Dwarf Elliptical Galaxies
介绍宇宙英语作文
The universe is a vast expanse that has fascinated human beings for centuries.It is the collection of all existing matter and energy,including galaxies,stars,planets,and other celestial bodies.Here is a detailed introduction to the universe in an English essay format.Title:The Enigma of the UniverseIntroduction:The universe,a boundless and aweinspiring concept,has been a subject of wonder and study for as long as humanity has gazed upon the stars.It is the ultimate frontier,a testament to the infinite possibilities that lie beyond our terrestrial realm.Composition of the Universe:The universe is composed of billions of galaxies,each containing billions of stars.Our own galaxy,the Milky Way,is just one of these celestial bodies.Surrounding these stars are planets,some of which,like our Earth,are capable of supporting life.The universe also contains vast amounts of dark matter and dark energy,which,despite being invisible, play a crucial role in the expansion and structure of the cosmos.The Big Bang Theory:The most widely accepted explanation for the origin of the universe is the Big Bang Theory.According to this theory,the universe began as an infinitely dense and hot point, and has been expanding ever since.This event occurred approximately13.8billion years ago and set in motion the creation of all the matter and energy that we observe today.Galaxies and Stars:Galaxies are massive collections of stars,gas,and dust held together by gravity.They come in various shapes and sizes,from spiral galaxies like the Milky Way to elliptical galaxies that are more rounded.Stars,the powerhouses of galaxies,are born in nebulae and can live for billions of years,undergoing various stages of evolution before they die, sometimes in spectacular supernova explosions.Planets and Solar Systems:Planets are celestial bodies that orbit stars.They are diverse in nature,ranging from rocky terrestrial planets like Earth to gas giants like Jupiter.Our solar system,with its eight planets,is just one example of the many solar systems that exist within galaxies.Life in the Universe:The search for extraterrestrial life is an ongoing endeavor.While Earth is the only known planet to harbor life,the vastness of the universe suggests that the conditions necessaryfor life could exist elsewhere.Scientists are continually searching for signs of life on other planets,moons,and even in the interstellar medium.The Expansion and Fate of the Universe:The universe is not static it is in a state of constant expansion.This expansion is driven by dark energy,a mysterious force that is causing the universe to stretch at an accelerating rate.The ultimate fate of the universe is still a topic of debate among cosmologists,with possibilities ranging from a Big Freeze to a Big Rip.Conclusion:The universe is a complex and dynamic entity that continues to reveal its secrets to us.As our understanding of the cosmos grows,so too does our appreciation for the intricate balance of forces that govern its existence.The universe is a reminder of our place in the grand scheme of things and the boundless potential for discovery that lies ahead. Further Exploration:The study of the universe is a collaborative effort that spans disciplines and cultures. From the earliest stargazers to modern astronomers and astrophysicists,the quest to understand the universe is a testament to human curiosity and our desire to explore the unknown.As technology advances,we can expect to uncover even more about the cosmos and our place within it.。
第四篇 银河系和河外星系2(河外星系)资料
▪ 在形态上，透镜状星系与旋涡星系的主要差别是没有 旋臂；与椭圆星系的主要差别是有星系盘。
▪ 主要由年老恒星组成，气体很少。
(5)不规则星系 ▪ 外型或结构无明显对称性的星系，符号为Irr。 ▪ 无旋臂和中心核区。 ▪ 富含星际气体、尘埃和年轻恒星。
银河系实际直径30 kpc！
沙普利—柯蒂斯 (Shaplry-Curtis) 关于“宇宙尺 度”的大辩论
▪ 辩论焦点：
(1) “旋涡星云”的距离是多大？
(2) “旋涡星云”是恒星系统还是气体 云？
宇宙是由无数类 似“旋涡星云” 的星系构成的。 “宇宙岛”
“旋涡星云”是银河系内气体 云，银河系就是整个宇宙。
仙女座大星系M31(Sb)
(3) 棒旋星系 (barred spiral galaxies)
▪ 中心有棒状结构的旋涡星 系，符号为SB。
▪ 旋臂源于棒的两端。 ▪ 按照核球的大小和旋臂的
缠卷程度，旋涡星系可以 分为SBa, SBb, SBc三个次 型。其中Sa型核球最大， 旋臂缠卷最紧。
(4) 透镜状星系
因此“仙女座大星云”必定是河外星 系!
