7. Small Galaxies Orbit Us (And Sometimes Crash Into Us)
When Magellan sailed through the Southern Hemisphere on his grand 16th-century voyage, he was among the first Europeans to note and describe circular clusters of stars in the southern sky. Can you imagine the excitement in his eyes? Scientists would later name these fantastic formations in his honor as the Greater and Lesser Magellanic clouds. However, they aren’t clouds at all. In fact, they are actually dwarf galaxies that orbit the Milky Way. Can they cause problems for the Milky Way, and, in turn, Earth?
So what are these little galaxies all about — and why are they crashing into us? Scientists have discovered millions of stars that move in strange needle-like orbits in our galaxy. It is hypothesized that these orbits result from an ancient dwarf galaxy dubbed the “Gaia Sausage” crashing into our galaxy. Even in the relative boonies, our universe is far from alone. However, just because things may bump into one another doesn’t mean they are anywhere near Earth. You don’t even notice it actually.
8. The Andromeda Galaxy Will Crash Into Us … In 4 Billion Years
However, one of those crashes can eventually destroy our galaxy, and, thus, our planet, too. Yes, our entire existence. Yet, even though all good things must eventually come to an end, we have a while. For the Milky Way Galaxy, that end will likely come in roughly 4 billion years. For some time, scientists have known that our galaxy is speeding towards our neighbor, the Andromeda Galaxy, at about 250,000 mph. At that speed, we will crash into them in billions of years.
Scientists initially believed that the Andromeda Galaxy was far more massive than ours and would consume our galaxy and survive the collision mostly undamaged. However, newer estimates put the Andromeda at a much more similar mass to the Milky Way, which leaves a great deal of uncertainty about which galaxy would emerge from the collision with less damage. Perhaps the Milky Way will continue to live as though it was virtually untouched. Only time will tell — unless dystopia comes from other means first.
9. Our Galaxy Receives Random Energy Pulses From Space
Over the last decade or so, astronomers have routinely detected what they called “fast radio bursts,” or flashes of light coming from a great distance across space. Until recently, there was only evidence of around 30 of these fast radio bursts or FRBs. A recent Australian study, however, found 20 additional FRBs within a short time. What does that mean? Aliens from another planet in a different galaxy are trying to communicate with humans on Earth? That sure would make for a great sci-fi story!
However, there is still no widely accepted explanation for these FRBs. It would appear that these FRBs travel over several billion light-years due to the signs of gas and dust that are left on the signal, implying a very long travel distance. Whatever they are, they are likely hallmarks of an event happening a truly astronomical range away from us. Yet, we can still detect them, so imagine how tremendous the commotion truly is when it happens! Overtime, scientists may learn more about this unusual action.
One thing that might make sense to you immediately is the fact that our galaxy is a spiral one. Undoubtedly, the pictures at least resemble that fact. Roughly two-thirds of the galaxies in the universe are believed to be spiral galaxies. Unlike traditional spiral galaxies, the Milky Way is a barred spiral galaxy, which means it has a dense bar across the galaxy center. If you could look down on our galaxy from above, you’d see a large, thick central bulge surrounded by spiral arms.
The Milky Way contains two significant spiral arms as well as two smaller spurs. Yes, the term is spurs. We all call one of those minor spurs the Orion Arm. More importantly, that is home for us humans on Earth. Like our solar system, the entire galaxy is continually rotating, and we travel along with it. Here is a question: how long would it take for our solar system to make a complete rotation around the whole universe? The answer is around 230 years.
Your address could be the Milky Way at Orion Arm — and you would be correct! It may be only a small spur, but it is home. The Orion Arm, one of the two minor spurs of the barred spiral galaxy we call home, contains our entire solar system. It truly puts our galaxy’s size into perspective to consider our solar system as a whole fits in just a minor spur. Nevertheless, there are multiple planets within that solar system, a giant sun, numerous moons, and one extraordinary world with nine continents.
