Galaxies can be incredibly fascinating and mind-boggling. Our Milky Way Galaxy alone is estimated to contain between 200-400 billion stars, while in our observable Universe are billions of galaxies that each contain literally trillions of objects.
What’s more, some galaxies are so enormous that they have been measured to span over three million light-years!
Yet, despite their immense size, the most distant galaxies we can see might have already disappeared from view due to the speed of space expansion.
Galaxies can make us awe-struck at times, marveling at the huge scale of our cosmos and what we are able to learn each day about it.
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Galaxy Facts for kids
- A galaxy is a collection of stars, gas, and dust.
- The Milky Way is our home galaxy.
- There are billions of galaxies in the Universe.
- Galaxies come in different shapes and sizes.
- The Universe is expanding, and galaxies are moving away from each other.
- Some galaxies have supermassive black holes at their center.
What is a galaxy?
Galaxies
The stars, dust particles, gaseous substances, and dark matter that form our Universe are all held together by gravity. Our night sky is filled with billions of stars, and contemporary science has uncovered an even greater number of galaxies waiting to be discovered in the galaxies beyond.
The sun is just one amongst millions of stars within our own galaxy, the Milky Way – a place where a supermassive black hole lurks at its core.
Aside from being a star-studded spectacle, other galaxies also contain the same massive black holes all embedded within them.
All these galaxies move away from each other as they travel through space at tremendous speeds while they continue to be strongly attracted to each other due to their immense gravitational force.
These awe-inspiring cosmic wonders provide us with immensely powerful proof that nothing stands still in this ever-changing Universe!
In 1920, astronomer Edwin Hubble discovered that there was more to the Universe than our Milky Way Galaxy. What was once seen as “fuzzy clouds” were classified as thousands of different galaxies in their own right.
Black holes
Black holes can be found in galaxies, having been formed through the collapse of massive stars or the release of gas clouds during their creation.
Supermassive black holes get even heavier over time – they are created due to multiple black holes merging and becoming billion times more mass than regular black holes.
These mysterious celestial objects enable us to investigate deeper into our Universe, with many unanswered questions still in need of exploration.
Yet, with 21st Century technology such as the Hubble telescope, we can witness and better understand these marvels of nature while being safely on Earth. Our deepening understanding of the Universe is a bridge between what we know and what remains unknown, allowing us to push boundaries even further than before.
The awe-inspiring creation of black holes shows just how immense and complex our Universe is – a vastness that we can strive to gain knowledge about despite not yet being able to fathom its depths entirely.
Types of galaxies
In 1936, Edwin Hubble determined four main types of galaxies based on their shapes. He named these groups Ellipticals, Spirals, Lenticulars, and Irregulars.
Each of them is distinguished by specific features such as the presence or absence of a bulge and visible arms that form a spiral pattern, visible rings, or an irregular shape.
Knowing these categories helps to classify newly discovered galaxies accurately and understand how galaxies evolve over time.
These classic classifications are still being used today in order to further our knowledge of galaxies and explore the Universe.
Spiral galaxies
Spiral galaxies are majestic and beautiful. They spin at hundreds of kilometers per second, and their shape is like a pinwheel. A central bulge is surrounded by spiral arms, and this makes them one of the most common galaxies found in the Universe.
They’re a mesmerizing sight and ought to be appreciated because of their sheer beauty. Spiral galaxies represent the power of nature, grandeur, and evolution all in one.
Elliptical galaxies
Elliptical galaxies come in all shapes and sizes. The largest elliptical galaxies contain an astonishing number of stars – up to trillions in some cases! Even dwarf elliptical galaxies can be ten times the size of our very own Milky Way.
Seeing such vast expanses of galaxies gives us a sense of scale – and our place in the Universe! With hundreds of billions of stars scattered across such massive distances, it’s awe-inspiring to think of the astronomical possibilities out there.
Elliptical galaxies are monumental structures that we can only begin to comprehend – truly breathtaking examples of stellar masterpieces.
Lenticular Galaxies
Lenticular galaxies are between elliptical and spiral galaxies. They look like lenses in shape.
These galaxies have an edge-on disc-like appearance as they look flat with a bulge. The bulge is made of old stars, whilst the disc is newly formed stars and gas clouds.
They display a variety of features that cannot be annotated to either elliptical or spiral classifications – such as a combination of the structure characteristics from both classes.
Lenticular galaxies lie at the very edge of what we consider regular-shaped galaxies, providing us with some remarkable examples of stellar formation and evolution.
Lenticular Galaxies are fascinating galactic formations that appear between ellipticals and spirals and have distinct features unseen elsewhere in space, providing researchers with invaluable information about star formation and evolution.
