STAR
Stars are giant, luminous spheres of plasma. There
are billions of them — including our own sun — in
the Milky Way Galaxy. And there are billions of
galaxies in the universe.
Stars are the most widely recognized astronomical
objects, and represent the most fundamental
building blocks of galaxies. The age, distribution,
and composition of the stars in a galaxy trace the
history, dynamics, and evolution of that galaxy.
Moreover, stars are responsible for the manufacture
and distribution of heavy elements such as carbon,
nitrogen, and oxygen.
Facts about STARS
1. There could be over a Septillion stars in the
universe.
2. No, the stars do not twinkle.
3. The sun, the closest star to earth is moving.
4. It would take roughly 35,000 years to reach the
nearest sun next to the Sun.
5. The Sun produces the energy equivalent to 100
billion typical hydrogen bombs every second.
6. One day, the sun will die.
7. All you need are clouds of dust with great
turbulence within to create a star.
8. You would need 1,100 years to circle the largest
known star in the universe.
Types of Stars
1. Main Sequence Stars
Is the point in a stars evolution
during which it maintains a stable
nuclear reaction. In this stage during
which a star will spend most of its life.
Sun is a main sequence star.
2. Red Giants Stars
Is a large star that is reddish or
orange in color. A star that has a low
surface temperature and a diameter that
is large relative to the sun.
3. White Dwarfs Stars
Is a remnant of average-sized
star that has passed through the red
giant stage of its life after the star has
used up its remaining fuel.
4. Brown Dwarfs Stars
It is also called a failed star. During
the process of star formation, some
protostars never reach the critical mass
required to ignite the fires of nuclear
fusion.
5. Variable Stars
A star whose brightness changes
usually in more or less regular period.
6. Binary Stars
A system of two stars that
revolve around each other under their
natural gravitation.
Multiple Star System
9. The larger the star, the shorter the life span.
1. Open Star Cluster
10. If you look at the stars, you are actually looking
back in time.
An open, or galactic, cluster is a group of relatively
young, loosely bound stars. Astronomers have
cataloged more than 1,000 galactic clusters within
the Milky Way.
An open cluster is a group of up to a few thousand
stars that were formed from the same giant
molecular cloud, and are still loosely gravitationally
bound to each other.
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2. Globular Star Cluster
CONSTELLATION
A globular cluster is a spherical collection
of stars that orbits a galactic core as a satellite.
Constellations are fixed star groups or clusters of
stars arranged in a definite pattern. These clusters of
stars were named in honor of mythological
characters, great heroes and even animals.
A constellation is a group of stars that, when seen
from Earth, form a pattern. The stars in the sky are
divided
into
88constellations.
The
brightest constellation is Crux (the Southern Cross).
Globular clusters are very tightly bound by
gravity, which gives them their spherical shapes and
relatively high stellar densities toward their centers.
A globular cluster is sometimes known more
simply as a globular. Globular clusters, which are
found in the halo of a galaxy, contain considerably
more stars and are much older than the less dense
galactic, or open clusters, which are found in the
disk.
STELLER EVOLUTION
Stellar evolution is the process by which
a star changes during its lifetime. Depending on the
mass of the star, this lifetime ranges 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 born from collapsing clouds
of gas and dust, often called nebulae or molecular
clouds. Over the course of millions of years, these
proto stars settle down into a state of equilibrium,
becoming what is known as a main-sequence star.
In modern astronomy, a constellation is a specific
area of the celestial sphere as defined by
the International Astronomical Union (IAU). These
areas had their origins in star patterns from which
the constellations take their names. There are 88
officially recognized constellations, covering the
entire sky.
The brightest constellation is Crux (the Southern
Cross). The constellation with the greatest number
of visible stars in it is Centaurus (the Centaur - with
101 stars).
Constellations are formed of bright stars which
appear close to each other on the sky, but are really
far apart in space. The shapes you see all depend on
your point of view. Many societies saw patterns
among the stars with gods and goddesses or stories
from their culture. The stars allowed farmers to plan
ahead and form agriculture, and constellations made
it easier to recognize and interpret the patterns in
the sky. The constellations also helped with
navigation.
BLACK HOLE
Black hole is an object whose surface
gravity is exceedingly high that nothing, even light
can escape. Any ray of light or object that enters the
black hole is trapped. It can take in radiation and
objects but can never send anything back.
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