There are numerous types of galaxies that can be found in outer space, each with their own unique colors, shapes, and sizes. If you were to look at them through a telescope, you’d notice quite a few characteristics, such as some looking flatter than others. But this leads us to the question, are they actually flat? Well, here is everything you are going to want to know.
So, are galaxies flat? Galaxies are not typically flat; elliptical, irregular and lenticular galaxies tend to have a spherical shape. However, spiral galaxies are usually flat. They look this way due to gravitational forces that create a centrifugal reaction, causing the galaxy to stretch outward into a flat-like shape.
One thing to note here is that elliptical, irregular and lenticular galaxies can hold any number of shapes.
And even more interestingly, if two spiral galaxies collide they could become an elliptical.
Got your head around that?
Well, if you can try and with this all in mind, let us continue to explore the interesting shapes of galaxies in much further detail, answering some questions you likely still have.
Are Galaxies Actually Flat?
Every galaxy starts out as a relatively round cloud of elements such as rocks, dust, and many different gases. Over time, some galaxies may eventually become flat, and this only happens to what are known as spiral galaxies. As the galaxy spins and gets compressed due to gravitational force, the celestial objects within it are sent outward, giving the galaxy a flat appearance.
Other galaxies, such as lenticular, elliptical, and irregular galaxies, are known to have many different shapes, but spiral galaxies are the only ones known to develop a flat appearance.
If you were to look at a number of galaxies side by side, there would be many different shapes and sizes.
It’s also important to note that galaxies don’t start out with a flat appearance; it requires a blend of specific circumstances for that to occur.
Even among spiral galaxies, not all of them have the exact flat-looking shape.
Sure, they’re flatter than their counterparts, but different spiral galaxies can be at varying stages of this process.
Moreover, spiral galaxies are divided into two groups, which are normal spirals and barred spirals.
With normal spiral galaxies, the “arms” tend to protrude from the nucleus in every direction, and the nucleus is surrounded by a spiral nebular from all sides.
Barred spiral galaxies are a little different, as they boast a central bar-shaped structure made from a range of celestial objects.
This is so prominent that they can be seen with the naked eye, and it’s known that most spiral galaxies are of the barred variety.
Interestingly, spiral galaxies make up a significant portion of all the galaxies in our universe, which is why so many of them seem to boast a relatively flat shape.
These flat galaxies are also a good representation of the power of gravitational forces, as it’s able to manipulate everything from our movement on Earth to massive celestial bodies.
However, for a galaxy to become flat, it requires a certain mix of cosmic events.
What Makes A Galaxy Flat?
You can thank the power of gravity for the peculiar, flat shape that spiral galaxies are known for. Each spiral galaxy starts out as a ball of slow-rotating gases, and as it starts collapsing upon itself, they continue to spin faster until a disk-like shape starts to form. Due to the sheer amount of force this process creates, any object within the galaxy will remain in that flat spiral shape.
In short, what’s happening with spiral galaxies are the effects of angular momentum, just on a much more massive scale.
Every celestial body within spiral galaxies has its place for a reason as well.
Objects that are experiencing less sideways motion will end up closer to the center of the galaxy, while the faster-moving objects will inevitably end up farther away from the center.
Depending on gravitational forces and the speed at which these objects move can have an effect on the overall look of a spiral galaxy.
This is how we get some that look flatter or wider than others.
On another interesting note, if most of the moving objects align with one band of rotation, this will become the equator of the rotating galaxy.
The objects that spin in closer proximity to the center of the galaxy are bound to collide and merge with objects that are near this equatorial band.
This is another factor in what makes a spiral galaxy start to develop a flat shape as the major axis starts to form an accretion disk.
The overall shape of spiral galaxies isn’t uniform, even if they do share many similar characteristics.
This is mainly due to varying gravitational forces and how long the galaxies have existed.
