🌠 Galaxies

Facts About Galaxies: The Islands of Stars

Galaxies are gravitationally bound systems of stars, gas, and dark matter. The smallest contain a few thousand stars. The largest contain a hundred trillion.

30 FactsVerifiedA FactFacts Post

Our Milky Way is a barred spiral galaxy with roughly 200–400 billion stars. It's average — neither the biggest nor smallest in the neighborhood. We orbit the galactic center once every 230 million years.

Galaxies cluster gravitationally. They merge, collide, and reshape each other over billions of years. The Andromeda galaxy is on a collision course with the Milky Way; the merger begins in about 4.5 billion years.

The verified facts below cover galaxy types, supermassive black holes, dark matter halos, the largest known structures in the universe, and what happens when two galaxies meet.

Below: every fact from our verified archive that touches this topic. Each is independently sourced; click through to its dedicated page.

01
Space

The Hubble Space Telescope has captured deep images of distant galaxies.

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02
Space

The Milky Way is just one of billions of galaxies in the universe.

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03
Space

The Milky Way is on a slow collision course with Andromeda.

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04
Space

The Milky Way is estimated to be over 100,000 light-years wide.

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05
Space

Fast radio bursts are powerful millisecond-long radio pulses from distant galaxies.

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06
Space

The Great Attractor is a gravitational anomaly influencing the motion of galaxies.

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07
Space

Some galaxies contain supermassive black holes millions of times the Sun’s mass.

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08
Space

The Milky Way and Andromeda galaxies are on a slow collision course.

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09
Space

Supernovae can briefly outshine entire galaxies.

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10
Space

Some galaxies appear distorted due to gravitational effects.

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11
Space

The James Webb Space Telescope observes distant galaxies in infrared light.

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12
Space

Light from distant galaxies shows us the past.

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13
Space

Some galaxies are trillions of miles wide.

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14
Space

There are black holes at galaxy centers.

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15
Space

The light you see from some stars today began traveling before humans existed.

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16
Space

The light you see from some stars today began traveling before humans existed.

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17
Space

The light you see from some stars today began traveling before humans existed.

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18
Space

The light you see from some stars today began traveling before humans existed.

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19
Space

The light you see from some stars today began traveling before humans existed.

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20
Space

The universe is so large that light from most of it will never reach Earth.

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21
Space

Some black holes formed before galaxies existed.

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22
Space

There are galaxies billions of years older than Earth.

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23
Space

There are stars that died before Earth existed.

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24
Space

There are galaxies that formed shortly after the universe began.

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25
Space

The universe contains billions of galaxies.

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26
Space

Some galaxies collide.

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27
Space

There are distant galaxies.

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28
Space

Some galaxies contain trillions of stars.

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29
Space

There are galaxies moving away faster than light due to expanding space.

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30
Space

The observable universe contains hundreds of billions of galaxies.

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