{"id":595905,"date":"2026-08-25T21:48:16","date_gmt":"2026-08-25T21:48:16","guid":{"rendered":"https:\/\/www.newsbeep.com\/il\/595905\/"},"modified":"2026-08-25T21:48:16","modified_gmt":"2026-08-25T21:48:16","slug":"a-comet-photobombed-a-powerful-telescope-and-revealed-something-astronomers-rarely-see","status":"publish","type":"post","link":"https:\/\/www.newsbeep.com\/il\/595905\/","title":{"rendered":"A Comet Photobombed a Powerful Telescope and Revealed Something Astronomers Rarely See"},"content":{"rendered":"

\"\"<\/a>Naked Photo-Bombing Comet 28P\/Neujmin captured by the Subaru Telescope (white box and enlarged inset). Image Credits: NAOJ.<\/p>\n

A comet slipped unnoticed into images taken by one of the world\u2019s most powerful telescopes. Nearly a decade later, astronomers realized the cosmic photobomb had captured something exceptionally difficult to see: a comet stripped of its familiar glowing shroud.<\/p>\n

The accidental appearance of Comet 28P\/Neujmin by the Subaru Telescope gave researchers a rare look directly at its solid nucleus. It also showed astronomers something they weren\u2019t expecting.<\/p>\n

The surprise came when they examined how that dark surface reflected sunlight. Although the comet 28P looks much like some of the Solar System\u2019s<\/a> darkest asteroids, its surface behaves strikingly differently \u2014 a clue that billions of years of comet activity may have physically reshaped its skin.<\/p>\n

The comet nobody was looking for<\/p>\n

Subaru Telescope (\u3059\u3070\u308b\u671b\u9060\u93e1) is an 8.2-metre (320 in) telescope of the National Astronomical Observatory of Japan, located at the Mauna Kea Observatory on Hawaii. <\/p>\n

Subaru is one of the few state-of-the-art telescopes to have been used with the naked eye, but mostly, it\u2019s used to study distant galaxies<\/a> and stars. No one aimed it at a comet.<\/p>\n

Instead, the comet wandered through images collected in 2016 by Subaru\u2019s Hyper Suprime-Cam, or HSC. The telescope\u2019s field of view spans roughly the area of nine full moons, making it particularly good at catching objects that were never intended to be in the picture.<\/p>\n

\"\"<\/a>Typical example of a (different) comet, 12P. Image via Wiki Commons.<\/p>\n

Researchers later searched publicly available HSC survey data for known Solar System bodies<\/a> and found 28P hiding among observations originally taken for other science. One Subaru image containing the comet also holds more than 2,000 stars and galaxies, so it\u2019s understandable that the comet just slipped by.<\/p>\n

But when they found it, researchers realized the image had extraordinary timing.<\/p>\n

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When Subaru photographed it, 28P sat more than 10 astronomical units<\/a> from the Sun \u2014 more than 10 times the Earth-Sun distance. That\u2019s farther out than Saturn is from the Sun. At that distance, the comet was so cold that the usual release of gas and dust had essentially shut down. Images showed no detectable coma, the fuzzy cloud that normally hides a comet\u2019s nucleus.<\/p>\n

That\u2019s great news because it gives astronomers a chance to look directly at the solid body itself. Even better, Earth, the comet and the Sun happened to be almost perfectly lined up. <\/p>\n

\"-3\"<\/a>Schematic illustration of opposition geometry. Image Credits: NAOJ.<\/p>\n

When sunlight strikes an airless object almost directly from behind the observer, the object can suddenly brighten. Shadows between surface grains disappear, while some light can scatter through the material and return toward its source. Astronomers call this the opposition effect, or opposition surge.<\/p>\n

It\u2019s like the entire universe conspired to give Subaru a fantastic shot of the comet, and we almost missed it.<\/p>\n

It looked like a dark asteroid \u2014 until the light hits it<\/p>\n

Comets and asteroids<\/a> are often lumped together as leftover building blocks of the Solar System, but they behave very differently. <\/p>\n

Asteroids are generally rocky or metal-rich bodies that remain relatively unchanged as they orbit the Sun. Comets contain more volatile ices, and when they swing close enough to the Sun, those ices vaporize and carry dust into space. This creates the glowing coma and tail that make comets so distinctive. Yet when a comet travels far from the Sun and goes dormant, that difference can become much harder to see. Stripped of its coma, a comet nucleus can look remarkably asteroid-like \u2014 which is exactly what made 28P so intriguing.<\/p>\n

Measurements across three colors of light showed a reddish surface similar to a D-type asteroid, extremely dark primitive bodies found throughout the outer Solar System.<\/p>\n

But 28P did not reflect sunlight like the dark asteroids it resembles. When Earth, the comet and the Sun were almost perfectly aligned, 28P brightened much more sharply than C- and D-type asteroids usually do.<\/p>\n

The researchers think this may come from the way light bounces through tiny grains on the comet\u2019s surface<\/a> and reflects back toward us. That suggests 28P\u2019s surface is built differently, with a different grain size, spacing or texture. Even though its color looks asteroid-like, its structure is different.<\/p>\n

A lot of science from a random photobomb<\/p>\n

The result raises a tantalizing possibility. A comet and an asteroid might start with similar primitive material but acquire very different surfaces. Each time a comet approaches the Sun, escaping gas and sublimating ice can disturb, remove and rearrange material. Repeated over many orbits, that process could remodel its outermost layers. This is something that\u2019s been theorized, but not conclusively proven.<\/p>\n

These comet photobombs could help with that, and there may be many more of them waiting to be uncovered.<\/p>\n

\u201cThe same archive likely contains many more Solar System<\/a> objects waiting to be found,\u201d lead author Takafumi Ootsubo of the University of Occupational and Environmental Health said in a Subaru Telescope release. \u201cBy applying the same observational approach to many more comets in the future, we hope to uncover how the surface structures of cometary nuclei have evolved over time.,\u201d<\/p>\n

In other words, some of astronomy\u2019s next comet discoveries may already have been photographed. Scientists just have to notice what wandered into the frame.<\/p>\n

The study can be read for free <\/a>here<\/a>.<\/p>\n


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\n <\/a><\/p>\n","protected":false},"excerpt":{"rendered":"Naked Photo-Bombing Comet 28P\/Neujmin captured by the Subaru Telescope (white box and enlarged inset). Image Credits: NAOJ. A…\n","protected":false},"author":2,"featured_media":595906,"comment_status":"","ping_status":"","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[7],"tags":[3720,8570,85,46,141,134739],"class_list":["post-595905","post","type-post","status-publish","format-standard","has-post-thumbnail","category-science","tag-asteroid","tag-comet","tag-il","tag-israel","tag-science","tag-subaru-telescope"],"_links":{"self":[{"href":"https:\/\/www.newsbeep.com\/il\/wp-json\/wp\/v2\/posts\/595905","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.newsbeep.com\/il\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.newsbeep.com\/il\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.newsbeep.com\/il\/wp-json\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/www.newsbeep.com\/il\/wp-json\/wp\/v2\/comments?post=595905"}],"version-history":[{"count":0,"href":"https:\/\/www.newsbeep.com\/il\/wp-json\/wp\/v2\/posts\/595905\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.newsbeep.com\/il\/wp-json\/wp\/v2\/media\/595906"}],"wp:attachment":[{"href":"https:\/\/www.newsbeep.com\/il\/wp-json\/wp\/v2\/media?parent=595905"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.newsbeep.com\/il\/wp-json\/wp\/v2\/categories?post=595905"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.newsbeep.com\/il\/wp-json\/wp\/v2\/tags?post=595905"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}