Size of The Universe
The Totality of Everything that Exists



Size of The Universe
The Totality of Everything that Exists

 
Scientists are still in debate regarding the size of our universe. Some scientists believe the universe is infinite, while others believe it is not.

 
For us mostly stuck on our rocky little planet the view of the universe begins with Earth which is a part of our solar system.

Our solar system is spinning, flying through space at 134 miles per second. Turning in circles as part of a vast collection of stars and star systems.


There may be 200 billion stars in this collection called the milky way galaxy. An estimated 6 billion of those stars with planetary systems like ours.

Our solar system orbits the center of the milky way on one of its outer arms. The milky way is one of more then 125 billion galaxies that make up the visible universe. This is the universe. It's really, really big.


Since we cannot observe space beyond the limitations of light (or any electromagnetic radiation), it is uncertain whether the size of the Universe is finite or infinite.

Throughout recorded history, several cosmologies  and cosmogonies  have been proposed to account for observations of the Universe.


The earliest quantitative geocentric models were developed by the ancient Greeks, who proposed that the Universe possesses infinite space and has existed eternally, but contains a single set of concentric spheres of finite size – corresponding to the fixed stars, the Sun and various planets – rotating about a spherical but unmoving Earth.

Over the centuries, more precise observations and improved theories of gravity led to Copernicus's heliocentric model and the Newtonian model of the Solar System, respectively. 


Further improvements in astronomy led to the realization that the Solar System is embedded in a galaxy composed of millions of stars, the Milky Way, and that other galaxies exist outside it, as far as astronomical instruments can reach.

Careful studies of the distribution of these galaxies and their spectral lines have led to much of modern cosmology. Discovery of the red shift and cosmic microwave background radiation revealed that the Universe is expanding and apparently had a beginning.


Welcome to the Universe: The Size of Things
The universe is immensely large

According to the prevailing scientific model of the Universe, known as the Big Bang, the Universe expanded from an extremely hot, dense phase called the Planck epoch, in which all the matter and energy of the observable universe was concentrated.

Since the Planck epoch, the Universe has been expanding to its present form, possibly with a brief period (less than 10−32 seconds) of cosmic inflation.

Several independent experimental measurements support this theoretical expansion and, more generally, the Big Bang theory.


Recent observations indicate that this expansion is accelerating because of dark energy, and that most of the matter in the Universe may be in a form which cannot be detected by present instruments, and so is not accounted for in the present models of the universe; this has been named dark matter.

The imprecision of current observations has hindered predictions of the ultimate fate of the Universe.

Current interpretations of astronomical observations indicate that the age of the Universe is 13.75 ±0.17 billion years, and that the diameter of the observable universe is at least 93 billion light years, or 8.80  × 1026 metres.


According to general relativity, space can expand faster than the speed of light, although we can view only a small portion of the universe due to the limitation imposed by light speed.

Since we cannot observe space beyond the limitations of light (or any electromagnetic radiation), it is uncertain whether the size of the Universe is finite or infinite.