2. 星系的哈勃分类
▪ 根据星系形态的不同，1926年哈勃首先提出星系 可以分为椭圆星系、透镜状星系、旋涡星系、棒 旋星系和不规则星系5种类型，称为哈勃分类。
椭圆星系
旋涡星系 透镜状星系
不规则星系
棒旋星系
宇宙星系的数目1010数量级！ 哈勃“音叉”图
(1) 椭圆星系 (elliptical galaxies)
1920年4月26日美国科学院在华盛顿博 物馆礼堂召开了“宇宙的尺度”的辩论 会。
最常见的天文英语词汇
十二星座：Twelve ConstellationsAries 白羊Mar. 21 - April 19 Taurus 金牛April 20 - May 20Gemini 双子May 21 - June 21 Cancer 巨蟹June 22 - July 22Leo 狮子July 23 - Aug. 22 Virgo 处女Aug. 23 - Sept. 22Libra 天秤Sept. 23 - Oct. 23 . Scorpio 天蝎Oct. 24 - Nov. 21Sagittarius 射手Nov. 22 - Dec. 21 Capricorn 摩羯Dec. 22 - Jan. 19Aquarius 水瓶Jan. 20 - Feb. 18 Pisces 双鱼Feb. 19 - Mar. 20太阳系八大行星Eight major planets of the solar system水星Mercury 金星Venus地球Earth 火星Mars木星Jupiter 土星Saturn天王星Uranus 海王星Neptune88星座 Constellation1 Andromeda 仙女座2 Antlia 唧筒座3 Apus 天燕座4 Aquila 天鹰座5 Aquarius 宝瓶座6 Ara 天坛座7 Aries 白羊座8 Auriga 御夫座9 Bootes 牧夫座10 Caelum 雕具座11 Camelopardalis 鹿豹座12 Capricornus 摩羯座13 Carina 船底座14 Cassiopeia 仙后座15 Centaurus 半人马座16 Cepheus 仙王座17 Cetus 鲸鱼座18 Chamaeleon 堰蜓座19 Circinus 圆规座20 Canis Major 大犬座21 Canis Minor 小犬座22 Cancer 巨蟹座23 Columba 天鸽座24 Coma Berenices 后发座25 Corona Australis 南冕座26 Corona Borealis 北冕座27 Crater 巨爵座28 Crux 南十字座29 Corvus 乌鸦座30 Canes Venatici 猎犬座31 Cygnus 天鹅座32 Delphinus 海豚座33 Dorado 剑鱼座34 Draco 天龙座35 Equuleus 小马座36 Eridanus 波江座37 Fornax 天炉座38 Gemini 双子座39 Grus 天鹤座40 Hercules 武仙座41 Horologium 时钟座42 Hydra 长蛇座43 Hydrus 水蛇座44 Indus 印地安座45 Lacerta 蝎虎座46 Leo 狮子座47 Lepus 天兔座48 Libra 天秤座49 Leo Minor 小狮座50 Lupus 豺狼座51 Lynx 天猫座52 Lyra 天琴座53 Mensa 山案座54 Microscopium 显微镜座55 Monocers 麒麟座56 Musca 苍蝇座57 Norma 矩尺座58 Octans 南极座59 Ophiuchus 蛇夫座60 Orion 猎户座61 Pavo 孔雀座62 Pegasus 飞马座63 Perseus 英仙座64 Phoenix 凤凰座65 Pictor 绘架座66 Piscis Australis 南鱼座67 Pisces 双鱼座68 Puppis 船舻座69 Pyxis 罗盘座70 Reticulum 网罟座71 Sculptor 玉夫座72 Scorpius 天蝎座73 Scutum 盾牌座74 Serpens 巨蛇座75 Sextans 六分仪座76 Sagitta 天箭座77 Sagittarius 人马座78 Taurus 金牛座79 Telescopium 望远镜座80 Triangulum Australe 南三角座81 Triangulum 三角座82 Tucana 杜鹃座83 Ursa Major 大熊座84 Ursa Minor 小熊座85 Vela 船帆座86 Virgo 处女座87 Volans 飞鱼座88 Vulpecula 狐狸座其他词汇望远镜telescope [ˈteliskəup] 双筒望远镜binoculars [baiˈnɔkjuləz]反射式望远镜reflecting telescope [ri'flektiŋ]折射式望远镜牛顿式反射望远镜Newtonian reflector 天区Sky coverage星系galaxy [ˈgæləkəsi] 恒星star [stɑ:]行星planet [ˈplænit] 卫星satellite [ˈsætəlait]星云nebula [ˈnebjulə] 银河the Milky Way类木行星：四大行星之一：木星、土星、天王星、海王星:Jovian planet ：Any of the four largest planets: Jupiter, Saturn, Uranus, and Neptune. 星云、星团新总表（简称NGC）New General Catalogue (NGC)太阳活动solar activity 太阳风solar wind太阳活动周solar cycle 太阳耀斑solar flare白矮星White dwarf 红巨星red giant主星系dominant galaxy 球状星系spherical galaxy旋涡星系spiral galaxy 椭圆星系elliptical galaxy不规则星系irregular galaxy 河外星系Extragalactic开普勒定律Kepler's laws 光年light year近地小行星earth-approaching asteroid近地天体earth-approaching object太阳系外行星extrasolar planet太阳系外行星系extrasolar planetary system地外智慧生物extraterrestrial intelligence不明飞行物(UFO) Unidentified Flying Object哈勃空间望远镜HST, Hubble Space Telescope国际空间站International Space Station美国航天局NASA（National Aeronautics and Space Administration）中国航天局CNSA（China National Space Administration）狭义相对论special theory of relativity木星环Jovian ring 海王星环Nepturian ring天王星环Uranian ring 疏散星团open cluster星际尘埃interstellar dust 星际气体interstellar gas大气视宁度atmospheric seeing 光污染light pollution近地小行星near-earth asteroi 近地小行星带near-earth asteroid belt 小行星asteroid (minor planet) 小行星带asteroid belt近地彗星near-earth comet 近地天体NEO, near-earth object环食带path of annularity 光感light sensation全食total eclipse 偏食partial eclipse近日点perihelion 近地点perigee远日点aphelion 远地点apogee残月waning crescent 亏凸月waning gibbous娥眉月waxing crescent 盈凸月waxing gibbous满月full moon 月相phases (of the Moon)轨道orbit 新星novaastronaut 航天员capsule 太空舱carrier rocket 运载火箭artificial satellite 人造卫星launch a satellite 发射卫星low Earth orbit 近地轨道manned space 载人航天计划manned space flight 载人航天manned spaceship/ spacecraft 载人飞船orbit the earth 绕地球飞行outer space; deep space 外太空space shuttle 航天飞机unmanned spaceship / spacecraft 无人飞船weather satellite 气象卫星black holes 黑洞pulsar 脉冲星绝对星等absolute magnitude 极限星等limiting magnitude流星Meteor 流星雨meteor shower反物质antimatter 天文学astronomy极光aurora 天体物理学astrophysics宇宙大爆炸Big Bang 双星binary star天极celestial poles 天球celestial sphere目镜eyepiece 物镜objective len /objective glass。
星系
旋涡星系的3个次型
按照核球的大小和旋臂的缠卷程度，旋涡星系 又分为Sa, Sb, Sc三个次型。Sa型核球最大， 旋臂缠卷最紧；Sc型核球最小，旋臂缠卷最松
2.3 棒旋星系 Barred spiral galaxies
中心有棒状结构的旋涡星 系，符号为SB 旋臂源于棒的两端
银河系很可能是一个 SBb 或 SBc 型星系
星系的速度弥散—光度经验关系
星系质量越大 → 星系转动或恒星、气体运动速度越快 → 速度弥散越大 → 谱线越宽
星系质量越大 → 光度越高
谱线宽度 光度
旋涡星系： 塔利-费舍尔（Tully-Fisher）关系
旋涡星系的速度 弥散可由光学谱 或射电望远镜测 得。例如H原子21 厘米谱线宽度 速度弥散光度 距离 ~ 200 Mpc 的距离
介于椭圆星系和旋涡星系之间的、无旋臂的盘星系。 在形态上，透镜状星系与旋涡星系的主要差别是没有 旋臂；与椭圆星系的主要差别是有星系盘 根据核心是否有棒状结构，符号相应为S0或SB0。主 要由年老恒星组成，气体很少
2.5 不规则星系 Irregular galaxies
外型或结构没有明显对称性的星系，符号为 Irr 无旋臂和中心核区。富含星际气体、尘埃和年轻恒星
• 星系群 (group of galaxies) • 星系团 (cluster of galaxies)
星系群与星系团又组成为超星系团 (supercluster of galaxies)
4.1 本星系群The Local Group (of Galaxies)
银河系所处的星系群，大小 约1.2Mpc 由银河系、仙女星系（M 31） 等附近至少40个星系组成。 包含3个旋涡星系（银河系、 M31、M33），4个不规则 星系（大、小麦哲伦云等）， 20多个矮椭圆星系 银河系和仙女星系是本星系 群中质量最大的两个星系， 分别位于本星系群的两端， 在引力作用下分别带领周围 质量较小的星系相互绕转
宇宙英语小作文带翻译
宇宙英语小作文带翻译Title: The Wonders of the Universe。
