Almost every week we read news of new meteorites and comets approaching Earth and we have wondered why this topic is increasingly being talked about: is it sensationalism, to generate excitement, or do we simply now have more means to detect them? “Today we have more tools: there are more space telescopes, and the terrestrial ones are already very sophisticated devices with a high capacity for detecting celestial objects,” explains the director of the University Master’s Degree in Astrophysics and Observation Techniques in Astronomy at UNIR Francisco Espartero. “In addition, the number of space agencies around the world has grown , there are countries like India that until a few years ago had not developed a quality space industry and now have their own missions, all this increases the number of registrations” .
As the astrobiologist Carlos Briones explains in his book Are we alone? In search of other lives in the cosmos , the asteroids and meteoroids closest to Earth are called NEA ( Near Earth Asteroids ) and, together with comets whose trajectories intersect Earth’s orbit at some point, they are grouped into so-called NEO ( Near Earth Objects ). About 800 of these objects are under constant observation because they are less than 7.5 million kilometers from us and present a potential danger. Both for Briones and for Espartero, the yellow press is giving too much importance to these objects: “You have to inform and train public opinion, but always within prudence and not getting news every two by three as if the world, you cannot sell things that are not true ”, reflects the professor from UNIR.
Are there reasons to be alarmed?
According to Espartero, the percentage of known celestial objects that pose a real risk to the planet is very low, but we should be more concerned with objects that we do not know. “The danger is there, most of it is controlled, but some of it is not, and obviously that is a real risk. There are small objects, such as the one from the Chelyabinsk explosion in 2013, which escaped the detection media and caught us by surprise ”, recalls the expert.
“The greatest risk is in small asteroids and meteoroids, with sizes between 15 and 150 meters, given their difficulty in detecting them with telescopes until they are ‘very close’ in astronomical terms,” explains Briones in his book. “It would be necessary to establish a very precise and well-coordinated global network to have real information on what threatens us, because we must not minimize risk,” says Espartero. “Some of these NEOs even approach distances less than the one that separates us from the Moon, and in the event of an impact with the Earth they would cause a planetary debacle.”
How to avoid collisions
As we have already commented, there is an increasing capacity for detection that allows us to discover new celestial objects and anticipate potential impacts. In addition to large telescopes and space agencies, there is a good network of amateur astronomers around the world who, thanks to robotic astrophysics, are making important contributions and helping to detect bolides and meteors.
On the other hand, the only possible way to avoid that an asteroid collides with the Earth is, a priori, to divert its trajectory. To do this, NASA scientists have been working for years on methods that could be effective and in November the DART mission or ‘Double Asteroid Redirection Test’ will take off. The objective is to carry out a test to deflect the asteroid Didymos using a spacecraft that will hit it in October 2022. With this, it is expected to modify its speed by one millimeter per second at about 11 million kilometers away from Earth.
