Information: - The Sun is the star at the center of the Solar System. It is a nearly perfect sphere of hot plasma, with internal convective motion that generates a magnetic field via a dynamo process.<ref name="doi10.1146/annurev-astro-081913-040012"></ref> It is by far the most important source of energy for life on Earth. Its diameter is about 109 times that of Earth, and its mass is about 330,000 times that of Earth, accounting for about 99.86% of the total mass of the Solar System. About three quarters of the Sun's mass consists of hydrogen (~73%); the rest is mostly helium (~25%), with much smaller quantities of heavier elements, including oxygen, carbon, neon, and iron. - A star is a luminous sphere 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 from Earth during the night, appearing as a multitude of fixed luminous points in the sky due to their immense distance from Earth. Historically, the most prominent stars were grouped into constellations and asterisms, the brightest of which gained proper names. Astronomers have assembled star catalogues that identify the known stars and provide standardized stellar designations. However, most of the stars in the Universe, including all stars outside our galaxy, the Milky Way, are invisible to the naked eye from Earth. Indeed, most are invisible from Earth even through the most powerful telescopes. - A terrestrial planet, telluric planet, or rocky planet is a planet that is composed primarily of silicate rocks or metals. Within the Solar System, the terrestrial planets are the inner planets closest to the Sun, i.e. Mercury, Venus, Earth, and Mars. The terms "terrestrial planet" and "telluric planet" are derived from Latin words for Earth ("Terra" and "Tellus"), as these planets are, in terms of composition, "Earth-like". - The center of the Eridanus Cluster is roughly 23 Mpc ( 75 Mly ) from Earth , and contains about 73 main galaxies and about 200 total galaxies . About 30 % have Hubble classifications of elliptical or S0 and the remaining 70 % are spiral or irregular . These galaxies reside in smaller groups which are all loosely gravitationally bound to each other , suggesting that the system is still condensing from the Hubble flow and may eventually form a cluster of about 1014 M . A low velocity dispersion compared to that of , for example , the Coma cluster , supports this hypothesis . The Eridanus Cluster is located in the constellation Eridanus near the Fornax Cluster , and is sometimes called the '' Fornax II Cluster '' . - Fornax is a constellation in the southern sky, partly ringed by the celestial river Eridanus. Its name is Latin for furnace. It was named by French astronomer Nicolas Louis de Lacaille in 1756. Fornax is one of the 88 modern constellations. - The Virgo Cluster is a cluster of galaxies whose center is 53.8 0.3 Mly (16.5 0.1 Mpc) away in the constellation Virgo. Comprising approximately 1300 (and possibly up to 2000) member galaxies, the cluster forms the heart of the larger Virgo Supercluster, of which the Local Group is an outlying member. However, the Local Group experiences the mass of the Virgo Supercluster as the Virgocentric flow. It is estimated that the Virgo Cluster's mass is 1.2 out to 8 degrees of the cluster's center or a radius of about 2.2 Mpc. - Life is a characteristic distinguishing physical entities having biological processes, such as signaling and self-sustaining processes, from those that do not, either because such functions have ceased, or because they never had such functions and are classified as inanimate. Various forms of life exist, such as plants, animals, fungi, protists, archaea, and bacteria. The criteria can at times be ambiguous and may or may not define viruses, viroids, or potential artificial life as "living". Biology is the primary science concerned with the study of life, although many other sciences are involved. - NGC 1427A is an irregular galaxy in the constellation Eridanus. Its distance modulus has been estimated using the globular cluster luminosity function to be 31.01 0.21 which is about 52 Mly. It is the brightest dwarf irregular member of the Fornax cluster and is in the foreground of the cluster's central galaxy NGC 1399. - A parsec (symbol: pc) is a unit of length used to measure large distances to objects outside our Solar System. One parsec is the distance at which one astronomical unit subtends an angle of one arcsecond. A parsec is equal to about 3.26 light-years (31trillion kilometres or 19trillion miles) in length. The nearest star, Proxima Centauri, is about from the Sun. Most of the stars visible to the unaided eye in the nighttime sky are within 500 parsecs of the Sun. - The Universe is all of time and space and its contents. It includes planets, moons, minor planets, stars, galaxies, the