How big are different objects in space? How far away are they from Earth? Try this activity to find out and learn how relative size and distance help us understand our universe.
Step 1: Take a look at the images below and read the descriptions.
Step 2: Use the numbered images to put them in order based on:
Tip: Here are three options to help you organize your thinking:
Step 3: When you're ready, check your answers below.
1. Sun
The Sun is the star at the center of our solar system.
Image credit: NASA / ESA Solar Orbiter
2. Saturn
Saturn is the sixth planet from the Sun in our solar system. It is the second largest planet, after Jupiter.
Image credit: NASA Hubble Space Telescope
3. Earth's Moon
The Moon is Earth's only natural satellite. This means it is the only object in orbit around Earth that isn't human-made.
Image Credit: NASA Lunar Reconnaissance Orbiter
4. Pleiades Star Cluster
Star clusters are large groups of up to a few thousand stars. The Pleiades Star Cluster is visible to the naked eye! You can see it without binoculars or a telescope, even in a city.
Image credit: Robert Gendler
5. Whirlpool Galaxy
A galaxy is a system of millions or billions of stars, planets, dust, and gas all held together by gravity. Spiral galaxies like the Whirlpool Galaxy are actively forming new stars.
Image Credit: NASA, ESA, STScI, Hubble Heritage Team
6. Hubble Space Telescope
In 1990, the Hubble Telescope was launched into orbit around Earth to help us learn more about the universe. This was a big advancement because even as telescopes became more advanced on Earth, the atmosphere can block our view and distort the light we see from space.
Image credit: NASA
7. Ultra Deep Field Galaxies
This image was taken by the Hubble Telescope over the course of 400 orbits around Earth.
Image Credit: NASA, ESA, STScI, Hubble UDF Team
8. James Webb Space Telescope
The James Webb Telescope was launched in December 2021. It is now the biggest telescope in space. Its advanced technology allows it to view objects in space that are too far or faint in space for the Hubble Telescope to see.
Image credit: NASA, ESA, CSA
The Hubble Space Telescope is about the size of a large tractor trailer truck. It is smaller than our Moon and any stars or planets in space.
The James Webb Space Telescope (JWST) is about 6 times larger than the Hubble Telescope. JWST's sunshield is about half as big as a Boeing 737 airplane!
Earth's Moon is the next biggest object. The Moon's average diameter is about 160,000 times bigger than the length of JWST's sunshield.
Saturn is bigger than Earth and our Moon. Saturn is about 33 times bigger than Earth's Moon.
The Sun is about 12 times bigger than Saturn. All the planets in our solar system are smaller than our Sun.
The Sun is a star, but the Pleiades Star Cluster is a group of many stars, so the Pleiades is bigger! The Pleiades cluster contains over 3,000 stars.
The Whirlpool Galaxy is bigger than any one star or star cluster since it contains billions of stars.
The Hubble Ultra Deep Field image is bigger than all the other images combined because it shows many galaxies, even though they look like small specks. An estimated 10,000 galaxies are in this small patch of sky.
Size matters in nature because objects much bigger than Saturn are destined to collapse under their own weight and become stars like our Sun. Size also matters to us because it determines how visible an object is in space.
Check out this interactive website by Neal Argawal to see the relative size of objects in space, from as small as an astronaut to galaxies and more!
The Hubble Telescope can take images of very far objects in space, but it is within low Earth orbit, only 350 miles away from Earth's surface.
Our Moon orbits Earth and is about 250,000 miles away.
The James Webb Telescope is in orbit around the Sun, about 1 million miles away from Earth. This orbit is special because it lets the telescope stay in line with Earth as it moves around the Sun.
The Sun is the next closest object to Earth. Earth is the third planet from the Sun and is 93 million miles from the Sun.
Saturn is farther from Earth than the Sun. Saturn is about 794 million miles from Earth.
The Pleiades Star Cluster is the most visible star cluster to the naked eye! All stars that are visible to us in the night sky are closer than any galaxy. The Pleiades is about 444 light years, or 2.6 quadrillion miles, from Earth and is one of the closest star clusters to Earth.
The Whirlpool Galaxy is not our galaxy, the Milky Way, so it is the next furthest from Earth after the Pleiades. It is about 31 million light-years, or 182 quintillion miles, away from Earth.
The Hubble Ultra Deep Field images were the deepest space images ever made before the new images from the James Webb Telescope. It includes light from some of the oldest galaxies that existed 13 billion years ago.
We can understand a lot about objects in our universe by their distance from Earth. This include things like age and their speed towards or away from Earth.
Watch these videos to learn more about the newest and biggest space telescope, which is allowing us to see farther than ever in new kinds of light.
Listen to Amy Lo and Stephanie Milan, scientists who worked on the James Webb Space Telescope (JWST), describe why we need the JWST and what we hope to learn from the data it can collect.
Talk about it: Amy and Stephanie talked about many things they are excited to discover, both within our solar system and beyond it. Imagine you are a scientist looking at data from JWST. What topic in the video do you want to learn more about?
Explore more: The Infrared Light activity shows two of the first images from JWST!
On July 12, 2022, NASA revealed the first five full-color images from JWST. See the images here and watch this video to hear the highlights of what we learned from these first images!
Talk about it: Did any of the images or discoveries surprise you? Which one did you like best? Why?
How does color help us understand what we see in pictures of space? How are the images from the Hubble and James Webb space telescopes colored? Find out through this activity!
Step 1: Download the coloring page you will use for this activity.
