| Stelleroidea | |
|---|---|
 | |
| Ochre sea star on beach at Olympic National Park | |
Scientific classification  | |
| Kingdom: | Animalia |
| Phylum: | Echinodermata |
| Superclass: | Stelleroidea |
| Classes | |
Stelleroidea is a superclass of marine echinoderms including three classes:
A constellation is an area on the celestial sphere in which a group of visible stars forms a perceived outline or pattern, typically representing an animal, mythological person or creature, or an inanimate object.
The flag of the United States of America, often referred to as the American flag or the U.S. flag, is the national flag of the United States. It consists of thirteen equal horizontal stripes of red alternating with white, with a blue rectangle in the canton bearing fifty small, white, five-pointed stars arranged in nine offset horizontal rows, where rows of six stars alternate with rows of five stars. The 50 stars on the flag represent the 50 states of the United States of America, and the 13 stripes represent the thirteen British colonies that declared independence from the Kingdom of Great Britain, and became the first states in the U.S. Nicknames for the flag include the Stars and Stripes, Old Glory, and the Star-Spangled Banner.
A galaxy is a gravitationally bound system of stars, stellar remnants, interstellar gas, dust, and dark matter. The word galaxy is derived from the Greek galaxias (γαλαξίας), literally "milky", a reference to the Milky Way. Galaxies range in size from dwarfs with just a few hundred million stars to giants with one hundred trillion stars, each orbiting its galaxy's center of mass.
A nebula is an interstellar cloud of dust, hydrogen, helium and other ionized gases. Originally, the term was used to describe any diffused astronomical object, including galaxies beyond the Milky Way. The Andromeda Galaxy, for instance, was once referred to as the Andromeda Nebula before the true nature of galaxies was confirmed in the early 20th century by Vesto Slipher, Edwin Hubble and others.
A neutron star is the collapsed core of a massive supergiant star, which had a total mass of between 10 and 25 solar masses, possibly more if the star was especially metal-rich. Except for black holes, and some hypothetical objects, neutron stars are the smallest and densest currently known class of stellar objects. Neutron stars have a radius on the order of 10 kilometres (6.2 mi) and a mass of about 1.4 solar masses. They result from the supernova explosion of a massive star, combined with gravitational collapse, that compresses the core past white dwarf star density to that of atomic nuclei.
A star is an astronomical object consisting of a luminous spheroid of plasma held together by its own gravity. The nearest star to Earth is the Sun. Many other stars are visible to the naked eye at night, but due to their immense distance from Earth they appear as fixed points of light in the sky. The most prominent stars are grouped into constellations and asterisms, and many of the brightest stars have proper names. Astronomers have assembled star catalogues that identify the known stars and provide standardized stellar designations. The observable universe contains an estimated 1022 to 1024 stars, but most are invisible to the naked eye from Earth, including all individual stars outside our galaxy, the Milky Way.
Stellar evolution is the process by which a star changes over the course of time. Depending on the mass of the star, its lifetime can range from a few million years for the most massive to trillions of years for the least massive, which is considerably longer than the age of the universe. The table shows the lifetimes of stars as a function of their masses. All stars are formed from collapsing clouds of gas and dust, often called nebulae or molecular clouds. Over the course of millions of years, these protostars settle down into a state of equilibrium, becoming what is known as a main-sequence star.
In astronomy, stellar classification is the classification of stars based on their spectral characteristics. Electromagnetic radiation from the star is analyzed by splitting it with a prism or diffraction grating into a spectrum exhibiting the rainbow of colors interspersed with spectral lines. Each line indicates a particular chemical element or molecule, with the line strength indicating the abundance of that element. The strengths of the different spectral lines vary mainly due to the temperature of the photosphere, although in some cases there are true abundance differences. The spectral class of a star is a short code primarily summarizing the ionization state, giving an objective measure of the photosphere's temperature.
The zodiac is an area of the sky that extends approximately 8° north or south of the ecliptic, the apparent path of the Sun across the celestial sphere over the course of the year. The paths of the Moon and visible planets are also within the belt of the zodiac.
Astronomy is a natural science that studies celestial objects and phenomena. It uses mathematics, physics, and chemistry in order to explain their origin and evolution. Objects of interest include planets, moons, stars, nebulae, galaxies, and comets. Relevant phenomena include supernova explosions, gamma ray bursts, quasars, blazars, pulsars, and cosmic microwave background radiation. More generally, astronomy studies everything that originates outside Earth's atmosphere. Cosmology is a branch of astronomy that studies the universe as a whole.
