{"id":273938,"date":"2026-01-08T10:45:12","date_gmt":"2026-01-08T10:45:12","guid":{"rendered":"https:\/\/www.europesays.com\/ie\/273938\/"},"modified":"2026-01-08T10:45:12","modified_gmt":"2026-01-08T10:45:12","slug":"from-an-interstellar-comet-to-alien-worlds-these-are-the-biggest-weirdest-space-discoveries-of-2025","status":"publish","type":"post","link":"https:\/\/www.europesays.com\/ie\/273938\/","title":{"rendered":"From an interstellar comet to alien worlds, these are the biggest, weirdest space discoveries of 2025"},"content":{"rendered":"

The year 2025 was a vintage one for astronomy. In January, we were hooked on reports of a building-sized asteroid \u2013\u00a02024 YR4<\/a> \u2013\u00a0on course to collide with Earth.<\/p>\n

The risk was quickly downgraded from worrying to virtually non-existent, but it set the tone for a year packed with discoveries and surprises.\u00a0<\/p>\n

We\u2019re living in a golden era of space observation.<\/p>\n

Telescopes on the ground and up in orbit are revealing more of the Universe than ever before, and in exceptional detail.<\/p>\n

And we\u2019re not just talking about the distant cosmos \u2013 some incredible discoveries have taken place close to home.<\/p>\n

Visitors from outer space, leopard print on Mars, vast hydrogen clouds hiding in plain sight\u2026. At times
it\u2019s felt like science fiction.<\/p>\n

\"AnCredit: NASA\/ESA\/G. Bacon<\/p>\n

So, let\u2019s take a whistle-stop tour through 10 of 2025\u2019s most astonishing discoveries.<\/p>\n

Records have been broken, new objects discovered, and we\u2019re ending the year with more questions than answers.<\/p>\n

But hey, that\u2019s how science should be\u2026<\/p>\n

The Quipu superstructure<\/strong>
\n\"TheThe Perseus cluster of galaxies, captured by the European Space Agency’s Euclid mission. Credit: ESA\/Euclid\/Euclid Consortium\/NASA, image processing by J.-C. Cuillandre (CEA Paris-Saclay), G. Anselmi; CC BY-SA 3.0 IGO<\/p>\n

Let\u2019s start BIG<\/strong>. Early in 2025, astronomers revealed the largest cosmic superstructure ever detected.<\/p>\n

It\u2019s a vast chain of galaxy clusters linked together in three-dimensional space. The team behind the discovery named it \u2018Quipu\u2019 after the Incan knotted cords used for record keeping, both because of its resemblance and as a nod to the key observations being made at the European Southern Observatory in Chile.\u00a0<\/p>\n

So, how big are we talking? The answer is almost unfathomable. Quipu consists of 68 galaxy clusters<\/a>. Its length is at least 1.4 billion lightyears.<\/p>\n

Its mass is approximately 240 million billion times the mass of the Sun. So yes, this is huge, and not just on a physical scale \u2013 superstructures such as Quipu help us understand how matter is distributed across the Universe.<\/p>\n

A rogue black hole<\/strong>
\n\"Artist'sCredit: solarseven \/ Getty Images<\/p>\n

Everyone loves a <\/strong>black hole<\/a> \u2013 but only from afar.<\/p>\n

Our Galaxy feels safest when black holes stay exactly where we expect them \u2013 in galactic centres \u2013 given their proclivity to indiscriminately feed off the matter around them. But not all black holes stay put. Some go rogue.\u00a0<\/p>\n

In 2025, researchers discovered a new candidate for a wandering black hole in a dwarf galaxy named MaNGA 12772-12704, around 230 million lightyears from the Sun.<\/p>\n

The black hole isn\u2019t in the galaxy\u2019s centre, but roughly 3,000 lightyears from it. As if that isn\u2019t surprising enough, this black hole is emitting huge radio jets, showing it\u2019s still actively accreting material despite having been kicked out of its usual home.\u00a0<\/p>\n

