International Asteroid Day: What Happened on June 30, 1908?

International Asteroid Day

NEW DELHI: International Asteroid Day is celebrated on June 30 each year to remember the Tunguska event that happened in Siberia in 1908. This day is meant to make people aware of the dangers of asteroid impacts and to support global efforts to protect our planet. The Tunguska event was a massive explosion caused by an asteroid, which flattened a large area of forest. In 2016, the United Nations declared June 30 as International Asteroid Day to encourage people to learn about asteroids and the technologies that can prevent future impacts.

The Tunguska event took place at 7:15 am local time when an asteroid exploded in the atmosphere over Siberia, Russia. The explosion flattened 80 million trees over an area of 830 square miles and created a shock wave that was felt hundreds of miles away. Luckily, because the area was remote, there were very few human casualties. Some reindeer herders from the local Evenki people witnessed the event from about 20 miles away. People further away saw a large column of smoke rising into the sky. The asteroid, known as a bolide when it enters the Earth’s atmosphere, was about 130 feet in diameter. It entered the atmosphere at an angle of about 30 degrees and exploded at an altitude of about 6 miles.

In 2016, the United Nations designated June 30 as International Asteroid Day to emphasize the importance of planetary defense. NASA’s Planetary Defense Coordination Office (PDCO) was created to monitor Near-Earth Objects (NEOs) and develop technologies to prevent potential impacts. “A collision of a NEO with Earth is the only natural disaster we now know how humanity could completely prevent,” said NASA Planetary Defense Officer Lindley Johnson. “We must keep searching for what we know is still out there, and we must continue to research and test planetary defense technologies and capabilities that could one day protect our planet’s inhabitants from a devastating event.”

One of the PDCO’s major projects is the Double Asteroid Redirection Test (DART) mission, which successfully demonstrated asteroid deflection technology. Launched in November 2021, DART impacted the asteroid Dimorphos in September 2022, changing its orbit. This mission showed that humanity has the ability to alter the path of potentially dangerous asteroids.

The Tunguska event remains the largest recorded asteroid impact on Earth in recent history. However, the planet has evidence of past impacts that had catastrophic results. The Chicxulub crater in Mexico, caused by an asteroid impact 65 million years ago, is linked to the extinction of the dinosaurs and 75% of Earth’s species. More recent impacts, such as the Meteor Crater in Arizona and the Chelyabinsk event in Russia in 2013, remind us of the ongoing threat posed by NEOs.

NASA’s continuous efforts to track and study NEOs involve global cooperation and advancements in technology. “The recent positive experience with DART shows that technologies exist to mitigate against possible NEO impacts with Earth,” said Johnson. “We must stay vigilant and prepared to protect our planet from future threats.”