International Asteroid Day
Understanding asteroids protects Earth and opens the solar system.
About
International Asteroid Day is observed on June 30 each year to raise awareness about asteroids — their role in our solar system, the resources they may contain, and the global effort to detect and deflect any that pose a threat to Earth. Planetary defence is a serious, growing scientific field.
History
June 30 marks the anniversary of the Tunguska event of 1908, when an asteroid exploded over Siberia with the energy of 1,000 Hiroshima bombs. International Asteroid Day was co-founded by physicist Brian May, astronaut Rusty Schweickart, and the B612 Foundation, and was declared by the United Nations in 2016.
Where It's Observed
How to Participate
- 01Watch a documentary about the Tunguska event or planetary defence
- 02Explore NASA's asteroid tracker to see near-Earth objects
- 03Learn about the DART mission — humanity's first planetary defence test
- 04Use a telescope app to spot asteroids in the night sky
Frequently asked questions
When is International Asteroid Day?+
International Asteroid Day is observed annually on June 30. The date is fixed each year — June 30 — and does not shift based on the lunar calendar or weekday.
What is International Asteroid Day?+
International Asteroid Day is observed on June 30 each year to raise awareness about asteroids — their role in our solar system, the resources they may contain, and the global effort to detect and deflect any that pose a threat to Earth. Planetary defence is a serious, growing scientific field.
Is International Asteroid Day a public holiday?+
International Asteroid Day is an international observance or awareness day, not a public holiday in most countries. It does not typically result in days off work or school closures, though some countries and organisations hold official events.
How can I participate in International Asteroid Day?+
Watch a documentary about the Tunguska event or planetary defence Explore NASA's asteroid tracker to see near-Earth objects Learn about the DART mission — humanity's first planetary defence test These are some of the most accessible ways to engage with the day's purpose.
Which countries observe International Asteroid Day?+
Global — United Nations initiative.
Mark the date
Download a free printable calendar for 2026 and never miss International Asteroid Day.