Astronomy Portal | Britannica

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class="font-serif mt-30 mb-20">Astronomy</h1> <div class="font-serif grid"> <div class="col-sm-70 col-sm-offset-15"> Human beings have long been fascinated by the celestial sphere above, whose twinkling lights have inspired not only scientific theories but also many artistic endeavors. Humankind's fascination with the world beyond Earth has led to many landmark moments in history, as when space exploration took a giant step forward with the advent of technology that allowed humans to successfully travel to the Moon and to build spacecraft capable of exploring the rest of the solar system and beyond.</div> </div> </div> </div> <div class="container"> <h2 class="label my-30">Astronomy Encyclopedia Articles</h2> <div class="grid top g-10 mb-40"> <div class="col-33 col-sm-20 col-md-16 col-lg-10"> <div class="border shadow p-10 text-center "> <a class="font-weight-bold font-14 " href="/browse/Astronomy/1">-AST</a> </div> </div> <div class="col-33 col-sm-20 col-md-16 col-lg-10"> <div class="border shadow p-10 text-center "> <a class="font-weight-bold font-14 " href="/browse/Astronomy/2">AST-CAN</a> </div> </div> <div class="col-33 col-sm-20 col-md-16 col-lg-10"> <div class="border shadow p-10 text-center "> <a class="font-weight-bold font-14 " href="/browse/Astronomy/3">CAN-COR</a> </div> </div> <div class="col-33 col-sm-20 col-md-16 col-lg-10"> <div class="border shadow p-10 text-center "> <a class="font-weight-bold font-14 " href="/browse/Astronomy/4">COR-ENE</a> </div> </div> <div class="col-33 col-sm-20 col-md-16 col-lg-10"> <div class="border shadow p-10 text-center "> <a class="font-weight-bold font-14 " href="/browse/Astronomy/5">ENE-GRA</a> </div> </div> <div class="col-33 col-sm-20 col-md-16 col-lg-10"> <div class="border shadow p-10 text-center "> <a class="font-weight-bold font-14 " href="/browse/Astronomy/6">GRA-HYA</a> </div> </div> <div class="col-33 col-sm-20 col-md-16 col-lg-10"> <div class="border shadow p-10 text-center "> <a class="font-weight-bold font-14 " href="/browse/Astronomy/7">HYA-LAN</a> </div> </div> <div class="col-33 col-sm-20 col-md-16 col-lg-10"> <div class="border shadow p-10 text-center "> <a class="font-weight-bold font-14 " href="/browse/Astronomy/8">LAN-MAS</a> </div> </div> <div class="col-33 col-sm-20 col-md-16 col-lg-10"> <div class="border shadow p-10 text-center "> <a class="font-weight-bold font-14 " href="/browse/Astronomy/9">MAS-NER</a> </div> </div> <div class="col-33 col-sm-20 col-md-16 col-lg-10"> <div class="border shadow p-10 text-center "> <a class="font-weight-bold font-14 " href="/browse/Astronomy/10">NER-POI</a> </div> </div> <div class="col-33 col-sm-20 col-md-16 col-lg-10"> <div class="border shadow p-10 text-center "> <a class="font-weight-bold font-14 " href="/browse/Astronomy/11">POI-SAR</a> </div> </div> <div class="col-33 col-sm-20 col-md-16 col-lg-10"> <div class="border shadow p-10 text-center "> <a class="font-weight-bold font-14 " href="/browse/Astronomy/12">SAR-SPA</a> </div> </div> <div class="col-33 col-sm-20 col-md-16 col-lg-10"> <div class="border shadow p-10 text-center "> <a class="font-weight-bold font-14 " href="/browse/Astronomy/13">SPA-TUC</a> </div> </div> <div class="col-33 col-sm-20 col-md-16 col-lg-10"> <div class="border shadow p-10 text-center "> <a class="font-weight-bold font-14 " href="/browse/Astronomy/14">TUR-ZWI</a> </div> </div> <div class="col-33 col-sm-20 col-md-16 col-lg-10"> <div class="border shadow p-10 text-center "> <a class="font-weight-bold font-14 " href="/browse/Astronomy/15">ÅNG-ṬūS</a> </div> </div> </div> <h2 class="label my-30 text-center">Featured Articles</h2> <div class="js-pinboard grid gy-20"> <div class="p-10 d-inline-flex js-pin col-100 col-sm-33 col-md-25 "> <div class="card text-normal col-100 "> <div class="card-media position-relative"> <a href="https://www.britannica.com/biography/Neil-Armstrong" style="--aspect-ratio: 16/9"> <img