The universe is a vast expanse of space filled with countless celestial bodies, each holding its own mysteries and wonders. From the twinkling stars to the massive galaxies, the universe never fails to captivate our imagination and curiosity.First and foremost, let us delve into the beauty of the stars. Stars are like beacons of light scattered across the dark canvas of space. They come in various sizes, colors, and temperatures, each telling its own unique story. Some stars burn brightly, emitting dazzling light that illuminates the surrounding cosmos, while others shine faintly, barely visible to the naked eye. However, regardless of their luminosity, stars play a crucial rolein shaping the universe as we know it. They are responsible for creating elements essential for life, such as carbon, oxygen, and iron, through processes like nuclear fusion.Moreover, galaxies stand as the building blocks of the universe. These vast systems, composed of stars, gas, dust, and dark matter, come in different shapes and sizes. Spiral galaxies, like our own Milky Way, showcase graceful arms swirling around a central bulge, while elliptical galaxies appear as smooth, featureless orbs. Furthermore, irregular galaxies defy conventional classification with their chaotic shapes and structures. Within these galaxies lie billions upon billions of stars, along with planets, nebulae, and other celestial objects, forming a mesmerizing tapestry of cosmic wonders.As we gaze deeper into the universe, we encounter phenomena that challenge our understanding of the laws of physics. Black holes, for instance, are regions of spacetime where gravity is so intense that nothing, not even light, can escape their grasp. These enigmatic objects are born from the remnants of massive stars that have reached the end of their life cycle. They serve as cosmic vacuum cleaners, devouring anything that strays too close to their event horizons. Despite their ominous reputation,black holes also play a vital role in shaping galaxies and influencing the distribution of matter in the universe.Furthermore, the universe is filled with cosmic spectacles that leave us in awe of its grandeur. Supernovae, the explosive deaths of massive stars, release unfathomable amounts of energy, briefly outshining entire galaxies. Nebulae, vast clouds of gas and dust, serve as stellar nurseries, where new stars are born amidst swirling cosmic debris. Additionally, pulsars, rapidly spinning neutron stars, emit beams of radiation that sweep across the cosmos like cosmic lighthouses.In conclusion, the universe is a realm of boundless wonder and discovery. From the twinkling stars to the majestic galaxies, from the enigmatic black holes to the dazzling supernovae, the universe never ceases to amaze us with its beauty and complexity. As we continue to explore and unravel its mysteries, we gain a deeper appreciationfor the intricate tapestry of existence that surrounds us.(翻译: 宇宙的奇迹。
50个星系小知识
50个星系小知识1. 银河系（Milky Way）：我们所在的星系，包含数百亿颗星星。
2. 仙女座星系（Andromeda Galaxy）：是离我们最近的大型螺旋星系，将在未来几十亿年内与银河系发生碰撞。
3. 大麦哲伦星云（Large Magellanic Cloud）：是银河系的伴随星云，可在南半球看到。
4. 小麦哲伦星云（Small Magellanic Cloud）：也是银河系的伴随星云，位于大麦哲伦星云附近。
5. 三角座大星系团（Triangulum Galaxy）：是本地群中的第三大星系，与银河系和仙女座星系一同组成本地群。
6. M87星系：包含了世界首张黑洞照片的星系，黑洞称为M87*。
7. 半人马座α星系（Alpha Centauri）：是距离地球最近的三颗恒星，包括Proxima Centauri。
8. 螺旋星云（Whirlpool Galaxy）：与伴随星系NGC 5195一同构成一对交互作用的星系。
9. 和平座流星团（Pleiades）：一群年轻的恒星，以七姐妹而闻名。
10. 狮子座不规则星系（Leo I）：是银河系的卫星星系之一。
11. NGC 1300：一座螺旋星系，以其引人注目的臂旋结构而著称。
12. 椭圆星系（Elliptical Galaxy）：具有椭圆形状的星系，通常由老年恒星组成。
13. 蝎子座X-1：包含一颗质量极大的恒星和一个紧密伴星，是X射线双星系统。
14. NGC 2244：位于猎户座大星云中的一个年轻星团。
15. 哈勃深空场（Hubble Deep Field）：是哈勃太空望远镜拍摄的一个小区域，显示了许多远离地球的星系。
16. 蓝色大理石星系（Blue Marble Galaxy）：以其蓝色的颜色而闻名，是由气体和尘埃组成的星系。
17. NGC 6822：也称为巧克力盒星系，是一个不规则星系。
18. 奇迹星系（Antennae Galaxies）：两个星系之间发生碰撞，形成引人注目的星系相互作用。
高一年级英语天文知识单选题40题
高一年级英语天文知识单选题40题1. Which planet is known as the "Red Planet" because of its reddish appearance?A. EarthB. MarsC. JupiterD. Venus答案：B。
解析：在太阳系中，火星（Mars）因为其表面呈现出红色的外观而被称为“Red Planet（ 红色星球）”。
地球（Earth）是我们居住的蓝色星球；木星（Jupiter）是一个巨大的气态行星，外观不是红色；金星 Venus）表面被浓厚的大气层覆盖，不是以红色外观著称。
2. Which planet has the most moons in the solar system?A. EarthB. MarsC. JupiterD. Mercury答案：C。
解析：木星（Jupiter）是太阳系中拥有最多卫星（moons）的行星。
地球（Earth）只有一颗卫星；火星（Mars）有两颗卫星；水星 Mercury）没有卫星。
3. The planet with the shortest orbit around the Sun is _.A. MercuryB. VenusC. EarthD. Mars答案：A。
解析：水星（Mercury）是距离太阳最近的行星，它的公转轨道是最短的。
金星 Venus）、地球 Earth）、火星 Mars）距离太阳比水星远，它们的公转轨道都比水星长。
4. Which planet has a thick atmosphere mainly composed of carbon dioxide?A. EarthB. MarsC. VenusD. Jupiter答案：C。
解析：金星（Venus）有一层非常厚的大气层，其主要成分是二氧化碳 carbon dioxide）。
地球 Earth）的大气层主要由氮气和氧气等组成；火星（Mars）大气层很稀薄，主要成分虽然有二氧化碳但比例和金星不同；木星（Jupiter）的大气层主要由氢和氦等组成。
奇妙星星作文英语
奇妙星星作文英语Title: The Wondrous Stars: Exploring the Marvels of the Universe。
