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2021年09月08日:仙女大星系方向的深空影像-(The Deep Sky Toward Andromeda)
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欢迎来到人生天地间
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2017年11月29日:M42:猎户座大星云-(M42: The Great Orion Nebula)
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2017年08月06日:银河与炸裂的流星-(Milky Way and Exploding Meteor)
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2024年02月11日:直指月亮的火箭烟尘影子-(Rocket Plume Shadow Points to the Moon)
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2023-04-15
2023年04月15日:火星的Z字形逆行轨迹-(When Z is for Mars)
[2023年04月15日:火星的Z字形逆行轨迹-(When Z is for Mars)--原图下载](https://apod.nasa.gov/apod/image/2304/Ma2022-3.jpg"onMouseOver="if (document.images)document.imagename1.src='image/2304/Ma2022-3La_1024.jpg';"onMouseOut="if (document.images)document.imagename1.src='image/2304/Ma2022-3_1024.jpg';){mtitle title="火星的Z字形逆行轨迹"/}Image Credit &Copyright:Tunc Tezel(TWAN)说明: 这幅影像是由一系列间隔一週的照片组合而成,以呈现赤红火星在2022年8月中旬到2023年3月下旬之间的逆行运动。从右下到左上,当火星通过金牛座的昴宿星团和毕宿星团时,在地球的夜空中留下了Z字形的轨迹。火星并没有真的在轨道上倒着走,只是因为地球本身也在进行轨道运动,所以从地球看出去,火星相对于背景恒星看似在倒退或逆行运动。这种逆行运动每隔大约两年会见到一次。当地球追过离太阳较远的行星时,因为地球在较邻近太阳的轨道上运行速度较快,所以得以看到逆行的现象。在影像中心附近,高悬在北半球夜空中的火星于12月8日位在与太阳反向的冲附近,因此是离地球最近且最明亮的时候。此外,在火星附近,还可见到太阳系内围备受关注的访客 - ZTF彗星(C/2022 E3),其身影分别出现在2月10日和2月16日这两天。{lamp/}原文:{mtitle title="When Z is for Mars"/}Image Credit &Copyright:Tunc Tezel(TWAN)Explanation: A composite of imagescaptured about a week apartfrom mid August 2022 through late March 2023,this series traces theretrograde motion of ruddy-colored Mars.Progressing from lower right to upper leftMars makes aZ-shaped path as it wanderspast the Pleiades and Hyades star clusters,through the constellation Taurus in planet Earth's night sky.Seen about every two years, Mars doesn'tactually reverse the direction of its orbitto trace out the Z-shape though.Instead, the apparent backwards or retrograde motion withrespect to the background stars is areflection of the orbital motion of Earth itself.Retrograde motion can be seen each time Earth overtakesand laps planets orbiting farther from the Sun, theEarth moving more rapidly through its own relatively close-in orbit. High in northern hemisphere skies theRed Planet was opposite the Sunand at its closest and brightest on December 8,near the center of the frame.Seen close to Mars,a popular visitor to the inner Solar System,comet ZTF (C/2022 E3),was also captured on two dates, February 10 and February 16.
2023年04月15日
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2023-03-28
2023年03月28日:落日的多重绿闪-(A Multiple Green Flash Sunset)
2023年03月28日:落日的多重绿闪-(A Multiple Green Flash Sunset)--原图下载{mtitle title="落日的多重绿闪"/}Image Credit & Copyright: T. Slovinský & P. Horálek (IoP Opava);CTIO, NOIRLab,NSF,AURA说明: 你看过的绿闪能玩这种把戏吗?日落时分的绿闪是一种罕见的事件,也因此,许多太阳观察者都以曾亲眼目睹为荣。绿闪曾被认为只是一种迷思,然而现在的人们知道,当地球大气兼具棱镜及透镜的功能时,就会发生绿闪。不同高度的大气分层所产生的光折射也不同,因此,可让源自太阳顶部的光线发生分光,形成2个影像,并将之适当放大,让日盘即将消失前的最后一抹银白带着泛绿的色泽。不过,这幅影像所呈现的则是更不寻常的日落。在去年4月的某一天,从位于智利的高海拔托洛洛山美洲天文台,拍摄到太阳往具有多个不同热分层的大气后方沈降,形成太阳的多重蜃像。而在这次及这个位置,数个分层同时产生了绿闪。就在这个多重绿闪事件,为2位大吃一惊的天文摄影者记录之后的数秒钟,太阳就没入云层之下。{lamp/}原文:{mtitle title="A Multiple Green Flash Sunset"/}Image Credit & Copyright: T. Slovinský & P. Horálek (IoP Opava);CTIO, NOIRLab,NSF,AURAExplanation: Yes, but can your green flash do this?A green flash at sunset is a rare event that many Sun watchers pride themselves on having seen. Once thought to be a myth, a green flash is now understood to occur when the Earth's atmosphere acts like both a prism and a lens.Different atmospheric layers create altitude-variable refraction that takes light from the top of the Sun and disperses its colors, creates two images, and magnifies it in just the right way to make a thin sliver appear green just before it disappears.Pictured, though, is an even more unusual sunset.From the high-altitude Cerro Tololo Inter-American Observatory in Chile one day last April, the Sun was captured setting beyond an atmosphere with multiple distinct thermal layers, creating several mock images of the Sun. This time and from this location, many of those layers produced a green flash simultaneously.Just seconds after this multiple-green-flash event was caught by two well-surprised astrophotographers, the Sun set below the clouds.