loading="lazy" src="https://cdn.britannica.com/72/163272-050-1C5BC2B7/Neil-Armstrong-American.jpg?w=400&h=225&c=crop" alt="Neil Armstrong" class="col-100" /> </a> </div> <div class="col"> <div class="card-body text-hyphenate"> <a href="https://www.britannica.com/biography/Neil-Armstrong" class="font-weight-bold font-16 lh-sm">Neil Armstrong</a> <div class="font-serif mt-10 font-14"> Neil Armstrong was a U.S. astronaut, and the first person to set foot on the Moon. Neil Armstrong was the eldest of three children born to Viola Louise Engel and Stephen Koenig Armstrong, a state auditor.... </div> </div> </div> </div> </div> <div class="p-10 d-inline-flex js-pin col-100 col-sm-33 col-md-25 "> <div class="card text-normal col-100 "> <div class="card-media position-relative"> <a href="https://www.britannica.com/science/star-astronomy" style="--aspect-ratio: 16/9"> <img loading="lazy" src="https://cdn.britannica.com/38/111338-050-D23BE7C8/Stars-NGC-290-Hubble-Space-Telescope.jpg?w=400&h=225&c=crop" alt="open cluster NGC 290" class="col-100" /> </a> </div> <div class="col"> <div class="card-body text-hyphenate"> <a href="https://www.britannica.com/science/star-astronomy" class="font-weight-bold font-16 lh-sm">star</a> <div class="font-serif mt-10 font-14"> Star, any massive self-luminous celestial body of gas that shines by radiation derived from its internal energy sources. Of the tens of billions of trillions of stars composing the observable universe,... </div> </div> </div> </div> </div> <div class="p-10 d-inline-flex js-pin col-100 col-sm-33 col-md-25 "> <div class="card text-normal col-100 "> <div class="card-media position-relative"> <a href="https://www.britannica.com/biography/Valentina-Tereshkova" style="--aspect-ratio: 16/9"> <img loading="lazy" src="https://cdn.britannica.com/96/177496-050-481E5616/Valentina-Tereshkova.jpg?w=400&h=225&c=crop" alt="Valentina Tereshkova" class="col-100" /> </a> </div> <div class="col"> <div class="card-body text-hyphenate"> <a href="https://www.britannica.com/biography/Valentina-Tereshkova" class="font-weight-bold font-16 lh-sm">Valentina Tereshkova</a> <div class="font-serif mt-10 font-14"> Valentina Tereshkova is a Soviet cosmonaut and the first woman to travel into space. On June 16, 1963, she was launched in the spacecraft Vostok 6, which completed 48 orbits in 71 hours. In space at the... </div> </div> </div> </div> </div> <div class="p-10 d-inline-flex js-pin col-100 col-sm-33 col-md-25 "> <div class="card text-normal col-100 "> <div class="card-media position-relative"> <a href="https://www.britannica.com/science/universe" style="--aspect-ratio: 16/9"> <img loading="lazy" src="https://cdn.britannica.com/00/185400-138-B50A215F/universe.jpg?w=400&h=225&c=crop" alt="Examine the observable universe's place within the whole universe" class="col-100" /> </a> </div> <div class="col"> <div class="card-body text-hyphenate"> <a href="https://www.britannica.com/science/universe" class="font-weight-bold font-16 lh-sm">universe</a> <div class="font-serif mt-10 font-14"> Universe, the whole cosmic system of matter and energy of which Earth, and therefore the human race, is a part. Humanity has traveled a long road since societies imagined Earth, the Sun, and the Moon as... </div> </div> </div> </div> </div> <div class="p-10 d-inline-flex js-pin col-100 col-sm-33 col-md-25 "> <div class="card text-normal col-100 "> <div class="card-media position-relative"> <a href="https://www.britannica.com/biography/Valery-Vladimirovich-Polyakov" style="--aspect-ratio: 16/9"> <img loading="lazy" src="https://cdn.britannica.com/60/102460-050-92F228E7/Valery-Vladimirovich-Polyakov.jpg?w=400&h=225&c=crop" alt="Valery Polyakov" class="col-100" /> </a> </div> <div class="col"> <div class="card-body text-hyphenate"> <a href="https://www.britannica.com/biography/Valery-Vladimirovich-Polyakov" class="font-weight-bold font-16 lh-sm">Valery Vladimirovich Polyakov</a> <div class="font-serif mt-10 font-14"> Valery Vladimirovich Polyakov was a Russian cosmonaut who holds the record for the longest single spaceflight in history. Polyakov