形似恒星之门的银河

形似恒星之门的银河

ByNASA中文

2022年8月17日 Stargate Milky Way Image Credit & Copyright: Maxime Oudoux Explanation: There is a huge gate of stars in the sky, and you pass through it twice a day. The stargate is actually our Milky Way Galaxy, and it is the spin of the Earth that appears to propel you through it. More typically, the central band of our Milky Way appears as a faint band stretching across the sky, only visible in away from bright city lights. In a long-exposure wide-angle image from a dark location like this, though, the Milky Way’s central plane is easily visible. The featured picture is a digital composite involving multiple exposures taken on the same night and with the same camera, but employing a stereographic projection that causes…

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…

银河系的黑洞

银河系的黑洞

ByNASA中文

2022年5月13日 The Milky Way’s Black Hole Image Credit: X-ray – NASA/CXC/SAO, IR – NASA/HST/STScI; Inset: Radio – Event Horizon Telescope Collaboration Explanation: There’s a black hole at the center of the Milky Way. Stars are observed to orbit a very massive and compact object there known as Sgr A* (say “sadge-ay-star”). But this just released radio image (inset) from planet Earth’s Event Horizon Telescope is the first direct evidence of the Milky Way’s central black hole. As predicted by Einstein’s Theory of General Relativity, the four million solar mass black hole’s strong gravity is bending light and creating a shadow-like dark central region surrounded by a bright ring-like structure. Supporting observations made by space-based telescopes and ground-based observatories provide a wider view of the galactic…

特殊星系Arp 273

特殊星系Arp 273

ByNASA中文

2022年2月19日 Peculiar Galaxies of Arp 273 Image Credit & Copyright: Jason Guenzel Explanation: The spiky stars in the foreground of this backyard telescopic frame are well within our own Milky Way Galaxy. But the two eye-catching galaxies lie far beyond the Milky Way, at a distance of over 300 million light-years. Their distorted appearance is due to gravitational tides as the pair engage in close encounters. Cataloged as Arp 273 (also as UGC 1810), the galaxies do look peculiar, but interacting galaxies are now understood to be common in the universe. Nearby, the large spiral Andromeda Galaxy is known to be some 2 million light-years away and approaching the Milky Way. The peculiar galaxies of Arp 273 may offer an analog of their far future…

好友之间的星系

好友之间的星系

ByNASA中文

2021年11月06日 The Galaxy Between Two Friends Image Credit & Copyright: Martin Lefranc Explanation: On an August night two friends enjoyed this view after a day’s hike on the Plateau d’Emparis in the French Alps. At 2400 meters altitude the sky was clear. Light from a setting moon illuminates the foreground captured in the simple vertical panorama of images. Along the plane of our Milky Way galaxy stars of Cassiopeia and Perseus shine along the panorama’s left edge. But seen as a faint cloud with a brighter core, the Andromeda galaxy, stands directly above the two friends in the night. The nearest large spiral galaxy, Andromeda is about 2.5 million light-years beyond the stars of the Milky Way. Adding to the evening’s shared extragalactic perspective, the…

帕洛玛6：球状星团

帕洛玛6：球状星团

ByNASA中文

2021年10月19日 Palomar 6: Globular Star Cluster Image Credit: ESA/Hubble and NASA, R. Cohen Explanation: Where did this big ball of stars come from? Palomar 6 is one of about 200 globular clusters of stars that survive in our Milky Way Galaxy. These spherical star-balls are older than our Sun as well as older than most stars that orbit in our galaxy’s disk. Palomar 6 itself is estimated to be about 12.5 billion years old, so old that it is close to — and so constrains — the age of the entire universe. Containing about 500,000 stars, Palomar 6 lies about 25,000 light years away, but not very far from our galaxy’s center. At that distance, this sharp image from the Hubble Space Telescope spans about…

星光和尘埃织就的夜晚

星光和尘埃织就的夜晚

ByNASA中文

2021年10月2日 A Light and Dusty Night Image Credit & Copyright: Rodrigo Guerra Explanation: Posing as a brilliant evening star, Venus lies near the western horizon in this southern hemisphere, early spring, night skyscape. To create the composite view exposures tracking the sky and fixed for the foreground were taken on September 25 from Cascavel in southern Brazil. In view after sunset, Venus appears immersed in a cone of zodiacal light, sunlight scattered from dust along the Solar System’s ecliptic plane. In fact from either hemisphere of planet Earth, zodiacal light is most visible after sunset near a spring equinox, (or before sunrise near an autumn equinox) when its luminous arc lies at steep angles to the horizon. Extending above the sunset on this night, the…

萤火虫与银河

萤火虫与银河

ByNASA中文

2021年9月6日 Firefly Milky Way over Russia Image Credit & Copyright: Anton Komlev Explanation: It started with a pine tree. The idea was to photograph a statuesque pine in front of the central band of our Milky Way Galaxy. And the plan, carried out two months ago, was successful — they both appear prominently. But the resulting 3-frame panorama captured much more. Colorful stars, for example, dot the distant background, with bright Altair visible on the upper left. The planet Saturn, a bit closer, was captured just over the horizon on the far left. Just beyond the Earth’s atmosphere, seen in the upper right, an Earth-orbiting satellite was caught leaving a streak during the 25-second exposure. The Earth’s atmosphere itself was surprisingly visible — as green…

英仙座流星与银河

英仙座流星与银河

ByNASA中文

2021年8月3日 A Perseid Fireball and the Milky Way Image Credit & Copyright: Dandan Huang Explanation: It was bright and green and flashed as it moved quickly along the Milky Way. It left a trail that took 30 minutes to dissipate. Given the day, August 12, and the direction, away from Perseus, it was likely a small bit from the nucleus of Comet Swift-Tuttle plowing through the Earth’s atmosphere — and therefore part of the annual Perseids meteor shower. The astrophotographer captured the fireball as it shot across the sky in 2018 above a valley in Yichang, Hubei, China. The meteor’s streak, also caught on video, ended near the direction of Mars on the lower left. Next week, the 2021 Perseids meteor shower will peak again….

树梢框住的银河系

树梢框住的银河系

ByNASA中文

2021年7月19日 Framed by Trees: A Window to the Galaxy Image Credit & Copyright: Will Godward Explanation: The photographer had this shot in mind for some time. He knew that objects overhead are the brightest — since their light is scattered the least by atmospheric air. He also that knew the core of our Milky Way Galaxy was just about straight up near midnight around this time of year in South Australia. Chasing his mental picture, he ventured deep inside the Kuipto Forest where tall radiata pines blocked out much of the sky — but not in this clearing. There, through a window framed by trees, he captured his envisioned combination of local and distant nature. Sixteen exposures of both trees and the Milky Way Galaxy…