In the vast expanse of the universe, amidst the silent darkness, twinkling jewels adorn the velvet canvas of the night sky—stars, the celestial beacons that havecaptivated humanity since time immemorial. Their enigmatic beauty and profound mysteries have inspired wonder, curiosity, and countless contemplations about the nature of existence. Let us embark on a journey through the wondrous realm of stars, exploring their significance, characteristics, and the awe-inspiring phenomena they embody.To begin with, stars are not merely distant luminous points in the sky; they are colossal spheres of glowing gas, primarily hydrogen and helium, held together by their own gravitational force. The process of nuclear fusionoccurring within their cores transforms these elements intoheavier ones, releasing immense amounts of energy in the form of light and heat. This fundamental process powers the radiant brilliance of stars, sustaining life and driving the dynamics of the cosmos.One of the most remarkable aspects of stars is their diverse range of sizes, luminosities, and colors. From the diminutive red dwarfs to the colossal blue giants, stars exhibit a staggering array of physical characteristics, each influencing its lifespan and behavior. The luminosity of a star, for instance, determines its brightness as seen from Earth, while its color—ranging from fiery red to dazzling blue—is indicative of its surface temperature and composition.Moreover, stars are not solitary entities adrift in the emptiness of space; they often congregate in vast stellar communities known as galaxies. Within these cosmic metropolises, stars form intricate patterns and configurations, from the swirling arms of spiral galaxies to the dense cores of elliptical galaxies. Our own Milky Way galaxy, home to billions of stars, serves as atestament to the mesmerizing complexity of galactic ecosystems.Yet, amidst this grandeur, stars also meet their inevitable fate. As they exhaust their nuclear fuel, stars undergo dramatic transformations, culminating in spectacular cosmic events such as supernovae or the serene brilliance of white dwarfs. These phenomena not only mark the end of a star's life but also contribute to the enrichment of the universe, dispersing elements crucial for the formation of new stars, planets, and ultimately, life itself.Beyond their scientific significance, stars hold profound cultural and symbolic meanings for civilizations throughout history. Across diverse cultures and traditions, stars have been revered as symbols of guidance, enlightenment, and transcendence. They have inspired myths, legends, and philosophical contemplations, inviting humanity to ponder its place within the vastness of the cosmos.In conclusion, the wondrous stars transcend mere astronomical objects; they are cosmic storytellers, illuminating the mysteries of the universe and igniting the imagination of humanity. From their humble beginnings in stellar nurseries to their glorious finales in the cosmic tapestry, stars embody the essence of cosmic evolution and the eternal dance of creation and destruction. As we gaze upon the shimmering canopy of the night sky, let us marvel at the majesty of the stars and embrace the profound journey they invite us to undertake—exploring the universe within and beyond.。
空间顺序作文 英文作文
空间顺序作文英文作文Title: Exploring the Depths of Space: A Journey Through the Cosmos。
Space, the final frontier, beckons humanity with its infinite expanse, captivating our imagination and fueling our desire for exploration. From the ancient astronomers who pondered the movements of celestial bodies to the modern-day space missions pushing the boundaries of our understanding, our quest to unravel the mysteries of the cosmos knows no bounds.As we embark on this cosmic journey, we are first drawn to the wonders of our own solar system. The Sun, ourradiant star, serves as the center of our celestial neighborhood, its immense gravity shaping the orbits of the planets that orbit around it. Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, and Neptune—all unique worlds with their own distinct features and mysteries waiting to be uncovered. From the scorching deserts of Mars to the icyplains of Europa, each planet and moon offers a glimpseinto the diverse landscapes that populate our cosmic backyard.Venturing beyond the familiar confines of our solar system, we encounter the vastness of interstellar space. Here, the stars twinkle like distant beacons, each one a sun in its own right, surrounded by its own retinue of planets and moons. Among them, exoplanets—worlds beyond our solar system—beckon with the possibility of harboring life, tantalizing us with the prospect of discovering extraterrestrial civilizations.But our journey does not end there. Beyond the realm of individual stars lies the vastness of the Milky Way galaxy, our cosmic home. Spiraling arms of dust and gas swirl around a central core, where a supermassive black hole lurks, exerting its gravitational influence over the entire galaxy. Within this bustling metropolis of stars, nebulae, and star clusters, new stars are born, while others meet their fiery end in spectacular supernova explosions.As we gaze upon the majesty of the Milky Way, we are reminded of the countless other galaxies that populate the universe. From the elegant spiral galaxies to the amorphous clouds of elliptical galaxies, each one tells a story of cosmic evolution and the interplay of gravity, gas, and dust on unimaginable scales. And yet, even as we marvel at the sheer diversity of galaxies, we are humbled by the realization that they represent only a fraction of the vastness of the cosmos.For beyond the galaxies lies the great cosmic web, a vast network of filaments and voids that stretch across the universe on scales beyond comprehension. Here, the laws of physics dictate the behavior of matter and energy on the grandest of scales, shaping the evolution of the cosmos from its fiery beginnings to the cold expanse of the present day. And yet, even as we strive to understand the workings of the universe, we are reminded of the limits of our knowledge and the boundless mysteries that still elude us.In the end, our journey through space is not just aquest for knowledge, but a testament to the human spirit of exploration and discovery. From the smallest asteroid to the largest galaxy cluster, the cosmos offers a wealth of wonders waiting to be explored and understood. And as we gaze upon the stars, we are reminded of our place in the universe—a tiny speck of dust in the vast cosmic ocean, yet endowed with the curiosity and ingenuity to reach for the stars and uncover the secrets of the cosmos.。