Discoveries like this are super exciting as it means we now get to figure out how the black hole got there and where it might go next. And that\u2019s the fun bit.<\/p>\n

Little red dots explained?<\/strong>
\n\"LittleLittle red dots (LRDs) captured by the James Webb Space Telescope. Credit: NASA, ESA, CSA, STScI, Dale Kocevski (Colby College)<\/p>\n

One of the<\/strong> coolest things that the James Webb Space Telescope (JWST) can do is look so deep into space it finds objects from our Universe\u2019s infancy. Even better, it sometimes finds stuff we don\u2019t recognise at all.<\/p>\n

This was the case with the aptly named \u2018little red dots\u2019 (LRDs). These bright, small and very red objects were detected in some of JWST\u2019s early images, but they\u2019ve been challenging to explain.\u00a0<\/p>\n

Initially, researchers suspected they were very early galaxies, but they\u2019re so small it would mean they were inexplicably compact.<\/p>\n

As of 2025, the leading theory is that LRDs are a new classification of object: a black hole star (BH*). Black hole stars are thought to be active black holes surrounded by hot, dense gas.<\/p>\n

The black hole itself is the thing that warms the gas enough that it glows. It\u2019s genuinely wild how much there is still to learn out there!<\/p>\n

Exoplanet milestones<\/strong>
\n\"Artist'sCredit: NASA\u2019s Goddard Space Flight Center<\/p>\n

We can\u2019t talk <\/strong>about space discoveries without mentioning exoplanets \u2013 and 2025 featured two epic milestones for exoplanetology.<\/p>\n

In October 2025, the very first planet discovered orbiting a Sun-like star turned 30! To clarify: 51 Pegasi b is likely to be billions of years old, but our knowledge of its existence has only been around for three decades.\u00a0<\/p>\n

The second epic milestone was in September \u2013 the 6,000th exoplanet<\/a> was discovered and added to the NASA Exoplanet Archive. We passed the 5,000-planet milestone back in 2022, but what\u2019s really exciting is that the newest planets are not just \u2018more of the same\u2019.<\/p>\n

Thanks to TESS, NASA\u2019s all-sky planet survey, many being discovered orbit far brighter stars. This means we can do more than just catalogue them: we can study them in exquisite detail.<\/p>\n

K2-18b’s ‘signs of life’<\/strong>
\n\"Artist'sArtist’s impression of exoplanet K2-18b. Credit: A. Smith, N. Madhusudhan (University of Cambridge)<\/p>\n

Ah, the <\/strong>K2-18b <\/strong>biosignature<\/a> debacle. If you were hiding in a hole in April, you may have missed the news that a \u201cpotential biosignature<\/a>\u201d had been \u201cdetected\u201d in the atmosphere of a \u201chabitable-zone\u201d \u201chycean planet\u201d. I\u2019m quoting, because we need to digest the report with caution.\u00a0<\/p>\n

There\u2019s a category of planet we often refer to simply as mini-Neptunes: too big to be super-Earths, much smaller than Neptune, and something of a mystery. One theory is that they\u2019re \u2018hycean worlds\u2019, hypothetical ocean-covered planets that could harbour life.\u00a0<\/p>\n

K2-18b is everyone\u2019s favourite hycean candidate (although there are several other competing theories as to its nature) and new JWST observations of its atmosphere were published in 2025.<\/p>\n

They revealed\u2026 well, it depends on how you model the data. There might be hints of dimethyl sulphide, a molecule that on Earth is only produced by life. However, other models show no evidence of this.\u00a0<\/p>\n

The exciting part is that we\u2019re now able to have this type of discussion. We\u2019re probing atmospheres of distant worlds and have new ideas on what \u2018habitable\u2019 might mean.<\/p>\n

So far, there has not been an unambiguous detection of a biosignature on another planet. Sorry to disappoint \u2013 but watch this space.<\/p>\n

