鹈鹕星云的恒星、尘埃、云柱与喷流

鹈鹕星云的恒星、尘埃、云柱与喷流

ByNASA中文

2022年10月11日 Stars, Dust, Pillars, and Jets in the Pelican Nebula Image Credit & Copyright: Adriano Almeida Explanation: What dark structures arise within the Pelican Nebula? On the whole, the nebula appears like a bird (a pelican) and is seen toward the constellation of a different bird: Cygnus, a Swan. But inside, the Pelican Nebula is a place lit up by new stars and befouled by dark dust. Smoke-sized dust grains start as simple carbon compounds formed in the cool atmospheres of young stars but are dispersed by stellar winds and explosions. Two impressive Herbig-Haro jets are seen emitted by the star HH 555 on the right, and these jets are helping to destroy the light year-long dust pillar that contains it. Other pillars and jets…

土耳其上空的双月行迹

土耳其上空的双月行迹

ByNASA中文

2022年10月10日 A Double Lunar Analemma over Turkey Image Credit & Copyright: Betul Turksoy Explanation: An analemma is that figure-8 curve you get when you mark the position of the Sun at the same time each day for one year. But the trick to imaging an analemma of the Moon is to wait bit longer. On average the Moon returns to the same position in the sky about 50 minutes and 29 seconds later each day. So photograph the Moon 50 minutes 29 seconds later on successive days. Over one lunation or lunar month it will trace out an analemma-like curve as the Moon’s actual position wanders due to its tilted and elliptical orbit. Since the featured image was taken over two months, it actually shows…

加拿大北部上空的极光

加拿大北部上空的极光

ByNASA中文

2022年10月9日 Auroras over Northern Canada Image Credit & Copyright: Kwon, O Chul (TWAN) Explanation: Gusting solar winds and blasts of charged particles from the Sun resulted in several rewarding nights of auroras back in 2014 December, near the peak of the last 11-year solar cycle. The featured image captured dramatic auroras stretching across a sky near the town of Yellowknife in northern Canada. The auroras were so bright that they not only inspired awe, but were easily visible on an image exposure of only 1.3 seconds. A video taken concurrently shows the dancing sky lights evolving in real time as tourists, many there just to see auroras, respond with cheers. The conical dwellings on the image right are tipis, while far in the background, near…

南天的二颗彗星

南天的二颗彗星

ByNASA中文

2022年10月8日 Two Comets in Southern Skies Image Credit & Copyright: Jose J. Chambo (Cometografia) Explanation: Heading for its closest approach to the Sun or perihelion on December 20, comet C/2017 K2 (PanSTARRS) remains a sight for telescopic observers as it sweeps through planet Earth’s southern hemisphere skies. First time visitor from the remote Oort cloud this comet PanSTARRS sports a greenish coma and whitish dust tail about half a degree long at the upper left in a deep image from September 21. It also shares the starry field of view toward the constellation Scorpius with another comet, 73P/Schwassmann-Wachmann 3, seen about 1 degree below and right of PanSTARRS. Astronomers estimate that first time visitor comet C/2017 K2 (PanSTARRS) has been inbound from the Oort cloud…

木卫三的影子之下

木卫三的影子之下

ByNASA中文

2022年10月7日 In Ganymede’s Shadow Image Credit & Copyright: Andrew McCarthy Explanation: At opposition, opposite the Sun in Earth’s sky, late last month Jupiter is also approaching perihelion, the closest point to the Sun in its elliptical orbit, early next year. That makes Jupiter exceptionally close to our fair planet, currently resulting in excellent views of the Solar System’s ruling gas giant. On September 27, this sharp image of Jupiter was recorded with a small telescope from a backyard in Florence, Arizona. The stacked video frames reveal the massive world bounded by planet girdling winds. Dark belts and light zones span the gas giant, along with rotating oval storms and its signature Great Red Spot. Galilean moon Ganymede is below and right in the frame. The…