Spiral galaxies that are older than others may have a flat appearance than others, and younger spiral galaxies may still carry a fairly round or even oval-like shape.
When you take a look at the other types of galaxies in our universe, they aren’t experiencing the same rotation and gravitational force that spiral galaxies are.
This is what makes them retain their relatively round shape, and these characteristics don’t really change either.
Once we’ve identified and labeled a galaxy, it’s because we’ve been able to discern its physical qualities, which have likely been that way ever since the galaxy’s creation.
It requires a very specific set of events to create any galaxy’s unique shape.
Spiral galaxies encounter a set of events that other galaxies don’t, and their shape is accrued after many years of consistent force and rotation.
There are particular reasons as to why they don’t boast a sphere-like shape like other known galaxies.
Why Are Spiral Galaxies Not A Sphere?
The main reason spiral galaxies don’t hold a spherical shape is due to the collapse of celestial objects due to gravitation and the simultaneous rotation they experience as well. This combination of events slowly flattens the galaxy as objects continue to spread outward from its nucleus.
The amount of force these galaxies are experiencing cause them to keep their flat shape, and there’s no chance of this effect reversing by any means.
If you were to look at different spiral galaxies side by side, you’d notice they still come in different shapes and sizes, even if they’re all somewhat flat.
This is because each is at its own stage in its life cycle, and some may be experiencing a more significant gravitational force.
Spiral galaxies that are flatter than others could be an indication of their age, as it takes years to develop such a shape.
Those with more of an oval shape could be younger, or it could simply be due to the unique amount of gravitational force it’s experiencing.
Although many galaxies boast similarities that make it easy for scientists to categorize them, this doesn’t mean they’re all the exact same.
Each one has its own number of celestial bodies and elements that play a part in the shape it holds.
Nevertheless, spiral galaxies are pretty easy to spot due to their physical characteristics.
Is The Milky Way Flat?
The Milky Way is not flat, instead it resembles a warped and twisted appearance.
You might be surprised to learn that we live in a spiral galaxy of our own, which is known as the Milky Way.
Of course, we have no way of viewing its shape with the naked eye, but we’re able to discern this due to the positioning, rotation, and many other physical characteristics of the galaxy itself.
It’s known that it takes billions of years for spiral galaxies to achieve their flat shape.
Considering we haven’t existed anywhere near as long, this is why there are so many spiral galaxies that are easily viewable with a telescope.
You could argue that there are young spiral galaxies that simply haven’t taken shape yet, but most have been in their rotation for a very long time by now.
Nevertheless, spiral galaxies stand out from the crowd as they carry some unique qualities that aren’t found in other kinds of galaxies.
Considering that they have a stretched-out look, they can also look much larger than other types of galaxies around them.
The universe always has a knack for showing us that possibilities are endless, even if they take billions of years to occur.
Although we may not be able to feel the rotational force of our own spiral galaxy, The Milky Way spins at a speed of 130 miles per second.
When you think about it, this is an extreme amount of force, and the fact we don’t feel a single bit of it is an amazing phenomenon.
We can thank The Milk Way’s spiral design for creating life as we know it.
This plays a part in why our sun and solar system are set up the way they are.
We’re simply a very small part of a much bigger equation when you look at The Milky Way as a whole.
This is also what leads many experts to believe that there must be other Earth-like planets out there, as the sun is only one of around one hundred thousand million stars.
The sheer size and capacity of our galaxy can be hard to visualize, but The Milky Way is rotation like all of the other spiral galaxies out there.
Scientists predict that our galaxy is 13.20 billion years old, which tells us it has had ample time to develop the shape it’s known for.
Hey, my name is Jeremy. I’m a passionate and seasoned astronomer who loves nothing more than observing the night sky. I also love researching, learning, and writing all things Space and the Universe. I created Astronomy Scope to share my knowledge, experience, suggestions, and recommendations of what I have learned along the way while helping anyone to get into and maximize their enjoyment of the hobby.