The Milky Way is so massive that even traveling at the speed of light, it would still take around 100,000 years to cross it. Somewhere inside this spinning galaxy are hundreds of billions of stars, mysterious black holes, invisible dark matter, and the tiny blue planet where you’re reading this right now.
And despite centuries of research, astronomers are still discovering strange new things hiding inside our galaxy.
From ancient myths about spilled milk in the heavens to stars older than Earth itself, these Milky Way facts reveal just how bizarre our corner of the universe really is.
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The Milky Way got its name from spilled milk
The word “galaxy” comes from the Greek word galaxias, meaning “milky.” In Greek mythology, the Milky Way formed when the goddess Hera spilled milk across the night sky.[2]
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Different cultures gave the Milky Way wildly different names
In China, it’s called “The Silver River.” In Sanskrit, it’s known as Akash Ganga, or “The Ganges of the Heavens.” Cherokee legend described it as “The Way the Dog Ran Away.”[2]
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You can only see a microscopic fraction of the Milky Way.
When a person sees the Milky Way at night, they are seeing only about 0.0000025% of the galaxy’s hundreds of billions of stars.[2]
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The Milky Way is moving incredibly fast right now
The Milky Way rotates at a speed of 168 miles per second. So, the actual place in space where you were an hour ago is now roughly 600,000 miles away.[4]
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The center of the Milky Way contains a monster black hole.
The very center of the Milky Way contains a powerful gravitational force that scientists believe is a black hole, which they have named Sagittarius A*. Astronomers believe this black hole weighs as much as 4 million of our suns put together.[3]
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The Milky Way is much bigger than most people imagine
The galaxy stretches roughly 100,000 to 120,000 light-years across. For perspective, one light-year equals nearly 6 trillion miles.[3]
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The Milky Way contains hundreds of billions of stars
Scientists believe that the Milky Way contains up to 400 billion stars, and at least as many planets. The largest galaxy known, IC 1101, has over 100 trillion stars. Smaller galaxies, like the Large Magellanic Cloud, have about 10 billion stars. The most stars a person can see from any point on Earth are about 2,500.[3]
![Amazing Milky Way Facts]()
According to Greek mythology, the Milky Way was formed when Hera was surprised to find another woman's son (Hercules) suckling her breast while she was asleep
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Our galaxy is small compared to some others
The Milky Way may seem enormous, but galaxies like Hercules A and IC 1101 dwarf it.
IC 1101 may contain more than 100 trillion stars.[2]
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Our solar system is trapped inside one of the galaxy’s spiral arms
The sun, Earth, and the rest of the solar system are located about 27,000 light-years away from the Milky Way’s Galactic Center, on the inner edge of a minor arm of the galaxy, named the Orion Arm.[2]
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The Milky Way is shaped like a giant cosmic whirlpool
Astronomers classify it as a barred spiral galaxy, meaning it has a bright central bar with curved spiral arms extending outward.[3]
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Some stars in the Milky Way are nearly as old as the universe
The oldest star in the Milky Way is at least 13.6 billion years old and most likely formed shortly after the Big Bang.[2]
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The Milky Way is mostly invisible
More than 90% of the galaxy’s mass may consist of mysterious dark matter, which cannot be directly seen.
Everything visible through telescopes, stars, planets, gas, and dust, makes up only a tiny fraction of the galaxy.[3]
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The galaxy is surprisingly thin
If the Milky Way had the same diameter as a Frisbee, the thickness of the disk would be about that of a sheet of paper.[2]
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Space inside galaxies is emptier than most people realize
Even the “dense” regions between stars contain only around 10,000 atoms per cubic meter on average. That’s far emptier than any vacuum humans can create on Earth.[3]
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Seven new stars are born in the Milky Way every year
New stars form inside enormous clouds of gas and dust scattered throughout the galaxy.[2]
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Our solar system is racing through space
Earth orbits the sun at about 67,000 miles per hour.
