Acrux
Acrux is a bright star. It is part of a cross shape in the sky. It looks like one star, but it is actually seven stars. This helps light up the night. Can you find it in the sky?
Early Reader · Change the reading level on the articleSpace articles — Page 6
Read about planets, stars, galaxies and the people and tools used to explore space. Choose an article below; its reading controls let you move between the available levels.
1,134 public articles · Page 6 of 24
Adam Riess
Adam Riess looks at the stars. He studies space. He found that space is growing very fast. This helps us learn about our world. He won a big prize for his work. Do you like to look at the stars?
Early Reader · Change the reading level on the articleAge of the universe
The universe is very old. It started a long time ago. It is billions of years old. We use stars to learn this. This helps us know our home. Do you like the stars?
Early Reader · Change the reading level on the articleAglaonice
Long ago, a woman named Aglaonice lived. People said she could move the moon. She knew when the moon would get dark. This made her look very powerful. Some say she had bad luck later. Do you like the moon?
Early Reader · Change the reading level on the articleAir mass (astronomy)
Stars look bright in the night sky. Light from stars must pass through air. Sometimes the light travels through a lot of air. This makes the stars look dim. This happens when stars are low. Do you like looking at stars?
Early Reader · Change the reading level on the articleAlan Bean
Alan Bean was a brave man. He flew high in space. He was one of the first to walk on the Moon. He also liked to paint pictures. He used real dust from the Moon! Do you want to see the Moon?
Early Reader · Change the reading level on the articleAlan Shepard
Alan Shepard was a brave man. He flew high in space. He was the first American in space. He even walked on the Moon! He even hit golf balls there. He was a great pilot. Do you want to fly to the Moon?
Early Reader · Change the reading level on the articleAldebaran
Aldebaran is a bright star. It is in a group called Taurus. This star is very big. It is much bigger than our Sun. It looks like a red dot in the sky. Can you find it at night?
Early Reader · Change the reading level on the articleAlexei Leonov
Alexei was a man who went to space. He was the first to walk outside a ship in space. He also liked to paint pictures. He even drew art in space! He was a very brave pilot. Do you want to go to space?
Early Reader · Change the reading level on the articleAlfred Worden
Alfred Worden was a man who flew to the Moon. He flew in a fast ship. He went around the Moon many times. He was very far from all people. He even went for a walk in space! Do you want to fly to the Moon too?
Early Reader · Change the reading level on the articleAlgol
Algol is a bright star. It is made of three stars. These stars spin around each other. Sometimes one star hides the other. This makes the star look dim. Can you find it in the sky?
Early Reader · Change the reading level on the articleAllan Sandage
Allan Sandage looked at the stars. He was a man who studied space. He helped us know how old the world is. He worked hard to learn many things. He was a very smart man. Do you like to look at the sky?
Early Reader · Change the reading level on the articleAlmagest
A man wrote a big book. It was about the stars. It tells us how they move. This book helped us for a long time. It is very special. Do you like to look at the stars?
Early Reader · Change the reading level on the articleAlpher–Bethe–Gamow paper
Long ago, the world began. It made the stuff we see. This stuff makes up the stars. It also makes up you and me. We can learn how it all works. Do you like to look at the stars?
Early Reader · Change the reading level on the articleAltair
Altair is a very bright star. It shines in the night sky. It is much bigger than our Sun. This star spins very fast. It is not a round ball. It is a little flat. Do you like to look at stars?
Early Reader · Change the reading level on the articleAmateur astronomy
People love to look at the sky. They use tools like big glass tubes. These help us see far stars. You can look at the moon too. It is fun to find new things. Do you like the stars?
Early Reader · Change the reading level on the articleAnders Celsius
Anders Celsius was a man who loved stars. He studied the sky. He also made a way to measure heat. This helps us know if it is hot or cold. He was a great thinker. Do you like looking at the stars?
Early Reader · Change the reading level on the articleAndrea M. Ghez
Andrea is a star watcher. She looks at the sky. She found a big, dark spot in space. It is at the center of our galaxy. This helps us learn about space. Do you like to look at stars?
Early Reader · Change the reading level on the articleAndromeda (constellation)
Andromeda is a group of stars. It looks like a shape in the sky. You can see it in the fall. It is very big. It has a bright galaxy too. Can you look for it at night?
Early Reader · Change the reading level on the articleAndromeda–Milky Way collision
Two big groups of stars are moving toward each other. One is our home. The other is called Andromeda. They may meet in a very long time. The stars are far apart. They will not hit each other. Do you like to look at…
Early Reader · Change the reading level on the articleAngular diameter
Things look different based on where you stand. A big ball looks small if it is far away. It looks big if it is near you. This helps us see stars and the moon. Can you see how big things look?
Early Reader · Change the reading level on the articleAnnie Jump Cannon
Annie Jump Cannon loved the stars. She looked at them every day. She put them in groups. This helps us know the stars. She was a great scientist. Do you like to look at the stars?
Early Reader · Change the reading level on the articleAnnie S. D. Maunder
Annie was a star watcher. She looked at the sun. She saw dark spots on it. She made a map of the spots. This map looks like a butterfly. Do you like to look at the stars?