满天星的英语作文要从远到近的英语作文
满天星的英语作文要从远到近的英语作文全文共3篇示例，供读者参考篇1The Vast Expanse: My Journey Through the Milky WayAs I gaze up at the twinkling stars that adorn the night sky, I can't help but feel a sense of wonder and curiosity about the vastness of our universe. Tonight, I embark on a literary journey, exploring the Milky Way galaxy from the farthest reaches to our cosmic backyard, unraveling the mysteries that have captivated stargazers for centuries.Part I: The Edge of the Observable UniverseLet us begin our adventure at the very limits of what our telescopes can detect, where the faint whispers of ancient galaxies beckon us. Here, we encounter the cosmic microwave background radiation, a faint glow that permeates the cosmos –a relic of the Big Bang itself. This primordial sea of light serves as a snapshot of the universe's infancy, a mere 380,000 years after its birth.Billions of light-years away, quasi-stellar radio sources, or quasars, blaze with the intensity of a trillion suns. Theseenigmatic objects, powered by supermassive black holes at the cores of distant galaxies, offer tantalizing glimpses into the earliest epochs of the universe's history. Their brilliant beacons serve as cosmic lighthouses, guiding our exploration ever deeper into the cosmos.Part II: The Realm of GalaxiesAs we journey inward, we encounter a vast tapestry of galaxies – cosmic cities teeming with billions of stars, each with its own story to tell. From the majestic spiral arms of the Andromeda Galaxy, our nearest galactic neighbor, to the elegant elliptical galaxies that grace the celestial canvas, these celestial metropolises showcase the incredible diversity of structures that populate the universe.Deep within these galactic realms, we witness the births and deaths of stars, cosmic crucibles where the elements that make up our world are forged. Nebulae, glowing clouds of gas and dust, serve as stellar nurseries, nurturing the next generation of suns. Simultaneously, the explosive finales of dying stars seed the cosmos with the building blocks of life, enriching the interstellar medium with the heavy elements that will one day form planets and, perhaps, life itself.Part III: Our Galactic HomeCloser still, we find ourselves within the embrace of our own celestial abode, the Milky Way Galaxy. This majestic spiral, a vast cosmic pinwheel spanning over 100,000 light-years, is our cosmic address – a place we call home.At the heart of our galaxy lies a supermassive black hole, a gravitational behemoth that exerts its influence over the entire system. Around this cosmic anchor, hundreds of billions of stars dance in a graceful cosmic ballet, tracing intricate orbits through the galactic disk.Among these countless stellar companions, we find our own sun, a humble yet vital star that sustains life on Earth. From our vantage point within the Milky Way's spiral arms, we can marvel at the rich tapestry of star clusters, nebulae, and even other galaxies that grace our celestial neighborhood.Part IV: Our Cosmic BackyardFinally, we arrive at our cosmic backyard, the solar system – a tiny corner of the universe that we have come to know and love. Here, we witness the intricate dance of planets, moons, and countless other celestial bodies, each with its own unique character and mysteries to unravel.From the scorching furnace of Mercury to the icy realms of the dwarf planets that dwell in the Kuiper Belt, our solar system is a microcosm of the universe itself. We stand in awe of the breathtaking vistas of the gas giants, Jupiter and Saturn, with their intricate systems of moons and rings. And closer to home, we find our own blue marble, Earth – a living, breathing world teeming with life and wonder.As I conclude my journey through the Milky Way, from the farthest reaches of the observable universe to our own cosmic backyard, I am filled with a profound sense of awe and humility. The vastness of the cosmos reminds us of our insignificance, yet the intricate dance of celestial bodies reminds us of the beauty and complexity that permeates the universe.This exploration has only scratched the surface of the wonders that lie beyond our planet, and I am filled with a renewed sense of curiosity and a thirst for knowledge. The universe is a vast tapestry of mysteries waiting to be unraveled, and I am eager to embark on further journeys of discovery, uncovering the secrets that lie hidden among the stars.