International Asteroid Day

Raising public awareness and educating people about the opportunities and risks presented by asteroids. The goal is to inform the public regarding various actions and efforts that should take place in case the need should arise.

Get ready to learn more about and enjoy International Asteroid Day!

How to Celebrate International Asteroid Day

Many opportunities are available for getting involved with International Asteroid Day. Try out some of these ideas:

Attend an International Asteroid Day Event

Events and activities for International Asteroid Day are located in communities all over the world. Whether attending a lecture, watching a program on Asteroid Day TV or reading a paper to learn more about the possibilities and preparedness that may be vital in the future, this day is a great time for it. In addition to simply attending an event, some people might want to volunteer.

Events are organized by museums, universities, schools, clubs, space agencies and educators all over the world. The list of officially sanctioned events can be found on the Asteroid Day website, with activities listed as happening in hundreds of cities on all of the inhabited continents.

Host an International Asteroid Day Event

Those who don’t have events taking place in their local area might want to consider hosting one. Invite local scientists to participate through lectures and discussions. Or get some local musicians to host a benefit concert in support of the day.

After all, one of the founding members of the day is astrophysicist and guitarist, Brian May, so the theme of music runs deeply here!

If hosting an event, don’t forget to officially register it with the Asteroid Day website so other interested parties in the local area can also get involved.

Throw an International Asteroid Day Party

Gather friends, family members and neighbors for a night of fun and entertainment centered around the idea of asteroids. Staying with the motif of space, it’s fun to ask guests to dress up as their favorite space-themed character.

Food can also be planned around the idea, with cookies decorated like planets, fruit and marshmallow kebabs shaped like rocket ships or popcorn balls shaped like…asteroids, of course!

For entertainment, get a blast from the past and dig up a version of the classic 80s video game, Asteroids. Blast them all before they blow up your spaceship!

Watch a Film with an Asteroid Theme

Perfectly tailored to International Asteroid Day, put on an educational documentary about asteroids. Or get a little more wacky and watch some sci-fi or comedy films revolving around the theme of space.

The first film to check out would be 51 Degrees North, a film that was created by some of the members of the team who founded International Asteroid Day and was, in fact, the inspiration for the day.

Filmmaker Grigorij Richters and Queen guitarist, Brain May, were both involved in the making of this fictional depiction of what might happen if an asteroid landed on London, England.

Other ideas for asteroid-themed films are:

• Meteor (1979). Starring Sean Connery, Natalie Wood and Henry Fonda, this film imagines what might happen if a meteor or asteroid was heading straight to earth and a nuclear weapon was the only thing that could stop it.
• The Day the Sky Exploded (1958). This science fiction drama has the similar theme of what scientists should or would do if an asteroid was headed towards Earth.
• Don’t Look Up (2021). Jennifer Lawrence and Leonardo DiCaprio lead an all-star cast as two astronomers who try to warn everyone that the world is about to be hit and explode.
• Seeking a Friend for the End of the World (2012). Keira Knightley and Steve Carell show the relationship of two people who take a road trip to find the man’s long lost love before the earth is destroyed by an asteroid.

History of International Asteroid Day

While it is unclear exactly how long asteroids have been floating around in the solar system, scientists believe that they go back tens of millions of years.

They can range from small to large – 10 meters across to more than 500 meters across. Added together, the total mass of all current asteroids in our solar systems would be less in size than the Earth’s moon.

Scientists estimate that approximately 65 million years ago, an enormous asteroid fell to the earth in the area that is presently Yucatan, Mexico. This is referred to as the Chicxulub impact and some scientists think this may be what contributed to the extinction of the dinosaurs.

This asteroid may have been the size of some small countries and left a crater that was somewhere around 150 km in size where a rim of mountains the size of the Himalayas formed around the edge.

In more recent history, the Tunguska Event occurred in a Siberian desert area in 1908. This explosion happened in the area that is now known as Krasnoyarsk Krai was classified as an impact event.

Though no impact crater was left behind, this asteroid is believed to have disintegrated in the earth’s atmosphere before hitting the surface. The Tunguska Event is the largest asteroid impact event to have been recorded in human history, with eyewitness reports that were gathered afterward.

The most recent event, one that can still be recalled by people who are alive today, also happened in Russia in an area in western Siberia known as Chelyabinsk, in 2013. No one died or was injured directly from the small asteroid that exploded prior to landing, but many injuries were reported from the side effects of the blast.

