How Did the Universe Begin?
How Did the Universe Begin?
When you look up at the night sky, what do you see?
If it's a clear night, you might see hundreds of thousands of tiny points of light, too numerous to count. Some are planets, some are stars, and some are even galaxies! Where did all these cosmic objects come from? Discover the answer below and play a game!
![Nighttime view of a rocket, meteor, and the Milky Way Galaxy over Thailand](/var/ezflow_site/storage/images/media/amnh/images/explore/ology-images/astronomy/how-did-the-universe-begin/milky-way-night-sky/3159620-1-eng-US/milky-way-night-sky_full_495.jpg 495w,/var/ezflow_site/storage/images/media/amnh/images/explore/ology-images/astronomy/how-did-the-universe-begin/milky-way-night-sky/3159620-1-eng-US/milky-way-night-sky_full_990.jpg 990w,/var/ezflow_site/storage/images/media/amnh/images/explore/ology-images/astronomy/how-did-the-universe-begin/milky-way-night-sky/3159620-1-eng-US/milky-way-night-sky_full_1468.jpg 1468w,/var/ezflow_site/storage/images/media/amnh/images/explore/ology-images/astronomy/how-did-the-universe-begin/milky-way-night-sky/3159620-1-eng-US/milky-way-night-sky_full_1980.jpg 1920w,/var/ezflow_site/storage/images/media/amnh/images/explore/ology-images/astronomy/how-did-the-universe-begin/milky-way-night-sky/3159620-1-eng-US/milky-way-night-sky_full_2475.jpg 1920w)
![Black and white photo of Edwin Hubble looking through a large telescope at the Mt. Wilson Observatory](/var/ezflow_site/storage/images/media/amnh/images/explore/ology-images/astronomy/how-did-the-universe-begin/edwin-hubble-1924-telescope/3159644-1-eng-US/edwin-hubble-1924-telescope_full_495.jpg 360w,/var/ezflow_site/storage/images/media/amnh/images/explore/ology-images/astronomy/how-did-the-universe-begin/edwin-hubble-1924-telescope/3159644-1-eng-US/edwin-hubble-1924-telescope_full_990.jpg 360w,/var/ezflow_site/storage/images/media/amnh/images/explore/ology-images/astronomy/how-did-the-universe-begin/edwin-hubble-1924-telescope/3159644-1-eng-US/edwin-hubble-1924-telescope_full_1468.jpg 360w,/var/ezflow_site/storage/images/media/amnh/images/explore/ology-images/astronomy/how-did-the-universe-begin/edwin-hubble-1924-telescope/3159644-1-eng-US/edwin-hubble-1924-telescope_full_1980.jpg 360w,/var/ezflow_site/storage/images/media/amnh/images/explore/ology-images/astronomy/how-did-the-universe-begin/edwin-hubble-1924-telescope/3159644-1-eng-US/edwin-hubble-1924-telescope_full_2475.jpg 360w)
Edwin Hubble looking through the telescope at Mt. Wilson Observatory in 1924.
In the 1920s in California, astronomer Edwin Hubble observed distant galaxies using an extremely powerful telescope . He made two mind-boggling discoveries.
First, Hubble figured out that the Milky Way isn’t the only galaxy. He realized that faint, cloud-like objects in the night sky are actually other galaxies far, far away. The Milky Way is just one of billions of galaxies.
Second, Hubble discovered that the galaxies are constantly moving away from each other. In other words, the universe is expanding. The biggest thing that we know about is getting bigger all the time.
A few years later, Belgian astronomer Georges Lemaître used Hubble‘s amazing discoveries to suggest an answer to a big astronomy question: How did the universe begin?
![illustration of George Lemaitre with finger pointing up](/var/ezflow_site/storage/images/media/amnh/images/explore/ology-images/astronomy/how-did-the-universe-begin/george-lemaitre/3159632-1-eng-US/george-lemaitre_full_495.png 352w,/var/ezflow_site/storage/images/media/amnh/images/explore/ology-images/astronomy/how-did-the-universe-begin/george-lemaitre/3159632-1-eng-US/george-lemaitre_full_990.png 480w,/var/ezflow_site/storage/images/media/amnh/images/explore/ology-images/astronomy/how-did-the-universe-begin/george-lemaitre/3159632-1-eng-US/george-lemaitre_full_1468.png 480w,/var/ezflow_site/storage/images/media/amnh/images/explore/ology-images/astronomy/how-did-the-universe-begin/george-lemaitre/3159632-1-eng-US/george-lemaitre_full_1980.png 480w,/var/ezflow_site/storage/images/media/amnh/images/explore/ology-images/astronomy/how-did-the-universe-begin/george-lemaitre/3159632-1-eng-US/george-lemaitre_full_2475.png 480w)
If the universe is always getting bigger, then long ago it was smaller. And long, LONG ago, it was much smaller. That means billions of years ago, everything in the universe was contained in a tiny ball that exploded! Wow!