So what is this majestic arm really like in terms of substance? Scientists have used a traffic jam analogy to understand the arms and spurs of a spiral galaxy. Gas and stars crowd together in the spiral arms and move more slowly, just like the masses of cars in a traffic jam. The density of these arms actually triggers even more star formation, further increasing the density. It may seem confusing — or not like much –, but it’s home!
12. Red Dwarfs Are the Most Common Stars in the Galaxy
In addition to being a great science fiction show, Red Dwarf is also the most common category of stars in our galaxy. Did you even know there were different types of stars? Of course! Red Dwarfs are cool stars and typically around one-tenth of the mass of our sun. By cool, we mean temperature-wise. (If they did have personalities, the Red Dwarfs would be equally cool, too.) It was initially believed that Red Dwarfs would not have planets capable of hosting life, but exciting new research strongly reconsiders this notion.
In fact, as many as six percent of our galaxy’s Red Dwarf stars are now considered potential hosts of habitable Earth-like planets. The habitable zone of a star’s planets is typically calculated by looking at the star’s brightness and temperature. Furthermore, the distance at which its plants would have liquid water present on the surface is another viable calculation. Does that mean we are getting closer to seeing lift on other planets within the galaxy? Keep reading to learn more about the Milky Way.
13. Our Solar System Is About 30,000 Light-Years From Galactic Center
Do you know someone who thinks the world revolves around them? Or even worse, a person who thinks they should be the center of attention all of the time? While it’s fun to think that our existence is very central to our galaxy, which is far, far from the truth — literally. Our presence on the minor Orion Arm spur of the galaxy is about 30,000 light-years from the galactic center. To put this distance in perspective, the nearest star that isn’t our sun, Alpha Centauri, is only four light-years away.
Furthermore, nothing in our solar system is even remotely close to one light-year away. That just goes to show how much space is within our galaxy. While it is challenging to even conceive of such a vast distance, it is easy to say we are an incomprehensibly and currently unbridgeable distance from the center of our galaxy. How does this notion affect the rest of the way things float around the galaxy? Keep reading to find out more about the incredible Milky Way.
14. There Are At Least 200 Billion Stars In Our Galaxy
How many stars are in the sky? And how heavy are they? While neither the exact mass nor the number of stars in our galaxy is known, the two numbers are closely interrelated. To guess at the number of stars, the most common method is to divide the estimated mass of our galaxy by the mass of an average star. As the estimates on the mass vary, anywhere between 400 billion and 2 trillion times the mass of our sun, the number of estimated stars varies.
An additional wrench in estimating stars is that the average mass of a star is used to calculate the estimated number. If our galaxy has more large or small stars than expected, this could drastically change the estimated quantity. At any rate, you can confidently state that our universe has many stars. Scientists have discovered several remarkable facts about these burning balls of gas, but some things are too tricky to determine as a matter of fact, including the average mass of a star.
15. Our Solar System Slides Through the Galaxy Sideways
Yes, you read that title correctly: our solar system does slide through the galaxy sideways. However, if you get motion sickness, don’t start feeling dizzy and nauseous! Thankfully, this strange fact about the galaxy isn’t as uncomfortable or weird as it sounds. It’s hard to visualize, and even NASA generated imagery takes a keen and trained eye to interpret. However, our solar system moves through the galaxy at about a 63-degree angle relative to the plane of the galaxy itself. That is quite a tilt, to say the least!
We also orbit about 20 light-years above the plane of the galaxy, meaning we are actually circling about five times higher from the galaxy’s plane than we are from the nearest non-sun star, Alpha Centauri. Our residence on an outlying minor arm means we travel not only higher than the plane of the galaxy but tilted. What a wild ride! However, you can’t tell at all. Thanks to gravity, we can still walk upright and not lean as though the world is riding on tilt.
Our sun, the center of our solar system, is a relatively young star by the rest of our home galaxy’s standards. More than half of the estimated 200 billion stars in our home galaxy are older than our sun’s expected 4.5 billion year age. In fact, our galaxy underwent a celestial baby boom around 10 billion years ago and created a significant number of its stars at that time. So, despite our sun’s incredible age, to us, to the rest of the galaxy, it’s basically a baby residing on a relatively insignificant outer arm spur of the galaxy.
