Discover the different ways our planet is being protected from asteroids and meteors.
Asteroids, comets, and meteors - these are the objects in space that scientists at agencies like NASA and the Department of Energy keep an eye on to make sure we are prepared in case one of them threatens the safety of our planet.
The asteroids and comets that orbit the Sun like the planets and have orbits that come within 30 million miles of Earth’s orbit are called Near-Earth Objects (NEOs).
According to NASA's Planetary Defense Coordination Office, in May 2023, 10 near-Earth asteroids passed closer to the Earth than the Moon. In the past year there were 103 near-Earth asteroids!
Potentially hazardous asteroids are NEOs that are orbiting close to Earth and are larger than 100 meters (328 feet), which is the length of a soccer field. There are five potentially hazardous asteroids that have already been studied using space probes - Bennu, Didymos, Itokawa, Ryugu, and Toutatis.
A composite image showing Near-Earth Objects (NEO).
A comet is a collection of ice and dust that orbits the sun. They sometimes have a tail of debris trailing behind them.
The comet in the image is Comet ISON. When this image was taken, it was some 44 million miles from the sun—and 80 million miles from Earth—moving at a speed of 136,700 miles per hour.
An asteroid is a small rocky object that orbits the sun. They are smaller than planets, but larger than meteoroids. There is a large asteroid belt between Mars and Jupiter that contain hundreds of thousands of asteroids.
A meteoroid is a piece of an asteroid, comet or planet that breaks off and travels in space.
A meteor is the streak of light that appears in the sky when a meteoroid enters the Earth's atmosphere. We also call this a shooting star, but it's not actually a star at all!
A meteorite is a meteor that has made it all the way down through Earth's atmosphere and landed on Earth's surface. This image shows NASA astronomer Peter Jenniskens with an asteroid meteorite found in the Nubian Desert of northern Sudan.
This video is a loop of photographs taking by the National Optical Astronomy Observatory in Tucson, AZ.
Watch the video. Can you spot the asteroid?
Look for a speck that is moving in a straight line, while everything else around it stays the same.
When asteroids enter the Earth's atmosphere or impact the Earth, they cause a lot of damage, which is why near-Earth objects and potentially hazardous asteroids are always being watched. Here are examples of evidence of asteroids near and on Earth:
10 years ago
A meteor weighing 10,000 metric tons exploded 14 miles above Chelyabinsk, Russia, on February 15, 2013. The energy from the blast damaged more than 7,000 buildings in six cities. Approximately 1,500 people were injured mostly from flying glass from the windows that were shattered by the asteroid’s blast wave.
115 years ago
An asteroid 50 meters across entered Earth's atmosphere and exploded above the surface of a forested area in Russia. The heat and energy from the asteroid flattened trees in a very large area of the forest.
The event happened in 1908 but scientists weren't able to study the site until 19 years later.
50,000 years ago
The Meteor Crater, which is about 3,900 feet (1,200 meters) in diameter and about 560 feet (170 meters) deep, was created by a 40 to 50 ton asteroid.
The crater has been preserved well because of the dry desert climate.
65 million years ago
This impact, which is buried partly underwater, was made by an asteroid 10 miles wide (14 kilometers). The impact is famous for its devastating effect on the Earth, which included the extinction of 75% of life on the planet, including the dinosaurs.
In this radar image of the Yucatan Peninsula, you can see the faint rim of the crater.
(modified from NASA's Jet Propulsion Lab learning resource)
Gather these materials:
Trial 1:
Trial 2:
This is an illustration for an activity that's part of the Soar Together on Planetary Defense.
What did you notice about the craters you made? What was different between the different rocks and ways of impacting your surface?
This is an illustration for an activity as part of the Soar Together on Planetary Defense.
Part of the job of Planetary Defense is to come up with plans and ideas for what to do if there is an asteroid endangering Earth and test them out.
One of the tests that NASA has conducted is called the Double Asteroid Redirection Test (DART). The purpose of DART is to test out whether we could use a spacecraft to change the path of an asteroid.
An infographic showing the asteroid Dimorphos in it's orbit, how the DART spacecraft will approach it and change it's orbit.
The DART spacecraft was launched in November 2021, and impacted its asteroid target on September 26, 2022. NASA confirmed that the mission was a success and that they did in fact redirect the asteroid's path!
Check out the DART webpage for cool video of the actual impact.
Members of the DART team celebrate on September 26, 2022, as images livestreamed from the spacecraft show it successfully impacted the asteroid Dimorphos, completing the world’s first planetary defense test mission.
Create your own model of the DART mission and redirect an asteroid!
What you'll need:
This photograph illustrates an activity for our Planetary Defense Soar Together virtual family day.
Set up your play area like this image.
Choose a person to play the role of the asteroid. The other person will play the role of the spacecraft.
This photograph illustrates an activity for our Soar Together virtual family day on Planetary Defense.
Once everyone is ready, roll the asteroid ball towards Earth.
The spacecraft person will roll their ball towards the asteroid and try to deflect it.
Tip: It may take many tries to deflect the asteroid! Experiment with different speeds and angles.
This photograph illustrated an activity for our Soar Together virtual family day on Planetary Defense.
Dr. Fast's job is to find near-Earth asteroids, learn more about them, and share information so that agencies can plan for any potential hazards.
Let's Imagine: if you could create an asteroid awareness poster, what would it look like? Draw or write out your message!
Learn more about asteroids, meteors and comets, and listen to a story about a comet on a journey. Then do the craft activity and create your own telescope to look for the near-Earth objects!
Materials Needed:
Watch this video for the story and craft instructions.
Let's Imagine
Asteroid Day is a global event that happens every year on June 30, to mark the anniversary of the Tunguska event. The purpose is to build awareness around planetary defense and asteroids.
The logo for Asteroid Day
Meteor showers occur when the Earth’s orbit around the Sun takes us through a debris field. These debris fields are often made up of a trail of cosmic dust left behind by a comet. The millions of tiny particles can create a “shower” of dozens of meteors per hour.
The best way to view a meteor shower is to get away from bright lights and to a place with darker skies.
Find a flat area with few trees or buildings, then lie back and let your eyes take in the whole sky. Any time a streak of light appears, your eyes will go right to it because you’ll sense the movement.
You can find out when the next meteor shower will happen from the American Meteor Society with their weekly forecasts.
Gather your skygazing supplies and enjoy the sight!
An illustration of a comet and Earth orbiting around the sun.
A shower of Perseid meteors lights up the sky in 2009 in this NASA time-lapse image.
Soar Together at Air and Space is made possible by the generous support of Northrop Grumman.
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