial objects. It has a few heavy elements, but those may be in the ambient gas, not the actual stars. You can read more about LAP1-B in my story on this discovery.

Directly spotting pop III stars would be a big deal. At the time the first stars were forming, the universe was full of just hydrogen and helium. To be frank, it was somewhat boring. Then stars came along and started making heavier elements, and those elements started combining in interesting ways, and those interesting compounds started to create planets and, eventually, life. Pop III stars were the first step along that path, so understanding them helps us understand the whole trajectory – not to mention what it would teach us about how modern stars and galaxies formed and evolved, and the makeup of the cosmos.

Credit: NASA/CXC/RIKEN & GSFC/T. Sato et al; DSS

It is widely accepted that the universe is expanding at an accelerating rate, but now researchers say our measurements of the mysterious force driving that may be wrong and that the universe began to slow 1.5 billion years ago – yet other scientists disagree. Read more

Interstellar objects like 3I/ATLAS are exciting, but there is no reason to claim that they are evidence of alien spacecraft – sometimes a comet is just comet. Read more

A distant black hole has been caught releasing the brightest flare ever, which is the result of it ripping apart and devouring an enormous star. Read more

A mathematical model suggests that when a pair of black holes gets quantum entangled, this can give rise to a lumpy space-time tunnel between them. Read more

Credit: Andrew McCarthy

This absolute stunner is comet C/2025 A6 (Lemmon), which made its closest approach to Earth on 21 October. Like most comets, it has two tails, one made of dust and the other of gas. If you’re in an area with dark-enough skies, you might be able to see comet Lemmon with basic binoculars or possibly even with the naked eye, roughly towards the west in the evening or the east in the early morning, depending on your location. Right now, it’s visible only in the northern hemisphere, but later this month it will become visible in the southern hemisphere, too. It’ll reach its closest point to the sun, when its tail will be biggest and brightest, on 8 November. Go out and have a look!

Berwyn asks: “Are we inside a black hole, and is that black hole inside another universe?”

The short answer? Nah, probably not. But you’re not here for the short answer, so let’s do the long answer. I’ll start with what some people consider evidence for the idea that we could live in a black hole: mainly, the possibility that our universe is rotating. This idea comes from measurements of galaxies that seem to mostly rotate in the same clockwise direction, hinting that perhaps the entire universe is spinning – and previous work has shown that if our universe is inside a black hole, it should rotate. But there are other calculations that don’t show such a rotation, so the conclusion that we’re beyond some event horizon that we can’t see is shaky at best.

Now, the other side of the evidence. At the centre of a black hole – we think – is a point of infinite density called a singularity, and everything inside the black hole is falling towards that point. Everything inside the universe is decidedly not falling towards a single point – rather, it’s doing the exact opposite, hurtling away from everything else at an increasing speed. In fact, the accelerating expansion of the universe is probably the strongest evidence against us being inside a black hole. Black holes shrink over cosmological timescales; they don’t expand. There are more technical mathematical reasons to think we’re not inside a black hole, which brings us back to the short answer: we’re probably not.

Credit: CTIO/NOIRLab/NSF/AURA/DECam DELVE Survey

The number of satellites orbiting our planet is rising fast, with some estimates suggesting it could increase from about 15,000 today to as much as 80,000 by 2030. Many of these satellites are deliberately deorbited after a few years, meaning they burn up in the atmosphere, leaving behind a cocktail of chemicals. We know this can have harmful effects, such as depleting the ozone layer. Now, researchers are racing to find out in more detail what this new form of pollution could do to our skies and better understand what we can do to tackle it. Read more

Thank you for reading! If you have any comments, questions or wild hypotheticals about space, let me know by emailing me at launchpad@newscientist.com and I’ll try to answer them in an upcoming newsletter.

And remember… satellites in geostationary orbit are 22,223 miles (35,786 kilometers) above the ground and move at a speed of about 7000 miles per hour. Those in low Earth orbit at 150 miles (200 kilometres) up, move at about 17,000 miles per hour. And if there was one at what I’m calling “human height orbit”, 2 metres up, it would have to go nearly 18,000 miles per hour.