However, just because it is much younger than its surrounding stars, doesn’t mean the sun doesn’t have some age spots. Thinking about the age of the sun might make your brain boil like the sun’s surface a little bit. However, scientists can determine all of these facts using technological advancements. It is really quite impressive all of the information we know about the sun considering humans short time on Earth. Nevertheless, we continue to discover and learn. Keep reading to find more out-of-this-world facts about the Milky Way.
17. The Band You See In the Night Sky Is the Center of Our Galaxy
The sky can make some fantastic patterns and even more mesmerizing colors. From the Northern Lights to a lunar eclipse, the sky holds vast power. If you are fortunate enough to be able to escape from modern light pollution and view the night sky in its pure form, you will be treated to a beautiful show of our home galaxy. The bright white band that gives the galaxy its “Milky Way” name is actually the galaxy’s center. Yes, you can indeed learn something new every single day!
Thanks to our home on the Orion Arm, a minor spur of the galaxy, we are treated to the visual feast of seeing the center of our galaxy from our viewpoint on an arm. We rotate along with our galaxy’s rotation and are always able to see the beautiful, glittering center of our galaxy from thousands of light-years away. Can you imagine how overwhelming the light would be if it were any closer? It truly is a wonder to gaze upon though.
It seems like a pretty simple question to ask how much something weighs. Even if is super small like a feather or very large like a car. Whether you use pounds or some other system, all you have to do is put the object on a scale. However, what if that object is as big as a planet — or multiple worlds? Is this answer even possible to discover? While we have estimates of the weight of our galactic home, nailing down the exact weight is quite the task.
The most significant difficulty for precise measurement lies in the fact that most of our galaxy’s mass is in the form of dark matter, which gives off no light and is currently impossible to observe. So, scientists must do a great deal of estimating when it comes to the galaxy’s mass. Current estimates put the Milky Way’s estimated weight anywhere between 700 billion and 2 trillion times the mass of our sun, a standard unit of mass in astronomy known as a solar mass.
19. Our Galaxy Has a Massive Halo of Gas and Old Stars
If you aren’t already staggered enough by the vastness of space and our galaxy, here’s another titanic measurement: our galaxy is surrounded by a halo of hot gas that extends for hundreds of thousands of light-years. What does this mean? The halo, which comprises gas and the remnants of old stars, is believed to be at least as large as the entire Milky Way Galaxy itself. Also, just like the galaxy, the halo is rotating rapidly. The CHANDRA telescope first found evidence of this halo, which is indicated to extend at least 300,000 light-years beyond our galaxy but may go even further.
And if there is a halo that enormous, what other possibilities are out there? We could say the sky is the limit, but we have already surpassed the atmosphere’s threshold. You will probably hear Beyonce’s song “Halo” in a completely different light now. Are you feeling pretty small in a big world full of billions of stars and opportunities? Just wait until you discover how many stars are floating in the sky — keep reading to see the magical number!
20. We Don’t Know Exactly How Many Stars Are There
Have you ever wondered how many stars are in the sky? On a clear night, you can spot hundreds of thousands of teeny tiny lights twinkling in the distance. However, counting stars is not as easy as it might sound, especially when we know there are at least 200 billion in our galaxy. Pinpointing an exact number is almost impossible by any sort of visual detection method, as many stars are too dim for our current equipment or shrouded behind dust. Even if you could count them all, would you really want to? It would take an astronomical amount of time to count each and every single one — and to keep track of the ones you already counted!
The more common method used is to observe the speed of stars’ orbits within the galaxy, which gives an idea of the gravitational tug and therefore allows a rough estimation of the mass of the galaxy. This mass is then divided by the average mass of a star. However, given the number of times we had to say “rough,” “estimate,” and “average,” it should come as no surprise that there is a fair bit of room for error in this calculation. When it comes to counting stars, would you accept a difference of a billion or so? We may never know the real answer to how many stars are in the sky.