had an early interest in spaceflight, and in 1971 he joined the Institute... </div> </div> </div> </div> </div> <div class="p-10 d-inline-flex js-pin col-100 col-sm-33 col-md-25 "> <div class="card text-normal col-100 "> <div class="card-media position-relative"> <a href="https://www.britannica.com/place/Great-Red-Spot" style="--aspect-ratio: 16/9"> <img loading="lazy" src="https://cdn.britannica.com/79/196079-050-A8735694/image-Jupiter-Great-Red-Spot-spacecraft-Juno.jpg?w=400&h=225&c=crop" alt="Great Red Spot" class="col-100" /> </a> </div> <div class="col"> <div class="card-body text-hyphenate"> <a href="https://www.britannica.com/place/Great-Red-Spot" class="font-weight-bold font-16 lh-sm">Great Red Spot</a> <div class="font-serif mt-10 font-14"> Great Red Spot, a long-lived enormous storm system on the planet Jupiter and the most conspicuous feature of its visible cloud surface. It is generally reddish in colour, slightly oval in shape, and approximately... </div> </div> </div> </div> </div> <div class="p-10 d-inline-flex js-pin col-100 col-sm-33 col-md-25 "> <div class="card text-normal col-100 "> <div class="card-media position-relative"> <a href="https://www.britannica.com/science/astrobiology" style="--aspect-ratio: 16/9"> <img loading="lazy" src="https://cdn.britannica.com/85/75385-050-E8279E3D/cracks-moons-one-Crescent-view-Europa-Galilean-1998.jpg?w=400&h=225&c=crop" alt="Europa" class="col-100" /> </a> </div> <div class="col"> <div class="card-body text-hyphenate"> <a href="https://www.britannica.com/science/astrobiology" class="font-weight-bold font-16 lh-sm">astrobiology</a> <div class="font-serif mt-10 font-14"> Astrobiology, a multidisciplinary field dealing with the nature, existence, and search for extraterrestrial life (life beyond Earth). Astrobiology encompasses areas of biology, astronomy, and geology.... </div> </div> </div> </div> </div> <div class="p-10 d-inline-flex js-pin col-100 col-sm-33 col-md-25 "> <div class="card text-normal col-100 "> <div class="card-media position-relative"> <a href="https://www.britannica.com/science/infrared-astronomy" style="--aspect-ratio: 16/9"> <img loading="lazy" src="https://cdn.britannica.com/30/128130-050-B9AC5C53/constellation-light-Orion-image-Infrared-Astronomical-Satellite.jpg?w=400&h=225&c=crop" alt="Orion in visible and infrared light" class="col-100" /> </a> </div> <div class="col"> <div class="card-body text-hyphenate"> <a href="https://www.britannica.com/science/infrared-astronomy" class="font-weight-bold font-16 lh-sm">infrared astronomy</a> <div class="font-serif mt-10 font-14"> Infrared astronomy, study of astronomical objects through observations of the infrared radiation that they emit. Various types of celestial objects—including the planets of the solar system, stars, nebulae,... </div> </div> </div> </div> </div> <div class="p-10 d-inline-flex js-pin col-100 col-sm-33 col-md-25 "> <div class="card text-normal col-100 "> <div class="card-media position-relative"> <a href="https://www.britannica.com/science/solar-system" style="--aspect-ratio: 16/9"> <img loading="lazy" src="https://cdn.britannica.com/93/95393-050-5329EE11/planets-distance-order-Sun.jpg?w=400&h=225&c=crop" alt="solar system" class="col-100" /> </a> </div> <div class="col"> <div class="card-body text-hyphenate"> <a href="https://www.britannica.com/science/solar-system" class="font-weight-bold font-16 lh-sm">solar system</a> <div class="font-serif mt-10 font-14"> Solar system, assemblage consisting of the Sun—an average star in the Milky Way Galaxy—and those bodies orbiting around it: 8 (formerly 9) planets with more than 210 known planetary satellites (moons);... </div> </div> </div> </div> </div> <div class="p-10 d-inline-flex js-pin col-100 col-sm-33 col-md-25 "> <div class="card text-normal col-100 "> <div class="card-media position-relative"> <a href="https://www.britannica.com/biography/Buzz-Aldrin" style="--aspect-ratio: 16/9"> <img loading="lazy" src="https://cdn.britannica.com/55/69055-050-8D293FF9/Buzz-Aldrin-1969.jpg?w=400&h=225&c=crop" alt="Buzz