Galaxy

The word galaxy comes from an ancient Greek word for milky (as in lactic). They called the Milky Way a milky circle.

The term Milky Way first came out in the English language in a poem by Chaucer.

"See yonder, lo, the Galaxyë
  Which men clepeth the Milky Wey,
  For hit is why”

The House of Fame c1380

Back in the early 1920s, humans believed that there's only one galaxy (ours) that's surrounded by infinite dark space. Today we know there are at least 400 Billion galaxies, some visible to the naked eye.

It was American astronomer Edwin Hubble who discovered that Andromeda, previously believed to be a nebula, is actually another galaxy, and that the Milky Way is only one of many such galaxies in the universe. His findings were first published in The New York Times on November 23, 1924.

Andromeda

There are probably over 170 billion galaxies in the observable universe, each comprising billions of stars orbiting the galaxy’s center of mass.

Galaxies vary from containing as few as ten million stars to giant galaxies with a 100 trillion stars.

There are an estimated 200 galaxies in the known universe for every human on Earth.

At a distance of about 130.62 Austronomical Units. (1.954×1010 km) from Earth as of December 6, 2014 Voyager 1 was the farthest spacecraft from our planet. If the Milky Way galaxy was the size of the Pacific Ocean, that would mean that the Voyager had traveled about 10 inches at that date.

Artist's concept of Voyager in flight

After a massive power outage in Los Angeles during the 90s, many residents called 911 and reported seeing strange clouds overhead – the Milky Way.

There are about 100 billion stars in the Milky Way galaxy, which is about the same as the number neurons in a human brain.

The Milky Way is on a collision course with the Andromeda galaxy in about 4.5 billion years’ time,

At the center of the Milky Way lies an object that has a mass four million times that of the Sun and is almost certainly a black hole.

Source Daily Express