MILKY WAY FACTS
The home of interesting Milky Way galaxy facts for kids and adults.
Milky Way Facts
The Milky Way is home to our solar system, which is called the Sol System (named after our sun). Milky Way is an English translation of the Latin words “via lactea” – which, in turn, comes from the Greek “galaktikos kýklos”, or “Milky Circle”.
Here are 10 other interesting facts about the Milky Way that you may not already know.
10 Facts about the Milky Way
1. The Milky Way is warped.
A disk that measures approximately 120,000 light-years across, the Milky Way has a central bulge that is around 12,000 light-years in diameter. The rest of the 'disk' is not flat though, it is warped because of its proximity to the Large and Small Magellanic Clouds.
Did you know?
The dwarf galaxies, the Large and Small Magellanic clouds, have been pulling matter in our galaxy between them like a galactic game of tug of war.
2. Milky Way has a halo.
Our Milky Way is comprised of roughly 90% dark matter (this cannot be seen), and around 10% luminous matter (this is matter that we can see). It is the large proportion of dark matter that gives the galaxy an invisible halo – its existence has been observed in simulations.
Did you know?
If the dark matter of our galaxy did not exist, the stars within the Milky Way would have a much slower orbit.
3. The Milky Way is home to over 200 billion stars.
Our Milky Way galaxy is known to be a medium-sized one. Even though it is 'just' a medium size, it is still home to over 200 billion stars – and our sun is just one of them. Most of the stars are to be found toward the centre, with relatively few at the edges.
Did you know?
The largest of the known galaxies is called IC 1101, which is home to over 100 trillion stars.
4. The Milky Way is actually quite dusty.
Somewhere in the region of 10-15% of the luminous matter in the Milky Way is comprised of gas and dust – the rest of the luminous matter being stars, comets etc. The dust of the Milky Way is so large in volume that it has formed a ring around the Galaxy.
Did you know?
On a clear night, the dusty ring of the Milky Way can be seen with the naked eye.
5. The Milky Way is made of other galaxies
The Milky Way got to its current size because it has ‘consumed’, or absorbed, other galaxies throughout its lifetime. Galaxies have been observed to collide and merge, ours is not the first to do this.
Did you know?
The Milky Way is currently being consumed by Andromeda, whilst simultaneously consuming the Canis Major Dwarf Galaxy.
6. There are no photos of the Milky Way.
Despite what many people think, there are no photographs of our Milky Way and there likely never will be. Because Earth is around 26,000 light-years from the centre, it is not currently possible to photograph it.
Did you know?
Any pictures that you may have seen of the Milky Way are either photographs of other spiral galaxies, or they are representations of what artists think it could look like.
7. There is a supermassive black hole in the centre.
Just like many other medium-to-large galaxies, the Milky Way has a black hole (a supermassive one at that) at its heart. This particular supermassive black hole is named Sagittarius A. This black hole has a 14 million mile diameter, and this does not include the area of mass around it that is being dragged inside.
Did you know?
The outer area, or disk, of Sagittarius A, ‘our’ supermassive black hole, has a mass of 14.6 million times greater than our Sun.
8. The Milky Way is incredibly old.
It is estimated that the Universe is around 13.7 billion years old. Our Milky Way is approximately 13.6 billion years old. This of course means that the Milky Way has been around from almost the very beginning.
Did you know?
While the disk of the galaxy is roughly 13.6 billion years old, its bulge is thought to be ‘only’ 10-12 billion years old.
9. The Milky Way has close neighbours.
There exist over 100 galaxy groups and clusters, of which the Milky Way is one, that form what is called the Virgo Supercluster. This Supercluster has a diameter of around 110 million light-years – that's a pretty large neighbourhood.
Did you know?
A study conducted in 2014 has shown that the Virgo Supercluster is just a small part of a much larger supercluster named Laniakea..
10. The Milky Way is not stationary.
Nothing in space stays still, everything is moving, and that includes the Milky Way. Our world moves around our sun, our sun moves through the Milky Way and the Milky Way is gliding through space. Cosmic Microwave Radiation (radiation left behind from the Big Bang) is used as a point of reference to measure the speed of items in space.
Did you know?
The Virgo Supercluster, that our galaxy is a part of, is thought to be travelling at 2.2 million kilometres an hour (1.6 million miles per hour)!