1998年12月08日:狮子座流星雨-（Leonids from Leo） 1998年12月08日:狮子座流星雨-（Leonids from Leo）--原图下载{mtitle title="狮子座流星雨"/}Credit:Juraj Toth (Comenius U. Bratislava), Modra Observatory说明：狮子座 (Leo)是天空中着名的星座，它就位于全天鱼眼照片的左边， 从上图可以看出，今年狮子座流星雨的流星都从狮子座的方向跑出来。狮子座流星 (Leonids)从狮子座跑出来，一点都不令人讶异，这就是为何 11月的流星雨(meteor shower)，称为狮子座流星雨的原因。从坦普-塔特彗星 (Comet Tempel-Tuttle)喷出砂粒般大小的残骸，沿着彗星的轨道绕着太阳运行，相对于地球，这轨道的方向就位于狮子座。当地球穿过彗星轨道时，下落的残骸形成的辐射点 (radiant)就会出现在狮子座。在上图 4个小时的曝光中，出现了 150颗以上的流星。着名的双子座流星雨 (Geminid Meteor Shower)出现在双子座 (Gemini)中，它在这个週末时，流星的数量将达到最大。{lamp/}原文：{mtitle title="Leonids from Leo"/}Credit:Juraj Toth (Comenius U. Bratislava), Modra ObservatoryExplanation: Is Leo leaking? Leo, the famous sky constellation visible on the left of the above all-sky photograph, appears to be the source of all the meteors seen in this year's Leonids Meteor Shower. That Leonids point back to Leo is not a surprise - it is the reason this November meteor shower is called the Leonids. Sand-sized debris expelled from Comet Tempel-Tuttle follows a well-defined orbit about our Sun, and the part of the orbit that approaches Earth is superposed in front of the constellation Leo. Therefore, when Earth crosses this orbit, the radiant point of falling debris appears in Leo. Over 150 meteorscan be seen in the above four-hour exposure. The Geminid Meteor Shower, which appears to eminate fromthe constellation of Gemini, peaks this coming weekend.

1998年11月22日:高能量的蟹状星云 (Crab Nebula)-（The High Energy Crab Nebula） 1998年11月22日:高能量的蟹状星云 (Crab Nebula)-（The High Energy Crab Nebula）--原图下载{mtitle title="高能量的蟹状星云 (Crab Nebula)"/}Credit: G. Hennessy (USNO) et al.,UIT,NASA说明：这一团杂乱无章的云气是恒星爆炸后留下来的，蟹状星云 (Crab Nebula)的能量非常高，它能发出各种波段的光，上图是蟹状星云从可见光到X射线的影像。NUV代表"近紫外线 (near ultraviolet)"，FUV是"远紫外线 (far ultraviolet)"，而 VIS为可见光 (visible light)的缩写。蟹状星云的中间有一颗高能的脉冲星 (pulsar)，脉冲星是快速旋转的中子星 (neutron star)，它的质量和我们的太阳相当，不过它的大小只有一个小城镇那么大，脉冲星所喷出的粒子束及发出的辐射以每秒 30次的频率扫过地球。形成蟹状星云的超新星 (supernova)于西元 1054年爆炸时被中国古代的天文学家记录下来，记录这天象的可能包含了 Anasazi的印地安人，当时超新星的亮度和满月差不多，这样的亮度持续了一个星期。蟹状星云至今仍有些未解之谜，例如脉冲星加上星云的总质量，还远小于原来的爆前超新星 (pre-supernova)！{lamp/}原文：{mtitle title="The High Energy Crab Nebula"/}Credit: G. Hennessy (USNO) et al.,UIT,NASAExplanation: This is the mess that is left when a star explodes. The Crab Nebula is so energetic that it glows in every kind of light known. Shown above are images of the Crab Nebula from visible light to the X-ray band.NUV stands for "near ultraviolet" light, FUV means "far ultraviolet" light, and VIS means visible light. In the center of the Crab Nebula lies the powerful Crab pulsar - a spinning neutron star with mass comparable to our Sun but with the diameter of only a small town. The pulsar expels particles and radiation in a beam that sweeps past the Earth 30 times a second. The supernova that created the Crab Nebula was seen by ancient Chinese astronomers and possibly even the Anasazi Indians -- in 1054 AD, perhaps glowing for a week as bright as the full moon. The Crab still presents mysteries today as the total mass of the nebula and pulsar appears much less than the mass of the original pre-supernova star!

