The Milky Way is the galaxy in which our solar system resides, and it’s one of the most interesting objects in the night sky. In fact, it might just be one of the most fascinating celestial bodies in existence! Here are 10 fascinating facts about the Milky Way that you should know.
You Can’t See It in Total
No matter how dark a night is, you can’t see the entire Milky Way with your naked eye. The reason is that our galaxy is absolutely huge—100,000 light years in diameter. For perspective, if you could travel at the speed of light, it would take you 100,000 years to go from one side of the Milky Way to the other! That means if you stood on Earth and looked up into the sky, you would only be able to see roughly half of the stars that make up our galaxy. Even looking through a telescope doesn’t help much because it still only captures a small portion of the stars in our galaxy. Plus, there are other galaxies visible in the sky too. It’s possible to photograph all of them together, but those pictures don’t show you what it looks like to see them in person. (1) You Can See All the Stars: If you want to get an idea of what it’s like to look up into space and see the Milky Way, (2) head outside on a moonless night when there are lots of stars out. If you have trouble finding it by sight alone, (3) grab a pair of binoculars or a telescope so that you can get an even better view. If you live near a big city, chances are good that there will be some ambient light in the sky. But if you’re far away from any large metropolitan areas, then it should be fairly easy to find some darkness for this activity. However, remember that no matter where you are on Earth, the Milky Way is always visible somewhere.
Its Center Contains 100 Million Solar Masses
Our galaxy is huge, and its center contains a whopping 100 million solar masses. That’s just mind-boggling to think about!
But what exactly is a solar mass? It’s basically the mass of our sun. So imagine 100 million suns all crammed into one place.
That would be pretty incredible to see!
And even though the Milky Way is huge, it’s actually just an average sized galaxy. In fact, there are many galaxies that are much bigger than ours. We can’t see them because they’re so far away from us.
As you might have guessed, our galaxy also has spiral arms that wrap around the center in a pinwheel shape. These arms hold billions of stars which together form hundreds of different clusters and star systems!
It takes 200 million years for The Milky Way to make one rotation around the galactic core which is located at the very heart of our galaxy.
It Contains 200–400 Billion Stars
The Milky Way is one of at least 170 billion galaxies in the observable universe. It contains between 200 and 400 billion stars and has a diameter of about 100,000 light-years. The Solar System, which includes Earth, is located in the Orion Arm, 26,000 light-years from the center of the galaxy. It takes 225–250 million years for our solar system to complete a single orbit around the center of the galaxy. And it takes 230 million years for the sun to go through its entire life cycle as it starts as a hot blue star and cools off into an orange dwarf before fading out as an inert white dwarf. But wait! Stars die every day too! We just don’t see them because they die so far away from us. When we look up at the sky, all we see are different stages of death because everything eventually dies. That’s why when you see someone or something that seems perfect, they will never be perfect forever. You need to appreciate what you have while you have it because tomorrow could be gone in an instant. So cherish the people who are with you now and take care of those who can’t take care of themselves. Love your family because without them, your world would end much sooner than expected. Spend time with people who give your life meaning instead of spending time trying to save people who refuse to change.
Red Dwarfs are Common
Red dwarfs are by far the most common type of star in the Milky Way. In fact, about three-quarters of all stars in the Milky Way are red dwarfs. And because they’re so small and faint, they make up only about 5% of the total mass of stars in the Milky Way. But don’t let their size fool you; red dwarfs can live a long time. The oldest known red dwarf is 14.5 billion years old! That’s over two billion years older than our sun.
Although red dwarfs are dimmer than other types of stars, they outshine them when it comes to longevity. The oldest known red dwarf is 14.5 billion years old! That’s over two billion years older than our sun. Although red dwarfs are dimmer than other types of stars, they outshine them when it comes to longevity. It may seem as if there should be plenty of habitable planets orbiting these red dwarfs—after all, one study found that 75% of nearby stars have an Earth-sized planet orbiting within the habitable zone.
Galaxy Has Spiral Arms
If you could take a cross-section of our galaxy, it would look like a spiral. The arms are actually areas where there is an increased density of interstellar gas and dust, and they are where new stars are born. Our sun resides in one of these arms, called the Orion Spur. It is located between two prominent arms that wrap around the center: Sagittarius Arm and Perseus Arm. The other two major arms are Scutum-Centaurus Arm (to which the Solar System belongs) and Carina-Sagittarius Arm. These three long arms form a classic pinwheel shape when seen from above. There’s also the Outer arm, which wraps all the way around from Cygnus to near Sagittarius; while this arm doesn’t extend as far into space as the others, it extends much farther towards Earth and contains some of the oldest stars in our galaxy. One important discovery was made by examining the widths of each arm at different distances from the core – scientists found that widths become larger with distance from the galactic center. They theorize that this may be due to perturbations caused by dark matter passing through or close to the disk plane of our galaxy, distorting it slightly.
The Space Between Stars is Filled With Gas and Dust
When you look up at the night sky, you’re seeing our galaxy, the Milky Way. It’s a giant spiral of stars, gas and dust that’s 100,000 light years across. And it’s home to our solar system. Here are 10 things you should know about the Milky Way. 1) Our Sun is just one of more than 200 billion stars in the Milky Way. 2) The Space Between Stars is Filled With Gas and Dust: Scientists have discovered this by observing how far different objects can be seen from Earth. They call this extinction. Astronomers estimate that there are some 7 trillion (7,000,000,000,000) particles per cubic inch in space! 3) We Have Spiral Arms: Like all galaxies (including Andromeda), the Milky Way has two major arms—the Sagittarius Arm and the Perseus Arm—that wrap around its center like a pinwheel.