Step 2: Pick 5 colors that you want to use. They can be any color! On the first page, write them down 1 through 5.
Step 3: Color your coloring page based on the color key you created. Make sure you follow your key!
Step 4: Watch the video to learn how a color-by-numbers page is connected to the way images from space are made.
How are the images from the Hubble and Webb Space Telescopes colored?
Coloring a Mad Libs style coloring sheet has a lot of connections with how the images from the Hubble Space Telescope, and the Webb Space Telescope are produced. Learn about that connection here, then be sure to catch the full episode of STEM in 30 to take a deep dive into Hubble and Webb.
How do infrared cameras help us see things our eyes cannot see on their own? Try making observations with this activity to learn more!
The light spectrum includes types of light that our eyes cannot see. One example is infrared light, which we experience as heat. Special cameras can detect infrared light and turn it into an image that we can see. Looking at the same object in different types of light reveals more about it. Astronomers use telescopes that can observe infrared light to study the Universe.
Jupiter is the fifth planet from the Sun and the biggest planet in our solar system.
Step 1: Look closely and compare the two images. What looks the same? What looks different about the bands in the atmosphere? What looks different about the Great Red Spot?
Step 2: Click on the + signs below to compare your observations with ours.
Jupiter - Infrared Light
Image captured at the Gemini Observatory.
Image Credit: International Gemini Observatory, NOIRLab, NSF, AURA; M. H. Wong
New stars are forming in this clouds of gas and dust nicknamed the Cosmic Cliffs.
Step 1: Compare the two images. What looks the same? What looks different about the stars? What looks different about the cliff?
Step 2: Click on the + signs below to compare your observations with ours.
A nebula is a cloud of dust and gas that is expelled when a star dies.
Step 1: Compare the two images. What looks the same? What looks different about the stars? What looks different about the shells or rings of gas and dust? What looks different about the space beyond the nebula?
Step 2: Click on the + signs below to compare your observations with ours.
Have you ever wondered how a black hole is formed? In this activity inspired by NASA's Creating a Black Hole activity, model the collapse of a star to find out!
Materials needed:
Step 1: Blow up the balloon to a medium size, about 5 to 7 inches long. Tie the end in a knot.
Step 2: Cover your balloon in 2 to 3 large sheets of aluminum foil. Make sure the entire balloon is covered. The balloon represents the core of the star, and the aluminum foil sheets represent the outer gas layers of the star. If you have a scale, measure how much the foil-covered balloon weighs and write down your measurement on a piece of paper.
Step 3: Gently squeeze the balloon. Your hands are the Hands of Gravity. What happens?
The balloon didn't pop! Air pressure from inside the balloon resists the force from your hands.
This is similar to what happens during the lifetime of a star. Gravity pushes inward on the outer layers of the star (the green arrows). This is balanced by fusion energy coming from the hot core of the star (the red arrows). This balance between forces is what keeps the star from collapsing.
Step 4: Without removing the layers of aluminum foil, carefully pop the balloon with a pin, needle, sharp pencil, or scissors. Your star has reached the end of its life. It doesn't have any more fuel in its core. If you have a scale, measure the foil ball and write down your measurement. If you don't have a scale, feel the ball in your hands. Does it feel heavier, lighter, or about the same?
Step 5: Be the Hands of Gravity again. Gently squeeze the ball of aluminum. What happens?
It doesn't push back! There isn't air pressure in the balloon to resist your hands. The balance between the gravity pushing inward on the star and the fusion from the core pushing out is broken.
Step 6: Crush the foil until it is about an inch smaller. Try to keep it in the shape of a round ball. If you have a scale, measure the weight of the foil ball and write down your measurement. If you don't have a scale, feel the ball in your hands. Does it feel heavier, lighter, or about the same? Write down your answer.
Repeat this step a few times, making the ball an inch smaller and recording the weight each time.
Step 7: For your final measurement, crush the foil into as small of a ball as possible. This represents a black hole. Measure the weight on the scale or feel it in your hands one last time.
Step 8: Think about it! Look at the measurements you recorded on your paper. Did the weight of the ball change? How?
Even though the size of the foil ball got smaller and smaller, its weight stayed the same. This means the ball became more dense - a lot of mass was crushed down into a tiny space.
This is what happens when a massive star collapses into a black hole. Black holes are incredibly dense objects in space that are believed to be at the centers of most galaxies.
A global network of telescopes has been working to capture images of black holes. This is the first image of a black hole. This is the first visual evidence of a supermassive black hole and it's shadow. Join the Astronomy Education team from the National Air and Space Museum as they discuss this amazing image, what a black hole is, and how the National Science Foundation and the Event Horizon Telescope accomplished this amazing feat.
Explore More
Watch this video to see a demonstration of how black holes affect other things in space and to see the first image taken of a black hole in 2019.
Light takes time to travel across distances. If you look at a far away object, such as a galaxy, its light has taken some time to reach your eyes. That means what you are seeing is how the galaxy looked when the light left it, not how it looks today. It's a strange thing to think about! Watch this video to explore this idea more!
Another way to think about it:
Find a picture of a small child or baby. Notice how the child looks in the image, then think about how different they might be five years later. If you were to look at that picture five years after it was taken, you would see the child as they appeared back then, even though time had passed and that person had changed. So by observing the picture, you are looking back in time!
Astronomer Vera Rubin, the main character of this book, followed her curiosity, defied those who didn't listen to her or take her seriously to make a huge, important discovery - the existence of dark matter!
Talk about it!
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