篇2The Wonders of the Stars: A Journey from the Cosmic to the TerrestrialAs I gaze up at the twinkling lights adorning the night sky, I am filled with a profound sense of wonder and humility. The stars, those celestial beacons that have captivated humanity since the dawn of time, hold within them a myriad of secrets waiting to be unraveled. Let us embark on a journey, one that spans the vast expanse of the cosmos, traversing the uncharted realms of the universe before returning to our terrestrial abode.Across the Cosmic ExpanseAt the heart of our exploration lies the enigmatic nature of galaxies, those colossal assemblages of stars, gas, and dust that populate the observable universe. The Milky Way, our celestial home, is but a single entity among billions of galaxies that stretch across the cosmic tapestry. Each galaxy harbors its own unique story, forged from the intricate interplay of gravitational forces, stellar evolution, and the relentless passage of time.As we peer deeper into the cosmic abyss, we encounter quasars – the brightest and most energetic celestial objects known to us. These enigmatic entities, powered by supermassive black holes at the cores of distant galaxies, shine with a brilliance that outshines entire galaxies. Their existence challenges ourunderstanding of the fundamental laws of physics and pushes the boundaries of our scientific knowledge.Closer to Home: Our Solar SystemVenturing inward, we find ourselves within the confines of our solar system, a cosmic oasis teeming with wonders. At its center lies the Sun, a brilliant sphere of plasma that sustains life on our planet and governs the intricate dance of the planets and moons that orbit it. The Sun's radiant energy, a product of thermonuclear fusion reactions, has shaped the celestial landscape we observe from Earth.Each planet in our solar system bears its unique characteristics, from the scorching temperatures of Mercury to the mesmerizing rings of Saturn. Jupiter, the gas giant, captivates us with its swirling storms, while Mars tantalizes our curiosity with its rusty hues and potential for harboring life. These celestial bodies serve as a testament to the diversity and complexity of our cosmic neighborhood.The Moon: Our Closest Celestial CompanionTurning our gaze skyward, we find the Moon, our closest celestial companion and a constant source of fascination. This natural satellite, forever locked in a gravitational embrace withEarth, has been a guiding light for sailors, a muse for poets, and a canvas for humanity's dreams of exploration.The Moon's cratered surface, etched by eons of cosmic bombardment, holds clues to the violent history of our solar system's formation. Its waxing and waning phases, governed by its intricate dance with Earth and the Sun, have shaped the tides and influenced countless cultural and religious traditions throughout human history.The Stars: Beacons in the NightFinally, we return to the stars, those brilliant points of light that have inspired awe and wonder since the dawn of humanity. Each star is a furnace of nuclear fusion, burning with an intensity that defies comprehension. From the scorching blue giants to the cool, red dwarfs, these celestial bodies represent the building blocks of the cosmos, forging the elements that make up our planet and ourselves.As we gaze upward, we are greeted by constellations, those celestial patterns that have guided travelers, sparked mythologies, and captured the imagination of cultures across the globe. The Big Dipper, Orion the Hunter, and countless others adorn the night sky, serving as celestial signposts in our cosmic journey.The stars hold within them the secrets of stellar evolution, from their birth in the dense clouds of interstellar gas and dust, to their eventual transformation into white dwarfs, neutron stars, or even the enigmatic black holes that lurk at the heart of galaxies.ConclusionAs we conclude our cosmic odyssey, we are reminded of the profound interconnectedness that binds us to the universe. The stars, galaxies, and celestial bodies that dot the night sky are not mere decorations but rather the manifestations of the fundamental laws that govern our existence.Through the tireless efforts of astronomers, astrophysicists, and space explorers, we inch ever closer to unraveling the mysteries that lie beyond our terrestrial confines. The celestial wonders that adorn the night sky serve as a constant reminder of the vastness of the cosmos and the boundless potential for discovery that awaits us.So, let us gaze upward, with wonder and curiosity, for in the stars, we find not only the answers to the deepest questions of our existence but also the inspiration to push the boundaries of human knowledge and exploration ever further.