尖峰石阵后方的人造卫星

尖峰石阵后方的人造卫星

ByNASA中文

2022年6月14日 Satellites Behind Pinnacles Image Credit & Copyright: Joshua Rozells Explanation: What are all those streaks across the background? Satellite trails. First, the foreground features picturesque rock mounds known as Pinnacles. Found in the Nambung National Park in Western Australia, these human-sized spires are made by unknown processes from ancient sea shells (limestone). Perhaps more eye-catching, though, is the sky behind. Created by low-Earth orbit satellites reflecting sunlight, all of these streaks were captured in less than two hours and digitally combined onto the single featured image, with the foreground taken consecutively by the same camera and from the same location. Most of the streaks were made by the developing Starlink constellation of communication satellites, but some are not. In general, the streaks are indicative…

M51：哈勃的涡状星系影像

M51：哈勃的涡状星系影像

ByNASA中文

2022年6月13日 M51: The Whirlpool Galaxy from Hubble Image Credit: NASA, ESA, Hubble, HLA; Processing & Copyright: Bernard Miller Explanation: The Whirlpool Galaxy is a classic spiral galaxy. At only 30 million light years distant and fully 60 thousand light years across, M51, also known as NGC 5194, is one of the brightest and most picturesque galaxies on the sky. The featured image is a digital combination of images taken in different colors by the Earth-orbiting Hubble Space Telescope, highlighting many sharp features. Anyone with a good pair of binoculars, however, can see this Whirlpool toward the constellation of the Hunting Dogs (Canes Venatici). M51 is a spiral galaxy of type Sc and is the dominant member of a whole group of galaxies. Astronomers speculate that…

寻找月面人

寻找月面人

ByNASA中文

2022年6月12日 Find the Man in the Moon Image Credit & Copyright: Dani Caxete Explanation: Have you ever seen the Man in the Moon? This common question plays on the ability of humans to see pareidolia — imagining familiar icons where they don’t actually exist. The textured surface of Earth’s full Moon is home to numerous identifications of iconic objects, not only in modern western culture but in world folklore throughout history. Examples, typically dependent on the Moon’s perceived orientation, include the Woman in the Moon and the Rabbit in the Moon. One facial outline commonly identified as the Man in the Moon starts by imagining the two dark circular areas — lunar maria — here just above the Moon’s center, to be the eyes. Surprisingly,…

道路与银河

道路与银河

ByNASA中文

2022年6月11日 The Road and the Milky Way Image Credit & Copyright: David Cruz Explanation: At night you can follow this road as it passes through the Dark Sky Alqueva reserve not too far from Alentejo, Portugal. Or you could stop, look up, and follow the Milky Way through the sky. Both stretch from horizon to horizon in this 180 degree panorama recorded on June 3. Our galaxy’s name, the Milky Way, does refer to its appearance as a milky path in the sky. The word galaxy itself derives from the Greek for milk. From our fair planet the arc of the Milky Way is most easily visible on moonless nights from dark sky areas, though not quite so bright or colorful as in this image….

Arp 286：室女三重星系

Arp 286：室女三重星系

ByNASA中文

2022年6月10日 Arp 286: Trio in Virgo Image Credit & Copyright: Nicolas Rolland, Telescope.Live Explanation: This colorful telescopic field of view features a trio of interacting galaxies almost 90 million light-years away, toward the constellation Virgo. On the right two spiky, foreground Milky Way stars echo the extragalactic hues, a reminder that stars in our own galaxy are like those in distant island universes. With sweeping spiral arms and obscuring dust lanes, the dominant member of the trio, NGC 5566, is enormous, about 150,000 light-years across. Just above it lies smaller, bluish NGC 5569. Near center a third galaxy, NGC 5560, is apparently stretched and distorted by its interaction with massive NGC 5566. The trio is also included in Halton Arp’s 1966 Atlas of Peculiar Galaxies…

