There is a consensus that the universe has a beginning as well as an end, as the “Big Bang” theory indicates that the universe was dense, hot, and small, and then a big explosion occurred 13.8 billion years ago that expanded this small point in less than a billionth of a second to become It is billions of times larger than its original size in the so-called cosmic inflation phenomenon.

1. The universe from the Big Bang
until now in ten steps
The accepted theory is widely about the origin of
the universe and its evolution is the theory of the
Big Bang, which says that the universe started from
the thick point very warm since nearly 13.7 billion
years ago, then how the universe began from just
parts of the inch ( a few millimeters ) to what it is
today? Here we will find an analysis of the Big Bang
from its occurrence until now in ten easy-to-
understand steps. It took a little more than seven
days for the universe to be created and become as
we know it today SPACE.com He explores the
mysteries of the heavens in our eight-part series

2. (The History & Future of the Cosmos)And this is the
third part of it.
Step one: How did it all start?
The Big Bang was not an explosion in space, as the
name of the theory suggests, but rather the
emergence of space everywhere in the universe,
according to the researchers. According to the Big
Bang theory, the beginning of the universe was
from a single point in space, with very intense
density and heat. Astronomers are not sure what
happened before this moment, but with advanced
space missions, ground-based telescopes, and
complex calculations, they are still working to paint

3. a clearer picture of the beginning and formation of
the universe. The main role in these discoveries
comes from observations of the cosmic microwave
background radiation, which contains the glow of
light and residual radiation from the Big Bang. The
remnants of the Big Bang dominate the universe,
and are visible to microwave detectors, allowing
scientists to link together evidence for the
beginning of the universe. NASA launched in 2001
Wilkinson Polyisometric Microwave Probe Mission
Wilkinson Microwave Anisotropy Probe (WMAP) To
study the conditions as they existed at the
beginning of the universe by measuring the
radiation emitted by the microwave background,
and through many discoveries, a mission was able
to WMAP The age of the universe has been
determined to be 13.7 billion years.

4. The second step: the first growth spurt
of the universe
When the universe was very young, a hundred
billionths of a trillionth of a second ( wow !), it
underwent an amazing birth boom, and during this
expanding explosion ( known as inflation ) the
universe grew exponentially and doubled in size at
least 90 times. David Spergel says David Spergel A
theoretical astrophysicist at Princeton University in
Princeton, New Jersey SPACE.com: "The universe
was expanding, and as it expanded, it began to cool
and become less dense .” The universe continued to
grow after inflation but at a slower rate, and as
space expanded as the universe cooled and the
matter was formed.

5. Step three: Too hot to radiate
Light chemical elements arose during the first three
minutes of the formation of the universe, and as the
universe expanded, the temperature decreased,
and protons collided with neutrons to form
deuterium, a radioactive isotope of hydrogen, and
then a lot of deuterium combined to form helium.
In the 380,000 years after the Big Bang, the intense
heat of the universe's formation made the
atmosphere too hot for light to radiate, and atoms
collided with each other hard enough to fragment
into a dense, opaque plasma of protons, neutrons,
and electrons that scattered the light like fog..

6. Fourth step: let the light be
About 380,000 years after the Big Bang, the matter
has cooled enough for electrons to combine with
nuclei to form electrically neutral atoms. This stage
is known as " reassembly ", as the absorption of
free electrons causes the universe to become
transparent. Today, this liberated light can be
detected in the form of cosmic microwave
background radiation. However, a period of
darkness followed before the formation of stars and
other luminous bodies
.

7. Step Five: Emergence from the Age of
Cosmic Darkness
After 400 million years almost after the Big Bang,
the universe began to get out of the era Zlmath,
where called this stage of the evolution of the
universe " the era of reionization ." This active
period is thought to have lasted more than half a
billion years, but according to recent observations,
scientists believe that reionization may have
occurred more quickly than previously thought.
Meanwhile, clumps of gas crumbled to form the
first galaxies and stars, and ultraviolet light from
these energetic events removed and destroyed
most of the surrounding electrically neutral
hydrogen gas.

8. Step Six: More Galaxies and Stars
Cosmologists have scoured for the most distant
and ancient galaxies to help them understand the
properties of the early universe. Similarly,
astronomers can now work backward in time to
connect previously occurred events by studying the
cosmic microwave background. Data from older
missions such as Expedition helps WMAP, cosmic
background explorer COBE Launched in 1989,
missions still in progress Like the Hubble Space
Telescope launched in 1990 Scientists attempt to
solve persistent mysteries and answer the most
controversial questions in cosmology.

9. Step Seven: The Birth of Our Solar
System
The time of our solar system's birth is estimated to
be 9 billion years after the Big Bang, making it 4.6
billion years old. According to current estimates, the
sun is considered one of the 100 billion stars in our
Milky Way galaxy alone and spins after 25 thousand
light-years from the center of the galaxy. Many
scientists believe that the Sun and the rest of our
solar system formed from a giant, rotating cloud of
dust and gas, also known as a solar nebula. When
gravity caused the nebula to collapse, it began to
spin faster and flatten into a disk. At this point,
most of the material was pulled toward the center
to form the Sun.

10. Step Eight: The Invisible Materials of the
Universe
In the 1960s and 1970s, scientists began to believe
that there was more matter in the universe than is
visible, as an astronomer at the Carnegie Institution
of Washington ( Vera Rubin) Vera Rubin observed
the velocities of stars in different locations of the
galaxies. Basic Newtonian physics states that stars
at the edges of the galaxy rotate at a slower speed
than the stars in the center, but Robin did not find a
difference in the speeds of the farthest stars, in
fact, she discovered that all the stars in the galaxy
rotate around the center at the same speed with
small differences. This mysterious and invisible
matter became known as dark matter, and dark

11. matter was inferred due to the gravitational
attraction it applies to regular matter. One
hypothesis is that the mysterious matter ( dark
matter ) may have formed from strange particles
that do not interact with light or natural matter,
and for this reason are difficult to detect. It is also
believed that dark matter makes up 23 percent of
the universe, while normal matter makes up only 4
percent of the universe and it includes stars,
planets, and humans.
Step Nine: The Expanding and
Accelerating Universe
In the 1920s, astronomer Edwin Hubble made a
revolutionary discovery about the universe, using a
newly built telescope at the Mount Wilson

12. Observatory in Los Angeles, where Hubble proved
that the universe is not stationary but expanding.
Decades later, in 1998, the space telescope with
copious results named after the famous scientist (
Hubble Space Telescope ) studied distant
supernovae ( supernovas ) , and found that the
universe long ago was expanding slower than it
does now, and this discovery was surprising. For a
long time, the gravity of the universe's matter will
slow down its expansion or even cause it to
contract. It is believed that dark energy is the
strange force that increases the separation of the
components of the universe from each other at
ever-increasing speeds, but it remains
undetermined and shrouded in mystery. The
existence of this elusive energy, which is believed to
make up 73 percent of the universe, is one of the
most hotly debated topics in cosmology.

13. Step 10: We still need to know more
With all that has been discovered about the
beginning of the universe and its evolution, there
are continuing questions that remain unanswered,
as dark matter and dark energy remain among the
most mysterious remaining mysteries, but
cosmologists are still probing the universe in the
hope of a better understanding of how it began. It
took a little more than seven days to create the
universe as we know it today SPACE.com He
explores the mysteries of the heavens in our eight-
part series (The History & Future of the Cosmos)And
this is the third part of it.

14. The Universe (Astronomy) Book by
Nicholson
https://ebay.us/RqnPz5
the reviewer
SPACE.com