{"id":474929,"date":"2026-03-14T08:49:13","date_gmt":"2026-03-14T08:49:13","guid":{"rendered":"https:\/\/www.newsbeep.com\/uk\/474929\/"},"modified":"2026-03-14T08:49:13","modified_gmt":"2026-03-14T08:49:13","slug":"astronomers-just-watched-two-planets-smashing-into-each-other-11000-light-years-away","status":"publish","type":"post","link":"https:\/\/www.newsbeep.com\/uk\/474929\/","title":{"rendered":"Astronomers Just Watched Two Planets Smashing Into Each Other 11,000 Light-Years Away"},"content":{"rendered":"

\"Illustration<\/a>Rendering of the planetary collision astronomers suspect occurred around star Gaia20ehk in 2021. Credit: Andy Tzanidakis<\/p>\n

Astronomers have captured a rare, real-time view of a planetary cataclysm 11,000 light-years away. While monitoring a stable, sun-like star called Gaia20ehk, deep in the constellation Puppis, researchers watched its light suddenly flicker and plunge as a massive cloud of hot debris drifted in front of it. <\/p>\n

This was the smoking gun that told them two planets had smashed into each other. It\u2019s a highly rare look at the same kind of violent impact that created our own moon billions of years ago when a Mars-sized planet called Theia smashed into early Earth. <\/p>\n

An Oddly Flickering Star<\/p>\n

The discovery began when Anastasios Tzanidakis, a doctoral candidate at the University of Washington, noticed the star behaving like nothing he had seen before. For years, Gaia20ehk was a boring main-sequence star with a flat, predictable light output.<\/p>\n

Starting in 2016, the star\u2019s brightness dipped briefly three times. Then, in 2021, the light levels became chaotic and erratic.<\/p>\n

\u201cThe star\u2019s light output was nice and flat, but starting in 2016, it had these three dips in brightness. And then, right around 2021, it went completely bonkers,\u201d Tzanidakis said. \u201cI can\u2019t emphasize enough that stars like our sun don\u2019t do that. So when we saw this one, we were like \u2018Hello, what\u2019s going on here?’\u201d <\/p>\n

The researchers concluded the star itself wasn\u2019t responsible for the flickering; rather, it was being eclipsed by a massive, spreading field of rock and dust.<\/p>\n

To confirm what was blocking the light, the team looked at the system through infrared telescopes. While the star\u2019s visible light was fading and flickering, its infrared signal was surging.<\/p>\n

Two Planets Head-on<\/p>\n

\u201cThe infrared light curve was the complete opposite of the visible light,\u201d Tzanidakis explained. \u201cAs the visible light began to flicker and dim, the infrared light spiked. Which could mean that the material blocking the star is hot \u2014 so hot that it\u2019s glowing in the infrared.\u201d<\/p>\n

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This heat signature \u2014 reaching roughly 900 K (627\u00b0C or 1,160\u00b0F) \u2014 suggests that the astronomers were witnessing a planetary collision. The early, smaller dips in brightness likely represented grazing impacts as two planets spiraled toward each other, coming increasingly closer with each orbit around a common center of mass.<\/p>\n

The massive spike in infrared marked the final, catastrophic head-on crash that pulverized the worlds into a cloud of glowing dust.<\/p>\n

While the study doesn\u2019t state the exact diameters of the two doomed worlds, researchers can estimate their scale by measuring the massive wake of \u201chot wreckage\u201d they left behind. Based on the intensity of the infrared glow, the freshly generated debris has a mass roughly equal to that of Saturn\u2019s icy moon Enceladus.<\/p>\n

However, this relatively small value only accounts for the dust fine enough to glow in the infrared. Because a collision typically only pulverizes a fraction of a planet\u2019s total bulk, the original colliding bodies were likely considerably larger.<\/p>\n

A Reminder of Our Own Origin Story<\/p>\n

This cosmic calamity feels like a d\u00e9j\u00e0 vu. Roughly 4.5 billion years ago, a Mars-sized object is thought to have slammed into the young Earth<\/a>, ejecting the debris that eventually cooled and clumped together to form the moon.<\/p>\n

The debris cloud around Gaia20ehk is currently orbiting at about one astronomical unit (93 million miles) from its star \u2014 the same distance Earth sits from the sun. This makes it a perfect laboratory for studying how terrestrial planets and moons are born.<\/p>\n

\u201cIt\u2019s incredible that various telescopes caught this impact in real time,\u201d Tzanidakis said. \u201cThere are only a few other planetary collisions of any kind on record, and none that bear so many similarities to the impact that created the Earth and moon.\u201d<\/p>\n

Catching these moments is incredibly challenging because the orbits must be perfectly aligned with Earth\u2019s line of sight. However, as new technology comes online, these once-in-a-career finds may become more common.<\/p>\n

James Davenport, a UW assistant research professor and senior author of the study, noted that the team\u2019s success is the result of \u201cslow\u201d astronomy that plays out over a decade or even longer timelines. He believes that the upcoming Vera C. Rubin Observatory could detect 100 similar collisions over the next ten years.<\/p>\n

\u201cHow rare is the event that created the Earth an moon? That question is fundamental to astrobiology,\u201d Davenport said. \u201cRight now, we don\u2019t know how common these dynamics are. But if we catch more of these collisions, we\u2019ll start to figure it out.\u201d<\/p>\n

The findings appeared in The Astrophysical Journal Letters<\/a>.<\/p>\n","protected":false},"excerpt":{"rendered":"Rendering of the planetary collision astronomers suspect occurred around star Gaia20ehk in 2021. Credit: Andy Tzanidakis Astronomers have…\n","protected":false},"author":2,"featured_media":474930,"comment_status":"","ping_status":"","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[23],"tags":[17961,1586,3726,90,416,95,56,54,55],"class_list":["post-474929","post","type-post","status-publish","format-standard","has-post-thumbnail","category-space","tag-exoplanets","tag-moon","tag-planets","tag-science","tag-space","tag-sun","tag-uk","tag-united-kingdom","tag-unitedkingdom"],"_links":{"self":[{"href":"https:\/\/www.newsbeep.com\/uk\/wp-json\/wp\/v2\/posts\/474929","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.newsbeep.com\/uk\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.newsbeep.com\/uk\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.newsbeep.com\/uk\/wp-json\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/www.newsbeep.com\/uk\/wp-json\/wp\/v2\/comments?post=474929"}],"version-history":[{"count":0,"href":"https:\/\/www.newsbeep.com\/uk\/wp-json\/wp\/v2\/posts\/474929\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.newsbeep.com\/uk\/wp-json\/wp\/v2\/media\/474930"}],"wp:attachment":[{"href":"https:\/\/www.newsbeep.com\/uk\/wp-json\/wp\/v2\/media?parent=474929"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.newsbeep.com\/uk\/wp-json\/wp\/v2\/categories?post=474929"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.newsbeep.com\/uk\/wp-json\/wp\/v2\/tags?post=474929"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}