Early Reader · Change the reading level on the articleAnousheh Ansari
Anousheh Ansari went to space. She was a very brave woman. She saw the stars from high up. This helps us learn new things. She wants you to follow your dreams too. Do you like to look at the stars?
Early Reader · Change the reading level on the articleAntares
Antares is a very big star. It looks red in the sky. It is part of a group called the scorpion. The star is very bright. It is much bigger than our sun. Can you find the red star?
Early Reader · Change the reading level on the articleAntennae Galaxies
Two big groups of stars are hitting each other. They look like long bug feelers. This makes many new stars. This helps make things like planets. It is a big space dance. Can you see the stars?
Early Reader · Change the reading level on the articleAnthropic principle
The world is just right for us. It has the right age. It has the right air. If it were different, we would not be here. We can see the stars because we live here. Do you like looking at the stars?
Early Reader · Change the reading level on the articleAntlia
Antlia is a group of stars. It looks like a pump. It is far away in the sky. You can see it from the south. It is very faint. Can you find it in the sky?
Early Reader · Change the reading level on the articleAntony Hewish
He looked at the stars. He used tools to hear space. He found something new in the sky. This helped him win a big prize. He was a great science man. Do you like to look at stars?
Early Reader · Change the reading level on the articleAperture synthesis
Many telescopes work as one big tool. They mix their signals to see far away. This helps us see things in space. It can even show a black hole! It is a very cool way to look. Can you look at the stars too?
Early Reader · Change the reading level on the articleApparent magnitude
Stars look different in the sky. Some stars look very bright. Others look very dim. We use numbers to show this. Low numbers mean the star is bright. High numbers mean it is dim. Can you find a bright star tonight?
Early Reader · Change the reading level on the articleApsis
Space things move in paths. Some paths go near a star. Some paths go far away. This happens to our Earth too. It is a big circle. It is not a perfect circle. Can you see the path?
Early Reader · Change the reading level on the articleApus
Apus is a group of stars. It looks like a bird. This bird is in the sky. It is far away from us. We can see it at night. Can you find it?
Early Reader · Change the reading level on the articleAquarius (constellation)
Aquarius is a group of stars. It looks like a person with a jar. The person pours water from the jar. This helps us find it in the sky. It is very old. Can you find it at night?
Early Reader · Change the reading level on the articleAquila (constellation)
Look up at the night sky. You can see an eagle. It is made of stars. This eagle lives in the Milky Way. It is very bright. Do you see the stars?
Early Reader · Change the reading level on the articleAra (constellation)
Ara is a group of stars. It looks like a big altar. Many bright stars live there. Some stars have planets too. It is high in the sky. Can you find it?
Early Reader · Change the reading level on the articleArecibo Observatory
There was a very big dish. It sat in a deep hole. It looked at the stars. It helped us learn about space. Now, a new center will be there. Can you look at the stars too?
Early Reader · Change the reading level on the articleArgo Navis
Long ago, people saw a big ship in the stars. It was very large. Now, the ship is split into three small parts. This helps us find the stars. Can you look for them at night?
Early Reader · Change the reading level on the articleAriel (moon)
Ariel is a moon. It goes around Uranus. It is made of ice and rock. It has big cracks on it. The moon might have water under the ice. Can you find the cracks?
Early Reader · Change the reading level on the articleAries (constellation)
Aries is a group of stars. It looks like a ram. A ram is a male sheep. It is high in the sky. We can see it at night. Do you like looking at stars?
Early Reader · Change the reading level on the articleAristarchus of Samos
A man named Aristarchus looked at the sky. He saw the Sun and Moon. He thought the Sun was the center. He said the Earth moves around it. This helps us know our place. Do you like looking at stars?
Early Reader · Change the reading level on the articleArno Allan Penzias
Arno was a man who studied space. He used a big tool to listen. He heard a sound from far away. It was a sound from the start of everything. This helped us learn about our world. Can you look at the stars tonight?
Early Reader · Change the reading level on the articleArp 220
Two big star groups hit each other. They are joining into one. This makes many new stars. It is very bright. It is far away in space. We can see it with big tools. Can you see the stars?
Early Reader · Change the reading level on the articleArtificial gravity
Space can feel very light. People can spin to feel heavy. This helps our bodies stay strong. It feels like being on Earth. It is a cool way to travel. Do you want to spin in space?
Early Reader · Change the reading level on the articleAsterism (astronomy)
Stars can make shapes in the sky. Some look like a big spoon. Others look like a teapot. These shapes are called asterisms. They help us find our way. Can you find a shape in the stars?
Early Reader · Change the reading level on the articleAsteroid family
Rocks in space travel in groups. They are like big families. A crash makes them break apart. These pieces stay close together. This helps us learn about space. Do you like looking at the stars?
Early Reader · Change the reading level on the articleAsteroseismology
Stars can shake and move. These shakes help us learn. They show us what is inside. We cannot see inside a star. But these shakes tell us a secret. Do you want to see?
Early Reader · Change the reading level on the articleAstrobiology
Some people study life in space. They look for life on far worlds. They look at stars and planets. This helps us learn about our home. It is very exciting work. Do you want to find life in space?
Early Reader · Change the reading level on the article