Asteroids: How science protects us from potential collisions

The International Asteroid Day, observed on June 30, serves as a reminder of the potential threat posed by asteroid impacts, recalling the 1908 Tunguska explosion. In response, the field of planetary defense is advancing through dedicated missions and technological innovations, preparing humanity for possible cosmic dangers.

While not an immediate crisis, the risk of an asteroid impact is real. Consequently, an increasing number of telescopes and space missions are focused on monitoring and studying these celestial bodies. A key example of this progress is the technology that successfully diverted an asteroid in 2022, demonstrating that planetary defense is no longer confined to science fiction.

Asteroids, ranging in size from centimeters to kilometers, are remnants from the solar system's formation. Scientists are particularly focused on Near-Earth Objects (NEOs) due to their potential proximity to Earth. The European Space Agency's Near-Earth Object Coordination Centre (NEOCC) has cataloged approximately 42,000 NEOs. Currently, none are on a collision course with Earth, according to Adriano Campo Bagatin, a physics professor at the University of Alicante.

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Although it is not an urgent problem, the impact of an asteroid against the Earth is real, which is why there are more and more telescopes and missions that monitor and scrutinize them, and cutting-edge technology such as that which managed to divert one of these bodies in 2022.

However, continuous monitoring and study of asteroids and comets remain vital for planetary defense. Major space agencies employ ground-based observatories, space telescopes, and sophisticated models for this purpose. An asteroid known as 2024 YR4, discovered nearly two years ago, briefly became the most dangerous NEO identified in the past two decades before NASA and ESA ruled out any impact risk for 2032, partly due to data from the James Webb Space Telescope.

Studying asteroids, even those that merely "graze" Earth, offers invaluable opportunities to understand their composition and structure. This knowledge is crucial for refining deflection techniques. For instance, the ESA is developing RAMSES, a spacecraft set to launch in 2028, to study Apophis, a 375-meter asteroid, as it passes within 32,000 kilometers of Earth in April 2029. RAMSES will observe how Apophis deforms and changes under Earth's gravitational influence during this close approach.

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To examine it, the ESA is building RAMSES, a ship that will be launched into space between April and May 2028 to meet Apophis and accompany it during the flyby to observe, among other things, how it deforms and changes due to the gravity of our planet.