1998年11月16日:1998狮子座流星雨：一场没有危险的流星暴-（Leonids 1998: A Safe Meteor Storm） 1998年11月16日:1998狮子座流星雨：一场没有危险的流星暴-（Leonids 1998: A Safe Meteor Storm）--原图下载{mtitle title="1998狮子座流星雨：一场没有危险的流星暴"/}Credit & Copyright: W. Pacholka说明：今天和明天将会有一场流星暴 (meteor storm)发生，期间将有数以千计的冰及石块，如下雨般地向地球落下，不过你不需要担心会有危险，因为只有非常少数的流星会撞击到地面。1998的狮子座流星雨 (Leonids)将受到全世界观察者的瞩目，这很可能是西元 1966年以来最活跃壮观的流星暴。流星暴是地球穿过坦普-塔特彗星 (Temple-Tuttle)遗留下的残骸而形成的。明天即将发生的流星暴最好的观测地点是在亚洲，随着流星量的增加，全球各地的人可看到流星雨的时间达数个小时之久。利用网路甚至还能及时的观看流星暴，上图是一颗1997英仙座流星雨 (Perseid)的流星划过加州沙漠的天空。{lamp/}原文：{mtitle title="Leonids 1998: A Safe Meteor Storm"/}Credit & Copyright: W. PacholkaExplanation: You're in no danger. During the meteor storm occurring tonight and tomorrow, thousands of bits of ice and rock will likely rain onto the Earth. Few, if any, will hit the ground. Touted as potentially the most active meteor shower since 1966, the Leonids of 1998 will be tracked by observers the world over. The meteor storm is caused by the Earth moving through the leftover debris of Comet Temple-Tuttle. The peak of the storm will be best visible tomorrow from Asia, though increased activity should be visible globally over many hours. It is even possible to monitor the storm live on the web. Pictured above is a Perseid 1997 meteor streaking across the sky behind an illuminated California desert.

1998年07月28日:鼻青脸肿的木星-（Impact on Jupiter） 1998年07月28日:鼻青脸肿的木星-（Impact on Jupiter）--原图下载{mtitle title="鼻青脸肿的木星"/}Credit: H. Hammel (MIT), WFPC2,HST, NASA说明: 1993年，在 木星附近发现了一串前所未见的彗星碎片。 这不寻常的现象，使它-舒梅克-李维九号彗星(Comet Shoemaker-Levy 9) (SL9)很快的成为科学研究的焦点。研究指出，太阳 的引力将会扰乱 SL9彗星 的轨道，使它在1994年7月撞向木星。事实证明，这项预测是正确的。上图显示出木星云层顶端， 被SL9彗星的G碎片所撞击的位置 。因撞击所产生的暗环，最外层的直径约有一个地球大 。由于 木星 几乎是由气体组成，因此彗星碎片在冲入木星大气深处之前，就已经融化或蒸发了。{lamp/}原文：{mtitle title="Impact on Jupiter"/}Credit: H. Hammel (MIT), WFPC2,HST, NASAExplanation: In 1993, a strange string of comet pieces was discovered near the planet Jupiter. So unusual a sight, Comet Shoemaker-Levy 9 (SL9) quickly became the object of much scientific curiosity. Studies showed that the Sun would soon perturb the orbit of SL9 so that it would actually strike Jupiter in July 1994. The studies were right. The above picture shows the impact site of SL9's fragment G on Jupiter's cloud-tops. The size of the dark outer ring is roughly the size of the Earth. Since Jupiter is mostly gas, the comet melted and evaporated before plunging too far into Jupiter's atmosphere.