A binary star is a star system consisting of two stars orbiting around their common barycenter. Systems of two or more stars are called multiple star systems. These systems, especially when more distant, often appear to the unaided eye as a single point of light, and are then revealed as multiple by other means.
The Pleiades, also known as the Seven Sisters and Messier 45, is an open star cluster containing middle-aged, hot B-type stars in the north-west of the constellation Taurus. It is among the star clusters nearest to Earth, it is the nearest Messier object to Earth, and is the cluster most obvious to the naked eye in the night sky.
The Dallas Stars are a professional ice hockey team based in Dallas. They compete in the National Hockey League (NHL) as a member of the Central Division. The team was founded during the 1967 NHL expansion as the Minnesota North Stars, based in Bloomington, Minnesota. Before the beginning of the 1978–79 NHL season, the team merged with the Cleveland Barons after the league granted them permission due to each team's respective financial struggles. Ultimately, the franchise relocated to Dallas for the 1993–94 NHL season. The Stars played out of Reunion Arena from their relocation until 2001, when the team moved less than 1.5 miles (2.4 km) into the American Airlines Center.
The Hollywood Walk of Fame comprises more than 2,690 five-pointed terrazzo and brass stars embedded in the sidewalks along 15 blocks of Hollywood Boulevard and three blocks of Vine Street in Hollywood, California. The stars are permanent public monuments to achievement in the entertainment industry, bearing the names of a mix of musicians, actors, directors, producers, musical and theatrical groups, fictional characters, and others. The Walk of Fame is administered by the Hollywood Chamber of Commerce and maintained by the self-financing Hollywood Historic Trust. It is a popular tourist destination, with an estimated 10 million annual visitors in 2010. The Hollywood Chamber of Commerce holds trademark rights to the Hollywood Walk of Fame.
Orion is a prominent constellation located on the celestial equator and visible throughout the world. It is one of the most conspicuous and recognizable constellations in the night sky. It is named after Orion, a hunter in Greek mythology. Its brightest stars are blue-white Rigel and red Betelgeuse.
The flags of the Confederate States of America have a history of three successive designs from 1861 to 1865. The flags were known as the "Stars and Bars", used from 1861 to 1863, the "Stainless Banner", used from 1863 to 1865, and the "Blood-Stained Banner", used in 1865 shortly before the Confederacy's dissolution. A rejected national flag design was also used as a Confederate army's battle flag and featured in the "Stainless Banner" and "Blood-Stained Banner" designs. Although this design was never a national flag, it is the most commonly recognized symbol of the Confederacy.
A service star is a miniature bronze or silver five-pointed star 3⁄16 inch in diameter that is authorized to be worn by members of the eight uniformed services of the United States on medals and ribbons to denote an additional award or service period. The service star may also be referred to as a campaign star or battle star depending on which award the star is authorized for and the manner in which the device is used for the award.
The Michelin Guides are a series of guide books published by the French tyre company Michelin for more than a century. The term normally refers to the annually published Michelin Red Guide, the oldest European hotel and restaurant reference guide, which awards up to three Michelin stars for excellence to a select few establishments. The acquisition or loss of a star can have dramatic effects on the success of a restaurant. Michelin also publishes a series of general guides to cities, regions, and countries, the Green Guides.
Dancing with the Stars is an American dance competition television series that premiered on June 1, 2005, on ABC. It is the US version of the UK series Strictly Come Dancing, and one of several iterations of the Dancing with the Stars franchise. The show was first hosted by Tom Bergeron from its inception until 2019. Lisa Canning was co-host in the first season, Samantha Harris co-hosted seasons two through nine, Brooke Burke-Charvet in seasons ten through seventeen, and Erin Andrews from season eighteen through twenty-eight. The show was renewed for its twenty-ninth season which premiered on September 14, 2020 with the addition of new host Tyra Banks, replacing Bergeron.
The Milky Way is the galaxy that contains our Solar System, with the name describing the galaxy's appearance from Earth: a hazy band of light seen in the night sky formed from stars that cannot be individually distinguished by the naked eye. The term Milky Way is a translation of the Latin via lactea, from the Greek γαλακτικός κύκλος. From Earth, the Milky Way appears as a band because its disk-shaped structure is viewed from within. Galileo Galilei first resolved the band of light into individual stars with his telescope in 1610. Until the early 1920s, most astronomers thought that the Milky Way contained all the stars in the Universe. Following the 1920 Great Debate between the astronomers Harlow Shapley and Heber Curtis, observations by Edwin Hubble showed that the Milky Way is just one of many galaxies.
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