Our Milky Way galaxy resides on the inner edge of one of the spiral-shaped bands of gas and dust particles called the Orion Arm. Measuring some 120,000–180,000 light-years in diameter, our Solar System stays roughly 27,000 light-years away from the Galactic Center. If someone could travel at the speed of light it would take 100,000 years to get from one side to the other for that person. Here are some other interesting facts about our Milky Way Galaxy.
Interesting Facts About The Milky Way Galaxy
1. The Structure:
The Milky Way is a disk with a central bulge that has a diameter of about 12,000 light years, surrounded by four arms that are wrapped around it. The disk is not perfectly flat though instead it’s warped due to our neighbouring galaxies Large and Small Magellanic Clouds. These two galaxies have been pulling on the matter in our galaxy. The milky way is a barred spiral galaxy as two-thirds of all the galaxies in our universe. Our galaxy has a mass between 400 and 780 billion times the mass of our own sun and 90% of its mass is believed to be the dark matter with about 10% “luminous matter”.
2. The Invisible Halo:
The large quantity of dark matter causes an invisible halo of hot gas surrounding our galaxy that stretches for hundreds of thousands of light-years. While it is believed to be as huge as all of the stars put together in the Milky Way, the halo itself only has around 2% of the number of stars that are found inside of the disk. About 10-15% of the Milky Way’s visible matter is composed of dust and gas, the rest are stars. Some researchers believe that there are between 400 and 700 billion stars in our galaxy. It’s estimated that the Milky Way contains over 200 billion stars, and enough dust and gas to make billions more.
3. It’s on the move:
The Milky Way does not sit still but is constantly moving. Like the Sun moves in the Milky Way, the Milky Way sails through space. The radiation left over from the Big Bang, the Cosmic Microwave Background radiation is used as a reference point to measure the velocity of things moving in space. The Milky Way is part of the Local Group of galaxies, which is estimated to be moving at about 600 km/s or 2.2 million km/hr. As such, the arms are moving through space, the sun and the solar system travel with them.
4. The Black Hole:
It is believed that most of the galaxies have a supermassive black hole at their centre. The Milky Way is no exception, it has one that weighs as much as 4 million suns, called Sagittarius A*. It is located in the centre of our galaxy and has an estimated diameter of 14 million miles. The outer disk has about 14.6 million times the mass of our Sun in what would be similar to the orbit of the Earth. Researchers also indicate that a rare Jupiter-sized black hole is wandering around our galaxy, according to the Atacama Large Millimeter/submillimeter Array.
5. Other Planetary Systems And Galaxies:
According to NASA, 2,917 planetary systems have already been discovered. Kepler-90 is a planetary system very similar to our own solar system located approximately 2,500 light years away from us towards the Draco Constellation. Almost 4,000 exoplanets and nearly 3,000 planetary systems have been confirmed to exist in our galaxy, yet. Previously it was thought that there were around 200 billion galaxies in the universe. Now it is believed that there are at least ten times more galaxies out there in space. Around 90% of the galaxies in the observable universe are said to be too far away and even too faint to see with our telescopes.
6. It was made from other galaxies.:
Not long after the Big Bang, the Milky Way began as a series of dense regions in the early universe. The first stars to form were in globular clusters that still exist, the oldest stars formed in the Milky Way region. Scientists estimate that the Milky Way is about 13.6 billion years old same as the Universe. Although the main parts of the galaxy like the disk and the bulge did not fully form until about 10-12 billion years ago. It has grown by colliding with other galaxies through time, such as the Sagittarius Dwarf Galaxy. It is currently taking stars from a galaxy called the Canis Major Dwarf Galaxy the closest galaxy to the Milky Way.
7. The Andromeda Galaxy:
The Local Group is a group of more than 54 galaxies that includes our Milky Way galaxy, the Andromeda Galaxy and Triangulum Galaxy, the three largest in the group. In about 4.5 billion years our galaxy the Milky Way is set to collide with the neighbouring Andromeda galaxy. Though it is unlikely that our solar system will be affected there is still a 12 per cent chance that we’ll be ejected out of these merging galaxies.
8. Sagittarius B2:
Our galaxy contains a cloud called Sagittarius B2. The enormous cloud contains 10 billion, billion, billion litres of alcohol and ethyl formate. As a result, it could smell like rum and taste like raspberries.
9. The Great Attractor:
The Great Attractor, an area in space located at the centre of the local Laniakea Supercluster, that is pulling our galaxy in at 22 million km/h. Though it’s still a mystery what it is and what it is made of.
10. Galactic Year:
One trip around the Sun makes a year. But a Galactic Year is how long it takes for our solar system to revolve around the Milky Way’s centre. One orbit takes an estimated 225 to 250 million terrestrial years. Since humans have evolved, only .0008 orbits have been completed.
Image Source: Wikipedia