![](https://steemitimages.com/DQmPpBKK3CK2f2edcxfmHD2cyZWu4FAcbHAgVnXoR93wV15/image.png) June 30 has been declared by the United Nations to be International Asteroid Day. To celebrate the day, there will be a 24-hour global telethon with scientists, astronauts space agencies and even rock stars taking part. The Asteroid Day Live Stream event will be broadcast worldwide from Luxembourg as well as online and will highlight the threat posed to our planet by asteroids and near-Earth objects (NEOs). The decision to make June 30th Asteroid Day was taken back in December 2016. What that date specifically? Because on June 30, 1908 a meteoroid, thought to be a comet or small asteroid, exploded over the Tunguska region in Siberia. It was the largest known impact in modern times, dwarfing the Chelyabinsk meteor that detonated over Russia in 2013. ![](https://steemitimages.com/DQmdS4x3Z5FkPMxUvfxHxs1zmnsrZVj2T9e7JDpKVYcAYyc/image.png) Trees felled by the Tunguska event in 1908 That meteor was estimated to be 20 metres (about 65 feet) in size. The Tunguska meteor is thought to have measured 40 metres (131 feet) across and it devastated an uninhabited area the size of a major metropolitan city. The Chelyabinsk meteor exploded with 20–30 times the energy of the Hiroshima atomic bomb. The Tunguska event is estimated to have been 1,000 more powerful than the bomb dropped on Hiroshima. ![](https://steemitimages.com/DQmXusMmg4j9P9jZGmETX6KDhfB55Zuh5RUS7Bm7ZWVYwHH/image.png) Amateur picture of the Chelyabinsk asteroid, an approximately 20-metre Near-Earth Object, that entered Earth's atmosphere over Russia on 15 February 2013. These two events, slightly more than a century apart serve as illustrations of how NEOs and unforeseen objects can threaten human health and property. The Asteroid Live event will feature a variety of astrophysicists, astronomers, including French ESA astronaut and former Head of the European Astronaut Centre Michel Tognini and British physicist Prof. Brian Cox along with and asteroid experts from NASA, ESA and JAXA (the Japanese space agency). The event starts at 03:00 Central European Summer Time (CEST). It's the same as UTC+2. ESA’s NEO experts will host a series of presentations in front of a live audience, including ‘Armageddon the movie: separating fact from fiction’, followed by discussions on the need for timely and accurate NEO information. The full list of speaker is here.

Resources

Asteroid Day Website Asteroid Day Live Stream The Tunguska Event The Chelyabinsk Meteor Time Zone Converter