Although scientists are working to improve the detection and study of these objects, there is still no clear strategy to mitigate the consequences of a possible impact.
In the recent history of humanity there is evidence of the risk of an asteroid colliding with our planet. One of the most recent was the aerial explosion of an asteroid 20 kilometers above the city of Chelyabinsk (Russia) on February 15, 2013. A rock of about 15 meters in size and with a mass of 10,000 tons entered the atmosphere land at a speed of approximately 65,000 kilometers per hour. This object, when exploding in the air, released thirty times more energy than the Hiroshima nuclear bomb. After the explosion, up to 5,000 kilograms of fragments of the asteroid were found on the Earth’s surface. The phenomenon caused damage to buildings and 1,500 people were injured, 100 of them hospitalized.
But, without a doubt, the most outstanding event of the last century was that of Tunguska, in 1908 , in which a fireball of about 80 meters in size entered the Earth’s atmosphere and, without impacting the surface, released an approximate power of 30 megatons, the equivalent of 1,800 times the energy generated by the Hiroshima atomic bomb. Fortunately, the event took place in an unpopulated region of Siberia, otherwise it would have devastated an entire city. It devastated an area of trees of more than 2,000 square kilometers and its effects lingered in the atmosphere for several days.
To commemorate the Tunguska fireball and become aware of the need to increase efforts in the detection and study of dangerous asteroids, UNESCO declared June 30 Asteroid Day in 2016.
It is an initiative taken by astronomers from the United Kingdom and supported by more than one hundred scientists, astronauts, Nobel laureates and artists from around the world, which aims to learn about asteroids and raise public awareness of the need to advance detection of these objects.
From the analysis of the impacts that have occurred on our planet during history and the information from the discoveries made to date, it is deduced that 90% of the asteroids that could cause a planetary cataclysm have already been discovered ; however, there are still many asteroids of a few hundred meters that could cause a disaster locally or even regionally.
To date, 16,207 near-Earth asteroids have been discovered and of these, 1,809 are classified as potentially dangerous (PHA asteroids, potentially hazardous asteroid), with a non-zero probability of impacting the Earth in the future. According to experts, only 10% of these asteroids with a size of more than 20 meters have been discovered, and with the current rate of detections it would take almost 1,000 years to discover the rest dangerous asteroids. We are facing a time problem, which goes against us, because it is a matter of time before an asteroid hits the Earth.
To commemorate Asteroid Day, scientific institutions, universities, astronomical observatories and other entities have organized events in many countries. Specifically in Spain, eleven events will be held for all audiences.
In cities such as Madrid, Las Palmas de Gran Canaria, Barcelona, Granada, Gandía, Puçol, Puerto Lumbreras or Puerto de Santa María there will also be events such as conferences, exhibitions or documentary screenings, all of them free of charge and aimed at the public in general.
Amadeo Aznar
APT Observatories Group
EURONEAR member
Regional Coordinator Asteroid Day
www.aptog.com
[email protected]
