Milky Way Galaxy
The Milky Way Galaxy was one of two trillion galaxies believed to exist. The number of stars it contained was variously estimated to be over three billion to over four hundred billion stars. It generated its own magnetic field, which experienced dips and peaks. The galaxy was 100,000 light years wide. (; ; ; )

Characteristics
The Milky Way Galaxy was theorized to have been created following a great explosion, and it was further theorized that its center might still be creating new matter. This theory was proved correct with the finding of the creation point in 2269. The core was surrounded by the Great Barrier, containing a planet thought to be Sha Ka Ree by Sybok. (; )

The rim of the Milky Way's disc was surrounded by a massive energy field of negative energy called the galactic barrier, which makes travel into and out of the galaxy difficult. () By 2369, the extragalactic space was being charted by starships. ()

In the science of stellar cartography, the Milky Way was divided into four major areas called quadrants: Alpha, Beta, Gamma, and Delta (the first four letters of the Greek alphabet), each of which composed one-quarter of the galaxy. Each quadrant was divided into thousands of sectors. The Galactic Core was the intersection of all four quadrants. (; ; )

In the mid-22nd century, scientists estimated that one out of every 43,000 planets in the galaxy supported intelligent lifeforms. () Thus, in the galaxy there were millions of planets that could support intelligent life. ()

According to Dr. Leonard McCoy, there was a mathematical probability of three million Earth-type planets in the galaxy. ()

History
In the 12th century, the Sphere-Builders built a network of spheres in the Milky Way, which created trans-dimensional disturbances as a prelude to invading the Milky Way. (, )

By 2267, there were Humans on a thousand planets in the galaxy. () Between 2064 and 2364, Humans had charted 11% of the galaxy. () Within a year, the Federation had charted an additional 8% of the galaxy. ()

By 2268, research expeditions of the Federation had catalogued hundreds of uninhabited planets suitable for colonization. ()

An expedition sent by the Kelvan Empire, from the radiation-imperiled Andromeda Galaxy, scouted the Milky Way for possible invasion in 2268. ()

In a potential alternate timeline, by the 26th century the Sphere-Builders had transformed 50,000 light-years of space in the Milky Way, wiping out thousands of planets, before finally being defeated and expelled from the galaxy by the Federation at the Battle of Procyon V. ()

In a possible 3186 experienced by Gabrielle Burnham, she found every world in the galaxy rendered lifeless by Control. She noted that this represented the loss of tens of trillions of lives. ()

Depictions
A map of the Milky Way Galaxy was on display in the security station aboard the  in 2365. This map depicted the lines of longitude. ()

A map of the Milky Way Galaxy was on display in astrometrics aboard the  from 2377 through 2378. (, et al.)

Appendices

Related topics
 Species, listing all inhabitant species
 Alpha Quadrant
 Beta Quadrant
 Gamma Quadrant
 Delta Quadrant

External links 
 
 
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Galaxies