Earth at risk from 'invisible' asteroids

Valerio Carruba, an astronomer at São Paulo State University, said his research revealed a population of potentially hazardous asteroids that are invisible to current observation tools. These celestial bodies are not located in the main asteroid belt between Mars and Jupiter; instead, they orbit the Sun in resonance with Venus.

Because of their position, observing them requires looking towards the Sun, and the light they reflect is lost in the Sun's brightness, causing them to remain "invisible."

CHAOS IN ORBIT

So far, about 20 Venus co-orbital asteroids have been detected. These orbit the Sun synchronously with Venus—not around Venus itself. They sometimes lead, sometimes trail, and occasionally intersect Venus's orbit in complex patterns.

The orbits of these objects are quite chaotic. They change shape approximately every 12,000 years and can only be reliably predicted for 150 years into the future. During these shifts, an asteroid can leave Venus's orbit and approach Earth, potentially even intersecting our orbit.

Carruba emphasized that an asteroid approximately 300 meters in diameter could create a crater between 3 and 4.5 kilometers wide and release hundreds of megatons of energy, causing devastating effects on a major city.

DETECTION CHALLENGES

A common feature of the Venus co-orbitals detected so far is that they all have an orbital eccentricity above 0.38. This is why it is possible to spot them in the sky during sunset when they drift away from Venus and approach Earth.

Researchers have determined that asteroids with lower eccentricity could also pose a threat to Earth. However, the Vera Rubin Observatory will only be able to spot these during specific times of the year and within limited windows.