{"id":233820,"date":"2025-10-30T10:33:09","date_gmt":"2025-10-30T10:33:09","guid":{"rendered":"https:\/\/www.newsbeep.com\/uk\/233820\/"},"modified":"2025-10-30T10:33:09","modified_gmt":"2025-10-30T10:33:09","slug":"3i-atlas-rapidly-brightens-and-gets-bluer-than-the-sun-near-perihelion-by-avi-loeb-oct-2025","status":"publish","type":"post","link":"https:\/\/www.newsbeep.com\/uk\/233820\/","title":{"rendered":"3I\/ATLAS Rapidly Brightens and Gets Bluer than the Sun Near Perihelion | by Avi Loeb | Oct, 2025"},"content":{"rendered":"

\"Avi<\/a>Press enter or click to view image in full size\"\"New images of 3I\/ATLAS prior to perihelion from various instruments. Left panel: Stack of all CCOR-1 frames of 3I\/ATLAS (top), and an equivalent stack centered on a nearby star on the same frames (bottom). Right panel: Similar stacks of all HI1 (top), COR2 (middle), and LASCO C3 Clear (bottom) frames. All stacks are aligned with north up. The heliocentric velocity (+v), and sunward (\u2299) or anti-sunward (\u2212\u2299) directions are labeled. (Credit: Q. Zhang and K. Dattams<\/a>)<\/p>\n

New images of the interstellar object 3I\/ATLAS<\/a> as it approached perihelion on October 29, 2025, reveal rapid brightening and a color bluer than the Sun.<\/p>\n

3I\/ATLAS is currently hidden from terrestrial telescopes behind the Sun, as it went through solar conjunction relative to Earth on October 21, 2025. However, this unfavorable geometry of opposition from Earth \u2014 a possible hint of design, placed 3I\/ATLAS within the fields of view of several space-based solar coronagraphs and heliospheric imagers, enabling its continued observation during its final approach toward perihelion.<\/p>\n

The new observations were taken by the following set of instruments:<\/p>\n

1. STEREO (\u201cSolar TErrestrial RElations Observatory\u201d) consists of two identical spacecraft launched in 2006: STEREO-A, which orbits slightly more quickly than Earth around the Sun, and STEREO-B, which orbits slightly more slowly than Earth around the Sun. STEREO-B has not been operational since 2014, so only STEREO-A observed 3I\/ATLAS. The observations were made by two cameras, HI1 and COR2, on the SECCHI (\u201cSun Earth Connection Coronal and Heliospheric Investigation\u201d) instrument suite.<\/p>\n

2. SOHO (\u201cSOlar and Heliospheric Observatory\u201d), launched in 1995, orbits the Sun\u2013Earth first Lagrange (L1) point, carrying the LASCO (\u201cLarge Angle and Spectrometric COronagraph\u201d) coronagraphs.<\/p>\n

3. GOES-19, launched in 2024, is a weather satellite operating in a geostationary orbit, carrying the CCOR-1 (\u201cCompact CORonagraph 1\u201d) coronagraph.<\/p>\n

The new paper (accessible here<\/a>) reports observations of 3I\/ATLAS from STEREO-A\u2019s SECCHI HI1 and COR2, SOHO\u2019s LASCO C3, and GOES-19\u2019s CCOR-1 instruments during the months of September and October 2025.<\/p>\n

The data shows a rapid rise in the brightness of 3I\/ATLAS, scaling inversely with distance from the Sun to the power of -7.5 (\u00b11).<\/p>\n

CCOR-1 resolves a glow extending out to 300,000 kilometers around 3I\/ATLAS, comparable to the scale of the plume of carbon dioxide, traced by the SPHEREx Space Observatory on August 8\u201312, 2025 (accessible here<\/a>).<\/p>\n

In addition, 3I\/ATLAS appears distinctly bluer than the Sun in LASCO\/CCOR-1 color photometry \u2014 in contrast to earlier observations showing it to be red \u2014 suggesting that emission contributes a substantial fraction of the overall visible brightness.<\/p>\n

Following its 2025 October 29 perihelion, 3I\/ATLAS will return to be observable from Earth at twilight. As it arrives at closest approach to Earth on December 19, 2025, ground-based observations as well as data from the Hubble and Webb space telescopes during the month of December will be able to characterize 3I\/ATLAS in great detail. The new data suggests that 3I\/ATLAS will likely emerge from perihelion brighter than before.<\/p>\n

The authors of the new paper state: \u201cThe reason for 3I\/ATLAS\u2019s rapid brightening, which far exceeds the brightening rate of most Oort cloud comets at similar distances from the Sun, remains unclear.\u201d<\/p>\n

Press enter or click to view image in full size\"\"An image of 3I\/ATLAS from the PUNCH constellation of satellites, based on a co-added stack of all of the images from a filter centered around a wavelength of 0.550 micrometer, taken on October 27, 2025. (Credit: Dan Fischer, Kevin Walsh and Marshall Eubanks)<\/p>\n

ABOUT THE AUTHOR<\/p>\n

Press enter or click to view image in full size\"\"(Image Credit: Chris Michel, National Academy of Sciences, 2023)<\/p>\n

Avi Loeb is the head of the Galileo Project, founding director of Harvard University\u2019s \u2014 Black Hole Initiative, director of the Institute for Theory and Computation at the Harvard-Smithsonian Center for Astrophysics, and the former chair of the astronomy department at Harvard University (2011\u20132020). He is a former member of the President\u2019s Council of Advisors on Science and Technology and a former chair of the Board on Physics and Astronomy of the National Academies. He is the bestselling author of \u201cExtraterrestrial:<\/a> The First Sign of Intelligent Life Beyond Earth<\/a>\u201d and a co-author of the textbook \u201cLife in the Cosmos<\/a>\u201d, both published in 2021. The paperback edition of his new book, titled \u201cInterstellar<\/a>\u201d, was published in August 2024.<\/p>\n","protected":false},"excerpt":{"rendered":"Press enter or click to view image in full sizeNew images of 3I\/ATLAS prior to perihelion from various…\n","protected":false},"author":2,"featured_media":233821,"comment_status":"","ping_status":"","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[23],"tags":[90,416,56,54,55],"class_list":{"0":"post-233820","1":"post","2":"type-post","3":"status-publish","4":"format-standard","5":"has-post-thumbnail","7":"category-space","8":"tag-science","9":"tag-space","10":"tag-uk","11":"tag-united-kingdom","12":"tag-unitedkingdom"},"_links":{"self":[{"href":"https:\/\/www.newsbeep.com\/uk\/wp-json\/wp\/v2\/posts\/233820","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=233820"}],"version-history":[{"count":0,"href":"https:\/\/www.newsbeep.com\/uk\/wp-json\/wp\/v2\/posts\/233820\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.newsbeep.com\/uk\/wp-json\/wp\/v2\/media\/233821"}],"wp:attachment":[{"href":"https:\/\/www.newsbeep.com\/uk\/wp-json\/wp\/v2\/media?parent=233820"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.newsbeep.com\/uk\/wp-json\/wp\/v2\/categories?post=233820"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.newsbeep.com\/uk\/wp-json\/wp\/v2\/tags?post=233820"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}