When is Asteroid Day?
Asteroid Day 2027 is on Wednesday
Wednesday, June 30, 2027
June 30 every year. That's in 269 days.
until Asteroid Day begins, in your time zone
Asteroid Day is a UN-recognized day for learning about asteroids, the risk of impacts on Earth and the work scientists do to find, track and possibly deflect dangerous space rocks. It marks the anniversary of the 1908 Tunguska event in Siberia.
About Asteroid Day
On June 30, 1908, an object from space exploded over the remote Tunguska region of Siberia and devastated more than 2,000 square kilometers of forest. The UN calls it the largest asteroid impact in recorded history. Asteroid Day uses that anniversary to explain what near-Earth objects are, how astronomers discover and track them, and what planetary defense involves.
The campaign was started by astrophysicist and Queen guitarist Brian May, Apollo astronaut Rusty Schweickart and German filmmaker Grig Richters, who also drafted a declaration calling for much faster asteroid discovery. The European Space Agency dates the first Asteroid Day to 2015. In December 2016 the UN General Assembly adopted resolution 71/90, proclaiming June 30 International Asteroid Day. The proposal came from the Association of Space Explorers and was endorsed by the UN Committee on the Peaceful Uses of Outer Space. Space agencies including ESA now hold talks, broadcasts and events on the day.
The hazard is not only historical. On February 15, 2013, an asteroid estimated at about 18 meters across exploded in the sky over Chelyabinsk, Russia, the most energetic impact event recognized since Tunguska. Building on recommendations endorsed by the UN space committee in 2013, the International Asteroid Warning Network and the Space Mission Planning Advisory Group were set up in 2014 to coordinate detection and any response. The UN has also named 2029 the International Year of Asteroid Awareness and Planetary Defence, timed to asteroid Apophis's close but safe pass by Earth on April 13, 2029.
Sources: United Nations: International Asteroid Day, European Space Agency: About Asteroid Day, NASA: Double Asteroid Redirection Test (DART). How we check dates.
How to mark Asteroid Day
- Watch a planetary defense talk or livestream from a space agency, observatory or university around June 30.
- Read about NASA's DART mission, which crashed into the small asteroid Dimorphos in September 2022 to test whether an impact could nudge an asteroid's path.
- Visit a planetarium or a museum meteorite collection, or join a local astronomy club's public observing night.
- Explain to kids the difference between an asteroid, a meteor and a meteorite, and why most small space rocks burn up harmlessly in the atmosphere.
- Use a space agency's online orbit viewer to see where known near-Earth asteroids are right now.
Asteroid Day dates
| Year | Date |
|---|---|
| 2025 | Monday, June 30, 2025 |
| 2026 | Tuesday, June 30, 2026 |
| 2027 | Wednesday, June 30, 2027 |
| 2028 | Friday, June 30, 2028 |
| 2029 | Saturday, June 30, 2029 |
| 2030 | Sunday, June 30, 2030 |
| 2031 | Monday, June 30, 2031 |
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Frequently asked questions
When is Asteroid Day 2027?
Asteroid Day 2027 is on Wednesday, June 30, 2027. It falls on June 30 every year. In 2028, it is on Friday, June 30, 2028.
Why is Asteroid Day on June 30?
It marks the anniversary of the Tunguska event of June 30, 1908, when an object from space exploded over Siberia. The UN describes it as the largest asteroid impact in recorded history.
What is planetary defense?
It is the work of finding asteroids and comets that come near Earth, tracking their orbits, judging the risk and preparing ways to respond. NASA's DART mission tested one method in 2022 by deliberately striking a small asteroid.
Is Asteroid Day a public holiday?
No. Asteroid Day is an observance, not a public holiday, so schools, banks, government offices and most businesses keep their normal hours.