2023年03月28日
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2023-01-29
2023年01月29日:巴纳德68:黝黑的分子云-(Barnard 68: Dark Molecular Cloud)
2023年01月29日:巴纳德68:黝黑的分子云-(Barnard 68: Dark Molecular Cloud)--原图下载{mtitle title="巴纳德68:黝黑的分子云"/}Image Credit: FORS Team,8.2-meter VLT Antu,ESO说明: 恒星都上那儿去了?这种以往认为是天空之洞的结构,现在天文学家知道它们是暗分子云。在此例分子云中,緻密的尘埃和分子气体几乎完全吸收了背景恒星所发出的可见光。而诡异幽暗的环境,更让分子云内部成为宇宙最寒冷和最孤寂的地方。其中最着名的暗星云之一,是上面这幅影像所示、位在蛇夫座方向的巴纳德68。这团星云的中心完全看不到恒星,显示它离我们不远,而量测也指出巴纳德68离我们大约5百光年远,宽度则在半光年左右。像巴纳德68这种分子云是如何形成的,目前还不清楚,但确知的是,它们是新恒星的可能诞生之处。事实上研究也指出,巴纳德68极可能会塌缩形成新恒星系统。最后,用红外光其实是有机会透视这团星云。{lamp/}原文:{mtitle title="Barnard 68: Dark Molecular Cloud"/}Image Credit: FORS Team,8.2-meter VLT Antu,ESOExplanation: Where did all the stars go? What used to be considered a hole in the skyis now known to astronomers as a dark molecular cloud. Here, a high concentration ofdust andmolecular gasabsorb practically all the visible lightemitted from background stars. The eerily dark surroundings help make the interiors ofmolecular clouds some of the coldestand most isolated places in the universe. One of the most notable of thesedark absorption nebulaeis a cloud toward the constellationOphiuchus known asBarnard 68,pictured here. That no stars are visible in the center indicates thatBarnard68 is relatively nearby, with measurements placing it about500 light-years away and half a light-year across. It is not known exactly howmolecular clouds likeBarnard 68 form, but it is known that these clouds are themselveslikely placesfor new stars to form.In fact, Barnard 68 itself hasbeen found likely to collapse and form a new star system.It is possible tolook right through the cloud in infrared light.
2023年01月29日
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2022-12-10
2022年12月10日:美国号与宁静海-(America and the Sea of Serenity)
2022年12月10日:美国号与宁静海-(America and the Sea of Serenity)--原图下载{mtitle title="美国号与宁静海"/}Image Credit:Gene Cernan,Apollo 17,NASA;Anaglyph byPatrick Vantuyne说明: 请取出你的红/蓝眼镜,来观赏这幅另一颗天体的精采立体图。这片景观是由阿波罗17号任务指挥官色南,摄于50年前的1972年12月11日,时值降落月表的前一个绕月轨道。这张立体影像组合自二张照片(AS17-147-22465、AS17-147-22466);拍照时,他和施密特位在挑战号登月舱内,正好飞过阿波罗17号在金牛-利特罗峡谷内的预订着陆点上方。在这幅影像中心处,受阳光照耀的宽广山头名为南方高地 (South Massif),而它左方则是谷底部分隐没在暗影中的金牛-利特罗峡谷。在绕月轨道上,由艾文斯所驾驶的美国号指挥舱,刚好飞过南方高地的顶峰前方。在山头的后方靠月球临边附近,则有宁静海。{lamp/}原文:{mtitle title="America and the Sea of Serenity"/}Image Credit:Gene Cernan,Apollo 17,NASA;Anaglyph byPatrick VantuyneExplanation: Get out yourred/blue glasses andcheck out this stereo view of another world.Fifty years agothescene was recordedby Apollo 17 mission commanderEugene Cernan on December 11, 1972,one orbit before descending to land on the Moon.The stereo anaglyph was assembled from two photographs(AS17-147-22465, AS17-147-22466)captured from his vantage point on board the Lunar Module Challenger as heand Dr. Harrison Schmitt flew over Apollo 17'slanding site in theTaurus-LittrowValley.The broad, sunlit face of the mountain dubbedSouth Massif rises near the centerof the frame, above the dark floor ofTaurus-Littrow to its left.Piloted by Ron Evans, the Command Module America isvisible in orbit in the foreground against theSouth Massif's peak.Beyond the mountains, toward the lunar limb, lies the Moon'sMare Serenitatis.