This breakthrough idea later became known as the Big Bang!
The Big Bang was the moment 13.8 billion years ago when the universe began as a tiny, dense, fireball that exploded. Most astronomers use the Big Bang theory to explain how the universe began. But what caused this explosion in the first place is still a mystery.
So, what has happened since the Big Bang?
![Big Bang explosion icon](/var/ezflow_site/storage/images/media/amnh/images/explore/ology-images/astronomy/how-did-the-universe-begin/big-bang-graphic-art/3333103-1-eng-US/big-bang-graphic-art_full_495.png 495w,/var/ezflow_site/storage/images/media/amnh/images/explore/ology-images/astronomy/how-did-the-universe-begin/big-bang-graphic-art/3333103-1-eng-US/big-bang-graphic-art_full_990.png 600w,/var/ezflow_site/storage/images/media/amnh/images/explore/ology-images/astronomy/how-did-the-universe-begin/big-bang-graphic-art/3333103-1-eng-US/big-bang-graphic-art_full_1468.png 600w,/var/ezflow_site/storage/images/media/amnh/images/explore/ology-images/astronomy/how-did-the-universe-begin/big-bang-graphic-art/3333103-1-eng-US/big-bang-graphic-art_full_1980.png 600w,/var/ezflow_site/storage/images/media/amnh/images/explore/ology-images/astronomy/how-did-the-universe-begin/big-bang-graphic-art/3333103-1-eng-US/big-bang-graphic-art_full_2475.png 600w)
Since the Big Bang, the universe has been expanding. In the early years, everything was made of gas. This gas, mostly hydrogen and helium, expanded and cooled. Over billions of years, gravity caused gas and dust to form galaxies, stars , planets, and more.
The matter that spread out from the Big Bang developed into everything in the universe, including you. You are made of star stuff!
![Play!](/var/ezflow_site/storage/images/media/amnh/images/explore/ology-images/astronomy/how-did-the-universe-begin/play-label/3352744-1-eng-US/play-label_full_495.png 240w,/var/ezflow_site/storage/images/media/amnh/images/explore/ology-images/astronomy/how-did-the-universe-begin/play-label/3352744-1-eng-US/play-label_full_990.png 240w,/var/ezflow_site/storage/images/media/amnh/images/explore/ology-images/astronomy/how-did-the-universe-begin/play-label/3352744-1-eng-US/play-label_full_1468.png 240w,/var/ezflow_site/storage/images/media/amnh/images/explore/ology-images/astronomy/how-did-the-universe-begin/play-label/3352744-1-eng-US/play-label_full_1980.png 240w,/var/ezflow_site/storage/images/media/amnh/images/explore/ology-images/astronomy/how-did-the-universe-begin/play-label/3352744-1-eng-US/play-label_full_2475.png 240w)
Timeline of the Universe
Astronomers have figured out that the universe is about 13 billion years old. (We’d better skip the candles on the birthday cake!) They have also determined, approximately, when different cosmic events happened, such as when our galaxy and our planet formed.
Can you put these cosmic events in order from the oldest to the most recent? To play, click and drag the pictures left or right to place them in the correct order.
Can you put these cosmic events in order from the oldest to the most recent? To play, click and drag the pictures up or down to place them in the correct order.