篇3The Brilliance of the Cosmos: A Journey Through the StarsAs I gaze up at the inky blackness of the night sky, a tapestry of twinkling lights unfolds before my eyes. These celestial beacons, scattered across the vast expanse of the cosmos, have captivated humanity since the dawn of time. From the most distant galaxies to the celestial bodies that grace our own cosmic neighborhood, the stars offer a gateway into the mysteries of the universe, igniting our curiosity and fueling our thirst for knowledge.Far Beyond Our Cosmic BackyardLet us embark on a journey that transcends the boundaries of our own Milky Way galaxy, venturing into the farthest reaches of the observable universe. Here, we encounter galaxies so distant that their light has traveled for billions of years before reaching our eyes. These cosmic metropolises, teeming with billions of stars, are but mere specks in the grand canvas of the cosmos.The Hubble Deep Field, a region of the sky no larger than a grain of rice held at arm's length, unveils a breathtaking tapestry of galaxies, each one a unique tapestry of stars woven togetherby the invisible threads of gravity. Some appear as elegant spirals, their arms gracefully unfurling into the void, while others take on the form of elliptical or irregular shapes, each a testament to the diversity of the universe.Quasars, the brilliant beacons powered by supermassive black holes at the hearts of distant galaxies, shine with an intensity that defies comprehension. Their light, emitted billions of years ago, serves as a cosmic lighthouse, guiding our understanding of the universe's earliest epochs and the processes that shaped the cosmos as we know it today.The Cosmic Web and the Birth of StarsAs we draw closer to our cosmic home, we encounter the intricate cosmic web – a vast, interconnected network of filaments composed of dark matter and gas. Within this web, matter accumulates, forming the seeds from which galaxies are born and stars ignite their brilliant fires.It is within these dense regions of the cosmic web that we witness the birth of stars, a process that unfolds over millions of years. Vast clouds of gas and dust, drawn together by gravity, collapse under their own weight, igniting nuclear fusion at their cores and giving birth to brilliant stellar furnaces that will illuminate the cosmos for billions of years.The stellar nurseries within our own Milky Way galaxy offer a glimpse into this celestial genesis. The Orion Nebula, a vast cloud of gas and dust visible to the naked eye, is a celestial nursery where thousands of stars are being born. Here, we can witness the raw materials of star formation – the swirling eddies of gas and dust, sculpted by the fierce winds and radiation from newly formed stars, painting a vivid picture of the cosmic cycle of birth and renewal.Our Galactic NeighborhoodAs we draw ever closer to our cosmic home, we encounter the stars that grace our own galactic neighborhood. The Milky Way, a vast spiral galaxy containing hundreds of billions of stars, stretches across the night sky like a celestial river, its misty band of light a testament to the countless stars that call it home.Within this cosmic city, we find a diverse array of stellar residents. The brilliant, blue-white stars burn with a ferocity that belies their relatively short lifespans, while the cooler, reddish stars smolder for billions of years, their steady glow a beacon of stability in the ever-changing cosmos.Among these stellar citizens, we find the familiar faces of our celestial neighbors. The North Star, Polaris, has guided travelers and explorers for millennia, its unwavering position a celestialcompass in the night sky. Sirius, the brightest star in the night sky, shines with a brilliance that outshines all others, its blue-white hue a testament to its searing temperatures.The Celestial Companions in Our Cosmic BackyardAs we draw ever nearer to our cosmic home, we encounter the celestial bodies that grace our own celestial backyard. The planets, those wandering worlds that have captivated our imaginations for centuries, offer a glimpse into the diversity of our solar system.From the scorched and cratered surface of Mercury to the gentle azure skies of Neptune, each planet is a unique world unto itself, shaped by the interplay of gravity, geology, and the relentless forces of the cosmos. We marvel at the towering storms of Jupiter, the rings of Saturn, and the icy mysteries of the outer solar system, each a testament to the incredible diversity that exists within our cosmic neighborhood.Yet, it is our closest celestial companion, the Moon, that holds a special place in our hearts. This ever-present orb, waxing and waning in the night sky, has been a constant companion to humanity throughout our existence. Its phases have guided our calendars, its movements have shaped our tides, and its crateredsurface bears witness to the cosmic impacts that have sculpted its landscape over billions of years.As we gaze upon the Moon's familiar face, we are reminded of our cosmic roots – born from the same primordial clouds of gas and dust that gave rise to the stars and planets. We are humbled by the realization that we are but tiny specks in the vast expanse of the cosmos, yet we are inextricably linked to the celestial tapestry that surrounds us.The Journey ContinuesAs I stand beneath the brilliant tapestry of the night sky, my journey through the stars has only just begun. With each new discovery, each new revelation, our understanding of the cosmos deepens, and our sense of wonder grows. The stars, those celestial beacons that have guided humanity for millennia, continue to beckon us, inviting us to explore the mysteries that lie beyond the boundaries of our cosmic backyard.It is a journey that transcends time and space, a quest to unravel the secrets of the universe and to understand our place within the grand cosmic tapestry. And as we gaze upon the stars, we are reminded that we are all travelers on this cosmic journey, united by our shared sense of awe and our unquenchable thirst for knowledge.。
