Facts About the Milky Way - The Galaxy

The Milky Way is a barred spiral galaxy, which means that it is a spiral galaxy with a bar-shaped structure that consists of stars. The Milky Way is just one of the several galaxies of the universe. However, it is important for us because it houses our solar system. You will find it interesting to know that our Earth itself, is situated on one of the arms of the galaxy. Here are some interesting facts about the Milky Way.

Facts about the Milky Way - the Galaxy

As seen from the Earth, the Milky Way appears as a hazy band of white light in the sky during the nights. It divides the night sky into two somewhat equal hemispheres.

The stellar disk of the galaxy is of the size of about 100,000 light-years in diameter. It is around 1000 light-years in thickness. It consists of as many as 200 to 400 billion stars. It is nearly impossible to estimate the exact age of the Milky Way. However, the age of the oldest star in the Galaxy is about 13.2 billion years

Let us look at the structure of the galaxy. Its center is in the direction of Sagittarius. It then goes through Scorpio, Ara, Norma, Canis Major, Orion, Gemini, Taurus and back to Sagittarius through Scutum. The Milky Way appears brightest towards the constellation of Sagittarius.

The Galaxy is composed of a disk of gas, dust and stars that surround a bar-shaped region. The disk forms four arm structures that take a spiral shape. The galactic center of the Milky Way is in the direction of Sagittarius. The galactic disk bulges outward at the galactic center. It has a diameter of a value between 70,000 to 100,000 light-years.

The mass of the Galaxy is estimated to be 5.8x10¹¹ solar masses. Most of its mass is dark matter, a hypothetical matter that is not reactive towards electromagnetic force. But the existence of dark matter is apparent through the study of the effects of gravity on visible matter.

Active star formation takes place in the galactic disk and in the high-density areas in the spiral arms. How are stars born? Go through the life cycle of a star to know the answer.

The Sun, needless to say, is a huge star central to our solar system. It traverses through the space in the Milky Way. The Sun’s galactic motion is in the direction of star Vega and is tilted at an angle of 60 sky degrees to the galactic center. The Sun oscillates up and down relative to the galactic plane. For the solar system to complete one orbit around the galaxy, it takes as many as 225 to 250 million years! This time period is referred to as the galactic year.

The Galaxy is believed to have four logarithmic spiral arms. They are named as Perseus Arm, the Scutum-Crux Arm, the Carina and Sagittarius arm and the Norma and Cygnus Arm. According to a recent discovery, there is an outer extension to the Cygnus Arm. The Orion Arm, which is a relatively smaller arm, contains our solar system. This fact just makes us realize the insignificance of our existence in relation to the infinite expanse of the Universe.

To delve deeper into the principles of astronomy, go through the Astronomy Articles.