NGC 4631：鲸鱼星系

NGC 4631：鲸鱼星系

ByNASA中文

2022年10月6日 NGC 4631: The Whale Galaxy Image Credit & Copyright: Michael Sherick Explanation: NGC 4631 is a big beautiful spiral galaxy. Seen edge-on, it lies only 25 million light-years away in the well-trained northern constellation Canes Venatici. The galaxy’s slightly distorted wedge shape suggests to some a cosmic herring and to others its popular moniker, The Whale Galaxy. Either way, it is similar in size to our own Milky Way. In this sharp color image, the galaxy’s yellowish core, dark dust clouds, bright blue star clusters, and red star forming regions are easy to spot. A companion galaxy, the small elliptical NGC 4627 is just above the Whale Galaxy. Faint star streams seen in deep images are the remnants of small companion galaxies disrupted by…

DART撞击所造成的扩张烟尘

DART撞击所造成的扩张烟尘

ByNASA中文

2022年10月5日 Expanding Plume from DART’s Impact Video Credit: Les Makes Observatory, J. Berthier, F. Vachier, A. Klotz, P. Thierry, T. Santana-Ros, ESA NEOCC, D. Föhring, E. Petrescu, M. Micheli Explanation: What happens if you crash a spaceship into an asteroid? In the case of NASA’s DART spaceship and the small asteroid Dimorphos, as happened last week, you get quite a plume. The goal of the planned impact was planetary protection — to show that the path of an asteroid can be slightly altered, so that, if done right, a big space rock will miss the Earth. The high brightness of the plume, though, was unexpected by many, and what it means remains a topic of research. One possibility is that 170-meter wide Dimorphos is primarily…

移除恒星的老鹰星云

移除恒星的老鹰星云

ByNASA中文

2022年10月4日 Star-Forming Eagle Nebula without Stars Image Credit & Copyright: Yannick Akar Explanation: The whole thing looks like an eagle. A closer look at the Eagle Nebula’s center, however, shows the bright region is actually a window into the center of a larger dark shell of dust. Through this window, a brightly-lit workshop appears where a whole open cluster of stars is being formed. In this cavity tall pillars and round globules of dark dust and cold molecular gas remain where stars are still forming. Paradoxically, it is perhaps easier to appreciate this impressive factory of star formation by seeing it without its stars — which have been digitally removed in the featured image. The Eagle emission nebula, tagged M16, lies about 6500 light years…

诺号的木卫二影像

诺号的木卫二影像

ByNASA中文

2022年10月3日 Jupiter’s Europa from Spacecraft Juno Image Credit & License: NASA, JPL-Caltech, SwRI, MSSS; Processing: Andrea Luck Explanation: What mysteries might be solved by peering into this crystal ball? In this case, the ball is actually a moon of Jupiter, the crystals are ice, and the moon is not only dirty but cracked beyond repair. Nevertheless, speculation is rampant that oceans exist under Europa’s fractured ice-plains that could support life. Europa, roughly the size of Earth’s Moon, is pictured here in an image taken a few days ago when the Jupiter-orbiting robotic spacecraft Juno passed within 325 kilometers of its streaked and shifting surface. Underground oceans are thought likely because Europa undergoes global flexing due to its changing gravitational attraction with Jupiter during its slightly…

超新星加农炮抛射脉冲星J0002

超新星加农炮抛射脉冲星J0002

ByNASA中文

2022年10月2日 Supernova Cannon Expels Pulsar J0002 Image Credit: F. Schinzel et al. (NRAO, NSF), Canadian Galactic Plane Survey (DRAO), NASA (IRAS); Composition: Jayanne English (U. Manitoba) Explanation: What could shoot out a neutron star like a cannon ball? A supernova. About 10,000 years ago, the supernova that created the nebular remnant CTB 1 not only destroyed a massive star but blasted its newly formed neutron star core — a pulsar — out into the Milky Way Galaxy. The pulsar, spinning 8.7 times a second, was discovered using downloadable software Einstein@Home searching through data taken by NASA’s orbiting Fermi Gamma-Ray Observatory. Traveling over 1,000 kilometers per second, the pulsar PSR J0002+6216 (J0002 for short) has already left the supernova remnant CTB 1, and is even fast…