The Milky Way is one of the billions of galaxies in the Universe. The Milky Way is the galaxy where the earth is

The cover image is a photograph from the ALMA Observatory, in the Atacama desert in Chile.  Credit: ESO y web “walhere.com”

When looking at the sky on a moonless night, in a lonely place, it is impossible not to feel an intense emotion when contemplating the beauty and magnitude of the Milky Way.

Its mysterious presence in the middle of the sky, overwhelms anyone.

The brilliant creator of the science fiction novels “Foundation” and “Robots and Empire“, Isaac Asimov (1920-1992) places all the actions of his protagonists within the” galaxy. The jumps he imagine into hyper space always end on some planet orbiting a star in “the” galaxy.

All the kingdoms of the Galactic Empire are in “the” galaxy and all possible invasions of conquest come from one of its planets.

Galaxies
In the Universe there are billions of galaxies. Credit: web “cosmosmagazine.com”

This is so because until very few years ago it was considered that the entire universe was made up of this galaxy, the Milky Way; which although really immense, is only one of the more than 100,000 million galaxies.

All theses galaxies are been discovered in the observable universe thanks to the research of astrophysicists who, aided by wonderful technical means that have been refined exponentially in the last 50 years, they have come to discover the vastness of the universe.

The Milky Way is the galaxy in which the Solar System is located.

It is part of a set of about 40 galaxies called the Local Group. One of the brightest galaxies close to our Milky Way is the Andromeda galaxy.

Milky Way
Marveling at the beauty of the Milky Way Credit: web “observatorio.info”

In Spain, the Milky Way receives the popular name of “Camino de Santiago”, as it was used as a guide by pilgrims.

In Chinese and Japanese allegories, it is called “heavenly silver river.” Average diameter of about 100,000 light years. (The speed of light is 300,000 km / sec. A year has 31,390,000 seconds).

It is estimated that it contains more than 200,000 million stars.

The distance from the Sun to the center of the galaxy is around 27,700 light years

A recent study shows that our galaxy is 50% more massive than previously believed and that it is moving through space at the dizzying speed of 965,000 km per hour (and we are so calm, without knowing it).

The Milky Way
The Milky Way is a spiral galaxy very similar to the one seen in this image.  Credit: web “bbc.com/mundo”

The name Milky Way comes from Greek mythology. It is known that Democritus suggested that that white beam in the sky was actually a conglomeration of many, many stars, which were too individual and could not be individually recognized with the naked eye.

In 1609, Galileo Galilei using the telescope that he built following the guidelines of a recent invention made in Holland, was able to verify that Democritus was right.

And that wherever he looked, the sky was full of stars. He could never imagine that this Milky Way was a thousand times more wonderful still.

Milky Way
Self-portrait of the astronomer Alan Fitzsimmons, on May 13, 2013. Credit: ESO/A

The Milky Way is currently home to more than 200 billion stars.

Scientists and experts do not stop making progress in the field of outer space exploration and have obtained information that allows simulations of the position and nature of the stars closest to the sun. Click here to see this wonder.

Google wanted to offer users a representation of the progress made in this field.

To do this, the company has developed an experiment for Chrome that allows you to navigate the Milky Way and learn more about the most important stars.

Christened “100,000 stars”, the initiative makes it possible to “visualize the stellar neighborhood.”

To develop this project, the company has used information from NASA and the European Space Agency.

Users can navigate this interactive star map, which allows them to get closer to the most important stars in the Milky Way and see their name, position and relationship with other stars.

In addition, you can click on each star to find out more technical information about its nature, composition and arrangement in the galaxy. Google also offers the possibility of taking a guided ‘tour’ of the Milky Way.

At the top of 100,000 stars, users can activate an option whereby the system presents some of the most special stars in the Milky Way, so that the user does not have to search for them on their own.

As a curiosity, Google has explained that the project has the music of Sam Hulick, responsible for the soundtrack of Mass Effect. The company has highlighted that the composer has donated his music for the creation of this work.

Parts of the Milky Way

The Milky Way is divided into three distinct parts: halo, disk, and bulb.

The halo is a spheroidal structure that envelops the galaxy.

In it there is little concentration of stars and it has hardly any gas clouds, so it lacks regions with star formation. The presence of a large amount of dark matter is detected in it, the existence of which was deduced from anomalies in the galactic rotation.

Hat Galaxy
Galaxy OM104 called hat galaxy. Credit: Wikipedia

In the halo are most of the globular clusters, which are groupings of stars.

It is likely that these clusters were formed when the galaxy was a large cloud of gas that was collapsing and that was flattened more and more.

The Large Magellanic Cloud is a dwarf galaxy and the third closest to our Milky Way. In it you can see the impressive Magellanic Nebula.

Magellanic Cloud
This image from NASA’s Spitzer Space Telescope shows the Large Magellanic Cloud. Credit: web “nasa.goc/multimedia”

The disk is the part of the galaxy that contains more gas and where there are still processes of formation of new stars.

The most characteristic of the disc are the 4 spiral arms. Our Solar System is in the arm called Orion.

The brightness of the arms is greater than in the rest of the areas of the galaxy and there are the stars called blue giants. These stars are short-lived, they are born and die in the spiral arm.

Longer-lived stars, such as the Sun, have time throughout their existence to repeatedly enter and exit the different spiral arms of the galaxy.

These stars can also be found outside the arms.

Galaxy M74
Galaxy M74 also known as the Fan Galaxy or NGC 628, is a spiral galaxy. Credit: Wikipedia

The disk is attached to the galactic bulge by a ring that concentrates, in addition to a large amount of the galaxy’s molecular hydrogen, a large star-forming activity.

This ring is the most remarkable structure in our galaxy and from it the spiral arms emerge.

The bulge or galactic nucleus, located in the center of the galaxy, is the area with the highest density of stars. The bulb has a flattened spheroidal shape and rotates as a rigid solid.

Apparently, in our galactic center, there is a large black hole that would have a mass equivalent to 2,600,000 times the mass of the Sun.

This black hole was detected by observing a group of stars that rotated, at more than 1.00 km per second, around a dark point.

The Milky way
Actually astronomers are mapping the arms of the Milky Way. Credit: web “sciencemag.org/news”

According to recent NASA estimates, the Milky Way is home to some 17 billion planets similar in size to Earth.

The work of the Kepler mission, created in 2009, consists of locating extrasolar planets with characteristics similar to ours around the stars of the Milky Way in “habitable zones”, that is, with temperatures neither very cold nor very hot and with water in its surface.

The fact that there are 17,000 million planets similar in size to Earth in our galaxy does not imply that all of them are habitable, but it increases the probability that in the future, worlds with the capacity to support life may be discovered in the Milky Way.