But the entire solar system orbits the Milky Way’s center at roughly 514,000 miles per hour.[4]
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The emptiest places in the universe are between galaxies
Intergalactic space averages roughly one atom per cubic meter.[3]
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If the solar system were the size of a quarter, the Milky Way would be the size of the United States
If our solar system were the size of a U.S. quarter, the sun would be a microscopic piece of dust and the Milky Way would be about the size of the United States.[1]
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The closest star to Earth is still unimaginably far away
Earth’s closest star in the Milky Way, Proxima Centauri, is more than four light-years away (a light-year is about 5.9 trillion miles, about 10 trillion kilometers). Proxima is Latin for “close.”[2]
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Every full image of the Milky Way is either simulated or imagined
It would take a spaceship thousands of years traveling at the speed of light to get far enough to capture a picture of the entire galaxy. Every picture of the Milky Way that we have is either a picture of another galaxy or an artist’s interpretation.[3]
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The Andromeda Galaxy is heading straight toward us
The Milky Way and Andromeda are moving toward each other at about 75 miles per second and will collide in about 2 billion years. The collision may last about 5.5 billion years.[3]
![Interesting Facts about Galaxies]()
Astronomers predict that the Andromeda Galaxy will collide with the Milky way in 4 billion years
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One trip around the galaxy takes an unbelievably long time
It takes the solar system around 225–250 million years to complete one orbit around the Milky Way.
Astronomers call this a “galactic year.”[3]
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Humans have existed for only a tiny fraction of one galactic orbit
Since humans first appeared, the solar system has completed only about 1/1250th of a single orbit around the galaxy.[3]
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Since the dinosaurs died out, the sun has moved about one-third around the galaxy
The dinosaurs disappeared roughly 65 million years ago, which means the solar system has traveled about a third of the way around the Milky Way since then.[4]
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The Milky Way formed shortly after the Big Bang
Scientists believe the galaxy began forming around 13.6 billion years ago, making it nearly as old as the universe itself[2]
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The Milky Way’s central bulge is gigantic
The bulging center of the galaxy is around 10,000 light-years thick.[4]
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If Earth orbited the sun as fast as stars orbit the Milky Way, a year would last only three days
That’s how fast stars travel around the galactic center.[3]
![Interesting Hubble Fact]()
Hubble is considered one of the most important astronomers of the 20th century
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Edwin Hubble helped prove other galaxies existed
In the 1920s, astronomer Edwin Hubble showed that distant “spiral nebulae” were actually separate galaxies far beyond the Milky Way.
His discovery dramatically expanded humanity’s understanding of the universe.[2]
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The Milky Way emits far more than visible light
The galaxy also produces infrared radiation, radio waves, gamma rays, and X-rays.[2]
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The Large and Small Magellanic Clouds are neighboring galaxies
These two smaller galaxies orbit near the Milky Way and can sometimes be seen from the Southern Hemisphere.[2]
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There aren’t more stars in the arms of the Milky Way’s spiral than elsewhere
The stars in the arms are bigger stars, which die out quicker and burn brighter, which illuminates those around them and make the arms more visible.[4]
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Earth probably won’t be destroyed during the collision.
Even though the galaxies will crash into each other, the distance between stars is so enormous that direct stellar collisions are unlikely.[3]
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As, pricked out with less and greater lights, between the poles of the universe, the Milky Way so gleameth white as to set very sages questioning.
- Dante Alighieri
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The center of the Milky Way is full of mostly old stars
Its spiral arms contain more newborn stars.[3]
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The center of the Milky Way
It has both the greatest concentration of stars and the most massive stars.[3]
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The sun and our solar system have orbited the galaxy fewer than 20 times since our solar system was born about 4.6 billion years ago
It has made 1/1250 of a revolution since the origin of humans.[3]
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The Milky Way contains giant rivers of stars
Astronomers have discovered enormous stellar streams wrapping around the galaxy.
These streams are likely the shredded remains of smaller star clusters and galaxies torn apart by gravity.[2]
![Interesting Milky Facts]()
These streams high over the Milky Way are between 13,000 and 130,000 light years from Earth and contain millions of stars
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The center of the galaxy is hidden behind cosmic dust
Visible-light telescopes can’t clearly see through the thick clouds of gas and dust near the galactic center.
Astronomers instead use infrared, radio, and X-ray telescopes.[4]
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Galileo was the first person to see the Milky Way’s stars clearly
Using a telescope in 1610, Galileo discovered the glowing band across the night sky was made of countless individual stars.[4]
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Ancient astronomers once believed the Milky Way was the entire universe
Until the early 1900s, many scientists thought our galaxy contained everything that existed.[2]
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The Milky Way is slowly eating other galaxies
Astronomers believe our galaxy has already absorbed several smaller galaxies and is currently consuming the Sagittarius Dwarf Galaxy.[2]
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The Milky Way belongs to a larger galactic neighborhood
Our galaxy is part of the Local Group, a cluster of more than 40 galaxies held together by gravity.[3]