Irregular Galaxies
These warped galaxies have no definite shape. They’re normally weaker and can be stretched out of shape by the strong gravity from other galaxies close by.
Even though their form is distorted, it doesn’t stop them from captivating us with their fascinating appearances.
These unusual galaxies have the power to draw us in with their beauty and curious charm.
As stellar artworks, they insist on captivating us with their distorted forms and distinct lack of structure.
Distorted galaxies bring an extraordinary aesthetic, which astounds spectators despite the absence of traditional symmetry.
The Birth and Evolution of Galaxies
The Big Bang, believed to be the beginning of the Universe and life as we know it, occurred 14 billion years ago. What happened after that is something theories have long speculated upon.
One such theory is that massive clouds of gas and dust collapsed to form stars, which in turn evolved into galaxies. As these galaxies bump up against one another, they merge together, creating new galaxies and potentially huge black holes depending on the distance between them. Even today, galaxies continue to merge while other smaller ones are sucked in by larger ones.
The first galaxies may have formed around a billion years after the Big Bang.
This would explain why some elliptical galaxies appeared out of nowhere and why our galaxy – The Milky Way – swallowed two smaller ones.
Time frames for this merging of galaxies range from just a few hundred million to several billion years, proving that galaxies are constantly evolving even now.
Exploring the Characteristics and Wonders of the Milky Way Galaxy
The Milky Way is an ancient and majestic spiral galaxy estimated to be almost as old as the Big Bang. Its speed of nearly 9,00,000 kilometers per hour makes it one of the fastest galaxies ever.
Lying in its path are billions of stars shining bright in the night sky, from which its name originates from.
It has inspired awe among many cultures around the world through stories and myths, such as the Greek goddess Hera spraying milk across the sky.
Our Solar System is part of this cosmic tapestry that revolves around the Milky Way at a distance of 30,000 light years away.
We make a complete loop every 250 million years – a blink of an eye compared to how long it has been around.
The unique history between our Solar System and the Milky Way perfectly illustrates just how connected we are within our Universe.
Fun Fascinating Facts About Galaxies
A galaxy is a massive collection of stars, gas, and dust bound together by gravity. Aside from stars, galaxies include other celestial objects such as planets, comets, and asteroids. The gravitational attraction of all the other stuff in the galaxy holds the stars in place.
The Milky Way galaxy, of which Earth is a part, is a spiral galaxy. The Milky Way is formed like a flat disk with a central bulge in the middle. It is thought to have 400 billion stars and a supermassive black hole in its core.
Galaxies are frequently seen in groupings or clusters. These clusters can range in size from a few dozen galaxies to thousands of galaxies. A cluster of galaxies is bound together by their mutual gravitational attraction.
Galaxies have the ability to collide and merge with one another. When this occurs, the galaxies may lose their unique forms and merge to form a new, bigger galaxy. This procedure might take millions or billions of years.
The cosmos is expanding, and galaxies are getting farther apart. Scientists estimate that the Universe began to expand some 13.8 billion years ago with the Big Bang. The distance between galaxies has risen as the Universe has expanded, leading them to migrate further apart.
Galaxies come in a variety of shapes and sizes, including spiral galaxies, elliptical galaxies, and irregular galaxies. The Milky Way is a spiral galaxy with a disk-like structure and a central bulge. Elliptical galaxies have a smooth, diffuse look and are more oval or football-shaped. Irregular galaxies have a less defined form and might look more chaotic.
Scientists examine galaxies to learn more about the Universe’s history and structure. Scientists can learn more about how the cosmos evolved through time by analyzing the features of various types of galaxies and how they interact with one another. This can help us comprehend the origin of galaxies and their roles in the broader Universe.
Galaxies are frequently classed based on their form and appearance. There are lenticular galaxies and dwarf galaxies in addition to spiral, elliptical, and irregular galaxies. Lenticular galaxies are between spiral and elliptical galaxies in form, and dwarf galaxies are smaller than most other types of galaxies.
The Andromeda Galaxy is the Milky Way’s closest major galaxy. It’s a spiral galaxy 2.537 million light-years distant from Earth.
Some galaxies have very active cores known as active galactic nuclei (AGN), which produce massive amounts of radiation. AGN can be driven by supermassive black holes at the galaxy’s center, which can consume tremendous amounts of matter.
Many galaxies contain a halo, which is a spherical area of stars and other materials that surrounds the galaxy’s main core. Globular clusters, which are dense groupings of stars that circle the galaxy, can be found in a galaxy’s halo.
GN-z11, the most distant galaxy ever seen, is around 13.4 billion light-years away from Earth. It was discovered to be producing stars 100 times quicker than the Milky Way using the Hubble Space Telescope.
