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It is not magic, but simply optics sculpted by air and ice where the atmosphere<\/a> thins dramatically. From that altitude, the Moon sat behind the atmosphere along the astronaut\u2019s line of sight, and the arc revealed how moonlight bends and fans through tiny crystals.<\/p>\n Spotting a lunar halo<\/p>\n The work was led by the ISS Crew Earth Observations Facility at NASA\u2019s Johnson Space Center<\/a>.\u00a0The program focuses on astronaut photography that documents Earth\u2019s atmosphere, land, water, and light for science and the public.<\/p>\n From low Earth orbit, the station<\/a> loops the planet a touch above 200 nautical miles, clearing nearly all clouds below.\u00a0<\/p>\n That geometry occasionally places the Moon behind the atmosphere, turning the air into a lens that reshapes its glow for the camera.<\/p>\n The horizon stacks into layers: the troposphere glowing orange, the stratosphere pale white, and the upper layer deep blue.\u00a0<\/p>\n The mesosphere, a frigid region 30 to 54 miles high where temperatures plunge, sometimes hosts the rare ice that completes this optical puzzle.<\/p>\n How a lunar halo forms<\/p>\n When moonlight crosses ice crystals, light changes direction inside those crystals and separates slightly by color, producing arcs and rings.\u00a0<\/p>\n A halo is a ring or light that forms around the sun or moon as the sun or moon light refracts off ice crystals present in a thin veil of cirrus clouds.<\/p>\n The standard definition<\/a> catalogs the familiar ring spanning about 22 degrees from the Moon, with a darker sky inside the circle.\u00a0<\/p>\n The refraction, or bending of light as it crosses from one medium into another, fixes that characteristic radius for ordinary crystal shapes.<\/p>\n The astronaut\u2019s photograph shows only an arc because the ice-bearing layer did not fully encircle the Moon<\/a> from that line of sight.\u00a0<\/p>\n Subtle shifts in crystal orientation at grazing angles can trim the circle into a bright, delicate curve. Crystal geometry matters enormously, since hexagonal plates and columns deflect light in different ways.\u00a0<\/p>\n In thin high clouds, even slight tilts change where the arc sharpens or fades, which matches the partial halo recorded above the dark limb.<\/p>\n Ice this high is rare<\/p>\n Water vapor can drift upward, meet dust, and freeze into microscopic ice well above ordinary clouds.\u00a0<\/p>\n Recent research<\/a> describes how these high ice layers, the highest in Earth\u2019s atmosphere, thrive in the coldest summer regions near 50 miles.<\/p>\n Their altitude makes them exquisitely sensitive to small temperature wiggles and vertical motions.\u00a0<\/p>\n The gravity waves, upward traveling ripples in air density from storms and terrain, can seed fine structure that appears and vanishes as orbit tracks shift.<\/p>\n Years of satellite observations have revealed changing behavior in these night-shining formations and their tight coupling to the lower atmosphere.\u00a0<\/p>\n The findings have altered our previous understanding of why PMCs form and vary according to Dr. James Russell III, principal investigator of NASA\u2019s AIM mission<\/a> at Hampton University.<\/p>\n That context helps explain why the halo sat near the top of the blue layer rather than inside common lower clouds.\u00a0<\/p>\n The ice was not typical cirrostratus; it likely resided where cold and chemistry allow only the thinnest veils to survive.<\/p>\n Why the Moon looked full<\/p>\n During the pass, the Moon<\/a> was a waxing crescent, but the camera\u2019s exposure brightened the entire disk and smeared highlights along its edge.\u00a0<\/p>\n The result makes a sliver appear rounded, while the hard bright crescent still marks the sunlit limb with clinical clarity.\u00a0<\/p>\n Longer exposures also amplify the faint glow from Earth-lit terrain on the lunar<\/a> night side. That glow, called Earthshine<\/a>, softens the disk and deepens the impression of a fuller phase.<\/p>\n Lessons from this lunar halo<\/p>\n Photographs from Earth orbit capture momentary alignments that automated sensors often miss, and they carry the context of a human vantage point.\u00a0<\/p>\n Each frame can connect textbook physics to real skies, turning an arc of light into evidence of ice and motion in the thin air.<\/p>\n This image reads like a field note from the edge of space, where optics meets weather and chemistry.\u00a0<\/p>\n A partial lunar halo hanging above the limb lets us watch physics work at planetary scale without leaving the comfort of a 200-mile-high perch.<\/p>\n \u2014\u2013<\/p>\n Like what you read? Subscribe to our newsletter<\/a> for engaging articles, exclusive content, and the latest updates.<\/p>\n Check us out on EarthSnap<\/a>, a free app brought to you by Eric Ralls<\/a> and Earth.com.<\/p>\n \u2014\u2013<\/p>\n","protected":false},"excerpt":{"rendered":"An astronaut circling above the Indian Ocean onboard the ISS captured a stunning image of the moon and…\n","protected":false},"author":2,"featured_media":210943,"comment_status":"","ping_status":"","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[23],"tags":[61,60,82,247],"class_list":{"0":"post-210942","1":"post","2":"type-post","3":"status-publish","4":"format-standard","5":"has-post-thumbnail","7":"category-space","8":"tag-ie","9":"tag-ireland","10":"tag-science","11":"tag-space"},"_links":{"self":[{"href":"https:\/\/www.newsbeep.com\/ie\/wp-json\/wp\/v2\/posts\/210942","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.newsbeep.com\/ie\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.newsbeep.com\/ie\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.newsbeep.com\/ie\/wp-json\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/www.newsbeep.com\/ie\/wp-json\/wp\/v2\/comments?post=210942"}],"version-history":[{"count":0,"href":"https:\/\/www.newsbeep.com\/ie\/wp-json\/wp\/v2\/posts\/210942\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.newsbeep.com\/ie\/wp-json\/wp\/v2\/media\/210943"}],"wp:attachment":[{"href":"https:\/\/www.newsbeep.com\/ie\/wp-json\/wp\/v2\/media?parent=210942"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.newsbeep.com\/ie\/wp-json\/wp\/v2\/categories?post=210942"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.newsbeep.com\/ie\/wp-json\/wp\/v2\/tags?post=210942"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}