![1st](/var/ezflow_site/storage/images/media/amnh/images/explore/ology-images/astronomy/how-did-the-universe-begin/time-marker-1/3159957-2-eng-US/time-marker-1_full_495.png 320w,/var/ezflow_site/storage/images/media/amnh/images/explore/ology-images/astronomy/how-did-the-universe-begin/time-marker-1/3159957-2-eng-US/time-marker-1_full_990.png 320w,/var/ezflow_site/storage/images/media/amnh/images/explore/ology-images/astronomy/how-did-the-universe-begin/time-marker-1/3159957-2-eng-US/time-marker-1_full_1468.png 320w,/var/ezflow_site/storage/images/media/amnh/images/explore/ology-images/astronomy/how-did-the-universe-begin/time-marker-1/3159957-2-eng-US/time-marker-1_full_1980.png 320w,/var/ezflow_site/storage/images/media/amnh/images/explore/ology-images/astronomy/how-did-the-universe-begin/time-marker-1/3159957-2-eng-US/time-marker-1_full_2475.png 320w)
![2nd](/var/ezflow_site/storage/images/media/amnh/images/explore/ology-images/astronomy/how-did-the-universe-begin/time-marker-2/3159969-2-eng-US/time-marker-2_full_495.png 320w,/var/ezflow_site/storage/images/media/amnh/images/explore/ology-images/astronomy/how-did-the-universe-begin/time-marker-2/3159969-2-eng-US/time-marker-2_full_990.png 320w,/var/ezflow_site/storage/images/media/amnh/images/explore/ology-images/astronomy/how-did-the-universe-begin/time-marker-2/3159969-2-eng-US/time-marker-2_full_1468.png 320w,/var/ezflow_site/storage/images/media/amnh/images/explore/ology-images/astronomy/how-did-the-universe-begin/time-marker-2/3159969-2-eng-US/time-marker-2_full_1980.png 320w,/var/ezflow_site/storage/images/media/amnh/images/explore/ology-images/astronomy/how-did-the-universe-begin/time-marker-2/3159969-2-eng-US/time-marker-2_full_2475.png 320w)
![3rd](/var/ezflow_site/storage/images/media/amnh/images/explore/ology-images/astronomy/how-did-the-universe-begin/time-marker-3/3159986-2-eng-US/time-marker-3_full_495.png 320w,/var/ezflow_site/storage/images/media/amnh/images/explore/ology-images/astronomy/how-did-the-universe-begin/time-marker-3/3159986-2-eng-US/time-marker-3_full_990.png 320w,/var/ezflow_site/storage/images/media/amnh/images/explore/ology-images/astronomy/how-did-the-universe-begin/time-marker-3/3159986-2-eng-US/time-marker-3_full_1468.png 320w,/var/ezflow_site/storage/images/media/amnh/images/explore/ology-images/astronomy/how-did-the-universe-begin/time-marker-3/3159986-2-eng-US/time-marker-3_full_1980.png 320w,/var/ezflow_site/storage/images/media/amnh/images/explore/ology-images/astronomy/how-did-the-universe-begin/time-marker-3/3159986-2-eng-US/time-marker-3_full_2475.png 320w)
![4th](/var/ezflow_site/storage/images/media/amnh/images/explore/ology-images/astronomy/how-did-the-universe-begin/time-marker-4/3159998-2-eng-US/time-marker-4_full_495.png 320w,/var/ezflow_site/storage/images/media/amnh/images/explore/ology-images/astronomy/how-did-the-universe-begin/time-marker-4/3159998-2-eng-US/time-marker-4_full_990.png 320w,/var/ezflow_site/storage/images/media/amnh/images/explore/ology-images/astronomy/how-did-the-universe-begin/time-marker-4/3159998-2-eng-US/time-marker-4_full_1468.png 320w,/var/ezflow_site/storage/images/media/amnh/images/explore/ology-images/astronomy/how-did-the-universe-begin/time-marker-4/3159998-2-eng-US/time-marker-4_full_1980.png 320w,/var/ezflow_site/storage/images/media/amnh/images/explore/ology-images/astronomy/how-did-the-universe-begin/time-marker-4/3159998-2-eng-US/time-marker-4_full_2475.png 320w)
![5th](/var/ezflow_site/storage/images/media/amnh/images/explore/ology-images/astronomy/how-did-the-universe-begin/time-marker-5/3160010-2-eng-US/time-marker-5_full_495.png 320w,/var/ezflow_site/storage/images/media/amnh/images/explore/ology-images/astronomy/how-did-the-universe-begin/time-marker-5/3160010-2-eng-US/time-marker-5_full_990.png 320w,/var/ezflow_site/storage/images/media/amnh/images/explore/ology-images/astronomy/how-did-the-universe-begin/time-marker-5/3160010-2-eng-US/time-marker-5_full_1468.png 320w,/var/ezflow_site/storage/images/media/amnh/images/explore/ology-images/astronomy/how-did-the-universe-begin/time-marker-5/3160010-2-eng-US/time-marker-5_full_1980.png 320w,/var/ezflow_site/storage/images/media/amnh/images/explore/ology-images/astronomy/how-did-the-universe-begin/time-marker-5/3160010-2-eng-US/time-marker-5_full_2475.png 320w)
