彗星C/2017 K2（PanSTARRS）

彗星C/2017 K2（PanSTARRS）

ByNASA中文

2022年6月30日 Comet C/2017 K2 (PanSTARRS) Image Credit & Copyright: Jose J. Chambo (Cometografia) Explanation: Imaged on June 20 2022, comet C/2017 K2 (PanSTARRS) shares this wide telescopic field of view with open star cluster IC 4665 and bright star Beta Ophiuchi, near a starry edge of the Milky Way. On its maiden voyage to the inner Solar System from the dim and distant Oort cloud, this comet PanSTARRS was initially spotted over five years ago, in May 2017. Then it was the most distant active inbound comet ever found, discovered when it was some 2.4 billion kilometers from the Sun. That put it between the orbital distances of Uranus and Saturn. Hubble Space Telescope observations indicated the comet had a large nucleus less than 18…

太阳系家族的合照

太阳系家族的合照

ByNASA中文

2022年6月29日 Solar System Family Portrait Image Credit & Copyright: Alexis Trigo Explanation: Yes, but have you ever seen all of the planets at once? A rare roll-call of planets has been occurring in the morning sky for much of June. The featured fisheye all-sky image, taken a few mornings ago near the town of San Pedro de Atacama in Chile, caught not only the entire planet parade, but the Moon between Mars and Venus. In order, left to right along the ecliptic plane, members of this Solar System family portrait are Earth, Saturn, Neptune, Jupiter, Mars, Uranus, Venus, Mercury, and Earth. To emphasize their locations, Neptune and Uranus have been artificially enhanced. The volcano just below Mercury is Licancabur. In July, Mercury will move into…

贝比科隆博号太掠过水星

贝比科隆博号太掠过水星

ByNASA中文

2022年6月28日 Mercury from Passing BepiColombo Image Credit & License: ESA, JAXA, BepiColombo, MTM Explanation: Which part of the Moon is this? No part — because this is the planet Mercury. Mercury’s old surface is heavily cratered like that of Earth’s Moon. Mercury, while only slightly larger than Luna, is much denser and more massive than any Solar System moon because it is made mostly of iron. In fact, our Earth is the only planet more dense. Because Mercury rotates exactly three times for every two orbits around the Sun, and because Mercury’s orbit is so elliptical, visitors on Mercury could see the Sun rise, stop in the sky, go back toward the rising horizon, stop again, and then set quickly over the other horizon. From…

雪峰上空的甘姆星云

雪峰上空的甘姆星云

ByNASA中文

2022年6月27日 The Gum Nebula over Snowy Mountains Image Credit & Copyright: Wang Jin Explanation: The Gum Nebula is so large and close it is actually hard to see. This interstellar expanse of glowing hydrogen gas frequently evades notice because it spans 35 degrees — over 70 full Moons — while much of it is quite dim. This featured spectacular 90-degree wide mosaic, however, was designed to be both wide and deep enough to bring up the Gum — visible in red on the right. The image was acquired late last year with both the foreground — including Haba Snow Mountain — and the background — including the Milky Way’s central band — captured by the same camera and from the same location in Shangri-La, Yunnan,…

麒麟座V838的回光

麒麟座V838的回光

ByNASA中文

2022年6月26日 Light Echoes from V838 Mon Image Credit: NASA, ESA, H. E. Bond (STScI) Explanation: What caused this outburst of V838 Mon? For reasons unknown, star V838 Mon’s outer surface suddenly greatly expanded with the result that it became one of the brighter stars in the Milky Way Galaxy in early 2002. Then, just as suddenly, it shrunk and faded. A stellar flash like this had never been seen before — supernovas and novas expel matter out into space. Although the V838 Mon flash appears to expel material into space, what is seen in the featured image from the Hubble Space Telescope is actually an outwardly expanding light echo of the original flash. In a light echo, light from the flash is reflected by successively…

太阳系的行星

太阳系的行星

ByNASA中文

2022年6月25日 Planets of the Solar System Image Credit & Copyright: Antonio Canaveras, Chiara Tronci, Giovanni Esposito, Giuseppe Conzo, Luciana Guariglia, (Gruppo Astrofili Palidoro) Explanation: Simultaneous images from four cameras were combined to construct this atmospheric predawn skyscape. The cooperative astro-panorama captures all the planets of the Solar System, just before sunrise on June 24. That foggy morning found innermost planet Mercury close to the horizon but just visible against the twilight, below and left of brilliant Venus. Along with the waning crescent Moon, the other bright naked-eye planets, Mars, Jupiter, and Saturn lie near the ecliptic, arcing up and to the right across the wide field of view. Binoculars would have been required to spot the much fainter planets Uranus and Neptune, though they also…

太阳西侧临边的条珥

太阳西侧临边的条珥

ByNASA中文

2022年6月24日 Filaprom on the Western Limb Image Credit & Copyright: Martin Wise Explanation: A solar filament is an enormous stream of incandescent plasma suspended above the active surface of the Sun by looping magnetic fields. Seen against the solar disk it looks dark only because it’s a little cooler, and so slightly dimmer, than the solar photosphere. Suspended above the solar limb the same structure looks bright when viewed against the blackness of space and is called a solar prominence. A filaprom would be both of course, a stream of magnetized plasma that crosses in front of the solar disk and extends beyond the Sun’s edge. In this hydrogen-alpha close-up of the Sun captured on June 22, active region AR3038 is near the center of…

螺旋星系NGC 6744

螺旋星系NGC 6744

ByNASA中文

2022年6月23日 Spiral Galaxy NGC 6744 Image Credit & Copyright: Basudeb Chakrabarti Explanation: Beautiful spiral galaxy NGC 6744 is nearly 175,000 light-years across, larger than our own Milky Way. It lies some 30 million light-years distant in the southern constellation Pavo but appears as only a faint, extended object in small telescopes. We see the disk of the nearby island universe tilted towards our line of sight in this remarkably detailed galaxy portrait, a telescopic view that spans an area about the angular size of a full moon. In it, the giant galaxy’s elongated yellowish core is dominated by the light from old, cool stars. Beyond the core, grand spiral arms are filled with young blue star clusters and speckled with pinkish star forming regions. An…

超新星遗迹：面纱星云

超新星遗迹：面纱星云

ByNASA中文

2022年6月22日 Supernova Remnant: The Veil Nebula Image Credit & Copyright: Craig Stocks (Utah Desert Remote Observatories) Explanation: Ten thousand years ago, before the dawn of recorded human history, a new light would have suddenly have appeared in the night sky and faded after a few weeks. Today we know this light was from a supernova, or exploding star, and record the expanding debris cloud as the Veil Nebula, a supernova remnant. Imaged with color filters featuring light emitted by sulfur (red), hydrogen (green), and oxygen (blue), this deep wide-angle view was processed to remove the stars and so better capture the impressive glowing filaments of the Veil. Also known as the Cygnus Loop, the Veil Nebula is roughly circular in shape and covers nearly 3…

台北上空的日行迹

台北上空的日行迹

ByNASA中文

2022年6月21日 Analemma over Taipei Image Credit & Copyright: Meiying Lee Explanation: Does the Sun return to the same spot on the sky every day? No. A better and more visual answer to that question is an analemma, a composite of images taken at the same time and from the same place over the course of a year. The featured analemma was compiled at 4:30 pm many afternoons from Taiwan during 2021, with the city skyline of Taipei in the foreground, including tall Taipei 101. The Sun’s location in December — at the December solstice — is shown on the far left, while its location at the June solstice is captured on the far right. Also shown are the positions of the Sun throughout the rest…