破晓号的紫外金星

破晓号的紫外金星

ByNASA中文

2023年7月3日 Venus in Ultraviolet from Akatsuki Image Credit & Copyright: JAXA, Planet-C Project Team; h/t: Mehmet Hakan Özsaraç Explanation: Why is Venus so different from Earth? To help find out, Japan launched the robotic Akatsuki spacecraft which entered orbit around Venus late in 2015 after an unplanned five-year adventure around the inner Solar System. Even though Akatsuki was past its original planned lifetime, the spacecraft and instruments were operating so well that much of its original mission was reinstated. Also known as the Venus Climate Orbiter, Akatsuki’s instruments investigated unknowns about Earth’s sister planet, including whether volcanoes are still active, whether lightning occurs in the dense atmosphere, and why wind speeds greatly exceed the planet’s rotation speed. In the featured image taken by Akatsuki‘s UVI…

MAVEN的火星紫外影像

MAVEN的火星紫外影像

ByNASA中文

2023年6月27日 MAVEN’s Ultraviolet Mars Image Credit: MAVEN, Laboratory for Atmospheric and Space Physics, Univ. Colorado, NASA Explanation: These two global views of Mars were captured at ultraviolet wavelengths, beyond the spectrum visible to human eyes. Recorded by the MAVEN spacecraft’s Imaging Ultraviolet Spectrograph instrument in July 2022 (left) and January 2023, three otherwise invisible ultraviolet bands are mapped into red, green, and blue colors. That color scheme presents the Red Planet’s surface features in shades of tan and green. Haze and clouds appear white or blue, while high altitude ozone takes on a dramatic purple hue. On the left, Mars’ south polar ice cap is in brilliant white at the bottom but shrinking during the southern hemisphere’s summer season. On the right, the northern hemisphere’s…

河外星系特写: NGC 6744

河外星系特写: NGC 6744

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2022年11月25日 NGC 6744: Extragalactic Close-Up Image Credit: NASA, ESA, and the LEGUS team Explanation: Beautiful spiral galaxy NGC 6744 is nearly 175,000 light-years across. That’s larger than the Milky Way. It lies some 30 million light-years distant in the southern constellation Pavo, with its galactic disk tilted towards our line of sight. This Hubble close-up of the nearby island universe spans about 24,000 light-years or so across NGC 6744’s central region. The Hubble view combines visible light and ultraviolet image data. The giant galaxy’s yellowish core is dominated by the visible light from old, cool stars. Beyond the core are star-forming regions and young star clusters scattered along the inner spiral arms. NGC 6744’s young star clusters are bright at ultraviolet wavelengths, shown in blue…

金星与三个紫外波段的太阳

金星与三个紫外波段的太阳

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2022年3月6日 Venus and the Triply Ultraviolet Sun Image Credit: NASA/SDO & the AIA, EVE, and HMI teams; Digital Composition: Peter L. Dove Explanation: This was a very unusual type of solar eclipse. Typically, it is the Earth’s Moon that eclipses the Sun. In 2012, though, the planet Venus took a turn. Like a solar eclipse by the Moon, the phase of Venus became a continually thinner crescent as Venus became increasingly better aligned with the Sun. Eventually the alignment became perfect and the phase of Venus dropped to zero. The dark spot of Venus crossed our parent star. The situation could technically be labeled a Venusian annular eclipse with an extraordinarily large ring of fire. Pictured here during the occultation, the Sun was imaged in…

紫外光波段的仙女座星系

紫外光波段的仙女座星系

ByNASA中文

2021年7月18日 The Andromeda Galaxy in Ultraviolet Image Credit: NASA, JPL-Caltech, GALEX Explanation: What does the Andromeda galaxy look like in ultraviolet light? Young blue stars circling the galactic center dominate. A mere 2.5 million light-years away, the Andromeda Galaxy, also known as M31, really is just next door as large galaxies go. Spanning about 230,000 light-years, it took 11 different image fields from NASA’s Galaxy Evolution Explorer (GALEX) satellite telescope to produce this gorgeous portrait of the spiral galaxy in ultraviolet light in 2003. While its spiral arms stand out in visible light images, Andromeda’s arms look more like rings in ultraviolet. The rings are sites of intense star formation and have been interpreted as evidence that Andromeda collided with its smaller neighboring elliptical galaxy…