1998年05月24日:高能船队-（A High Energy Fleet） 1998年05月24日:高能船队-（A High Energy Fleet）--原图下载{mtitle title="高能船队"/}Courtesy:MSFC Historical Archive,NASA说明： 美国太空总署高度成功的一系列 高能天文观测站 (HEAO)， 像是悬在 地球 的上方， 而且乍看之下， 更像是未来的星际巡航舰。在这张当年的插画里， 这些太空望远镜的名称， 分别为 HEAO-1、 HEAO-2、 和HEAO-3 。HEAO-1和HEAO-2的主要贡献， 在于让地球人注意到 奇妙的 X射线波段天空， 它们发现了超过 1,000个 宇宙高能辐射源。 HEAO-2另一个名字是 爱恩斯坦 观测站， 它发射于1978年11月， 约在这位着名物理学家 的100岁冥诞附近， 它也是第一个大型的 太空X射线影像望远镜。HEAO-3是这系列中的最后一艘， 它于1979年昇高运转， 负责量测高能的 宇宙射线粒子 和 伽玛射线。这些卫星观测站长约6公尺， 约有3200公斤重。 它们在任务完成之后， 皆坠回地球， 并 在大气层中安全地焚毁。{lamp/}原文：{mtitle title="A High Energy Fleet"/}Courtesy:MSFC Historical Archive,NASAExplanation: Looking like a fleet of futuristic starcruisers,NASA's highly successful series ofHigh Energy Astrophysical Observatory (HEAO) spacecraftappear poised over planet Earth.Labeled A, B, and C in this vintage illustration,the spacebased telescopes were known asHEAO-1,HEAO-2, andHEAO-3 respectively.HEAO-1 and HEAO-2 were responsible for revealing to earthlingsthe wonders ofthe x-ray sky, discovering 1,000s of celestialsources of high-energy radiation.HEAO-2, also knownas the EinsteinObservatory, was launched near thedate of the famous physicist's 100th birthday (November, 1978)and was the first large,fully imaging x-ray telescope in space.HEAO-3, the last in the series,was launched in 1979 and measured high energycosmic-ray particlesand gamma-rays.These satellite observatories were roughly 18 feet long and weighedabout 7,000 pounds. Their missions completed, all have fallen from orbitand burned up harmessly in the atmosphere.

1998年04月21日:猎户座的水-（Water in Orion） 1998年04月21日:猎户座的水-（Water in Orion）--原图下载{mtitle title="猎户座的水"/}Credit: Anglo-Australian Telescopephotograph by David Malin Copyright: Anglo-Australian TelescopeBoard说明：猎户座是湿答答的吗？近来的一些观测 证实着名的猎户座中的水分子，乃持续在形成 与增加之中。 猎户座大星云 (M42, 参见上图) 主要是由 氢气所组成，当然也含有微量的 其他原子与分子。猎户座大星云非常的巨大，所以纵然所测得水的产生速率很小，但 M. Harwit (康乃尔大学) 所领导的研究群揣测，猎户座大星云每天所生成的水量，是 地球海洋总 水量的六十倍以上。 彗星里的水、地球海洋里的水、甚至 人类身体内的水，可能都是在类似猎户 座大星云的云气中形成的。{lamp/}原文：{mtitle title="Water in Orion"/}Credit: Anglo-Australian Telescopephotograph by David Malin Copyright: Anglo-Australian TelescopeBoardExplanation: Is Orion all wet? Recent observations have confirmed that water molecules now exist in the famous Orion Nebula, and are still forming. The Orion Nebula (M42, shown above) is known to be composed mostly of hydrogen gas, with all other atoms and molecules being comparativelyrare. The nebula is so vast, though, that even the measuredminuscule production rate creates enough water to fill Earth's oceans 60 times over every day, speculate discoverers led by M. Harwit (Cornell). The water that composes comets, the