The Sagittarius Arm, which winds around the galactic center, contains lots of young blue stars and open clusters. The Perseus Arm begins near the Milky Way’s outer edge, where old red giants live. Along with these two major arms, astronomers also see smaller spurs and features that help us learn about how the Milky Way formed. 4) What Are Dark Matter and Dark Energy? A lot of what we don’t know about our universe comes down to two words: dark matter and dark energy. These mysterious substances comprise 95% of the cosmos but scientists still don’t understand them very well. 5) The Centers are Mostly Empty: That’s because they’re filled with dense concentrations of stars, leaving less room for anything else.
Supermassive Black Holes Are at Galaxies’ Centers
A black hole is an object so massive and dense that not even light can escape its gravitational pull. But black holes aren’t just randomly floating through space—most, if not all, galaxies are thought to have a supermassive black hole (SMBH) at their center. Our own galaxy, the Milky Way, is no exception. In fact, its central black hole, Sagittarius A*, is one of the best studied black holes in the universe. Astronomers studying Sagittarius A* found evidence that it had formed from a series of smaller, merging black holes before gobbling up more nearby stars and other matter from around it. And like many SMBHs, Sagittarius A* is surrounded by a swirling disk of hot gas which helps feed the monster’s insatiable appetite for more matter. It’s this swirling disk that makes it really interesting, said astronomer Tomoharu Oka of Japan’s Tohoku University. We’re finally starting to understand how these disks form. When two galaxies collide, they merge into one, said Oka. A new galactic nucleus forms at the merged point with a supermassive black hole. The two huge clouds of gas collapse together and form what we call a quasar or active galactic nucleus. From there, everything goes according to plan: some stars fall into the newly forming quasar while others fly out into space. Eventually, those jets die down as they get closer to the SMBH’s event horizon.
Spiral Galaxies Are Dimerized
One of the most distinguishing features of spiral galaxies is their bright, central bulge of stars surrounded by sweeping arms of gas and dust. But what’s even more interesting is that these galaxies often come in pairs! Our own galaxy has a sister, Andromeda Galaxy. These galaxies are said to be dimerized because they are connected through gravity, so one can’t exist without the other.
The Sun Is Located Near The Galactic Center: Spiral Galaxies Are Dimerized:
The sun resides at around 2/3rds of the way out from the center of our galaxy, meaning that it takes an average 220 million years for it to complete one orbit around the center. It Is Covered In Dust And Gas: There are two main types of interstellar material that cover the Milky Way; hydrogen gas, which was expelled during the Big Bang 13.7 billion years ago, and interstellar dust which accumulates as part of natural stellar evolution processes such as when dying stars eject material into space before exploding in supernovae. There is also dark matter which forms a halo around the galaxy but doesn’t interact with visible light or electromagnetic radiation at all. However, despite being called dark, astronomers believe that this type of matter makes up 25% of the mass-energy content in the Universe. The Milky Way Contains 100 Billion Stars: Our home galaxy contains about 100 billion stars according to the recent estimation of Professor Kailash Sahu who used data gathered by NASA’s Kepler satellite and many ground-based telescopes. And scientists estimate that there may be hundreds of billions more than we currently know. Plus, while the name may make you think otherwise, no new stars have been formed since 4 billion years ago – long after our Earth was created!
Galactic Rotation Curve Slows Down in Outer Regions
In 1925, American astronomer Edwin Hubble published a paper showing that the Andromeda nebula was actually an external galaxy. This greatly increased the size of the known universe and meant that our own Milky Way was just one among many galaxies. With this new information, astronomers began to wonder just how big our galaxy actually is. The answer came in 1956 when Dutch-American astronomer Jacobus Kapteyn discovered that the stars near the outside edge of The Milky Way are rotating much slower than those on the inside. From this discovery it became clear that The Milky Way isn’t spherical, but is rather shaped like a disk with a bulge in its center. Astronomers estimate that there are as many as 400 billion stars in the Milky Way, making it approximately 100,000 light years across. A light year is the distance light travels in one year at 300 million meters per second, which equals roughly 9 trillion kilometers or 5 trillion miles. The sun lies in the outer region of The Milky Way and rotates around it once every 225 million years. It would take a spacecraft travelling at the speed of light 150,000 years to reach Earth from any other planet in our solar system.
A star can be classified as either red or blue depending on its temperature, surface temperature being cooler corresponds to red and hotter corresponds to blue. Temperature plays a significant role in determining what type of star it is. For example, if a star’s surface temperature is above 4,200 Kelvin (K), then it is classed as blue; whereas if its surface temperature falls below 3,700 K then it becomes red.
There May be Thousands of Smaller Galaxies Orbiting the Milky Way
Most people are familiar with the major galaxies in our universe, but did you know that there may be thousands of smaller galaxies orbiting the Milky Way? This is just one of the many fascinating facts about our galaxy. The center of The Milky Way contains a supermassive black hole which is four million times more massive than the sun and it’s surrounded by giant clouds of dust and gas.
The hydrogen atoms have been ionized by radiation from nearby stars. It’s believed that much of this material will eventually fall into the central black hole at the heart of The Milky Way. There are also many new stars being born in this region due to an ongoing collision between two different arms of The Milky Way. Galaxies come together, exchange gas and other material, then move apart again. The Earth resides within one of these spiral arms called the Orion Arm.
Our solar system orbits around the center of the Milky Way once every 230 million years or so. We would need millions of years to see all the way across The Milky Way because it is 100 thousand light-years wide. The Milky Way has been moving towards Andromeda since they both started spinning billions of years ago, but they won’t collide for another 4 billion years. When they do collide, they’ll merge into one large elliptical galaxy, forming what astronomers call Milkdromeda. Scientists believe that each star in The Milky Way has its own planetary system made up of rocky planets like Earth and watery planets like Neptune.
