This breakthrough idea later became known as the Big Bang The Big Bang was the moment 13.8 billion years ago when the universe began as a tiny, dense, fireball that exploded.
Most astronomers use the Big Bang theory to explain how the universe began..
Our universe began with an explosion of space itself - the Big Bang.
Starting from extremely high density and temperature, space expanded, the universe cooled, and the simplest elements formed.
Gravity gradually drew matter together to form the first stars and the first galaxies..
The Big Bang was the moment 13.8 billion years ago when the universe began as a tiny, dense, fireball that exploded.
Most astronomers use the Big Bang theory to explain how the universe began.
But what caused this explosion in the first place is still a mystery..
The temperature of the fireball drives the resulting mix of particles and radiation, and we can divide the Universe evolution into four stages; heavy particle era; light particle era; a radiation era and the present day era of matter.
As the Universe expands its temperature and density decline..
The density of galaxies in space should also diminish with time in a big-bang universe.
Therefore, galaxies at great distances should be more densely crowded together than nearby galaxies are.
But in a steady-state universe, the average density of galaxies should be about the same everywhere and at every time..
Big Bang Cosmology.
The Big Bang Model is a broadly accepted theory for the origin and evolution of our universe.
It postulates that 12 to 14 billion years ago, the portion of the universe we can see today was only a few millimeters across.Mar 1, 2012.
big-bang model
The second assumption, called the cosmological principle, states that an observer's view of the universe depends neither on the direction in which he looks nor on his location.
This principle applies only to the large-scale properties of the universe, but it does imply that the universe has no edge, so….
How did the universe start? Most physicists believe the universe was born in a big bang 13.8 billion years ago.
In it, the energy making up everything in the cosmos we see today was squeezed inside an inconceivably small space – far tinier than a grain of sand, or even an atom..
The Big Bang models offer a comprehensive explanation for a broad range of observed phenomena
According to the Big Bang models, the universe at the beginning was very hot and very compact, and since then it has been expanding and cooling
English astronomer Fred Hoyle is credited with coining the term "Big Bang" during a talk for a March 1949 BBC Radio broadcast
The earliest and most direct observational evidence of the validity of the theory are the expansion of the universe according to Hubble's law (as
As with any theory, a number of mysteries and problems have arisen as a result of the development of the Big Bang models