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Henry C. Ferguson1 Space Telescope Science Institute 2 3700 San Martin Drive, Baltimore, MD 21218 ferguson@ Bruno Binggeli Astronomisches Institut der Universitat Basel Venusstrasse 7, CH-4102 Binningen, Switzerland binggeli2@urz.unibas.ch
astro-ph/9409079 28 Sep 94
Association of Universities for Research in Astronomy, Inc. under contract with the National Aeronautics and Space Administration
1 Hubble Fellow 2 Operated by the
Dwarf elliptical (dE) galaxies, with blue absolute magnitudes typically fainter than MB = 16, are the most numerous type of galaxy in the nearby universe. Tremendous advances have been made over the past several years in delineating the properties of both Local Group satellite dE's and the large dE populations of nearby clusters. We review some of these advances, with particular attention to how well currently available data can constrain (a) models for the formation of dE's, (b) the physical and evolutionary connections between di erent types of galaxies (nucleated and nonnucleated dE's, compact E's, irregulars, and blue compact dwarfs) that overlap in the same portion of the mass-spectrum of galaxies, (c) the contribution of dE's to the galaxy luminosity functions in clusters and the eld, (d) the star-forming histories of dE's and their possible contribution to faint galaxy counts, and (e) the clustering properties of dE's. In addressing these issues, we highlight the extent to which selection e ects temper these constraints, and outline areas where new data would be particularly valuable.
ABSTRACT
2ቤተ መጻሕፍቲ ባይዱ
The properties of dwarf galaxies are central to two current issues in observational cosmology: understanding the results from deep redshift surveys, and interpreting the constraints of the galaxy luminosity function on the primordial uctuation spectrum. Deep redshift surveys have revealed a dominant population of star-forming dwarf galaxies at redshifts (0:2 < z < 0:5) (Broadhurst et al. 1988; Colless et al. 1990; Cowie et al. 1991). A large dwarf population is expected from simulations of galaxy evolution (White and Frenk 1991) based on the Cold-Dark-Matter (CDM) model. However, both the redshift surveys and the theory predict far more dwarfs than are observed locally. This puzzle points to a need to understand better the physics of dwarf galaxies. The last decade has seen a surge of activity in the study of dwarf galaxies, inspired in part by such cosmological issues, but more directly by the availability of new technology: wide- eld imaging telescopes and good photographic emulsions, CCD's, and sensitive spectrographs. This activity has resulted in major advances in our knowledge of the internal structure and kinematics, stellar populations, clustering properties, luminosity function, and evolution of dwarf galaxies. Our aim in this review is to examine some of the recent data with the cosmological issues in mind: do current observations of dwarf galaxies really constrain the theories? What future observations are most relevant to testing the models of galaxy evolution? To make the subject tractable, we have chosen to concentrate on dwarf elliptical (dE) galaxies, linking together both Local Group satellite dE's and the large dE populations of nearby clusters, and examining the data critically to try to decide what we know and what we only think we know about these galaxies. We will mention only in passing star-forming dwarf galaxies such as Magellanic irregulars or blue compact dwarf galaxies. Excellent reviews of the properties of these galaxies can be found in Kunth et al. (1986), Hunter & Gallagher (1989), and Meylan & Prugniel (1994).
Keywords: galaxies: general { galaxies: luminosity function, mass function { galaxies: evolution { galaxies: structure { galaxies: stellar content { galaxies: fundamental parameters
1.1. What is a dE Galaxy? Low-luminosity elliptical galaxies are distinguished from late-type galaxies (spirals and irregulars) by their smooth surface-brightness pro les. Below luminosities of MB 18 the smooth-pro le galaxies divide into two classes: compact galaxies with high central surface brightnesses (exempli ed by M32), and di use galaxies with low central surface brightnesses (exempli ed by the Local Group dwarf spheroidals). The terms \dwarf elliptical" (dE) and \dwarf spheroidal" (dSph) have been used most often to describe smooth, low surface brightness (LSB) galaxies. However, the lack of a universally accepted de nition has led to some confusion over whether these terms refer to the same thing, and in particular whether the dE class includes galaxies like M32. In the discussions that follow, we adopt the classi cation scheme set out in the extensive Virgo cluster dwarf atlas of Sandage & Binggeli (1984). In this scheme the term dE encompasses both local dSph galaxies and similar-looking galaxies beyond the Local Group. Faint ellipticals with pro les that are more nearly r1=4-law are referred to simply as \ellipticals" (E), or sometimes \compact ellipticals," but never dE's. A di erent name for \dwarf elliptical" frequently encountered in the literature is \spheroidal". The pros and cons of either name convention are discussed in Binggeli (1994b) and Kormendy