[Asteroid flying towards a planet. Photo credits to unsplash]

On May 23, 2025, experts disclosed that 3 “city-killer” asteroids may soon alter their  trajectories toward Earth.

A newly published study in the journal Astronomy and Astrophysics reported that Venus currently hosts at least 20 co-orbital asteroids that have the potential to approach Earth.

“Co-orbital status protects these asteroids from close approaches to Venus, but it does not protect them from encountering Earth,” the researchers warned. 

In fact, a study led by Valerio Carruba from the University of São Paulo concluded that several of these asteroids are “capable of numerous close encounters—and perhaps collisions—with Earth.”  

Carruba & Co. reached this conclusion by conducting simulations using imitation space rocks, exploring a wide range of possible outcomes across a 36,000-year period. 

Through these simulations, they discovered that a significant number of low-eccentricity asteroids, previously thought to be harmless, could be propelled toward Earth by just a small gravitational change or other force.

Asteroids with unstable orbits are especially susceptible to these external forces.

Three of these asteroids- 2020 SB, 524522, and 2002 CL-1- currently pose the greatest threat. 

These three asteroids, each ranging between 330 to 1,300 feet in diameter, have the potential to completely destroy cities and trigger catastrophic fires and tsunamis if they were to collide with Earth.

In fact, each collision is estimated to release millions of times more energy than the Hiroshima bomb and create a crater over two miles wide in diameter.

For these reasons, experts have dubbed these asteroids as “city-killers.”

To compound the danger, by the time these asteroids are detected, there may not be sufficient time to prepare for impact.

This is due to the fact that their orbits are nearly invisible to Earthly detection equipment.

Although scientists at NASA and other space agencies routinely track potentially hazardous near-Earth asteroids, their telescopes can fail to detect those on a suborbital path with Venus due to the sun's glare.

The Sun effectively conceals these asteroids from detection, acting as a natural barrier that renders them nearly invisible to telescopic surveys.

This limited detectability is also why experts persist in warning that “There are still undetected asteroids in the inner Solar System with the potential to cause significant damage to Earth”.

Due to this observational blind spot, even if surveys like those from the Vera Rubin Observatory in Chile detect some of these asteroids in the near future, there would be only two to four weeks left to prepare for impact.

This presents a formidable challenge, as developing a mission capable of deflecting killer space rocks typically takes years to plan and engineer.

The Vera Rubin Observatory is expected to begin full operations in July 2025.

While it will enhance the detection of these potentially dangerous asteroids, the Sun's position will still limit the available observation windows.

“We believe that only a dedicated observational campaign from a space-based mission near Venus could potentially map and discover all the still ‘invisible’ potentially hazardous asteroids among Venus’ co-orbital asteroids,” the researchers stated.

However, time is of the essence. Researchers warn that the trajectories of these co-orbital asteroids could become unpredictable in just over 150 years.

It is more critical than ever to locate and track these hidden threats before it's too late.