![6th](/var/ezflow_site/storage/images/media/amnh/images/explore/ology-images/astronomy/how-did-the-universe-begin/time-marker-6/3160022-2-eng-US/time-marker-6_full_495.png 320w,/var/ezflow_site/storage/images/media/amnh/images/explore/ology-images/astronomy/how-did-the-universe-begin/time-marker-6/3160022-2-eng-US/time-marker-6_full_990.png 320w,/var/ezflow_site/storage/images/media/amnh/images/explore/ology-images/astronomy/how-did-the-universe-begin/time-marker-6/3160022-2-eng-US/time-marker-6_full_1468.png 320w,/var/ezflow_site/storage/images/media/amnh/images/explore/ology-images/astronomy/how-did-the-universe-begin/time-marker-6/3160022-2-eng-US/time-marker-6_full_1980.png 320w,/var/ezflow_site/storage/images/media/amnh/images/explore/ology-images/astronomy/how-did-the-universe-begin/time-marker-6/3160022-2-eng-US/time-marker-6_full_2475.png 320w)
![dinosaur icon with text first dinosaurs appeared](/var/ezflow_site/storage/images/media/amnh/images/explore/ology-images/astronomy/how-did-the-universe-begin/drag_vertical_5/3159933-1-eng-US/drag_vertical_5_full_495.jpg 320w,/var/ezflow_site/storage/images/media/amnh/images/explore/ology-images/astronomy/how-did-the-universe-begin/drag_vertical_5/3159933-1-eng-US/drag_vertical_5_full_990.jpg 320w,/var/ezflow_site/storage/images/media/amnh/images/explore/ology-images/astronomy/how-did-the-universe-begin/drag_vertical_5/3159933-1-eng-US/drag_vertical_5_full_1468.jpg 320w,/var/ezflow_site/storage/images/media/amnh/images/explore/ology-images/astronomy/how-did-the-universe-begin/drag_vertical_5/3159933-1-eng-US/drag_vertical_5_full_1980.jpg 320w,/var/ezflow_site/storage/images/media/amnh/images/explore/ology-images/astronomy/how-did-the-universe-begin/drag_vertical_5/3159933-1-eng-US/drag_vertical_5_full_2475.jpg 320w)
![human hand icon with text First humans evolved](/var/ezflow_site/storage/images/media/amnh/images/explore/ology-images/astronomy/how-did-the-universe-begin/drag_vertical_6/3159945-1-eng-US/drag_vertical_6_full_495.jpg 320w,/var/ezflow_site/storage/images/media/amnh/images/explore/ology-images/astronomy/how-did-the-universe-begin/drag_vertical_6/3159945-1-eng-US/drag_vertical_6_full_990.jpg 320w,/var/ezflow_site/storage/images/media/amnh/images/explore/ology-images/astronomy/how-did-the-universe-begin/drag_vertical_6/3159945-1-eng-US/drag_vertical_6_full_1468.jpg 320w,/var/ezflow_site/storage/images/media/amnh/images/explore/ology-images/astronomy/how-did-the-universe-begin/drag_vertical_6/3159945-1-eng-US/drag_vertical_6_full_1980.jpg 320w,/var/ezflow_site/storage/images/media/amnh/images/explore/ology-images/astronomy/how-did-the-universe-begin/drag_vertical_6/3159945-1-eng-US/drag_vertical_6_full_2475.jpg 320w)
![Milky Way icon with text Milky Way formed](/var/ezflow_site/storage/images/media/amnh/images/explore/ology-images/astronomy/how-did-the-universe-begin/drag_vertical_1/3159893-1-eng-US/drag_vertical_1_full_495.jpg 320w,/var/ezflow_site/storage/images/media/amnh/images/explore/ology-images/astronomy/how-did-the-universe-begin/drag_vertical_1/3159893-1-eng-US/drag_vertical_1_full_990.jpg 320w,/var/ezflow_site/storage/images/media/amnh/images/explore/ology-images/astronomy/how-did-the-universe-begin/drag_vertical_1/3159893-1-eng-US/drag_vertical_1_full_1468.jpg 320w,/var/ezflow_site/storage/images/media/amnh/images/explore/ology-images/astronomy/how-did-the-universe-begin/drag_vertical_1/3159893-1-eng-US/drag_vertical_1_full_1980.jpg 320w,/var/ezflow_site/storage/images/media/amnh/images/explore/ology-images/astronomy/how-did-the-universe-begin/drag_vertical_1/3159893-1-eng-US/drag_vertical_1_full_2475.jpg 320w)
