Stars in the universe
Stars
A star is a huge sphere of very
hot, glowing gas mostly hydrogen and helium
held together by its own gravity. Stars
produce their own light and energy by a process called nuclear fusion. Nuclear fusion reactions in its core support the
star against gravity and produce photons and heat, as well as small amounts of
heavier elements. The Sun is the closest star to Earth.
The Sun
is the closest star to Earth.Every star you see in the night sky is bigger and
brighter than our sun, only a handful of very faint stars are approximately the same size and
brightness of our sun and the rest are all bigger and brighter than our sun by
a large percentage.
The
nearest neighbor is Alpha Centauri, it's actually a triple-star system
bound together by gravity Alpha Centauri A and B are two bright, closely orbiting
stars with a distant, dim companion named Proxima Centauri, it lies 4.37
light years from the Sun.
Our Sun
is an average star, Stars can be bigger than the Sun, and stars can be smalle.
Example a
red dwarf star is Proxima Centauri the closest star to Earth. This star has
about 12% the mass of the Sun, and about 14% the size of the Sun – about
200,000 km across, which is only a little larger than Jupiter.
Our own
Sun is an example of an average star. It has a diameter of 1.4 million
kilometers… today. But when our Sun nears the end of its life, it will bloat up
as a red giant, and grow to 300 times its original size. This will consume the
orbits of the inner planets: Mercury, Venus, and yes, even Earth.
An
example of a larger is the blue supergiant Rigel in the constellation
Orion. This is a star with 17 times the mass of the Sun, which puts out 66,000
times as much energy. Rigel is estimated to be 62 times as big as the Sun.
Let’s
take a look at the red supergiant Betelgeuse, also in the constellation Orion.
Betelgeuse has 20 times the mass of the Sun, and it’s nearing the end of its
life
But the
biggest star in the Universe is thought to be the monster VY Canis Majoris.
This red hypergiant star is thought to be 1,800 times the size of the
Sun.
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How a
star is born
Stars are born in Nebulas, A large clouds of gas and dust, mostly
made up of hydrogen. These clouds are called "Nebulae." If the cloud
becomes large enough, then its own gravity begins to overcome the gas pressure,
and the cloud can begin to collapse. As the cloud collapses, gravity,
temperature, and pressure increase, until the cloud has collapsed enough to
raise the temperature to that required to fuse the hydrogen. Once that fusion
begins, the energy released halts the contraction, and the outer layers of gas
are blown away. What's left is an incandescent ball of mostly hydrogen, set
aglow by the fusion reactions in its core. And that’s how a star is born in
space
·
How the
star dies
Basically
a star die when it runs out of fuel which is hydrogen, when the star does not
have enough hydrogen to carry on the nuclear fusion then it start to burn (fuse)
helium which is heavier then hydrogen and start to produce more heavier
elements such as carbon, oxygen etc. Once the core has turned to iron, it can
burn no longer. The star collapses by its own gravity and
explodes to form a supernova and after the supernova a neutron star is left
which is so dense.
End of the article
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