What is a star ?

Question

Short answers .

Answer 1

A large ball of burning gas in outer space that you see as a small point of light in the sky at night .

Answer 2

A star is a massive, luminous ball of plasma. Stars group together to form galaxies, and they dominate the visible universe. The nearest star to Earth is the Sun, which is the source of most of the energy on Earth, including daylight. Other stars are visible in the night sky, when they are not outshone by the Sun. A star shines because nuclear fusion in its core releases energy which traverses the star's interior and then radiates into outer space. Without stars, life and most atomic elements present in the Universe would not exist.

Astronomers can determine the mass, age, chemical composition and many other properties of a star by observing its spectrum, luminosity and motion through space. The total mass of a star is the principal determinant in its evolution and eventual fate. Other characteristics of a star that are determined by its evolutionary history include the diameter, rotation, movement and temperature. A plot of the temperature of many stars against their luminosities, known as a Hertzsprung-Russell diagram (H-R diagram), allows the current age and evolutionary state of a particular star to be determined.

A star begins as a collapsing cloud of material that is composed primarily of hydrogen along with some helium and heavier trace elements. Once the stellar core is sufficiently dense, some of the hydrogen is steadily converted into helium through the process of nuclear fusion. The remainder of the star's interior carries energy away from the core through a combination of radiative and convective processes. These processes keep the star from collapsing upon itself and the energy generates a stellar wind at the surface and radiation into outer space.

Once the hydrogen fuel at the core is exhausted, a star of at least 0.4 times the mass of the Sun expands to become a red giant, fusing heavier elements at the core, or in shells around the core. It then evolves into a degenerate form, recycling a portion of the matter into the interstellar environment where it will form a new generation of stars with a higher proportion of heavy elements.

Binary and multi-star systems consist of two or more stars that are gravitationally bound, and generally move around each other in stable orbits. When two such stars have a relatively close [orbit], their gravitational interaction can have a significant impact on their evolution

Answer 3

A star starts as a cloud of hydrogen gas. The cloud starts to condense more and more and thereby the gas gets hotter and hotter and starts rotating around an axis. Eventually the heat and pressure become enough to start a nuclear reaction that is to fuse the 2 hydrogen atomes into 1 helium atom and release a tremendous amount of energy. This is when the star becomes a nuclear furnace. From that moment on 2 force keep the star balanced: first is the gravity of its mass trying to squeeze it to its center and second force is the explosions of the nuclear reactions trying to tear it apart in a massive explosion. As long as these 2 forces are balanced the star is stable. After certain time depending on the mass of the star it starts to run out of hydrogen and starts to fuse other elements and this is when the death of the star begin. The star starts consume more and more of its resources till it finally dies in one of 3 ways. It cools down and become a cold rigid ball of condensed matter floating in space and this is a quiet death. Or if its a heavy star it explodes violently in a phenomena called supernova. Or if its a very heavy star it turns into a black hole swallowing other objects come near it.

Answer 4

A multi-billion ton unshielded nuclear fusion reactor generating huge amounts of energy every second, yet which by some quirk of British weather can still manage to look slightly cold and damp.

Answer 5

It is a hot ball of gases and dust at really high pressure and temperature. The nearest star is the sun.

Answer 6

A star is a massive luminous ball of plasma.

Answer 7

There is no perfect definition for star but we can say that it is a giant self luminous body.

Answer 8

It's an engine that turns wispy hydrogen and helium into heavier elements like oxygen and carbon and gold.

Answer 9

a large Nuclear Furnace

Answer 10

A ball of gas.That gas is especifically helium.