what is a star?

Answer 1

star

Any massive celestial body of gas that shines by radiant energy generated inside it. The Milky Way Galaxy contains hundreds of billions of stars; only a very small fraction are visible to the unaided eye. The closest star is about 4.2 light-years from the Sun; the most distant are in galaxies billions of light-years away. Single stars such as the Sun are the minority; most stars occur in pairs, multiple systems, or clusters (see binary star; globular cluster; open cluster). Constellations consist not of such groupings but of stars in the same direction as seen from Earth. Stars vary greatly in brightness (magnitude), colour, temperature, mass, size, chemical composition, and age. In nearly all, hydrogen is the most abundant element. Stars are classified by their spectra (see spectrum), from blue-white to red, as O, B, A, F, G, K, or M; the Sun is a spectral type G star. Generalizations on the nature and evolution of stars can be made from correlations between certain properties and from statistical results (see Hertzsprung-Russell diagram). A star forms when a portion of a dense interstellar cloud of hydrogen and dust grains collapses from its own gravity. As the cloud condenses, its density and internal temperature increase until it is hot enough to trigger nuclear fusion in its core (if not, it becomes a brown dwarf). After hydrogen is exhausted in the core from nuclear burning, the core shrinks and heats up while the star’s outer layers expand significantly and cool, and the star becomes a red giant. The final stages of a star’s evolution, when it no longer produces enough energy to counteract its own gravity, depend largely on its mass and whether it is a component of a close binary system (see black hole; neutron star; nova; pulsar; supernova; white dwarf star). Some stars other than the Sun are known to have one or more planets (see planets of other stars). See also Cepheid variable; dwarf star; eclipsing variable star; flare star; giant star; Populations I and II; supergiant star; T Tauri star; variable star.

Answer 2

Sorry to make what looks like a joke but when I first looked at your handle I seriously thought it was 'dunderhead'. But enough rudeness!

Being a star has little to do with size and nothing to do with distance away.

Jupiter is a gas giant planet, just below the mass at which its mainly hydrogen atmosphere would have been sufficient to create a self-sustaining thermo-nuclear fusion reaction when its original collapse into a spherical body occurred. Had it become sufficiently hot to promote the start of a fusion reaction it would be a second sun in our solar system.

A star then is any body that has or has had a self-sustaining thermo-nuclear origin; a sun. Thus although not 'burning' or gaseous a neutron star is a star because it was once a sun.

Answer 3

star  /stɑr/ Pronunciation Key - Show Spelled Pronunciation[stahr] Pronunciation Key - Show IPA Pronunciation, noun, adjective, verb, starred, star‧ring.

–noun 1. any of the heavenly bodies, except the moon, appearing as fixed luminous points in the sky at night.
2. Astronomy. any of the large, self-luminous, heavenly bodies, as the sun, Polaris, etc.
3. any heavenly body.
4. Astrology. a heavenly body, esp. a planet, considered as influencing humankind and events.
5. a person's destiny, fortune, temperament, etc., regarded as influenced and determined by the stars.
6. a conventionalized figure usually having five or six points radiating from or disposed about a center.
7. this figure used as an ornament, award, badge, mark of excellence, etc.: The movie was awarded three stars.
8. Jewelry. a. a gem having the star cut.
b. the asterism in a crystal or a gemstone, as in a star sapphire.
c. a crystal or a gemstone having such asterism.
d. star facet.

9. Printing. an asterisk.
10. a person who is celebrated or distinguished in some art, profession, or other field.
11. a prominent actor, singer, or the like, esp. one who plays the leading role in a performance.

Answer 4

A star is a big ball of burning gas in outer space. It is normally fuelled by nuclear reactions at it's core and gives out light and heat to the surrounding space.

If it is close enough to a planet and the planet is at the right distance from it, there is a chance that the radiation from the star could work on amino acids to cause life.

Eventually these Amino acids develop into life forms, look up and revere the star as a god and call it their Sun.

To see the effects a star has on a planet, look outside in the daytime, oh the moonlight is reflected sunlight from our local star.

Answer 5

I think you have asked a great question because recently scientists just defined the word "PLANET:|"...and I can bet you whatever defination scientists have of a STAR will keep on chnaging in future(As did of PLANET)...
YAHOO EDUCATION website has defined it as: "A self-luminous celestial body consisting of a mass of gas held together by its own gravity in which the energy generated by nuclear reactions in the interior is balanced by the outflow of energy to the surface, and the inward-directed gravitational forces are balanced by the outward-directed gas and radiation pressures".
There you have it :-)
although my question is that the fact that a celstial body not orbiting any other celestial body should also come in a STARs defination or not(considering the fact that stars do not orbit or rotate around another celestial body?

Answer 6

When you have enough mass in one place, the collective gravitational pull will produce so much energy that nuclear fusion will take place in the center of the mass.

75% of all observable matter is hydrogen, and most of the remainder is helium. Our sun, for example, started as a 99% hydrogen ball and is progressively fusing the hydrogen at its core into helium. Larger stars can have enough mass to fuse heavier elements.

Here's the part I may be foggy about:
Iron, I believe, is the heaviest element created in this process. Any element heavier than Iron is created in stellar explosions where the mass of a star becomes so great at its core that atoms are no longer fused, but crushed together in a process that involves both fusion and fission (nova / supernova).

Answer 7

A star is a blazing hot mass of gas , giving off heat and light .Each star is ' born ' from a cloud of gas . Stars are being born and they die all the time .

Answer 8

A star is any of millions of gaseous bodies of great mass,heat and light, (like the sun) that radiate energy and can be seen as points of light in the sky.

Answer 9

A star is a small sun.

Answer 10

A star is a person glorified by his work in the Entertainment Industry such as Brad Pitt.