緑の光まとう月の日没撮影　米宇宙企業の無人着陸船

【ワシントンＡＦＰ＝時事】米宇宙企業ファイアフライ・エアロスペースの無人月着陸船が、月の地平線に太陽が沈む様子を高解像度で撮影した。かすみのような光が捉えられており、米航空宇宙局（ＮＡＳＡ）は、１９６０年代に月面で初めて観測された同様の現象を解明する一助になると期待している。（写真は、米宇宙企業ファイアフライ・エアロスペースの無人月着陸船が撮影した、月面に沈む太陽。小さな点は金星、上は地球）
　同社の着陸船「ブルーゴースト」は今月２日、月の表側の北東に位置する盆地内の火山地形近くに着陸。１６日、月の夜が訪れ電源が切れるまで、稼働していた。
　同日に送られてきた画像の一つには、太陽が地平線のすぐ上で輝き、ハロ（光輪、日暈〈ひがさ〉）が緑色に染まる様子が捉えられている。
　太陽の上には小さな点の金星が映っている。太陽の光で明るく照らされる地球は、太陽とほぼ同じ大きさに見える。別の画像には、西向きのカメラから、緑色の輝きを伴った沈む太陽が映し出されている。
　ＮＡＳＡ科学ミッション局のジョエル・カーンズ氏によると、日没時の光学現象は「地平線の輝き」や「ちりの浮遊」と呼ばれるもので、月のちりの粒子が太陽からの紫外線によって帯電し、月面から浮かび上がっている可能性があると考えられている。この現象は１９６０年代にＮＡＳＡのサーベイヤー探査機が初めて観察。その後、アポロ計画で月面に降り立った宇宙飛行士によっても観察された。【翻訳編集ＡＦＰＢＢＮｅｗｓ】
〔ＡＦＰ＝時事〕（2025/03/19-16:49）

A private US lander has captured eerie high-definition images of a lunar sunset, which NASA hopes will help unravel the mystery of a strange haze first observed on the Moon in the 1960s.
Texas-based Firefly Aerospace, which published the pictures on Tuesday, became the first private company to land a robotic spacecraft upright on the Moon earlier this month.
Its Blue Ghost lander -- roughly the size of two rhinos side by side -- touched down on March 2 at Mons Latreille, a volcanic feature within Mare Crisium on the Moon's northeastern near side, and operated until March 16 when it powered down with the onset of the lunar night.
One of the new images shows the Sun glowing just above the horizon, its halo tinged with green.
Above it, a small dot marks Venus, while Earth's bright reflection appears almost as large as the Sun at the top of the frame. Another view reveals the setting Sun bathed in a green glow, as seen from a west-facing camera.
We are taking time to have scientific specialists go over all the imagery, said Joel Kearns, deputy associate administrator for exploration at NASA's Science Mission Directorate.
One of the things they will be looking for is to see if they can identify 'horizon glow' or a mechanism called 'dust lofting.'
Scientists believe lunar dust particles may become electrically charged due to ultraviolet radiation from the Sun, causing them to levitate above the surface. The phenomenon was first spotted by NASA's Surveyor probes in the 1960s and later observed by Apollo astronauts.
Kearns noted that scientists will compare the images with complementary readings from Blue Ghost's instruments, including electromagnetic field and radiation sensors, to refine existing theories.
The images themselves are beautiful, they're really aesthetic, he said.
The west-facing image, in particular, shows soil in front of the lander illuminated by light reflected from mountains behind it. The picture's level of detail could help scientists refine models of how light scatters on the lunar surface.
Earlier in the mission, Blue Ghost also captured high-definition imagery of a total solar eclipse from the Moon on March 14.
The mission was part of a NASA-industry collaboration aimed at cutting costs and supporting Artemis, the program to return astronauts to the Moon and use lessons learned there to go to Mars.
Firefly Aerospace's spaceflight program director, Ray Allensworth, said the company is already applying lessons to future flights, including Blue Ghost-2 and Blue Ghost-3.
The lander is absolutely not designed to survive the extreme cold of lunar night, so I think the probability is very low that we will power back on -- but this lander has surprised me, she added.