2022年12月10日
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2022-10-08
2022年10月08日:南天的二颗彗星-(Two Comets in Southern Skies)
[2022年10月08日:南天的二颗彗星-(Two Comets in Southern Skies)--原图下载](https://apod.nasa.gov/apod/image/2210/2017K2_2022-09-21_media.jpg"onMouseOver="if (document.images)document.imagename1.src='https://apod.nasa.gov/apod/image/2210/2017K2_2022-09-21_web-label.jpg';"onMouseOut="if (document.images)document.imagename1.src='image/2210/2017K2_2022-09-21_web.jpg';){mtitle title="南天的二颗彗星"/}Image Credit &Copyright: Jose J. Chambo (Cometografia)说明: 在地球南天飞掠,将在12月20日抵达近日点的泛星彗星(C/2017 PanSTARRS),仍然是望远镜观星者巡天的好标的。在这幅摄于9月21日的深空影像里,来自遥远欧特云的首航彗星泛星,是影像左上角那个曳着泛绿彗发及约半度长泛白尘尾的天体。与它分享这片天蝎座天空视野的,还有它右下方相隔约1度、名为施瓦斯曼-瓦赫曼3号(73P/Schwassmann-Wachmann 3)的另一颗彗星。天文学家估计首次到访的彗星C/2017 K2(泛星),循着双曲线轨道从欧特云入境已飞行了约300万年。不过,我们对施瓦斯曼-瓦赫曼3号彗星则较熟悉。这颗週期彗星,沿着稍远于木星及地球附近的椭圆轨道,每5.4年环绕一圈。在9月21日那晚拍下的这幅影像时,泛星彗星距离地球约20光分。而自1995年以来就开始解体的施瓦斯曼-瓦赫曼3号彗星,距离我们则约有7.8光分。{lamp/}原文:{mtitle title="Two Comets in Southern Skies"/}Image Credit &Copyright: Jose J. Chambo (Cometografia)Explanation: Heading for its closest approach to the Sunor perihelion on December 20, cometC/2017 K2 (PanSTARRS) remains a sightfor telescopic observers as it sweepsthrough planet Earth's southern hemisphere skies. First time visitorfrom theremote Oort cloudthis comet PanSTARRS sportsa greenish coma and whitish dust tail about half adegree long at the upper left in a deep image from September 21.It also shares the starry field of view toward the constellationScorpius with another comet,73P/Schwassmann-Wachmann 3,seen about 1 degreebelow and rightof PanSTARRS.Astronomers estimate that first time visitor cometC/2017 K2 (PanSTARRS)has been inbound from the Oort cloud for some 3 million yearsalong a hyperbolic orbit.Schwassmann-Wachmann 3 is more familiar though. The periodic comet loops through its ownelliptical orbit, from just beyond the orbit of Jupiter to the vicinityof Earth's orbit, once every 5.4 years.Just passing in the night, this comet PanSTARRS is about 20light-minutes from Earth in theSeptember 21 image.Seen to be disintegrating since 1995,Schwassmann-Wachmann 3was about 7.8 light-minutes away.
2022年10月08日
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2022-08-04
2022年08月04日:M13: 武仙大星团-(M13: The Great Globular Cluster in Hercules)
2022年08月04日:M13: 武仙大星团-(M13: The Great Globular Cluster in Hercules)--原图下载{mtitle title="M13: 武仙大星团"/}Image Credit &Copyright:Joan Josep Isach Cogollos说明: 在1716年,英国天文学家哈雷写下了这个注记:「它只是夜空的一个小亮斑,不过当夜空清朗无月时,用肉眼就能看见它。」 如今我们当然知道所谓的”它“是M13,一个位在武仙座方向的大型球状星团,同时也是北天最明亮的球状星团之一。类似上面的这种清晰之望远镜影像,则显示这个的庞大星团拥有数十万颗恒星。以这个星团25,000光年的距离来估算,星团的成员星挤在直径为约为150光年的範围内。而在星团的核心附近,边长3光年的空间内就有100颗恒星。相较之下,离太阳最近的恒星超过4光年远。这幅影像拥有极大的亮度範围,因此可分辨星团核心的恒星。此外,在这幅中等视野的影像里,还可见到包括上左方NGC 6207在内的遥远背景星系。{lamp/}原文:{mtitle title="M13: The Great Globular Cluster in Hercules"/}Image Credit &Copyright:Joan Josep Isach CogollosExplanation: In1716, English astronomerEdmond Halley noted,"This is but a little Patch, but it shows itself to the naked Eye, whenthe Sky is serene and the Moon absent."Of course, M13is now less modestly recognized as the Great Globular Cluster inHercules, one of the brightestglobularstar clusters in the northern sky.Sharp telescopic views like this onereveal the spectacular cluster'shundreds of thousands of stars.At a distance of 25,000 light-years, thecluster stars crowdinto a region 150 light-years in diameter.Approaching the cluster coreupwards of 100 stars could be containedin a cube just 3 light-years on a side.For comparison, theclosest star to the Sun is over4 light-years away.The remarkable range of brightnessrecorded in this imagefollows stars into the dense cluster core.Distant background galaxies in the medium-wide field of viewinclude NGC 6207 at the upper left.
2022年08月04日
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