天鹅座的宇宙云

天鹅座的宇宙云

ByNASA中文

2022年6月9日 Cosmic Clouds in Cygnus Image Credit & Copyright: Wolfgang Zimmermann Explanation: These cosmic clouds of gas and dust drift through rich star fields along the plane of our Milky Way Galaxy toward the high flying constellation Cygnus. They’re too faint to be seen with the unaided eye though, even on a clear, dark night. Image data from a camera and telephoto lens using narrowband filters was used to construct this 10 degree wide field of view. The deep mosaic reveals a region that includes star forming dust clouds seen in silhouette against the characteristic glow of atomic hydrogen and oxygen gas. NGC 6888 is the standout emission nebula near the top. Blown by winds from an massive Wolf-Rayet star it’s about 25 light-years across…

太平洋面的船舶轨迹

太平洋面的船舶轨迹

ByNASA中文

2022年6月8日 Ship Tracks over the Pacific Ocean Image Credit: NASA, Terra, MODIS; Text: Raymond Shaw (MTU) Explanation: What are those unusual streaks? Some images of planet Earth show clear bright streaks that follow the paths of ships. Known as ship tracks, these low and narrow bands are caused by the ship’s engine exhaust. Water vapor condenses around small bits of exhaust known as aerosols, which soon grow into floating water drops that efficiently reflect sunlight. Ship tracks were first discovered in 1965 in Earth images taken by NASA’s TIROS satellites. Multiple ship tracks are visible across the featured image that was captured in 2009 over the Pacific Ocean by the MODIS instrument on NASA’s Terra satellite. Inspired by ship-tracks, some scientists have suggested deploying a…

NGC 6188：天坛座的龙形云气

NGC 6188：天坛座的龙形云气

ByNASA中文

2022年6月7日 NGC 6188: Dragons of Ara Image Credit & Copyright: Shaun Robertson Explanation: Do dragons fight on the altar of the sky? Although it might appear that way, these dragons are illusions made of thin gas and dust. The emission nebula NGC 6188, home to the glowing clouds, is found about 4,000 light years away near the edge of a large molecular cloud unseen at visible wavelengths, in the southern constellation Ara (the Altar). Massive, young stars of the embedded Ara OB1 association were formed in that region only a few million years ago, sculpting the dark shapes and powering the nebular glow with stellar winds and intense ultraviolet radiation. The recent star formation itself was likely triggered by winds and supernova explosions, from previous…

银河系的末日：将与仙女座星系互撞

银河系的末日：将与仙女座星系互撞

ByNASA中文

2022年6月6日 Milky Way Galaxy Doomed: Collision with Andromeda Pending Image Credit: NASA, ESA, Z. Levay and R. van der Marel (STScI); T. Hallas; and A. Mellinger Explanation: Will our Milky Way Galaxy collide one day with its larger neighbor, the Andromeda Galaxy? Most likely, yes. Careful plotting of slight displacements of M31’s stars relative to background galaxies on recent Hubble Space Telescope images indicate that the center of M31 could be on a direct collision course with the center of our home galaxy. Still, the errors in sideways velocity appear sufficiently large to admit a good chance that the central parts of the two galaxies will miss, slightly, but will become close enough for their outer halos to become gravitationally entangled. Once that happens, the…

3C 75里的旋舞双黑洞

3C 75里的旋舞双黑洞

ByNASA中文

2022年6月5日 Two Black Holes Dancing in 3C 75 Image Credit: X-Ray: NASA/CXC/D. Hudson, T. Reiprich et al. (AIfA); Radio: NRAO/VLA/ NRL Explanation: What’s happening at the center of active galaxy 3C 75? The two bright sources at the center of this composite x-ray (blue)/ radio (pink) image are co-orbiting supermassive black holes powering the giant radio source 3C 75. Surrounded by multimillion degree x-ray emitting gas, and blasting out jets of relativistic particles the supermassive black holes are separated by 25,000 light-years. At the cores of two merging galaxies in the Abell 400 galaxy cluster they are some 300 million light-years away. Astronomers conclude that these two supermassive black holes are bound together by gravity in a binary system in part because the jets’ consistent…