An interstellar visitor<\/strong>
\n\"ImageImage of comet 3I\/ATLAS captured by the Gemini North telescope, 26 November 2025. Credit: International Gemini Observatory\/NOIRLab\/NSF\/AURA\/B. Bolin. Image Processing: J. Miller & M. Rodriguez (International Gemini Observatory\/NSF NOIRLab), T.A. Rector (University of Alaska Anchorage\/NSF NOIRLab), M. Zamani (NSF NOIRLab)<\/p>\n

Right now, the <\/strong>oldest object in the Solar System could be significantly older than the Sun. How can that be? It\u2019s because we\u2019re currently hosting an interstellar visitor, an object from outside our Solar System.\u00a0<\/p>\n

The comet 3I\/ATLAS<\/a> (the \u2018I\u2019 stands for interstellar and the \u20183\u2019 refers to this being only the third such interstellar object ever found) was first spotted making its way through our bit of space in July, and astronomers have been pointing every telescope possible at it ever since<\/a>. They even pointed NASA\u2019s Perseverance rover\u2019s cameras at it<\/a> from Mars.\u00a0<\/p>\n

3I\/ATLAS was likely ejected during the early formation of another planetary system. This means that examining its composition will provide us with insights into the formation environment around other stars \u2013 and that\u2019s something we almost never get the chance to study.<\/p>\n

The results have already been surprising: lots of carbon dioxide, nickel vapour and water activity all hint at chemical behaviour very different from comets formed in our own Solar System.<\/p>\n

A vast molecular cloud<\/strong>
\n\"Artist'sArtist’s impression of what the Eos molecular cloud would look like in the sky if it could be seen by the naked eye. Credit: NatureLifePhoto\/Flickr (New York City Skyline), Burkhart et al. 2025<\/p>\n

If we\u2019re discovering galaxies that are over 13 billion lightyears away, surely there\u2019s nothing sizeable left to discover nearby\u2026 right? Actually, very wrong.<\/p>\n

Bigger telescopes help us spot objects that are further and fainter, but other breakthroughs come when we look differently. That\u2019s how astronomers discovered an enormous molecular hydrogen cloud on our doorstep, a mere 300 lightyears from Earth.\u00a0<\/p>\n

Usually, these clouds are found by detecting radio signatures from carbon monoxide, another gas typically present in abundance. However, the team behind this discovery used a brand-new technique: detecting far-ultraviolet radiation emitted by the molecular hydrogen itself.<\/p>\n

The cloud, named Eos<\/a> after the goddess of dawn, doesn\u2019t emit any visible light, so we can\u2019t see it in the sky \u2013 but if we could, it would appear about 40 times the size of the Moon, like something straight out of Doctor Who.<\/p>\n

A new moon orbiting Uranus<\/strong>
\n\"AstronomersAstronomers using NASA\u2019s James Webb Space Telescope discovered a new moon orbiting Uranus. Credit: NASA, ESA, CSA, STScI, M. El Moutamid (SwRI), M. Hedman (University of Idaho)<\/p>\n

My favourite fact <\/strong>about Uranus is that its original name was George, a name I am personally quite partial to.<\/p>\n

It was changed (sensibly) after non-British astronomers pointed out that naming a planet after a monarch was a little too nationalistic. I like this silly bit of history, and I\u2019m overjoyed that as of August 2025, Uranus has 29 known moons.<\/p>\n

The new moon, provisionally designated S\/2025 U1, is only about 9.6km (6 miles) in diameter, which explains why it was missed in previous observations. While it would likely have been present in images taken by Voyager 2 and the Hubble Space Telescope, its faintness would have made it invisible.<\/p>\n

Thanks to new long-exposure, infrared observations from the JWST, astronomers finally detected it and calculated its orbit.<\/p>\n

Aurorae on Neptune<\/strong>
\n\"TwoTwo images of Neptune. Left is an image captured by the Hubble Space Telescope. Right is the Hubble image with James Webb Space Telescope data overlaid. Webb’s data shows aurora on Neptune, seen as cyan splotches. Credit: NASA, ESA, CSA, STScI, Heidi Hammel (AURA), Henrik Melin (Northumbria University), Leigh Fletcher (University of Leicester), Stefanie Milam (NASA-GSFC)<\/p>\n