contents of intergalactic space, and all matter and energy. The size of the entire Universe is unknown. - A constellation is formally defined as a region of the celestial sphere, with boundaries laid down by the International Astronomical Union (IAU). The constellation areas mostly had their origins in Western-traditional patterns of stars from which the constellations take their names. - The Eridanus Group, sometimes called the Eridanus Cloud, is a nearby loose grouping of galaxies at a mean distance of approximately 75 Mly (23 2 Mpc) in the constellation Eridanus. Redshift values show that there are approximately 200 galaxies associated with the group, approximately 70% of which are spiral and irregular type galaxies whilst the remaining 30% are elliptical and lenticular types. - NGC 1365, also known as the "Great Barred Spiral Galaxy", is a barred spiral galaxy about 56 million light-years away in the constellation Fornax. The core is an oval shape with an apparent size of about 50 40. The spiral arms extend in a wide curve north and south from the ends of the east-west bar and form an almost ring like Z-shaped halo. The central mass in active galactic nucleus rotates close to relativistic limit (the dimensionless spin parameter is larger than 0.84). - The International Astronomical Union (IAU UAI) is an international association of professional astronomers, at the PhD level and beyond, active in professional research and education in astronomy. Among other activities, it acts as the internationally recognized authority for assigning designations to celestial bodies (stars, planets, asteroids, etc.) and any surface features on them. - A light-year is a unit of length used to express astronomical distances. It is about 9 trillion kilometres or 6 trillion miles. As defined by the International Astronomical Union (IAU), a light-year is the distance that light travels in vacuum in one Julian year (365.25 days). Because it includes the word "year", the term light-year is sometimes misinterpreted as a unit of time. - The Solar System is the gravitationally bound system comprising the Sun and the objects that orbit it, either directly or indirectly. Of those objects that orbit the Sun directly, the largest eight are the planets, with the remainder being significantly smaller objects, such as dwarf planets and small Solar System bodies. Of the objects that orbit the Sun indirectly, the moons, two are larger than the smallest planet, Mercury. - NGC 1316 (also known as Fornax A) is a lenticular galaxy about 60 million light-years away in the constellation Fornax. NGC 1316 is a radio galaxy. It is the fourth-brightest radio source in the sky (as seen at 1400 MHz). - The Fornax Cluster is a cluster of galaxies lying at a distance of 62 million light-years (19 megaparsecs). It is the second richest galaxy cluster within 100 million light-years, after the considerably larger Virgo Cluster. It lies primarily in the constellation Fornax, and may be associated with the nearby Eridanus Group. The Fornax Cluster is a valuable source of information about the evolution of such clusters, showing the effects of a merger of a subgroup with the main group, which in turn lends clues about the associated galactic superstructure. At the centre of the cluster lies NGC 1399. Other cluster members include NGC 1316 (the group's brightest galaxy), NGC 1365, NGC 1427A, and NGC 1404. - In astronomy and navigation, the celestial sphere is an imaginary sphere of arbitrarily large radius, concentric with Earth. All objects in the observer's sky can be thought of as projected upon the inside surface of the celestial sphere, as if it were the underside of a dome or a hemispherical screen. The celestial sphere is a practical tool for spherical astronomy, allowing observers to plot positions of objects in the sky when their distances are unknown or unimportant. - Earth, otherwise known as the world, is the third planet from the Sun and the only object in the Universe known to harbor life. It is the densest planet in the Solar System and the largest of the four terrestrial planets. After reading the paragraphs above, choose the best answer for the entity that related to 'eridanus cluster' with the relationship of 'instance of'. Choices: - 1 - 25 - association - bacteria - biology - cloud - cluster - composition - constellation - curve - distance - dome - education - eight - energy - field - furnace - galaxy - galaxy cluster - group - harbor - irregular galaxy - may - member - motion - name - navigation - nucleus - object - orbit - planet - region - river - science - shape - show - size - space - sphere - spiral galaxy - star - study - symbol - system - terrestrial planet - three - time - two - union - unit of length - year
Answer:
galaxy cluster