![Earth icon with text Earth formed](/var/ezflow_site/storage/images/media/amnh/images/explore/ology-images/astronomy/how-did-the-universe-begin/drag_vertical_3/3159787-1-eng-US/drag_vertical_3_full_495.jpg 320w,/var/ezflow_site/storage/images/media/amnh/images/explore/ology-images/astronomy/how-did-the-universe-begin/drag_vertical_3/3159787-1-eng-US/drag_vertical_3_full_990.jpg 320w,/var/ezflow_site/storage/images/media/amnh/images/explore/ology-images/astronomy/how-did-the-universe-begin/drag_vertical_3/3159787-1-eng-US/drag_vertical_3_full_1468.jpg 320w,/var/ezflow_site/storage/images/media/amnh/images/explore/ology-images/astronomy/how-did-the-universe-begin/drag_vertical_3/3159787-1-eng-US/drag_vertical_3_full_1980.jpg 320w,/var/ezflow_site/storage/images/media/amnh/images/explore/ology-images/astronomy/how-did-the-universe-begin/drag_vertical_3/3159787-1-eng-US/drag_vertical_3_full_2475.jpg 320w)
![bacteria icon with text Single-celled life evolved](/var/ezflow_site/storage/images/media/amnh/images/explore/ology-images/astronomy/how-did-the-universe-begin/drag_vertical_4/3159921-2-eng-US/drag_vertical_4_full_495.jpg 320w,/var/ezflow_site/storage/images/media/amnh/images/explore/ology-images/astronomy/how-did-the-universe-begin/drag_vertical_4/3159921-2-eng-US/drag_vertical_4_full_990.jpg 320w,/var/ezflow_site/storage/images/media/amnh/images/explore/ology-images/astronomy/how-did-the-universe-begin/drag_vertical_4/3159921-2-eng-US/drag_vertical_4_full_1468.jpg 320w,/var/ezflow_site/storage/images/media/amnh/images/explore/ology-images/astronomy/how-did-the-universe-begin/drag_vertical_4/3159921-2-eng-US/drag_vertical_4_full_1980.jpg 320w,/var/ezflow_site/storage/images/media/amnh/images/explore/ology-images/astronomy/how-did-the-universe-begin/drag_vertical_4/3159921-2-eng-US/drag_vertical_4_full_2475.jpg 320w)
![Sun icon with text Sun formed](/var/ezflow_site/storage/images/media/amnh/images/explore/ology-images/astronomy/how-did-the-universe-begin/drag_vertical_2/3159909-1-eng-US/drag_vertical_2_full_495.jpg 320w,/var/ezflow_site/storage/images/media/amnh/images/explore/ology-images/astronomy/how-did-the-universe-begin/drag_vertical_2/3159909-1-eng-US/drag_vertical_2_full_990.jpg 320w,/var/ezflow_site/storage/images/media/amnh/images/explore/ology-images/astronomy/how-did-the-universe-begin/drag_vertical_2/3159909-1-eng-US/drag_vertical_2_full_1468.jpg 320w,/var/ezflow_site/storage/images/media/amnh/images/explore/ology-images/astronomy/how-did-the-universe-begin/drag_vertical_2/3159909-1-eng-US/drag_vertical_2_full_1980.jpg 320w,/var/ezflow_site/storage/images/media/amnh/images/explore/ology-images/astronomy/how-did-the-universe-begin/drag_vertical_2/3159909-1-eng-US/drag_vertical_2_full_2475.jpg 320w)
![1st](/var/ezflow_site/storage/images/media/amnh/images/explore/ology-images/astronomy/how-did-the-universe-begin/time_marker_1mobile/3321529-2-eng-US/time_marker_1mobile_full_495.png 100w,/var/ezflow_site/storage/images/media/amnh/images/explore/ology-images/astronomy/how-did-the-universe-begin/time_marker_1mobile/3321529-2-eng-US/time_marker_1mobile_full_990.png 100w,/var/ezflow_site/storage/images/media/amnh/images/explore/ology-images/astronomy/how-did-the-universe-begin/time_marker_1mobile/3321529-2-eng-US/time_marker_1mobile_full_1468.png 100w,/var/ezflow_site/storage/images/media/amnh/images/explore/ology-images/astronomy/how-did-the-universe-begin/time_marker_1mobile/3321529-2-eng-US/time_marker_1mobile_full_1980.png 100w,/var/ezflow_site/storage/images/media/amnh/images/explore/ology-images/astronomy/how-did-the-universe-begin/time_marker_1mobile/3321529-2-eng-US/time_marker_1mobile_full_2475.png 100w)
![2nd](/var/ezflow_site/storage/images/media/amnh/images/explore/ology-images/astronomy/how-did-the-universe-begin/time_marker_2mobile/3321481-2-eng-US/time_marker_2mobile_full_495.png 100w,/var/ezflow_site/storage/images/media/amnh/images/explore/ology-images/astronomy/how-did-the-universe-begin/time_marker_2mobile/3321481-2-eng-US/time_marker_2mobile_full_990.png 100w,/var/ezflow_site/storage/images/media/amnh/images/explore/ology-images/astronomy/how-did-the-universe-begin/time_marker_2mobile/3321481-2-eng-US/time_marker_2mobile_full_1468.png 100w,/var/ezflow_site/storage/images/media/amnh/images/explore/ology-images/astronomy/how-did-the-universe-begin/time_marker_2mobile/3321481-2-eng-US/time_marker_2mobile_full_1980.png 100w,/var/ezflow_site/storage/images/media/amnh/images/explore/ology-images/astronomy/how-did-the-universe-begin/time_marker_2mobile/3321481-2-eng-US/time_marker_2mobile_full_2475.png 100w)