Ever since Voyager<\/strong> 2 flew past Neptune in 1989 and imaged hints of auroral activity, astronomers have been trying to confirm its existence. All other giant planets in the Solar System have aurorae, but it took until March 2025 for the light show on Neptune to finally be recorded in all its glory.\u00a0<\/p>\n

Intriguingly, hypothetical Neptunian beings wouldn\u2019t need to trek to the poles of their planet to witness the spectacle, like we do on Earth. Neptune\u2019s magnetic field is tilted about 47\u00b0 away from its rotation axis, which means aurorae there occur roughly over a region where South America is on our planet.<\/p>\n

It was JWST\u2019s infrared capabilities that provided the critical data to reveal the long-hidden aurorae on Neptune<\/a>, and it turns out they were fainter than expected because the Neptunian atmosphere has cooled by hundreds of degrees in the last few decades. Clearly, there\u2019s a lot still to learn about our planetary siblings.<\/p>\n

Life on Mars<\/strong>
\n\"NASA\u2019sNASA\u2019s Perseverance Mars rover captured this image of a rock with ‘leopard spots’ nicknamed Cheyava Falls on 18 July 2024. Credit: NASA\/JPL-Caltech<\/p>\n

If only David<\/strong> Bowie had asked an easier question, then we\u2019d be closer to an answer. But alas, \u201cWas there ever life on Mars?\u201d doesn\u2019t fit the chorus quite so well.\u00a0<\/p>\n

In 2024, NASA\u2019s Perseverance rover recovered a rock sample with what looked like leopard spots<\/a> on it. In 2025, researchers announced they\u2019d identified them as minerals and textures that on Earth are often associated with microbial activity.<\/p>\n

A bit like with potential biosignatures in exoplanet atmospheres, this is a strong indication that once there might possibly have been life on Mars.\u00a0<\/p>\n

While other, non-biological explanations do exist and can\u2019t yet be ruled out, we don\u2019t have to dampen the excitement completely. We\u2019ve genuinely never been closer to finding evidence of life somewhere other than Earth.<\/p>\n

And if sample-return missions succeed, we\u2019ll get to study these striking speckled rocks in our labs, and perhaps get nearer to a definitive answer.<\/p>\n

What were your favourite space discoveries of 2025? Let us know by emailing contactus@skyatnightmagazine.com<\/a><\/strong><\/p>\n","protected":false},"excerpt":{"rendered":"The year 2025 was a vintage one for astronomy. In January, we were hooked on reports of a…\n","protected":false},"author":2,"featured_media":257625,"comment_status":"","ping_status":"","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[77],"tags":[18,19,17,133],"class_list":{"0":"post-273938","1":"post","2":"type-post","3":"status-publish","4":"format-standard","5":"has-post-thumbnail","7":"category-science","8":"tag-eire","9":"tag-ie","10":"tag-ireland","11":"tag-science"},"share_on_mastodon":{"url":"https:\/\/pubeurope.com\/@ie\/115859077538634196","error":""},"_links":{"self":[{"href":"https:\/\/www.europesays.com\/ie\/wp-json\/wp\/v2\/posts\/273938","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.europesays.com\/ie\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.europesays.com\/ie\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.europesays.com\/ie\/wp-json\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/www.europesays.com\/ie\/wp-json\/wp\/v2\/comments?post=273938"}],"version-history":[{"count":0,"href":"https:\/\/www.europesays.com\/ie\/wp-json\/wp\/v2\/posts\/273938\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.europesays.com\/ie\/wp-json\/wp\/v2\/media\/257625"}],"wp:attachment":[{"href":"https:\/\/www.europesays.com\/ie\/wp-json\/wp\/v2\/media?parent=273938"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.europesays.com\/ie\/wp-json\/wp\/v2\/categories?post=273938"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.europesays.com\/ie\/wp-json\/wp\/v2\/tags?post=273938"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}