1. Birth to Blackhole:
Life of a star
Introduction:
There are hundreds of billions of stars in the Milky Way alone; young and
old, large and small, quiet and violent. But they all started out in the same
way.
2. All stars start from a cloud of molecular hydrogen. These clouds are happy
to drift along in the Milky Way for millions and even billions of years until
some kind of event causes the cloud to collapse. It could be the collision
between two clouds, or the shockwave of a passing supernova. This pushes
the cloud over the top and gives gravity a chance to take over, and begin
collapsing the cloud together.
As the cloud collapses, big pieces shear off. Each of these will become a
star of their own. The mutual gravity on each chunk of the cloud
continues to pull the material inward. The conservation of momentum
from all the individual particles in the cloud makes it start to spin.
The Beginning
4. The stages of a star
All stars begin life in the same way. A cloud of dust and gas, also
known as a nebula.
It then later turns into a protostar.
which goes on to become a main sequence star. Following this, stars
develop in different ways depending on their size:
● Stars that are a similar size to the Sun follow the left hand path:
● red giant star → white dwarf → black dwarf
● Stars that are far greater in mass than the Sun follow the right
hand path:
● red super giant star → supernova → neutron star, or a black
hole (depending on size)
5. What is a Super nova?
A supernova is the biggest explosion that humans
have ever seen. Each blast is the extremely bright,
super-powerfulexplosion of a star.
Massive stars burn huge amounts of nuclear fuel at
their cores,or centers. This produces tonsof energy,
so the center gets very hot. Heat generates pressure,
and the pressurecreated by a star’s nuclear burning
also keepsthat star from collapsing.
A star is in balance between two opposite forces.The
star’s gravity tries to squeezethe star into the
smallest,tightest ball possible.But the nuclear fuel
burning in the star’s core creates strong outward
pressure.This outward push resists the inward
squeezeof gravity.
This causes it to explode! Supernova
6. A nebula is a giant cloud of dust and gas in space. Some
nebulae (more than one nebula) come from the gas and dust
thrown out by the explosion of a dying star, such as a
supernova.Other nebulae are regions where new stars are
beginning to form.
Nebulaeare made of dust and gases—mostlyhydrogen
and helium. The dust and gases in a nebula are very
spread out, but gravity can slowlybegin to pulltogether
clumps of dust and gas. As these clumps get bigger and
bigger, their gravity gets stronger and stronger.
Eventually,the clump of dust and gas gets so big that it
collapsesfrom its own gravity. The collapse causes the
material at the center of the cloud to heat up-and this hot
core is the beginning of a star
Nebulas!
Nebula
7. Black holes are thought to have formed in the
early universe, soon after the big bang. Stellar
black holes form when the center of a very
massive star collapses in upon itself. This
collapse also causes a supernova, or an
exploding star, that blasts part of the star into
space. Usually, black holes are results of the
death of a larger star. Scientists think
supermassive black holes formed at the same
time as the galaxy they are in. The size of the
supermassive black hole is related to the size
and mass of the galaxy it is in.
Formation of a Black Hole
8. Scientists can’t learn anything about matter after it becomes a
black hole, because it’s hidden behind the event horizon, the point
of no return. So there is not much confirmed theory about a
blackhole. This is what scientists have learned so far.
A black hole is a region of spacetime where gravity is so strong
that nothing — no particles or even electromagnetic radiation such
as light — can escape from it. The theory of general relativity
predicts that a sufficiently compact mass can deform spacetime to
form a black hole.
At the center of a black hole, it is often postulated there is
something called a gravitational singularity, or singularity. This is
where gravity and density are infinite and space-time extends into
infinity. Just what the physics is like at this point in the black hole
no one can say for sure.
What’s inside a Black Hole?