Aldrin" class="col-100" /> </a> </div> <div class="col"> <div class="card-body text-hyphenate"> <a href="https://www.britannica.com/biography/Buzz-Aldrin" class="font-weight-bold font-16 lh-sm">Buzz Aldrin</a> <div class="font-serif mt-10 font-14"> Buzz Aldrin is an American astronaut who was the second person to set foot on the Moon. A graduate of the U.S. Military Academy, West Point, New York (1951), Aldrin became an air force pilot. He flew 66... </div> </div> </div> </div> </div> <div class="p-10 d-inline-flex js-pin col-100 col-sm-33 col-md-25 "> <div class="card text-normal col-100 "> <div class="card-media position-relative"> <a href="https://www.britannica.com/biography/Yuri-Gagarin" style="--aspect-ratio: 16/9"> <img loading="lazy" src="https://cdn.britannica.com/22/115022-050-FA9D6901/Yury-Alekseyevich-Gagarin-1961.jpg?w=400&h=225&c=crop" alt="Yuri Gagarin" class="col-100" /> </a> </div> <div class="col"> <div class="card-body text-hyphenate"> <a href="https://www.britannica.com/biography/Yuri-Gagarin" class="font-weight-bold font-16 lh-sm">Yuri Gagarin</a> <div class="font-serif mt-10 font-14"> Yuri Gagarin was a Soviet cosmonaut who in 1961 became the first man to travel into space. The son of a carpenter on a collective farm, Gagarin graduated as a molder from a trade school near Moscow in... </div> </div> </div> </div> </div> <div class="p-10 d-inline-flex js-pin col-100 col-sm-33 col-md-25 "> <div class="card text-normal col-100 "> <div class="card-media position-relative"> <a href="https://www.britannica.com/topic/astronaut" style="--aspect-ratio: 16/9"> <img loading="lazy" src="https://cdn.britannica.com/18/102418-050-80A86A9E/hands-Robert-Gibson-Atlantis-Vladimir-Dezhurov-Russian-June-29-1995.jpg?w=400&h=225&c=crop" alt="Robert Gibson and Vladimir Dezhurov" class="col-100" /> </a> </div> <div class="col"> <div class="card-body text-hyphenate"> <a href="https://www.britannica.com/topic/astronaut" class="font-weight-bold font-16 lh-sm">astronaut</a> <div class="font-serif mt-10 font-14"> Astronaut, designation, derived from the Greek words for “star” and “sailor,” commonly applied to an individual who has flown in outer space. More specifically, in the West, astronaut refers to those from... </div> </div> </div> </div> </div> <div class="p-10 d-inline-flex js-pin col-100 col-sm-33 col-md-25 "> <div class="card text-normal col-100 "> <div class="card-media position-relative"> <a href="https://www.britannica.com/technology/optical-storage" style="--aspect-ratio: 16/9"> <img loading="lazy" src="https://cdn.britannica.com/80/63480-004-FBBAF5F1/discs-videodiscs-lands-series-information-pits-photodiode.jpg?w=400&h=225&c=crop" alt="optical disc" class="col-100" /> </a> </div> <div class="col"> <div class="card-body text-hyphenate"> <a href="https://www.britannica.com/technology/optical-storage" class="font-weight-bold font-16 lh-sm">optical storage</a> <div class="font-serif mt-10 font-14"> Optical storage, electronic storage medium that uses low-power laser beams to record and retrieve digital (binary) data. 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Glenn joined... </div> </div> </div> </div> </div> <div class="p-10 d-inline-flex js-pin col-100 col-sm-33 col-md-25 "> <div class="card text-normal col-100 "> <div class="card-media position-relative"> <a href="https://www.britannica.com/biography/Michael-Collins-American-astronaut" style="--aspect-ratio: 16/9"> <img loading="lazy" src="https://cdn.britannica.com/54/69054-050-2F5BA8B6/Michael-Collins-1969.jpg?w=400&h=225&c=crop" alt="Michael Collins" class="col-100" /> </a> </div> <div class="col"> <div class="card-body text-hyphenate"> <a href="https://www.britannica.com/biography/Michael-Collins-American-astronaut" class="font-weight-bold font-16 lh-sm">Michael Collins</a> <div class="font-serif mt-10 font-14"> Michael Collins was a U.S. astronaut who was the command module pilot of Apollo 11, the first crewed lunar landing mission. 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