{"id":3803,"date":"2026-05-05T20:13:12","date_gmt":"2026-05-05T20:13:12","guid":{"rendered":"https:\/\/terrarara.com.br\/en\/?page_id=3803"},"modified":"2026-05-05T20:13:12","modified_gmt":"2026-05-05T20:13:12","slug":"um-mundo-minusculo-alem-de-netuno-tem-uma-atmosfera-impossivel","status":"publish","type":"page","link":"https:\/\/terrarara.com.br\/en\/?page_id=3803","title":{"rendered":"A tiny world beyond neptune has an impossible atmosphere"},"content":{"rendered":"
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An artist’s impression of the occultation of 2002 XV93. (NAOJ\/Ko Arimatsu)<\/figcaption><\/figure><\/div>
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\r\n\tdoi.org\/10.1038\/s41550-026-02846-1<\/a>
Credibility<\/a>: 9<\/font>8<\/font>9<\/font>
#Solar System<\/a><\/p>

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\r\n\tScientists have discovered something surprising in the outer reaches of the Solar System<\/strong><\/p>

Far beyond Neptune’s orbit lies a small, icy world, about 500 kilometers in diameter, possessing a thin, tenuous atmosphere.<\/p>

\r\nThe most intriguing aspect is that, according to what was previously known, an object so small and with such weak gravity should not be able to retain any atmosphere.<\/p>

\r\nHowever, it is there, challenging our ideas about how celestial bodies retain gases around them.\r\n<\/p>

\r\nThis object, called (612533) 2002 XV93, is a plutino – a type of icy body that orbits the Sun in resonance with Neptune, at a distance about 40 times that of Earth.<\/p>

\r\nThese distant worlds, located in the Kuiper Belt, are like fossils from the early Solar System.<\/p>

\r\nThey hold valuable information about the formation of planets and the movement of materials when the system was still young.<\/p>

\r\nBut studying them is extremely difficult: they are very small, dark, and distant, reflecting little light to our telescopes.\r\n<\/p>

\r\nThe detection of the atmosphere was only possible thanks to a rare event called a stellar occultation.<\/p>

\r\nIn 2024, Japanese astronomers, led by Ko Arimatsu of the National Astronomical Observatory of Japan, were fortunate enough to observe the exact moment when 2002 XV93 passed in front of a distant star.<\/p>

\r\nUsing three different observation locations in Japan, they precisely recorded how the star’s light was blocked by the object.\r\n<\/p>

\r\nIn a body without an atmosphere, the star’s light would disappear abruptly and reappear in the same way.<\/p>

\r\nBut the data showed something different: for about 1.5 seconds before and after the total blockage, which lasted between 15 and 20 seconds, the light gradually decreased and increased.<\/p>

\r\nThis can only be explained if the light passed through a layer of gas that refracted (bent) it slightly.<\/p>

\r\nModels based on Pluto’s atmosphere have indicated that it is extremely rarefied, composed mainly of methane, nitrogen, or carbon monoxide, with a pressure of only 100 to 200 nanobars – about 5 to 10 million times thinner than Earth’s atmosphere at sea level.\r\n<\/p>

\r\nThis discovery is impressive for two main reasons.<\/p>

\r\nFirst, it demonstrates that our current instruments and techniques are capable of detecting almost non-existent atmospheres on very distant objects.<\/p>

\r\nSecond, calculations show that such a fragile atmosphere should dissipate in just a few hundred or thousand years due to low gravity.<\/p>

\r\nFor it to still exist today, it needs to be replenished somehow.\r\n<\/p>

\r\nThe researchers propose two main explanations.<\/p>

\r\nOne is that a comet recently collided with the object, releasing gases that formed this temporary atmosphere.<\/p>

\r\nAnother possibility is the existence of active cryovolcanoes – ice volcanoes that would expel icy mud and gases from the interior of the body, constantly renewing the atmosphere that escapes into space, as possibly happens on Pluto.\r\n<\/p>

\r\nThis is the first time an atmosphere has been confirmed on a small trans-Neptunian object other than Pluto.<\/p>

\r\nThe finding suggests that even tiny worlds can have atmospheres, at least for short periods, and that we need to revise the idea that only large planets can retain gases around them.<\/p>

\r\nAs the authors wrote in the article published in the journal Nature Astronomy: “Even an object a few hundred kilometers across in the Kuiper Belt can harbor, at least temporarily, an atmosphere.<\/p>

\r\nOur results indicate that a fraction of these distant icy bodies may have atmospheres sustained by cryovolcanic activity or recent impacts.”\r\n<\/p>

\r\nThis observation not only expands our knowledge of the outer reaches of the Solar System, but also opens new possibilities for studying other distant objects with innovative techniques.<\/p>

\r\nWhat seemed impossible may be more common than we imagined, revealing that the Universe continues to be full of surprises in the coldest and darkest places.

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Published in 05\/05\/2026 20h13<\/em><\/p>\r\n

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Portuguese version<\/a><\/em><\/p>\r\n

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Text adapted by AI (Grok) and translated via Google API in the English version. Images from public image libraries or credits in the caption. Information about DOI, author and institution can be found in the body of the article.<\/p>\r\n\t\t

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Reference article:<\/p>\r\n\t\t\r\n\t\t\r\n\r\n\r\n