![3rd](/var/ezflow_site/storage/images/media/amnh/images/explore/ology-images/astronomy/how-did-the-universe-begin/time_marker_3mobile/3321469-2-eng-US/time_marker_3mobile_full_495.png 100w,/var/ezflow_site/storage/images/media/amnh/images/explore/ology-images/astronomy/how-did-the-universe-begin/time_marker_3mobile/3321469-2-eng-US/time_marker_3mobile_full_990.png 100w,/var/ezflow_site/storage/images/media/amnh/images/explore/ology-images/astronomy/how-did-the-universe-begin/time_marker_3mobile/3321469-2-eng-US/time_marker_3mobile_full_1468.png 100w,/var/ezflow_site/storage/images/media/amnh/images/explore/ology-images/astronomy/how-did-the-universe-begin/time_marker_3mobile/3321469-2-eng-US/time_marker_3mobile_full_1980.png 100w,/var/ezflow_site/storage/images/media/amnh/images/explore/ology-images/astronomy/how-did-the-universe-begin/time_marker_3mobile/3321469-2-eng-US/time_marker_3mobile_full_2475.png 100w)
![4th](/var/ezflow_site/storage/images/media/amnh/images/explore/ology-images/astronomy/how-did-the-universe-begin/time_marker_4mobile/3321457-2-eng-US/time_marker_4mobile_full_495.png 100w,/var/ezflow_site/storage/images/media/amnh/images/explore/ology-images/astronomy/how-did-the-universe-begin/time_marker_4mobile/3321457-2-eng-US/time_marker_4mobile_full_990.png 100w,/var/ezflow_site/storage/images/media/amnh/images/explore/ology-images/astronomy/how-did-the-universe-begin/time_marker_4mobile/3321457-2-eng-US/time_marker_4mobile_full_1468.png 100w,/var/ezflow_site/storage/images/media/amnh/images/explore/ology-images/astronomy/how-did-the-universe-begin/time_marker_4mobile/3321457-2-eng-US/time_marker_4mobile_full_1980.png 100w,/var/ezflow_site/storage/images/media/amnh/images/explore/ology-images/astronomy/how-did-the-universe-begin/time_marker_4mobile/3321457-2-eng-US/time_marker_4mobile_full_2475.png 100w)
![5th](/var/ezflow_site/storage/images/media/amnh/images/explore/ology-images/astronomy/how-did-the-universe-begin/time_marker_5mobile/3321433-2-eng-US/time_marker_5mobile_full_495.png 100w,/var/ezflow_site/storage/images/media/amnh/images/explore/ology-images/astronomy/how-did-the-universe-begin/time_marker_5mobile/3321433-2-eng-US/time_marker_5mobile_full_990.png 100w,/var/ezflow_site/storage/images/media/amnh/images/explore/ology-images/astronomy/how-did-the-universe-begin/time_marker_5mobile/3321433-2-eng-US/time_marker_5mobile_full_1468.png 100w,/var/ezflow_site/storage/images/media/amnh/images/explore/ology-images/astronomy/how-did-the-universe-begin/time_marker_5mobile/3321433-2-eng-US/time_marker_5mobile_full_1980.png 100w,/var/ezflow_site/storage/images/media/amnh/images/explore/ology-images/astronomy/how-did-the-universe-begin/time_marker_5mobile/3321433-2-eng-US/time_marker_5mobile_full_2475.png 100w)
![6th](/var/ezflow_site/storage/images/media/amnh/images/explore/ology-images/astronomy/how-did-the-universe-begin/time_marker_6mobile/3321445-2-eng-US/time_marker_6mobile_full_495.png 100w,/var/ezflow_site/storage/images/media/amnh/images/explore/ology-images/astronomy/how-did-the-universe-begin/time_marker_6mobile/3321445-2-eng-US/time_marker_6mobile_full_990.png 100w,/var/ezflow_site/storage/images/media/amnh/images/explore/ology-images/astronomy/how-did-the-universe-begin/time_marker_6mobile/3321445-2-eng-US/time_marker_6mobile_full_1468.png 100w,/var/ezflow_site/storage/images/media/amnh/images/explore/ology-images/astronomy/how-did-the-universe-begin/time_marker_6mobile/3321445-2-eng-US/time_marker_6mobile_full_1980.png 100w,/var/ezflow_site/storage/images/media/amnh/images/explore/ology-images/astronomy/how-did-the-universe-begin/time_marker_6mobile/3321445-2-eng-US/time_marker_6mobile_full_2475.png 100w)