International Asteroid Day was founded by Stephen Hawking and a collection of other people, including an Apollo 9 astronaut, a filmmaker, and Brian May – who was the guitarist for Queen and also an astrophysicist. June 30 was chosen for the day as it is the anniversary of the 1908 incident in Siberia.

The day officially launched in 2014 with the support of more than 200 astronauts. It took two more years before it was officially recognized by the United Nations in 2016.

Facts About Asteroid Day

Asteroid Diversity Goes Far Beyond the Rocky “Space Rock” Stereotype  

Astronomers now recognize dozens of asteroid spectral classes, from carbon‑rich C‑types to metallic M‑types and ultra‑dark D‑types, each tied to different minerals and formation histories.

Surveys show that dark, carbonaceous C‑type asteroids dominate the outer main belt, while brighter, stony S‑types are more common closer to Mars, and very dark D‑ and P‑types cluster among the Jupiter Trojans, revealing that the asteroid population preserves a record of how material was mixed and redistributed when the solar system formed.  

Ceres Was First Thought to Be a New Planet Before Becoming the “Prototype” Asteroid  

When Italian astronomer Giuseppe Piazzi discovered Ceres on January 1, 1801, he initially classified it as a small planet; only after several similar bodies such as Pallas, Juno and Vesta were found in the same region did astronomers realize there was an entire belt of small worlds between Mars and Jupiter.

Ceres spent the nineteenth century as a planet in many textbooks, then was grouped with “asteroids,” and in 2006 was reclassified again as a dwarf planet, illustrating how asteroid studies have repeatedly forced astronomers to rethink what counts as a planet.  

Most Near‑Earth Asteroids Are Small, but the Biggest Ones Are Largely Accounted For  

NASA’s Center for Near‑Earth Object Studies reports that survey programs have discovered tens of thousands of near‑Earth asteroids, and more than 90% of those larger than 1 kilometer across are now known.

While kilometer‑scale impacts can cause global devastation, statistical models suggest hundreds of thousands of smaller, 30–140 meter objects remain undetected, which are far more numerous and capable of severe regional damage, so ongoing survey work increasingly focuses on finding these mid‑sized bodies.  

The First Close‑Up Asteroid Data Came from a Mission Not Designed to Land  

NASA’s NEAR Shoemaker spacecraft, launched in 1996, became the first mission to orbit an asteroid and, unexpectedly, the first to land on one when controllers gently set it down on Eros in 2001 after the nominal mission ended.

Measurements of Eros’s gravity, shape and composition showed it to be a fractured but coherent S‑type body with a density around 2.6–2.7 g/cm³, firmly linking such asteroids to ordinary chondrite meteorites that commonly fall to Earth.  

Sample‑Return Missions Proved Many Small Asteroids Are Rubble Piles  

Japan’s Hayabusa mission to asteroid Itokawa and NASA’s OSIRIS‑REx mission to Bennu both found their targets to be extremely low‑density “rubble piles,” loose conglomerates of boulders and dust with large internal voids.

Hayabusa’s returned grains matched LL chondrite meteorites, while OSIRIS‑REx data showed Bennu’s surface is so weak that the sampling head sank into it like into a fluidized gravel pile, findings that reshape expectations for how small asteroids respond to natural impacts or human attempts at deflection.  

A Real‑World Deflection Test Has Already Nudged an Asteroid’s Orbit  

In 2022 NASA’s Double Asteroid Redirection Test (DART) deliberately crashed a spacecraft into Dimorphos, the small moon of asteroid Didymos, to test the kinetic‑impactor concept.

Post‑impact measurements showed Dimorphos’s orbital period shortened by roughly half an hour, far exceeding the minimum success criteria and confirming that ejecta blasted from the impact significantly boosts momentum transfer, a crucial real‑data anchor for future planetary‑defense planning.  

Asteroids Help Trace the Solar System’s Ancient Water and Organics  

Spectral observations and laboratory analysis of samples from carbon‑rich asteroids show that many carry hydrated minerals and complex organic molecules, indicating that their parent bodies once harbored liquid water.

OSIRIS‑REx’s studies of Bennu and Japan’s Hayabusa2 samples from asteroid Ryugu both reveal water‑bearing clays and primitive carbon chemistry, supporting the idea that asteroids were important delivery vehicles for water and organic material to the early Earth.