![dinosaur icon with text first dinosaurs appeared](/var/ezflow_site/storage/images/media/amnh/images/explore/ology-images/astronomy/how-did-the-universe-begin/drag_mobile_5/3321553-3-eng-US/drag_mobile_5_full_495.jpg 495w,/var/ezflow_site/storage/images/media/amnh/images/explore/ology-images/astronomy/how-did-the-universe-begin/drag_mobile_5/3321553-3-eng-US/drag_mobile_5_full_990.jpg 500w,/var/ezflow_site/storage/images/media/amnh/images/explore/ology-images/astronomy/how-did-the-universe-begin/drag_mobile_5/3321553-3-eng-US/drag_mobile_5_full_1468.jpg 500w,/var/ezflow_site/storage/images/media/amnh/images/explore/ology-images/astronomy/how-did-the-universe-begin/drag_mobile_5/3321553-3-eng-US/drag_mobile_5_full_1980.jpg 500w,/var/ezflow_site/storage/images/media/amnh/images/explore/ology-images/astronomy/how-did-the-universe-begin/drag_mobile_5/3321553-3-eng-US/drag_mobile_5_full_2475.jpg 500w)
![icon of human hand with text first humans evolved](/var/ezflow_site/storage/images/media/amnh/images/explore/ology-images/astronomy/how-did-the-universe-begin/drag_mobile_6/3321505-3-eng-US/drag_mobile_6_full_495.jpg 495w,/var/ezflow_site/storage/images/media/amnh/images/explore/ology-images/astronomy/how-did-the-universe-begin/drag_mobile_6/3321505-3-eng-US/drag_mobile_6_full_990.jpg 500w,/var/ezflow_site/storage/images/media/amnh/images/explore/ology-images/astronomy/how-did-the-universe-begin/drag_mobile_6/3321505-3-eng-US/drag_mobile_6_full_1468.jpg 500w,/var/ezflow_site/storage/images/media/amnh/images/explore/ology-images/astronomy/how-did-the-universe-begin/drag_mobile_6/3321505-3-eng-US/drag_mobile_6_full_1980.jpg 500w,/var/ezflow_site/storage/images/media/amnh/images/explore/ology-images/astronomy/how-did-the-universe-begin/drag_mobile_6/3321505-3-eng-US/drag_mobile_6_full_2475.jpg 500w)
![Milky Way icon with text Milky Way formed](/var/ezflow_site/storage/images/media/amnh/images/explore/ology-images/astronomy/how-did-the-universe-begin/drag_mobile_1/3321649-3-eng-US/drag_mobile_1_full_495.jpg 495w,/var/ezflow_site/storage/images/media/amnh/images/explore/ology-images/astronomy/how-did-the-universe-begin/drag_mobile_1/3321649-3-eng-US/drag_mobile_1_full_990.jpg 500w,/var/ezflow_site/storage/images/media/amnh/images/explore/ology-images/astronomy/how-did-the-universe-begin/drag_mobile_1/3321649-3-eng-US/drag_mobile_1_full_1468.jpg 500w,/var/ezflow_site/storage/images/media/amnh/images/explore/ology-images/astronomy/how-did-the-universe-begin/drag_mobile_1/3321649-3-eng-US/drag_mobile_1_full_1980.jpg 500w,/var/ezflow_site/storage/images/media/amnh/images/explore/ology-images/astronomy/how-did-the-universe-begin/drag_mobile_1/3321649-3-eng-US/drag_mobile_1_full_2475.jpg 500w)
![Earth icon with text Earth formed](/var/ezflow_site/storage/images/media/amnh/images/explore/ology-images/astronomy/how-did-the-universe-begin/drag_mobile_3/3321601-3-eng-US/drag_mobile_3_full_495.jpg 495w,/var/ezflow_site/storage/images/media/amnh/images/explore/ology-images/astronomy/how-did-the-universe-begin/drag_mobile_3/3321601-3-eng-US/drag_mobile_3_full_990.jpg 500w,/var/ezflow_site/storage/images/media/amnh/images/explore/ology-images/astronomy/how-did-the-universe-begin/drag_mobile_3/3321601-3-eng-US/drag_mobile_3_full_1468.jpg 500w,/var/ezflow_site/storage/images/media/amnh/images/explore/ology-images/astronomy/how-did-the-universe-begin/drag_mobile_3/3321601-3-eng-US/drag_mobile_3_full_1980.jpg 500w,/var/ezflow_site/storage/images/media/amnh/images/explore/ology-images/astronomy/how-did-the-universe-begin/drag_mobile_3/3321601-3-eng-US/drag_mobile_3_full_2475.jpg 500w)
![amoeba icon with text Single-celled life evolved](/var/ezflow_site/storage/images/media/amnh/images/explore/ology-images/astronomy/how-did-the-universe-begin/drag_mobile_4/3321577-3-eng-US/drag_mobile_4_full_495.jpg 495w,/var/ezflow_site/storage/images/media/amnh/images/explore/ology-images/astronomy/how-did-the-universe-begin/drag_mobile_4/3321577-3-eng-US/drag_mobile_4_full_990.jpg 500w,/var/ezflow_site/storage/images/media/amnh/images/explore/ology-images/astronomy/how-did-the-universe-begin/drag_mobile_4/3321577-3-eng-US/drag_mobile_4_full_1468.jpg 500w,/var/ezflow_site/storage/images/media/amnh/images/explore/ology-images/astronomy/how-did-the-universe-begin/drag_mobile_4/3321577-3-eng-US/drag_mobile_4_full_1980.jpg 500w,/var/ezflow_site/storage/images/media/amnh/images/explore/ology-images/astronomy/how-did-the-universe-begin/drag_mobile_4/3321577-3-eng-US/drag_mobile_4_full_2475.jpg 500w)
![Sun icon with text Sun formed](/var/ezflow_site/storage/images/media/amnh/images/explore/ology-images/astronomy/how-did-the-universe-begin/drag_mobile_2/3321625-3-eng-US/drag_mobile_2_full_495.jpg 495w,/var/ezflow_site/storage/images/media/amnh/images/explore/ology-images/astronomy/how-did-the-universe-begin/drag_mobile_2/3321625-3-eng-US/drag_mobile_2_full_990.jpg 500w,/var/ezflow_site/storage/images/media/amnh/images/explore/ology-images/astronomy/how-did-the-universe-begin/drag_mobile_2/3321625-3-eng-US/drag_mobile_2_full_1468.jpg 500w,/var/ezflow_site/storage/images/media/amnh/images/explore/ology-images/astronomy/how-did-the-universe-begin/drag_mobile_2/3321625-3-eng-US/drag_mobile_2_full_1980.jpg 500w,/var/ezflow_site/storage/images/media/amnh/images/explore/ology-images/astronomy/how-did-the-universe-begin/drag_mobile_2/3321625-3-eng-US/drag_mobile_2_full_2475.jpg 500w)
You got it! Check out the timeline below to explore exactly when these cosmic events occurred. See how the earliest humans didn't even appear until 1.8 million years ago? That's just a blink of an eye in the history of the universe!
![timeline measured in billions of years with history of the universe plotted at various points](/var/ezflow_site/storage/images/media/amnh/images/explore/ology-images/astronomy/how-did-the-universe-begin/timeline-ruler-graphic-desktop/3337398-3-eng-US/timeline-ruler-graphic-desktop_full_495.png 495w,/var/ezflow_site/storage/images/media/amnh/images/explore/ology-images/astronomy/how-did-the-universe-begin/timeline-ruler-graphic-desktop/3337398-3-eng-US/timeline-ruler-graphic-desktop_full_990.png 990w,/var/ezflow_site/storage/images/media/amnh/images/explore/ology-images/astronomy/how-did-the-universe-begin/timeline-ruler-graphic-desktop/3337398-3-eng-US/timeline-ruler-graphic-desktop_full_1468.png 1220w,/var/ezflow_site/storage/images/media/amnh/images/explore/ology-images/astronomy/how-did-the-universe-begin/timeline-ruler-graphic-desktop/3337398-3-eng-US/timeline-ruler-graphic-desktop_full_1980.png 1220w,/var/ezflow_site/storage/images/media/amnh/images/explore/ology-images/astronomy/how-did-the-universe-begin/timeline-ruler-graphic-desktop/3337398-3-eng-US/timeline-ruler-graphic-desktop_full_2475.png 1220w)
![timeline measured in billions of years with history of the universe plotted at various points](/var/ezflow_site/storage/images/media/amnh/images/explore/ology-images/astronomy/how-did-the-universe-begin/timeline-graphic-mobile-alt/3352393-1-eng-US/timeline-graphic-mobile-alt_full_495.png 352w,/var/ezflow_site/storage/images/media/amnh/images/explore/ology-images/astronomy/how-did-the-universe-begin/timeline-graphic-mobile-alt/3352393-1-eng-US/timeline-graphic-mobile-alt_full_990.png 646w,/var/ezflow_site/storage/images/media/amnh/images/explore/ology-images/astronomy/how-did-the-universe-begin/timeline-graphic-mobile-alt/3352393-1-eng-US/timeline-graphic-mobile-alt_full_1468.png 646w,/var/ezflow_site/storage/images/media/amnh/images/explore/ology-images/astronomy/how-did-the-universe-begin/timeline-graphic-mobile-alt/3352393-1-eng-US/timeline-graphic-mobile-alt_full_1980.png 646w,/var/ezflow_site/storage/images/media/amnh/images/explore/ology-images/astronomy/how-did-the-universe-begin/timeline-graphic-mobile-alt/3352393-1-eng-US/timeline-graphic-mobile-alt_full_2475.png 646w)
Image Credits:
Milky Way over Thailand, © Matipon Tangmatitham; Hubble at telescope, courtesy of NASA; George LeMaitre illustration by Amanda Duffy © AMNH; Icon illustrations by Daryl Collins © AMNH.